| /* Data flow analysis for GNU compiler. |
| Copyright (C) 1987, 88, 92-98, 1999 Free Software Foundation, Inc. |
| |
| This file is part of GNU CC. |
| |
| GNU CC is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU CC is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU CC; see the file COPYING. If not, write to |
| the Free Software Foundation, 59 Temple Place - Suite 330, |
| Boston, MA 02111-1307, USA. */ |
| |
| |
| /* This file contains the data flow analysis pass of the compiler. It |
| computes data flow information which tells combine_instructions |
| which insns to consider combining and controls register allocation. |
| |
| Additional data flow information that is too bulky to record is |
| generated during the analysis, and is used at that time to create |
| autoincrement and autodecrement addressing. |
| |
| The first step is dividing the function into basic blocks. |
| find_basic_blocks does this. Then life_analysis determines |
| where each register is live and where it is dead. |
| |
| ** find_basic_blocks ** |
| |
| find_basic_blocks divides the current function's rtl into basic |
| blocks and constructs the CFG. The blocks are recorded in the |
| basic_block_info array; the CFG exists in the edge structures |
| referenced by the blocks. |
| |
| find_basic_blocks also finds any unreachable loops and deletes them. |
| |
| ** life_analysis ** |
| |
| life_analysis is called immediately after find_basic_blocks. |
| It uses the basic block information to determine where each |
| hard or pseudo register is live. |
| |
| ** live-register info ** |
| |
| The information about where each register is live is in two parts: |
| the REG_NOTES of insns, and the vector basic_block->global_live_at_start. |
| |
| basic_block->global_live_at_start has an element for each basic |
| block, and the element is a bit-vector with a bit for each hard or |
| pseudo register. The bit is 1 if the register is live at the |
| beginning of the basic block. |
| |
| Two types of elements can be added to an insn's REG_NOTES. |
| A REG_DEAD note is added to an insn's REG_NOTES for any register |
| that meets both of two conditions: The value in the register is not |
| needed in subsequent insns and the insn does not replace the value in |
| the register (in the case of multi-word hard registers, the value in |
| each register must be replaced by the insn to avoid a REG_DEAD note). |
| |
| In the vast majority of cases, an object in a REG_DEAD note will be |
| used somewhere in the insn. The (rare) exception to this is if an |
| insn uses a multi-word hard register and only some of the registers are |
| needed in subsequent insns. In that case, REG_DEAD notes will be |
| provided for those hard registers that are not subsequently needed. |
| Partial REG_DEAD notes of this type do not occur when an insn sets |
| only some of the hard registers used in such a multi-word operand; |
| omitting REG_DEAD notes for objects stored in an insn is optional and |
| the desire to do so does not justify the complexity of the partial |
| REG_DEAD notes. |
| |
| REG_UNUSED notes are added for each register that is set by the insn |
| but is unused subsequently (if every register set by the insn is unused |
| and the insn does not reference memory or have some other side-effect, |
| the insn is deleted instead). If only part of a multi-word hard |
| register is used in a subsequent insn, REG_UNUSED notes are made for |
| the parts that will not be used. |
| |
| To determine which registers are live after any insn, one can |
| start from the beginning of the basic block and scan insns, noting |
| which registers are set by each insn and which die there. |
| |
| ** Other actions of life_analysis ** |
| |
| life_analysis sets up the LOG_LINKS fields of insns because the |
| information needed to do so is readily available. |
| |
| life_analysis deletes insns whose only effect is to store a value |
| that is never used. |
| |
| life_analysis notices cases where a reference to a register as |
| a memory address can be combined with a preceding or following |
| incrementation or decrementation of the register. The separate |
| instruction to increment or decrement is deleted and the address |
| is changed to a POST_INC or similar rtx. |
| |
| Each time an incrementing or decrementing address is created, |
| a REG_INC element is added to the insn's REG_NOTES list. |
| |
| life_analysis fills in certain vectors containing information about |
| register usage: reg_n_refs, reg_n_deaths, reg_n_sets, reg_live_length, |
| reg_n_calls_crosses and reg_basic_block. |
| |
| life_analysis sets current_function_sp_is_unchanging if the function |
| doesn't modify the stack pointer. */ |
| |
| /* TODO: |
| |
| Split out from life_analysis: |
| - local property discovery (bb->local_live, bb->local_set) |
| - global property computation |
| - log links creation |
| - pre/post modify transformation |
| */ |
| |
| #include "config.h" |
| #include "system.h" |
| #include "rtl.h" |
| #include "basic-block.h" |
| #include "insn-config.h" |
| #include "regs.h" |
| #include "hard-reg-set.h" |
| #include "flags.h" |
| #include "output.h" |
| #include "except.h" |
| #include "toplev.h" |
| #include "recog.h" |
| #include "insn-flags.h" |
| |
| #include "obstack.h" |
| #define obstack_chunk_alloc xmalloc |
| #define obstack_chunk_free free |
| |
| |
| /* EXIT_IGNORE_STACK should be nonzero if, when returning from a function, |
| the stack pointer does not matter. The value is tested only in |
| functions that have frame pointers. |
| No definition is equivalent to always zero. */ |
| #ifndef EXIT_IGNORE_STACK |
| #define EXIT_IGNORE_STACK 0 |
| #endif |
| |
| |
| /* The contents of the current function definition are allocated |
| in this obstack, and all are freed at the end of the function. |
| For top-level functions, this is temporary_obstack. |
| Separate obstacks are made for nested functions. */ |
| |
| extern struct obstack *function_obstack; |
| |
| /* List of labels that must never be deleted. */ |
| extern rtx forced_labels; |
| |
| /* Number of basic blocks in the current function. */ |
| |
| int n_basic_blocks; |
| |
| /* The basic block array. */ |
| |
| varray_type basic_block_info; |
| |
| /* The special entry and exit blocks. */ |
| |
| struct basic_block_def entry_exit_blocks[2] = |
| { |
| { |
| NULL, /* head */ |
| NULL, /* end */ |
| NULL, /* pred */ |
| NULL, /* succ */ |
| NULL, /* local_set */ |
| NULL, /* global_live_at_start */ |
| NULL, /* global_live_at_end */ |
| NULL, /* aux */ |
| ENTRY_BLOCK, /* index */ |
| 0 /* loop_depth */ |
| }, |
| { |
| NULL, /* head */ |
| NULL, /* end */ |
| NULL, /* pred */ |
| NULL, /* succ */ |
| NULL, /* local_set */ |
| NULL, /* global_live_at_start */ |
| NULL, /* global_live_at_end */ |
| NULL, /* aux */ |
| EXIT_BLOCK, /* index */ |
| 0 /* loop_depth */ |
| } |
| }; |
| |
| /* Nonzero if the second flow pass has completed. */ |
| int flow2_completed; |
| |
| /* Maximum register number used in this function, plus one. */ |
| |
| int max_regno; |
| |
| /* Indexed by n, giving various register information */ |
| |
| varray_type reg_n_info; |
| |
| /* Size of the reg_n_info table. */ |
| |
| unsigned int reg_n_max; |
| |
| /* Element N is the next insn that uses (hard or pseudo) register number N |
| within the current basic block; or zero, if there is no such insn. |
| This is valid only during the final backward scan in propagate_block. */ |
| |
| static rtx *reg_next_use; |
| |
| /* Size of a regset for the current function, |
| in (1) bytes and (2) elements. */ |
| |
| int regset_bytes; |
| int regset_size; |
| |
| /* Regset of regs live when calls to `setjmp'-like functions happen. */ |
| /* ??? Does this exist only for the setjmp-clobbered warning message? */ |
| |
| regset regs_live_at_setjmp; |
| |
| /* List made of EXPR_LIST rtx's which gives pairs of pseudo registers |
| that have to go in the same hard reg. |
| The first two regs in the list are a pair, and the next two |
| are another pair, etc. */ |
| rtx regs_may_share; |
| |
| /* Depth within loops of basic block being scanned for lifetime analysis, |
| plus one. This is the weight attached to references to registers. */ |
| |
| static int loop_depth; |
| |
| /* During propagate_block, this is non-zero if the value of CC0 is live. */ |
| |
| static int cc0_live; |
| |
| /* During propagate_block, this contains a list of all the MEMs we are |
| tracking for dead store elimination. |
| |
| ?!? Note we leak memory by not free-ing items on this list. We need to |
| write some generic routines to operate on memory lists since cse, gcse, |
| loop, sched, flow and possibly other passes all need to do basically the |
| same operations on these lists. */ |
| |
| static rtx mem_set_list; |
| |
| /* Set of registers that may be eliminable. These are handled specially |
| in updating regs_ever_live. */ |
| |
| static HARD_REG_SET elim_reg_set; |
| |
| /* The basic block structure for every insn, indexed by uid. */ |
| |
| varray_type basic_block_for_insn; |
| |
| /* The labels mentioned in non-jump rtl. Valid during find_basic_blocks. */ |
| /* ??? Should probably be using LABEL_NUSES instead. It would take a |
| bit of surgery to be able to use or co-opt the routines in jump. */ |
| |
| static rtx label_value_list; |
| |
| /* INSN_VOLATILE (insn) is 1 if the insn refers to anything volatile. */ |
| |
| #define INSN_VOLATILE(INSN) bitmap_bit_p (uid_volatile, INSN_UID (INSN)) |
| #define SET_INSN_VOLATILE(INSN) bitmap_set_bit (uid_volatile, INSN_UID (INSN)) |
| static bitmap uid_volatile; |
| |
| /* Forward declarations */ |
| static int count_basic_blocks PROTO((rtx)); |
| static rtx find_basic_blocks_1 PROTO((rtx, rtx*)); |
| static void create_basic_block PROTO((int, rtx, rtx, rtx)); |
| static void compute_bb_for_insn PROTO((varray_type, int)); |
| static void clear_edges PROTO((void)); |
| static void make_edges PROTO((rtx, rtx*)); |
| static void make_edge PROTO((basic_block, basic_block, int)); |
| static void make_label_edge PROTO((basic_block, rtx, int)); |
| static void mark_critical_edges PROTO((void)); |
| |
| static void commit_one_edge_insertion PROTO((edge)); |
| |
| static void delete_unreachable_blocks PROTO((void)); |
| static void delete_eh_regions PROTO((void)); |
| static int can_delete_note_p PROTO((rtx)); |
| static void delete_insn_chain PROTO((rtx, rtx)); |
| static int delete_block PROTO((basic_block)); |
| static void expunge_block PROTO((basic_block)); |
| static rtx flow_delete_insn PROTO((rtx)); |
| static int can_delete_label_p PROTO((rtx)); |
| static void merge_blocks_nomove PROTO((basic_block, basic_block)); |
| static int merge_blocks PROTO((edge,basic_block,basic_block)); |
| static void tidy_fallthru_edge PROTO((edge,basic_block,basic_block)); |
| static void calculate_loop_depth PROTO((rtx)); |
| |
| static int set_noop_p PROTO((rtx)); |
| static int noop_move_p PROTO((rtx)); |
| static void notice_stack_pointer_modification PROTO ((rtx, rtx)); |
| static void record_volatile_insns PROTO((rtx)); |
| static void mark_regs_live_at_end PROTO((regset)); |
| static void life_analysis_1 PROTO((rtx, int, int)); |
| static void init_regset_vector PROTO ((regset *, int, |
| struct obstack *)); |
| static void propagate_block PROTO((regset, rtx, rtx, int, |
| regset, int, int)); |
| static int insn_dead_p PROTO((rtx, regset, int, rtx)); |
| static int libcall_dead_p PROTO((rtx, regset, rtx, rtx)); |
| static void mark_set_regs PROTO((regset, regset, rtx, |
| rtx, regset)); |
| static void mark_set_1 PROTO((regset, regset, rtx, |
| rtx, regset)); |
| #ifdef AUTO_INC_DEC |
| static void find_auto_inc PROTO((regset, rtx, rtx)); |
| static int try_pre_increment_1 PROTO((rtx)); |
| static int try_pre_increment PROTO((rtx, rtx, HOST_WIDE_INT)); |
| #endif |
| static void mark_used_regs PROTO((regset, regset, rtx, int, rtx)); |
| void dump_flow_info PROTO((FILE *)); |
| static void dump_edge_info PROTO((FILE *, edge, int)); |
| |
| static int_list_ptr alloc_int_list_node PROTO ((int_list_block **)); |
| static int_list_ptr add_int_list_node PROTO ((int_list_block **, |
| int_list **, int)); |
| |
| static void add_pred_succ PROTO ((int, int, int_list_ptr *, |
| int_list_ptr *, int *, int *)); |
| |
| static void count_reg_sets_1 PROTO ((rtx)); |
| static void count_reg_sets PROTO ((rtx)); |
| static void count_reg_references PROTO ((rtx)); |
| static void notice_stack_pointer_modification PROTO ((rtx, rtx)); |
| static void invalidate_mems_from_autoinc PROTO ((rtx)); |
| void verify_flow_info PROTO ((void)); |
| |
| /* Find basic blocks of the current function. |
| F is the first insn of the function and NREGS the number of register |
| numbers in use. */ |
| |
| void |
| find_basic_blocks (f, nregs, file, do_cleanup) |
| rtx f; |
| int nregs ATTRIBUTE_UNUSED; |
| FILE *file ATTRIBUTE_UNUSED; |
| int do_cleanup; |
| { |
| rtx *bb_eh_end; |
| int max_uid; |
| |
| /* Flush out existing data. */ |
| if (basic_block_info != NULL) |
| { |
| int i; |
| |
| clear_edges (); |
| |
| /* Clear bb->aux on all extant basic blocks. We'll use this as a |
| tag for reuse during create_basic_block, just in case some pass |
| copies around basic block notes improperly. */ |
| for (i = 0; i < n_basic_blocks; ++i) |
| BASIC_BLOCK (i)->aux = NULL; |
| |
| VARRAY_FREE (basic_block_info); |
| } |
| |
| n_basic_blocks = count_basic_blocks (f); |
| |
| /* Size the basic block table. The actual structures will be allocated |
| by find_basic_blocks_1, since we want to keep the structure pointers |
| stable across calls to find_basic_blocks. */ |
| /* ??? This whole issue would be much simpler if we called find_basic_blocks |
| exactly once, and thereafter we don't have a single long chain of |
| instructions at all until close to the end of compilation when we |
| actually lay them out. */ |
| |
| VARRAY_BB_INIT (basic_block_info, n_basic_blocks, "basic_block_info"); |
| |
| /* An array to record the active exception region at the end of each |
| basic block. It is filled in by find_basic_blocks_1 for make_edges. */ |
| bb_eh_end = (rtx *) alloca (n_basic_blocks * sizeof (rtx)); |
| |
| label_value_list = find_basic_blocks_1 (f, bb_eh_end); |
| |
| /* Record the block to which an insn belongs. */ |
| /* ??? This should be done another way, by which (perhaps) a label is |
| tagged directly with the basic block that it starts. It is used for |
| more than that currently, but IMO that is the only valid use. */ |
| |
| max_uid = get_max_uid (); |
| #ifdef AUTO_INC_DEC |
| /* Leave space for insns life_analysis makes in some cases for auto-inc. |
| These cases are rare, so we don't need too much space. */ |
| max_uid += max_uid / 10; |
| #endif |
| |
| VARRAY_BB_INIT (basic_block_for_insn, max_uid, "basic_block_for_insn"); |
| compute_bb_for_insn (basic_block_for_insn, max_uid); |
| |
| /* Discover the edges of our cfg. */ |
| |
| make_edges (label_value_list, bb_eh_end); |
| |
| /* Delete unreachable blocks. */ |
| |
| if (do_cleanup) |
| delete_unreachable_blocks (); |
| |
| /* Mark critical edges. */ |
| |
| mark_critical_edges (); |
| |
| /* Discover the loop depth at the start of each basic block to aid |
| register allocation. */ |
| calculate_loop_depth (f); |
| |
| /* Kill the data we won't maintain. */ |
| label_value_list = 0; |
| |
| #ifdef ENABLE_CHECKING |
| verify_flow_info (); |
| #endif |
| } |
| |
| /* Count the basic blocks of the function. */ |
| |
| static int |
| count_basic_blocks (f) |
| rtx f; |
| { |
| register rtx insn; |
| register RTX_CODE prev_code; |
| register int count = 0; |
| int eh_region = 0; |
| int call_had_abnormal_edge = 0; |
| rtx prev_call = NULL_RTX; |
| |
| prev_code = JUMP_INSN; |
| for (insn = f; insn; insn = NEXT_INSN (insn)) |
| { |
| register RTX_CODE code = GET_CODE (insn); |
| |
| if (code == CODE_LABEL |
| || (GET_RTX_CLASS (code) == 'i' |
| && (prev_code == JUMP_INSN |
| || prev_code == BARRIER |
| || (prev_code == CALL_INSN && call_had_abnormal_edge)))) |
| { |
| count++; |
| |
| /* If the previous insn was a call that did not create an |
| abnormal edge, we want to add a nop so that the CALL_INSN |
| itself is not at basic_block_end. This allows us to |
| easily distinguish between normal calls and those which |
| create abnormal edges in the flow graph. */ |
| |
| if (count > 0 && prev_call != 0 && !call_had_abnormal_edge) |
| { |
| rtx nop = gen_rtx_USE (VOIDmode, const0_rtx); |
| emit_insn_after (nop, prev_call); |
| } |
| } |
| |
| /* Record whether this call created an edge. */ |
| if (code == CALL_INSN) |
| { |
| rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX); |
| int region = (note ? XINT (XEXP (note, 0), 0) : 1); |
| prev_call = insn; |
| call_had_abnormal_edge = 0; |
| |
| /* If there is a specified EH region, we have an edge. */ |
| if (eh_region && region > 0) |
| call_had_abnormal_edge = 1; |
| else |
| { |
| /* If there is a nonlocal goto label and the specified |
| region number isn't -1, we have an edge. (0 means |
| no throw, but might have a nonlocal goto). */ |
| if (nonlocal_goto_handler_labels && region >= 0) |
| call_had_abnormal_edge = 1; |
| } |
| } |
| else if (code != NOTE) |
| prev_call = NULL_RTX; |
| |
| if (code != NOTE) |
| prev_code = code; |
| else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG) |
| ++eh_region; |
| else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END) |
| --eh_region; |
| |
| } |
| |
| /* The rest of the compiler works a bit smoother when we don't have to |
| check for the edge case of do-nothing functions with no basic blocks. */ |
| if (count == 0) |
| { |
| emit_insn (gen_rtx_USE (VOIDmode, const0_rtx)); |
| count = 1; |
| } |
| |
| return count; |
| } |
| |
| /* Find all basic blocks of the function whose first insn is F. |
| Store the correct data in the tables that describe the basic blocks, |
| set up the chains of references for each CODE_LABEL, and |
| delete any entire basic blocks that cannot be reached. |
| |
| NONLOCAL_LABEL_LIST is a list of non-local labels in the function. Blocks |
| that are otherwise unreachable may be reachable with a non-local goto. |
| |
| BB_EH_END is an array in which we record the list of exception regions |
| active at the end of every basic block. */ |
| |
| static rtx |
| find_basic_blocks_1 (f, bb_eh_end) |
| rtx f; |
| rtx *bb_eh_end; |
| { |
| register rtx insn, next; |
| int call_has_abnormal_edge = 0; |
| int i = 0; |
| rtx bb_note = NULL_RTX; |
| rtx eh_list = NULL_RTX; |
| rtx label_value_list = NULL_RTX; |
| rtx head = NULL_RTX; |
| rtx end = NULL_RTX; |
| |
| /* We process the instructions in a slightly different way than we did |
| previously. This is so that we see a NOTE_BASIC_BLOCK after we have |
| closed out the previous block, so that it gets attached at the proper |
| place. Since this form should be equivalent to the previous, |
| find_basic_blocks_0 continues to use the old form as a check. */ |
| |
| for (insn = f; insn; insn = next) |
| { |
| enum rtx_code code = GET_CODE (insn); |
| |
| next = NEXT_INSN (insn); |
| |
| if (code == CALL_INSN) |
| { |
| /* Record whether this call created an edge. */ |
| rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX); |
| int region = (note ? XINT (XEXP (note, 0), 0) : 1); |
| call_has_abnormal_edge = 0; |
| |
| /* If there is an EH region, we have an edge. */ |
| if (eh_list && region > 0) |
| call_has_abnormal_edge = 1; |
| else |
| { |
| /* If there is a nonlocal goto label and the specified |
| region number isn't -1, we have an edge. (0 means |
| no throw, but might have a nonlocal goto). */ |
| if (nonlocal_goto_handler_labels && region >= 0) |
| call_has_abnormal_edge = 1; |
| } |
| } |
| |
| switch (code) |
| { |
| case NOTE: |
| { |
| int kind = NOTE_LINE_NUMBER (insn); |
| |
| /* Keep a LIFO list of the currently active exception notes. */ |
| if (kind == NOTE_INSN_EH_REGION_BEG) |
| eh_list = gen_rtx_INSN_LIST (VOIDmode, insn, eh_list); |
| else if (kind == NOTE_INSN_EH_REGION_END) |
| eh_list = XEXP (eh_list, 1); |
| |
| /* Look for basic block notes with which to keep the |
| basic_block_info pointers stable. Unthread the note now; |
| we'll put it back at the right place in create_basic_block. |
| Or not at all if we've already found a note in this block. */ |
| else if (kind == NOTE_INSN_BASIC_BLOCK) |
| { |
| if (bb_note == NULL_RTX) |
| bb_note = insn; |
| next = flow_delete_insn (insn); |
| } |
| |
| break; |
| } |
| |
| case CODE_LABEL: |
| /* A basic block starts at a label. If we've closed one off due |
| to a barrier or some such, no need to do it again. */ |
| if (head != NULL_RTX) |
| { |
| /* While we now have edge lists with which other portions of |
| the compiler might determine a call ending a basic block |
| does not imply an abnormal edge, it will be a bit before |
| everything can be updated. So continue to emit a noop at |
| the end of such a block. */ |
| if (GET_CODE (end) == CALL_INSN) |
| { |
| rtx nop = gen_rtx_USE (VOIDmode, const0_rtx); |
| end = emit_insn_after (nop, end); |
| } |
| |
| bb_eh_end[i] = eh_list; |
| create_basic_block (i++, head, end, bb_note); |
| bb_note = NULL_RTX; |
| } |
| head = end = insn; |
| break; |
| |
| case JUMP_INSN: |
| /* A basic block ends at a jump. */ |
| if (head == NULL_RTX) |
| head = insn; |
| else |
| { |
| /* ??? Make a special check for table jumps. The way this |
| happens is truely and amazingly gross. We are about to |
| create a basic block that contains just a code label and |
| an addr*vec jump insn. Worse, an addr_diff_vec creates |
| its own natural loop. |
| |
| Prevent this bit of brain damage, pasting things together |
| correctly in make_edges. |
| |
| The correct solution involves emitting the table directly |
| on the tablejump instruction as a note, or JUMP_LABEL. */ |
| |
| if (GET_CODE (PATTERN (insn)) == ADDR_VEC |
| || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC) |
| { |
| head = end = NULL; |
| n_basic_blocks--; |
| break; |
| } |
| } |
| end = insn; |
| goto new_bb_inclusive; |
| |
| case BARRIER: |
| /* A basic block ends at a barrier. It may be that an unconditional |
| jump already closed the basic block -- no need to do it again. */ |
| if (head == NULL_RTX) |
| break; |
| |
| /* While we now have edge lists with which other portions of the |
| compiler might determine a call ending a basic block does not |
| imply an abnormal edge, it will be a bit before everything can |
| be updated. So continue to emit a noop at the end of such a |
| block. */ |
| if (GET_CODE (end) == CALL_INSN) |
| { |
| rtx nop = gen_rtx_USE (VOIDmode, const0_rtx); |
| end = emit_insn_after (nop, end); |
| } |
| goto new_bb_exclusive; |
| |
| case CALL_INSN: |
| /* A basic block ends at a call that can either throw or |
| do a non-local goto. */ |
| if (call_has_abnormal_edge) |
| { |
| new_bb_inclusive: |
| if (head == NULL_RTX) |
| head = insn; |
| end = insn; |
| |
| new_bb_exclusive: |
| bb_eh_end[i] = eh_list; |
| create_basic_block (i++, head, end, bb_note); |
| head = end = NULL_RTX; |
| bb_note = NULL_RTX; |
| break; |
| } |
| /* FALLTHRU */ |
| |
| default: |
| if (GET_RTX_CLASS (code) == 'i') |
| { |
| if (head == NULL_RTX) |
| head = insn; |
| end = insn; |
| } |
| break; |
| } |
| |
| if (GET_RTX_CLASS (code) == 'i') |
| { |
| rtx note; |
| |
| /* Make a list of all labels referred to other than by jumps |
| (which just don't have the REG_LABEL notes). |
| |
| Make a special exception for labels followed by an ADDR*VEC, |
| as this would be a part of the tablejump setup code. |
| |
| Make a special exception for the eh_return_stub_label, which |
| we know isn't part of any otherwise visible control flow. */ |
| |
| for (note = REG_NOTES (insn); note; note = XEXP (note, 1)) |
| if (REG_NOTE_KIND (note) == REG_LABEL) |
| { |
| rtx lab = XEXP (note, 0), next; |
| |
| if (lab == eh_return_stub_label) |
| ; |
| else if ((next = next_nonnote_insn (lab)) != NULL |
| && GET_CODE (next) == JUMP_INSN |
| && (GET_CODE (PATTERN (next)) == ADDR_VEC |
| || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC)) |
| ; |
| else |
| label_value_list |
| = gen_rtx_EXPR_LIST (VOIDmode, XEXP (note, 0), |
| label_value_list); |
| } |
| } |
| } |
| |
| if (head != NULL_RTX) |
| { |
| bb_eh_end[i] = eh_list; |
| create_basic_block (i++, head, end, bb_note); |
| } |
| |
| if (i != n_basic_blocks) |
| abort (); |
| |
| return label_value_list; |
| } |
| |
| /* Create a new basic block consisting of the instructions between |
| HEAD and END inclusive. Reuses the note and basic block struct |
| in BB_NOTE, if any. */ |
| |
| static void |
| create_basic_block (index, head, end, bb_note) |
| int index; |
| rtx head, end, bb_note; |
| { |
| basic_block bb; |
| |
| if (bb_note |
| && ! RTX_INTEGRATED_P (bb_note) |
| && (bb = NOTE_BASIC_BLOCK (bb_note)) != NULL |
| && bb->aux == NULL) |
| { |
| /* If we found an existing note, thread it back onto the chain. */ |
| |
| if (GET_CODE (head) == CODE_LABEL) |
| add_insn_after (bb_note, head); |
| else |
| { |
| add_insn_before (bb_note, head); |
| head = bb_note; |
| } |
| } |
| else |
| { |
| /* Otherwise we must create a note and a basic block structure. |
| Since we allow basic block structs in rtl, give the struct |
| the same lifetime by allocating it off the function obstack |
| rather than using malloc. */ |
| |
| bb = (basic_block) obstack_alloc (function_obstack, sizeof (*bb)); |
| memset (bb, 0, sizeof (*bb)); |
| |
| if (GET_CODE (head) == CODE_LABEL) |
| bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, head); |
| else |
| { |
| bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, head); |
| head = bb_note; |
| } |
| NOTE_BASIC_BLOCK (bb_note) = bb; |
| } |
| |
| /* Always include the bb note in the block. */ |
| if (NEXT_INSN (end) == bb_note) |
| end = bb_note; |
| |
| bb->head = head; |
| bb->end = end; |
| bb->index = index; |
| BASIC_BLOCK (index) = bb; |
| |
| /* Tag the block so that we know it has been used when considering |
| other basic block notes. */ |
| bb->aux = bb; |
| } |
| |
| /* Records the basic block struct in BB_FOR_INSN, for every instruction |
| indexed by INSN_UID. MAX is the size of the array. */ |
| |
| static void |
| compute_bb_for_insn (bb_for_insn, max) |
| varray_type bb_for_insn; |
| int max; |
| { |
| int i; |
| |
| for (i = 0; i < n_basic_blocks; ++i) |
| { |
| basic_block bb = BASIC_BLOCK (i); |
| rtx insn, end; |
| |
| end = bb->end; |
| insn = bb->head; |
| while (1) |
| { |
| int uid = INSN_UID (insn); |
| if (uid < max) |
| VARRAY_BB (bb_for_insn, uid) = bb; |
| if (insn == end) |
| break; |
| insn = NEXT_INSN (insn); |
| } |
| } |
| } |
| |
| /* Free the memory associated with the edge structures. */ |
| |
| static void |
| clear_edges () |
| { |
| int i; |
| edge n, e; |
| |
| for (i = 0; i < n_basic_blocks; ++i) |
| { |
| basic_block bb = BASIC_BLOCK (i); |
| |
| for (e = bb->succ; e ; e = n) |
| { |
| n = e->succ_next; |
| free (e); |
| } |
| |
| bb->succ = 0; |
| bb->pred = 0; |
| } |
| |
| for (e = ENTRY_BLOCK_PTR->succ; e ; e = n) |
| { |
| n = e->succ_next; |
| free (e); |
| } |
| |
| ENTRY_BLOCK_PTR->succ = 0; |
| EXIT_BLOCK_PTR->pred = 0; |
| } |
| |
| /* Identify the edges between basic blocks. |
| |
| NONLOCAL_LABEL_LIST is a list of non-local labels in the function. Blocks |
| that are otherwise unreachable may be reachable with a non-local goto. |
| |
| BB_EH_END is an array indexed by basic block number in which we record |
| the list of exception regions active at the end of the basic block. */ |
| |
| static void |
| make_edges (label_value_list, bb_eh_end) |
| rtx label_value_list; |
| rtx *bb_eh_end; |
| { |
| int i; |
| |
| /* Assume no computed jump; revise as we create edges. */ |
| current_function_has_computed_jump = 0; |
| |
| /* By nature of the way these get numbered, block 0 is always the entry. */ |
| make_edge (ENTRY_BLOCK_PTR, BASIC_BLOCK (0), EDGE_FALLTHRU); |
| |
| for (i = 0; i < n_basic_blocks; ++i) |
| { |
| basic_block bb = BASIC_BLOCK (i); |
| rtx insn, x, eh_list; |
| enum rtx_code code; |
| int force_fallthru = 0; |
| |
| /* If we have asynchronous exceptions, scan the notes for all exception |
| regions active in the block. In the normal case, we only need the |
| one active at the end of the block, which is bb_eh_end[i]. */ |
| |
| eh_list = bb_eh_end[i]; |
| if (asynchronous_exceptions) |
| { |
| for (insn = bb->end; insn != bb->head; insn = PREV_INSN (insn)) |
| { |
| if (GET_CODE (insn) == NOTE |
| && NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END) |
| eh_list = gen_rtx_INSN_LIST (VOIDmode, insn, eh_list); |
| } |
| } |
| |
| /* Now examine the last instruction of the block, and discover the |
| ways we can leave the block. */ |
| |
| insn = bb->end; |
| code = GET_CODE (insn); |
| |
| /* A branch. */ |
| if (code == JUMP_INSN) |
| { |
| rtx tmp; |
| |
| /* ??? Recognize a tablejump and do the right thing. */ |
| if ((tmp = JUMP_LABEL (insn)) != NULL_RTX |
| && (tmp = NEXT_INSN (tmp)) != NULL_RTX |
| && GET_CODE (tmp) == JUMP_INSN |
| && (GET_CODE (PATTERN (tmp)) == ADDR_VEC |
| || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC)) |
| { |
| rtvec vec; |
| int j; |
| |
| if (GET_CODE (PATTERN (tmp)) == ADDR_VEC) |
| vec = XVEC (PATTERN (tmp), 0); |
| else |
| vec = XVEC (PATTERN (tmp), 1); |
| |
| for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j) |
| make_label_edge (bb, XEXP (RTVEC_ELT (vec, j), 0), 0); |
| |
| /* Some targets (eg, ARM) emit a conditional jump that also |
| contains the out-of-range target. Scan for these and |
| add an edge if necessary. */ |
| if ((tmp = single_set (insn)) != NULL |
| && SET_DEST (tmp) == pc_rtx |
| && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE |
| && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF) |
| make_label_edge (bb, XEXP (XEXP (SET_SRC (tmp), 2), 0), 0); |
| |
| #ifdef CASE_DROPS_THROUGH |
| /* Silly VAXen. The ADDR_VEC is going to be in the way of |
| us naturally detecting fallthru into the next block. */ |
| force_fallthru = 1; |
| #endif |
| } |
| |
| /* If this is a computed jump, then mark it as reaching |
| everything on the label_value_list and forced_labels list. */ |
| else if (computed_jump_p (insn)) |
| { |
| current_function_has_computed_jump = 1; |
| |
| for (x = label_value_list; x; x = XEXP (x, 1)) |
| make_label_edge (bb, XEXP (x, 0), EDGE_ABNORMAL); |
| |
| for (x = forced_labels; x; x = XEXP (x, 1)) |
| make_label_edge (bb, XEXP (x, 0), EDGE_ABNORMAL); |
| } |
| |
| /* Returns create an exit out. */ |
| else if (returnjump_p (insn)) |
| make_edge (bb, EXIT_BLOCK_PTR, 0); |
| |
| /* Otherwise, we have a plain conditional or unconditional jump. */ |
| else |
| { |
| if (! JUMP_LABEL (insn)) |
| abort (); |
| make_label_edge (bb, JUMP_LABEL (insn), 0); |
| } |
| } |
| |
| /* If this is a CALL_INSN, then mark it as reaching the active EH |
| handler for this CALL_INSN. If we're handling asynchronous |
| exceptions then any insn can reach any of the active handlers. |
| |
| Also mark the CALL_INSN as reaching any nonlocal goto handler. */ |
| |
| if (code == CALL_INSN || asynchronous_exceptions) |
| { |
| int is_call = (code == CALL_INSN ? EDGE_ABNORMAL_CALL : 0); |
| handler_info *ptr; |
| |
| /* Use REG_EH_RETHROW and REG_EH_REGION if available. */ |
| /* ??? REG_EH_REGION is not generated presently. Is it |
| inteded that there be multiple notes for the regions? |
| or is my eh_list collection redundant with handler linking? */ |
| |
| x = find_reg_note (insn, REG_EH_RETHROW, 0); |
| if (!x) |
| x = find_reg_note (insn, REG_EH_REGION, 0); |
| if (x) |
| { |
| if (XINT (XEXP (x, 0), 0) > 0) |
| { |
| ptr = get_first_handler (XINT (XEXP (x, 0), 0)); |
| while (ptr) |
| { |
| make_label_edge (bb, ptr->handler_label, |
| EDGE_ABNORMAL | EDGE_EH | is_call); |
| ptr = ptr->next; |
| } |
| } |
| } |
| else |
| { |
| for (x = eh_list; x; x = XEXP (x, 1)) |
| { |
| ptr = get_first_handler (NOTE_BLOCK_NUMBER (XEXP (x, 0))); |
| while (ptr) |
| { |
| make_label_edge (bb, ptr->handler_label, |
| EDGE_ABNORMAL | EDGE_EH | is_call); |
| ptr = ptr->next; |
| } |
| } |
| } |
| |
| if (code == CALL_INSN && nonlocal_goto_handler_labels) |
| { |
| /* ??? This could be made smarter: in some cases it's possible |
| to tell that certain calls will not do a nonlocal goto. |
| |
| For example, if the nested functions that do the nonlocal |
| gotos do not have their addresses taken, then only calls to |
| those functions or to other nested functions that use them |
| could possibly do nonlocal gotos. */ |
| |
| for (x = nonlocal_goto_handler_labels; x ; x = XEXP (x, 1)) |
| make_label_edge (bb, XEXP (x, 0), |
| EDGE_ABNORMAL | EDGE_ABNORMAL_CALL); |
| } |
| } |
| |
| /* We know something about the structure of the function __throw in |
| libgcc2.c. It is the only function that ever contains eh_stub |
| labels. It modifies its return address so that the last block |
| returns to one of the eh_stub labels within it. So we have to |
| make additional edges in the flow graph. */ |
| if (i + 1 == n_basic_blocks && eh_return_stub_label != 0) |
| make_label_edge (bb, eh_return_stub_label, EDGE_EH); |
| |
| /* Find out if we can drop through to the next block. */ |
| insn = next_nonnote_insn (insn); |
| if (!insn || (i + 1 == n_basic_blocks && force_fallthru)) |
| make_edge (bb, EXIT_BLOCK_PTR, EDGE_FALLTHRU); |
| else if (i + 1 < n_basic_blocks) |
| { |
| rtx tmp = BLOCK_HEAD (i + 1); |
| if (GET_CODE (tmp) == NOTE) |
| tmp = next_nonnote_insn (tmp); |
| if (force_fallthru || insn == tmp) |
| make_edge (bb, BASIC_BLOCK (i + 1), EDGE_FALLTHRU); |
| } |
| } |
| } |
| |
| /* Create an edge between two basic blocks. FLAGS are auxiliary information |
| about the edge that is accumulated between calls. */ |
| |
| static void |
| make_edge (src, dst, flags) |
| basic_block src, dst; |
| int flags; |
| { |
| edge e; |
| |
| /* Make sure we don't add duplicate edges. */ |
| |
| for (e = src->succ; e ; e = e->succ_next) |
| if (e->dest == dst) |
| { |
| e->flags |= flags; |
| return; |
| } |
| |
| e = (edge) xcalloc (1, sizeof (*e)); |
| |
| e->succ_next = src->succ; |
| e->pred_next = dst->pred; |
| e->src = src; |
| e->dest = dst; |
| e->flags = flags; |
| |
| src->succ = e; |
| dst->pred = e; |
| } |
| |
| /* Create an edge from a basic block to a label. */ |
| |
| static void |
| make_label_edge (src, label, flags) |
| basic_block src; |
| rtx label; |
| int flags; |
| { |
| if (GET_CODE (label) != CODE_LABEL) |
| abort (); |
| |
| /* If the label was never emitted, this insn is junk, but avoid a |
| crash trying to refer to BLOCK_FOR_INSN (label). This can happen |
| as a result of a syntax error and a diagnostic has already been |
| printed. */ |
| |
| if (INSN_UID (label) == 0) |
| return; |
| |
| make_edge (src, BLOCK_FOR_INSN (label), flags); |
| } |
| |
| /* Identify critical edges and set the bits appropriately. */ |
| static void |
| mark_critical_edges () |
| { |
| int i, n = n_basic_blocks; |
| basic_block bb; |
| |
| /* We begin with the entry block. This is not terribly important now, |
| but could be if a front end (Fortran) implemented alternate entry |
| points. */ |
| bb = ENTRY_BLOCK_PTR; |
| i = -1; |
| |
| while (1) |
| { |
| edge e; |
| |
| /* (1) Critical edges must have a source with multiple successors. */ |
| if (bb->succ && bb->succ->succ_next) |
| { |
| for (e = bb->succ; e ; e = e->succ_next) |
| { |
| /* (2) Critical edges must have a destination with multiple |
| predecessors. Note that we know there is at least one |
| predecessor -- the edge we followed to get here. */ |
| if (e->dest->pred->pred_next) |
| e->flags |= EDGE_CRITICAL; |
| else |
| e->flags &= ~EDGE_CRITICAL; |
| } |
| } |
| else |
| { |
| for (e = bb->succ; e ; e = e->succ_next) |
| e->flags &= ~EDGE_CRITICAL; |
| } |
| |
| if (++i >= n) |
| break; |
| bb = BASIC_BLOCK (i); |
| } |
| } |
| |
| /* Split a (typically critical) edge. Return the new block. |
| Abort on abnormal edges. |
| |
| ??? The code generally expects to be called on critical edges. |
| The case of a block ending in an unconditional jump to a |
| block with multiple predecessors is not handled optimally. */ |
| |
| basic_block |
| split_edge (edge_in) |
| edge edge_in; |
| { |
| basic_block old_pred, bb, old_succ; |
| edge edge_out; |
| rtx bb_note; |
| int i; |
| |
| /* Abnormal edges cannot be split. */ |
| if ((edge_in->flags & EDGE_ABNORMAL) != 0) |
| abort (); |
| |
| old_pred = edge_in->src; |
| old_succ = edge_in->dest; |
| |
| /* Remove the existing edge from the destination's pred list. */ |
| { |
| edge *pp; |
| for (pp = &old_succ->pred; *pp != edge_in; pp = &(*pp)->pred_next) |
| continue; |
| *pp = edge_in->pred_next; |
| edge_in->pred_next = NULL; |
| } |
| |
| /* Create the new structures. */ |
| bb = (basic_block) obstack_alloc (function_obstack, sizeof (*bb)); |
| edge_out = (edge) xcalloc (1, sizeof (*edge_out)); |
| |
| memset (bb, 0, sizeof (*bb)); |
| bb->local_set = OBSTACK_ALLOC_REG_SET (function_obstack); |
| bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (function_obstack); |
| bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (function_obstack); |
| |
| /* ??? This info is likely going to be out of date very soon. */ |
| CLEAR_REG_SET (bb->local_set); |
| if (old_succ->global_live_at_start) |
| { |
| COPY_REG_SET (bb->global_live_at_start, old_succ->global_live_at_start); |
| COPY_REG_SET (bb->global_live_at_end, old_succ->global_live_at_start); |
| } |
| else |
| { |
| CLEAR_REG_SET (bb->global_live_at_start); |
| CLEAR_REG_SET (bb->global_live_at_end); |
| } |
| |
| /* Wire them up. */ |
| bb->pred = edge_in; |
| bb->succ = edge_out; |
| |
| edge_in->dest = bb; |
| edge_in->flags &= ~EDGE_CRITICAL; |
| |
| edge_out->pred_next = old_succ->pred; |
| edge_out->succ_next = NULL; |
| edge_out->src = bb; |
| edge_out->dest = old_succ; |
| edge_out->flags = EDGE_FALLTHRU; |
| edge_out->probability = REG_BR_PROB_BASE; |
| |
| old_succ->pred = edge_out; |
| |
| /* Tricky case -- if there existed a fallthru into the successor |
| (and we're not it) we must add a new unconditional jump around |
| the new block we're actually interested in. |
| |
| Further, if that edge is critical, this means a second new basic |
| block must be created to hold it. In order to simplify correct |
| insn placement, do this before we touch the existing basic block |
| ordering for the block we were really wanting. */ |
| if ((edge_in->flags & EDGE_FALLTHRU) == 0) |
| { |
| edge e; |
| for (e = edge_out->pred_next; e ; e = e->pred_next) |
| if (e->flags & EDGE_FALLTHRU) |
| break; |
| |
| if (e) |
| { |
| basic_block jump_block; |
| rtx pos; |
| |
| if ((e->flags & EDGE_CRITICAL) == 0) |
| { |
| /* Non critical -- we can simply add a jump to the end |
| of the existing predecessor. */ |
| jump_block = e->src; |
| } |
| else |
| { |
| /* We need a new block to hold the jump. The simplest |
| way to do the bulk of the work here is to recursively |
| call ourselves. */ |
| jump_block = split_edge (e); |
| e = jump_block->succ; |
| } |
| |
| /* Now add the jump insn ... */ |
| pos = emit_jump_insn_after (gen_jump (old_succ->head), |
| jump_block->end); |
| jump_block->end = pos; |
| emit_barrier_after (pos); |
| |
| /* ... let jump know that label is in use, ... */ |
| ++LABEL_NUSES (old_succ->head); |
| |
| /* ... and clear fallthru on the outgoing edge. */ |
| e->flags &= ~EDGE_FALLTHRU; |
| |
| /* Continue splitting the interesting edge. */ |
| } |
| } |
| |
| /* Place the new block just in front of the successor. */ |
| VARRAY_GROW (basic_block_info, ++n_basic_blocks); |
| for (i = n_basic_blocks - 1; i > old_succ->index; --i) |
| { |
| basic_block tmp = BASIC_BLOCK (i - 1); |
| BASIC_BLOCK (i) = tmp; |
| tmp->index = i; |
| } |
| BASIC_BLOCK (i) = bb; |
| bb->index = i; |
| |
| /* Create the basic block note. */ |
| bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, old_succ->head); |
| NOTE_BASIC_BLOCK (bb_note) = bb; |
| bb->head = bb->end = bb_note; |
| |
| /* Not quite simple -- for non-fallthru edges, we must adjust the |
| predecessor's jump instruction to target our new block. */ |
| if ((edge_in->flags & EDGE_FALLTHRU) == 0) |
| { |
| rtx tmp, insn = old_pred->end; |
| rtx old_label = old_succ->head; |
| rtx new_label = gen_label_rtx (); |
| |
| if (GET_CODE (insn) != JUMP_INSN) |
| abort (); |
| |
| /* ??? Recognize a tablejump and adjust all matching cases. */ |
| if ((tmp = JUMP_LABEL (insn)) != NULL_RTX |
| && (tmp = NEXT_INSN (tmp)) != NULL_RTX |
| && GET_CODE (tmp) == JUMP_INSN |
| && (GET_CODE (PATTERN (tmp)) == ADDR_VEC |
| || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC)) |
| { |
| rtvec vec; |
| int j; |
| |
| if (GET_CODE (PATTERN (tmp)) == ADDR_VEC) |
| vec = XVEC (PATTERN (tmp), 0); |
| else |
| vec = XVEC (PATTERN (tmp), 1); |
| |
| for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j) |
| if (XEXP (RTVEC_ELT (vec, j), 0) == old_label) |
| { |
| RTVEC_ELT (vec, j) = gen_rtx_LABEL_REF (VOIDmode, new_label); |
| --LABEL_NUSES (old_label); |
| ++LABEL_NUSES (new_label); |
| } |
| } |
| else |
| { |
| /* This would have indicated an abnormal edge. */ |
| if (computed_jump_p (insn)) |
| abort (); |
| |
| /* A return instruction can't be redirected. */ |
| if (returnjump_p (insn)) |
| abort (); |
| |
| /* If the insn doesn't go where we think, we're confused. */ |
| if (JUMP_LABEL (insn) != old_label) |
| abort (); |
| |
| redirect_jump (insn, new_label); |
| } |
| |
| emit_label_before (new_label, bb_note); |
| bb->head = new_label; |
| } |
| |
| return bb; |
| } |
| |
| /* Queue instructions for insertion on an edge between two basic blocks. |
| The new instructions and basic blocks (if any) will not appear in the |
| CFG until commit_edge_insertions is called. */ |
| |
| void |
| insert_insn_on_edge (pattern, e) |
| rtx pattern; |
| edge e; |
| { |
| /* We cannot insert instructions on an abnormal critical edge. |
| It will be easier to find the culprit if we die now. */ |
| if ((e->flags & (EDGE_ABNORMAL|EDGE_CRITICAL)) |
| == (EDGE_ABNORMAL|EDGE_CRITICAL)) |
| abort (); |
| |
| if (e->insns == NULL_RTX) |
| start_sequence (); |
| else |
| push_to_sequence (e->insns); |
| |
| emit_insn (pattern); |
| |
| e->insns = get_insns (); |
| end_sequence(); |
| } |
| |
| /* Update the CFG for the instructions queued on edge E. */ |
| |
| static void |
| commit_one_edge_insertion (e) |
| edge e; |
| { |
| rtx before = NULL_RTX, after = NULL_RTX, tmp; |
| basic_block bb; |
| |
| /* Figure out where to put these things. If the destination has |
| one predecessor, insert there. Except for the exit block. */ |
| if (e->dest->pred->pred_next == NULL |
| && e->dest != EXIT_BLOCK_PTR) |
| { |
| bb = e->dest; |
| |
| /* Get the location correct wrt a code label, and "nice" wrt |
| a basic block note, and before everything else. */ |
| tmp = bb->head; |
| if (GET_CODE (tmp) == CODE_LABEL) |
| tmp = NEXT_INSN (tmp); |
| if (GET_CODE (tmp) == NOTE |
| && NOTE_LINE_NUMBER (tmp) == NOTE_INSN_BASIC_BLOCK) |
| tmp = NEXT_INSN (tmp); |
| if (tmp == bb->head) |
| before = tmp; |
| else |
| after = PREV_INSN (tmp); |
| } |
| |
| /* If the source has one successor and the edge is not abnormal, |
| insert there. Except for the entry block. */ |
| else if ((e->flags & EDGE_ABNORMAL) == 0 |
| && e->src->succ->succ_next == NULL |
| && e->src != ENTRY_BLOCK_PTR) |
| { |
| bb = e->src; |
| if (GET_CODE (bb->end) == JUMP_INSN) |
| { |
| /* ??? Is it possible to wind up with non-simple jumps? Perhaps |
| a jump with delay slots already filled? */ |
| if (! simplejump_p (bb->end)) |
| abort (); |
| |
| before = bb->end; |
| } |
| else |
| { |
| /* We'd better be fallthru, or we've lost track of what's what. */ |
| if ((e->flags & EDGE_FALLTHRU) == 0) |
| abort (); |
| |
| after = bb->end; |
| } |
| } |
| |
| /* Otherwise we must split the edge. */ |
| else |
| { |
| bb = split_edge (e); |
| after = bb->end; |
| } |
| |
| /* Now that we've found the spot, do the insertion. */ |
| tmp = e->insns; |
| e->insns = NULL_RTX; |
| if (before) |
| { |
| emit_insns_before (tmp, before); |
| if (before == bb->head) |
| bb->head = before; |
| } |
| else |
| { |
| tmp = emit_insns_after (tmp, after); |
| if (after == bb->end) |
| bb->end = tmp; |
| } |
| } |
| |
| /* Update the CFG for all queued instructions. */ |
| |
| void |
| commit_edge_insertions () |
| { |
| int i; |
| basic_block bb; |
| |
| i = -1; |
| bb = ENTRY_BLOCK_PTR; |
| while (1) |
| { |
| edge e, next; |
| |
| for (e = bb->succ; e ; e = next) |
| { |
| next = e->succ_next; |
| if (e->insns) |
| commit_one_edge_insertion (e); |
| } |
| |
| if (++i >= n_basic_blocks) |
| break; |
| bb = BASIC_BLOCK (i); |
| } |
| } |
| |
| /* Delete all unreachable basic blocks. */ |
| |
| static void |
| delete_unreachable_blocks () |
| { |
| basic_block *worklist, *tos; |
| int deleted_handler; |
| edge e; |
| int i, n; |
| |
| n = n_basic_blocks; |
| tos = worklist = (basic_block *) alloca (sizeof (basic_block) * n); |
| |
| /* Use basic_block->aux as a marker. Clear them all. */ |
| |
| for (i = 0; i < n; ++i) |
| BASIC_BLOCK (i)->aux = NULL; |
| |
| /* Add our starting points to the worklist. Almost always there will |
| be only one. It isn't inconcievable that we might one day directly |
| support Fortran alternate entry points. */ |
| |
| for (e = ENTRY_BLOCK_PTR->succ; e ; e = e->succ_next) |
| { |
| *tos++ = e->dest; |
| |
| /* Mark the block with a handy non-null value. */ |
| e->dest->aux = e; |
| } |
| |
| /* Iterate: find everything reachable from what we've already seen. */ |
| |
| while (tos != worklist) |
| { |
| basic_block b = *--tos; |
| |
| for (e = b->succ; e ; e = e->succ_next) |
| if (!e->dest->aux) |
| { |
| *tos++ = e->dest; |
| e->dest->aux = e; |
| } |
| } |
| |
| /* Delete all unreachable basic blocks. Count down so that we don't |
| interfere with the block renumbering that happens in delete_block. */ |
| |
| deleted_handler = 0; |
| |
| for (i = n - 1; i >= 0; --i) |
| { |
| basic_block b = BASIC_BLOCK (i); |
| |
| if (b->aux != NULL) |
| /* This block was found. Tidy up the mark. */ |
| b->aux = NULL; |
| else |
| deleted_handler |= delete_block (b); |
| } |
| |
| /* Fix up edges that now fall through, or rather should now fall through |
| but previously required a jump around now deleted blocks. Simplify |
| the search by only examining blocks numerically adjacent, since this |
| is how find_basic_blocks created them. */ |
| |
| for (i = 1; i < n_basic_blocks; ++i) |
| { |
| basic_block b = BASIC_BLOCK (i - 1); |
| basic_block c = BASIC_BLOCK (i); |
| edge s; |
| |
| /* We care about simple conditional or unconditional jumps with |
| a single successor. |
| |
| If we had a conditional branch to the next instruction when |
| find_basic_blocks was called, then there will only be one |
| out edge for the block which ended with the conditional |
| branch (since we do not create duplicate edges). |
| |
| Furthermore, the edge will be marked as a fallthru because we |
| merge the flags for the duplicate edges. So we do not want to |
| check that the edge is not a FALLTHRU edge. */ |
| if ((s = b->succ) != NULL |
| && s->succ_next == NULL |
| && s->dest == c |
| /* If the last insn is not a normal conditional jump |
| (or an unconditional jump), then we can not tidy the |
| fallthru edge because we can not delete the jump. */ |
| && GET_CODE (b->end) == JUMP_INSN |
| && condjump_p (b->end)) |
| tidy_fallthru_edge (s, b, c); |
| } |
| |
| /* Attempt to merge blocks as made possible by edge removal. If a block |
| has only one successor, and the successor has only one predecessor, |
| they may be combined. */ |
| |
| for (i = 0; i < n_basic_blocks; ) |
| { |
| basic_block c, b = BASIC_BLOCK (i); |
| edge s; |
| |
| /* A loop because chains of blocks might be combineable. */ |
| while ((s = b->succ) != NULL |
| && s->succ_next == NULL |
| && (s->flags & EDGE_EH) == 0 |
| && (c = s->dest) != EXIT_BLOCK_PTR |
| && c->pred->pred_next == NULL |
| /* If the last insn is not a normal conditional jump |
| (or an unconditional jump), then we can not merge |
| the blocks because we can not delete the jump. */ |
| && GET_CODE (b->end) == JUMP_INSN |
| && condjump_p (b->end) |
| && merge_blocks (s, b, c)) |
| continue; |
| |
| /* Don't get confused by the index shift caused by deleting blocks. */ |
| i = b->index + 1; |
| } |
| |
| /* If we deleted an exception handler, we may have EH region begin/end |
| blocks to remove as well. */ |
| if (deleted_handler) |
| delete_eh_regions (); |
| } |
| |
| /* Find EH regions for which there is no longer a handler, and delete them. */ |
| |
| static void |
| delete_eh_regions () |
| { |
| rtx insn; |
| |
| for (insn = get_insns (); insn; insn = NEXT_INSN (insn)) |
| if (GET_CODE (insn) == NOTE) |
| { |
| if ((NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG) || |
| (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END)) |
| { |
| int num = CODE_LABEL_NUMBER (insn); |
| /* A NULL handler indicates a region is no longer needed */ |
| if (get_first_handler (num) == NULL) |
| { |
| NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED; |
| NOTE_SOURCE_FILE (insn) = 0; |
| } |
| } |
| } |
| } |
| |
| /* Return true if NOTE is not one of the ones that must be kept paired, |
| so that we may simply delete them. */ |
| |
| static int |
| can_delete_note_p (note) |
| rtx note; |
| { |
| return (NOTE_LINE_NUMBER (note) == NOTE_INSN_DELETED |
| || NOTE_LINE_NUMBER (note) == NOTE_INSN_BASIC_BLOCK); |
| } |
| |
| /* Unlink a chain of insns between START and FINISH, leaving notes |
| that must be paired. */ |
| |
| static void |
| delete_insn_chain (start, finish) |
| rtx start, finish; |
| { |
| /* Unchain the insns one by one. It would be quicker to delete all |
| of these with a single unchaining, rather than one at a time, but |
| we need to keep the NOTE's. */ |
| |
| rtx next; |
| |
| while (1) |
| { |
| next = NEXT_INSN (start); |
| if (GET_CODE (start) == NOTE && !can_delete_note_p (start)) |
| ; |
| else if (GET_CODE (start) == CODE_LABEL && !can_delete_label_p (start)) |
| ; |
| else |
| next = flow_delete_insn (start); |
| |
| if (start == finish) |
| break; |
| start = next; |
| } |
| } |
| |
| /* Delete the insns in a (non-live) block. We physically delete every |
| non-deleted-note insn, and update the flow graph appropriately. |
| |
| Return nonzero if we deleted an exception handler. */ |
| |
| /* ??? Preserving all such notes strikes me as wrong. It would be nice |
| to post-process the stream to remove empty blocks, loops, ranges, etc. */ |
| |
| static int |
| delete_block (b) |
| basic_block b; |
| { |
| int deleted_handler = 0; |
| rtx insn, end; |
| |
| /* If the head of this block is a CODE_LABEL, then it might be the |
| label for an exception handler which can't be reached. |
| |
| We need to remove the label from the exception_handler_label list |
| and remove the associated NOTE_EH_REGION_BEG and NOTE_EH_REGION_END |
| notes. */ |
| |
| insn = b->head; |
| |
| if (GET_CODE (insn) == CODE_LABEL) |
| { |
| rtx x, *prev = &exception_handler_labels; |
| |
| for (x = exception_handler_labels; x; x = XEXP (x, 1)) |
| { |
| if (XEXP (x, 0) == insn) |
| { |
| /* Found a match, splice this label out of the EH label list. */ |
| *prev = XEXP (x, 1); |
| XEXP (x, 1) = NULL_RTX; |
| XEXP (x, 0) = NULL_RTX; |
| |
| /* Remove the handler from all regions */ |
| remove_handler (insn); |
| deleted_handler = 1; |
| break; |
| } |
| prev = &XEXP (x, 1); |
| } |
| |
| /* This label may be referenced by code solely for its value, or |
| referenced by static data, or something. We have determined |
| that it is not reachable, but cannot delete the label itself. |
| Save code space and continue to delete the balance of the block, |
| along with properly updating the cfg. */ |
| if (!can_delete_label_p (insn)) |
| { |
| /* If we've only got one of these, skip the whole deleting |
| insns thing. */ |
| if (insn == b->end) |
| goto no_delete_insns; |
| insn = NEXT_INSN (insn); |
| } |
| } |
| |
| /* Selectively unlink the insn chain. Include any BARRIER that may |
| follow the basic block. */ |
| end = next_nonnote_insn (b->end); |
| if (!end || GET_CODE (end) != BARRIER) |
| end = b->end; |
| delete_insn_chain (insn, end); |
| |
| no_delete_insns: |
| |
| /* Remove the edges into and out of this block. Note that there may |
| indeed be edges in, if we are removing an unreachable loop. */ |
| { |
| edge e, next, *q; |
| |
| for (e = b->pred; e ; e = next) |
| { |
| for (q = &e->src->succ; *q != e; q = &(*q)->succ_next) |
| continue; |
| *q = e->succ_next; |
| next = e->pred_next; |
| free (e); |
| } |
| for (e = b->succ; e ; e = next) |
| { |
| for (q = &e->dest->pred; *q != e; q = &(*q)->pred_next) |
| continue; |
| *q = e->pred_next; |
| next = e->succ_next; |
| free (e); |
| } |
| |
| b->pred = NULL; |
| b->succ = NULL; |
| } |
| |
| /* Remove the basic block from the array, and compact behind it. */ |
| expunge_block (b); |
| |
| return deleted_handler; |
| } |
| |
| /* Remove block B from the basic block array and compact behind it. */ |
| |
| static void |
| expunge_block (b) |
| basic_block b; |
| { |
| int i, n = n_basic_blocks; |
| |
| for (i = b->index; i + 1 < n; ++i) |
| { |
| basic_block x = BASIC_BLOCK (i + 1); |
| BASIC_BLOCK (i) = x; |
| x->index = i; |
| } |
| |
| basic_block_info->num_elements--; |
| n_basic_blocks--; |
| } |
| |
| /* Delete INSN by patching it out. Return the next insn. */ |
| |
| static rtx |
| flow_delete_insn (insn) |
| rtx insn; |
| { |
| rtx prev = PREV_INSN (insn); |
| rtx next = NEXT_INSN (insn); |
| |
| PREV_INSN (insn) = NULL_RTX; |
| NEXT_INSN (insn) = NULL_RTX; |
| |
| if (prev) |
| NEXT_INSN (prev) = next; |
| if (next) |
| PREV_INSN (next) = prev; |
| else |
| set_last_insn (prev); |
| |
| if (GET_CODE (insn) == CODE_LABEL) |
| remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels); |
| |
| /* If deleting a jump, decrement the use count of the label. Deleting |
| the label itself should happen in the normal course of block merging. */ |
| if (GET_CODE (insn) == JUMP_INSN && JUMP_LABEL (insn)) |
| LABEL_NUSES (JUMP_LABEL (insn))--; |
| |
| return next; |
| } |
| |
| /* True if a given label can be deleted. */ |
| |
| static int |
| can_delete_label_p (label) |
| rtx label; |
| { |
| rtx x; |
| |
| if (LABEL_PRESERVE_P (label)) |
| return 0; |
| |
| for (x = forced_labels; x ; x = XEXP (x, 1)) |
| if (label == XEXP (x, 0)) |
| return 0; |
| for (x = label_value_list; x ; x = XEXP (x, 1)) |
| if (label == XEXP (x, 0)) |
| return 0; |
| for (x = exception_handler_labels; x ; x = XEXP (x, 1)) |
| if (label == XEXP (x, 0)) |
| return 0; |
| |
| /* User declared labels must be preserved. */ |
| if (LABEL_NAME (label) != 0) |
| return 0; |
| |
| return 1; |
| } |
| |
| /* Blocks A and B are to be merged into a single block. The insns |
| are already contiguous, hence `nomove'. */ |
| |
| static void |
| merge_blocks_nomove (a, b) |
| basic_block a, b; |
| { |
| edge e; |
| rtx b_head, b_end, a_end; |
| int b_empty = 0; |
| |
| /* If there was a CODE_LABEL beginning B, delete it. */ |
| b_head = b->head; |
| b_end = b->end; |
| if (GET_CODE (b_head) == CODE_LABEL) |
| { |
| /* Detect basic blocks with nothing but a label. This can happen |
| in particular at the end of a function. */ |
| if (b_head == b_end) |
| b_empty = 1; |
| b_head = flow_delete_insn (b_head); |
| } |
| |
| /* Delete the basic block note. */ |
| if (GET_CODE (b_head) == NOTE |
| && NOTE_LINE_NUMBER (b_head) == NOTE_INSN_BASIC_BLOCK) |
| { |
| if (b_head == b_end) |
| b_empty = 1; |
| b_head = flow_delete_insn (b_head); |
| } |
| |
| /* If there was a jump out of A, delete it. */ |
| a_end = a->end; |
| if (GET_CODE (a_end) == JUMP_INSN) |
| { |
| rtx prev; |
| |
| prev = prev_nonnote_insn (a_end); |
| if (!prev) |
| prev = a->head; |
| |
| #ifdef HAVE_cc0 |
| /* If this was a conditional jump, we need to also delete |
| the insn that set cc0. */ |
| |
| if (prev && sets_cc0_p (prev)) |
| { |
| rtx tmp = prev; |
| prev = prev_nonnote_insn (prev); |
| if (!prev) |
| prev = a->head; |
| flow_delete_insn (tmp); |
| } |
| #endif |
| |
| /* Note that a->head != a->end, since we should have at least a |
| bb note plus the jump, so prev != insn. */ |
| flow_delete_insn (a_end); |
| a_end = prev; |
| } |
| |
| /* By definition, there should only be one successor of A, and that is |
| B. Free that edge struct. */ |
| free (a->succ); |
| |
| /* Adjust the edges out of B for the new owner. */ |
| for (e = b->succ; e ; e = e->succ_next) |
| e->src = a; |
| a->succ = b->succ; |
| |
| /* Reassociate the insns of B with A. */ |
| if (!b_empty) |
| { |
| BLOCK_FOR_INSN (b_head) = a; |
| while (b_head != b_end) |
| { |
| b_head = NEXT_INSN (b_head); |
| BLOCK_FOR_INSN (b_head) = a; |
| } |
| a_end = b_head; |
| } |
| a->end = a_end; |
| |
| /* Compact the basic block array. */ |
| expunge_block (b); |
| } |
| |
| /* Attempt to merge basic blocks that are potentially non-adjacent. |
| Return true iff the attempt succeeded. */ |
| |
| static int |
| merge_blocks (e, b, c) |
| edge e; |
| basic_block b, c; |
| { |
| /* If B has a fallthru edge to C, no need to move anything. */ |
| if (!(e->flags & EDGE_FALLTHRU)) |
| { |
| /* ??? From here on out we must make sure to not munge nesting |
| of exception regions and lexical blocks. Need to think about |
| these cases before this gets implemented. */ |
| return 0; |
| |
| /* If C has an outgoing fallthru, and B does not have an incoming |
| fallthru, move B before C. The later clause is somewhat arbitrary, |
| but avoids modifying blocks other than the two we've been given. */ |
| |
| /* Otherwise, move C after B. If C had a fallthru, which doesn't |
| happen to be the physical successor to B, insert an unconditional |
| branch. If C already ended with a conditional branch, the new |
| jump must go in a new basic block D. */ |
| } |
| |
| /* If a label still appears somewhere and we cannot delete the label, |
| then we cannot merge the blocks. The edge was tidied already. */ |
| { |
| rtx insn, stop = NEXT_INSN (c->head); |
| for (insn = NEXT_INSN (b->end); insn != stop; insn = NEXT_INSN (insn)) |
| if (GET_CODE (insn) == CODE_LABEL && !can_delete_label_p (insn)) |
| return 0; |
| } |
| |
| merge_blocks_nomove (b, c); |
| return 1; |
| } |
| |
| /* The given edge should potentially a fallthru edge. If that is in |
| fact true, delete the unconditional jump and barriers that are in |
| the way. */ |
| |
| static void |
| tidy_fallthru_edge (e, b, c) |
| edge e; |
| basic_block b, c; |
| { |
| rtx q; |
| |
| /* ??? In a late-running flow pass, other folks may have deleted basic |
| blocks by nopping out blocks, leaving multiple BARRIERs between here |
| and the target label. They ought to be chastized and fixed. |
| |
| We can also wind up with a sequence of undeletable labels between |
| one block and the next. |
| |
| So search through a sequence of barriers, labels, and notes for |
| the head of block C and assert that we really do fall through. */ |
| |
| if (next_real_insn (b->end) != next_real_insn (PREV_INSN (c->head))) |
| return; |
| |
| /* Remove what will soon cease being the jump insn from the source block. |
| If block B consisted only of this single jump, turn it into a deleted |
| note. */ |
| q = b->end; |
| if (GET_CODE (q) == JUMP_INSN) |
| { |
| #ifdef HAVE_cc0 |
| /* If this was a conditional jump, we need to also delete |
| the insn that set cc0. */ |
| if (! simplejump_p (q) && condjump_p (q)) |
| q = PREV_INSN (q); |
| #endif |
| |
| if (b->head == q) |
| { |
| PUT_CODE (q, NOTE); |
| NOTE_LINE_NUMBER (q) = NOTE_INSN_DELETED; |
| NOTE_SOURCE_FILE (q) = 0; |
| } |
| else |
| b->end = q = PREV_INSN (q); |
| } |
| |
| /* Selectively unlink the sequence. */ |
| if (q != PREV_INSN (c->head)) |
| delete_insn_chain (NEXT_INSN (q), PREV_INSN (c->head)); |
| |
| e->flags |= EDGE_FALLTHRU; |
| } |
| |
| /* Discover and record the loop depth at the head of each basic block. */ |
| |
| static void |
| calculate_loop_depth (insns) |
| rtx insns; |
| { |
| basic_block bb; |
| rtx insn; |
| int i = 0, depth = 1; |
| |
| bb = BASIC_BLOCK (i); |
| for (insn = insns; insn ; insn = NEXT_INSN (insn)) |
| { |
| if (insn == bb->head) |
| { |
| bb->loop_depth = depth; |
| if (++i >= n_basic_blocks) |
| break; |
| bb = BASIC_BLOCK (i); |
| } |
| |
| if (GET_CODE (insn) == NOTE) |
| { |
| if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG) |
| depth++; |
| else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END) |
| depth--; |
| |
| /* If we have LOOP_DEPTH == 0, there has been a bookkeeping error. */ |
| if (depth == 0) |
| abort (); |
| } |
| } |
| } |
| |
| /* Perform data flow analysis. |
| F is the first insn of the function and NREGS the number of register numbers |
| in use. */ |
| |
| void |
| life_analysis (f, nregs, file, remove_dead_code) |
| rtx f; |
| int nregs; |
| FILE *file; |
| int remove_dead_code; |
| { |
| #ifdef ELIMINABLE_REGS |
| register size_t i; |
| static struct {int from, to; } eliminables[] = ELIMINABLE_REGS; |
| #endif |
| |
| /* Record which registers will be eliminated. We use this in |
| mark_used_regs. */ |
| |
| CLEAR_HARD_REG_SET (elim_reg_set); |
| |
| #ifdef ELIMINABLE_REGS |
| for (i = 0; i < sizeof eliminables / sizeof eliminables[0]; i++) |
| SET_HARD_REG_BIT (elim_reg_set, eliminables[i].from); |
| #else |
| SET_HARD_REG_BIT (elim_reg_set, FRAME_POINTER_REGNUM); |
| #endif |
| |
| /* Allocate a bitmap to be filled in by record_volatile_insns. */ |
| uid_volatile = BITMAP_ALLOCA (); |
| |
| /* We want alias analysis information for local dead store elimination. */ |
| init_alias_analysis (); |
| life_analysis_1 (f, nregs, remove_dead_code); |
| end_alias_analysis (); |
| |
| if (file) |
| dump_flow_info (file); |
| |
| BITMAP_FREE (uid_volatile); |
| free_basic_block_vars (1); |
| } |
| |
| /* Free the variables allocated by find_basic_blocks. |
| |
| KEEP_HEAD_END_P is non-zero if basic_block_info is not to be freed. */ |
| |
| void |
| free_basic_block_vars (keep_head_end_p) |
| int keep_head_end_p; |
| { |
| if (basic_block_for_insn) |
| { |
| VARRAY_FREE (basic_block_for_insn); |
| basic_block_for_insn = NULL; |
| } |
| |
| if (! keep_head_end_p) |
| { |
| clear_edges (); |
| VARRAY_FREE (basic_block_info); |
| n_basic_blocks = 0; |
| |
| ENTRY_BLOCK_PTR->aux = NULL; |
| ENTRY_BLOCK_PTR->global_live_at_end = NULL; |
| EXIT_BLOCK_PTR->aux = NULL; |
| EXIT_BLOCK_PTR->global_live_at_start = NULL; |
| } |
| } |
| |
| /* Return nonzero if the destination of SET equals the source. */ |
| static int |
| set_noop_p (set) |
| rtx set; |
| { |
| rtx src = SET_SRC (set); |
| rtx dst = SET_DEST (set); |
| if (GET_CODE (src) == REG && GET_CODE (dst) == REG |
| && REGNO (src) == REGNO (dst)) |
| return 1; |
| if (GET_CODE (src) != SUBREG || GET_CODE (dst) != SUBREG |
| || SUBREG_WORD (src) != SUBREG_WORD (dst)) |
| return 0; |
| src = SUBREG_REG (src); |
| dst = SUBREG_REG (dst); |
| if (GET_CODE (src) == REG && GET_CODE (dst) == REG |
| && REGNO (src) == REGNO (dst)) |
| return 1; |
| return 0; |
| } |
| |
| /* Return nonzero if an insn consists only of SETs, each of which only sets a |
| value to itself. */ |
| static int |
| noop_move_p (insn) |
| rtx insn; |
| { |
| rtx pat = PATTERN (insn); |
| |
| /* Insns carrying these notes are useful later on. */ |
| if (find_reg_note (insn, REG_EQUAL, NULL_RTX)) |
| return 0; |
| |
| if (GET_CODE (pat) == SET && set_noop_p (pat)) |
| return 1; |
| |
| if (GET_CODE (pat) == PARALLEL) |
| { |
| int i; |
| /* If nothing but SETs of registers to themselves, |
| this insn can also be deleted. */ |
| for (i = 0; i < XVECLEN (pat, 0); i++) |
| { |
| rtx tem = XVECEXP (pat, 0, i); |
| |
| if (GET_CODE (tem) == USE |
| || GET_CODE (tem) == CLOBBER) |
| continue; |
| |
| if (GET_CODE (tem) != SET || ! set_noop_p (tem)) |
| return 0; |
| } |
| |
| return 1; |
| } |
| return 0; |
| } |
| |
| static void |
| notice_stack_pointer_modification (x, pat) |
| rtx x; |
| rtx pat ATTRIBUTE_UNUSED; |
| { |
| if (x == stack_pointer_rtx |
| /* The stack pointer is only modified indirectly as the result |
| of a push until later in flow. See the comments in rtl.texi |
| regarding Embedded Side-Effects on Addresses. */ |
| || (GET_CODE (x) == MEM |
| && (GET_CODE (XEXP (x, 0)) == PRE_DEC |
| || GET_CODE (XEXP (x, 0)) == PRE_INC |
| || GET_CODE (XEXP (x, 0)) == POST_DEC |
| || GET_CODE (XEXP (x, 0)) == POST_INC) |
| && XEXP (XEXP (x, 0), 0) == stack_pointer_rtx)) |
| current_function_sp_is_unchanging = 0; |
| } |
| |
| /* Record which insns refer to any volatile memory |
| or for any reason can't be deleted just because they are dead stores. |
| Also, delete any insns that copy a register to itself. |
| And see if the stack pointer is modified. */ |
| static void |
| record_volatile_insns (f) |
| rtx f; |
| { |
| rtx insn; |
| for (insn = f; insn; insn = NEXT_INSN (insn)) |
| { |
| enum rtx_code code1 = GET_CODE (insn); |
| if (code1 == CALL_INSN) |
| SET_INSN_VOLATILE (insn); |
| else if (code1 == INSN || code1 == JUMP_INSN) |
| { |
| if (GET_CODE (PATTERN (insn)) != USE |
| && volatile_refs_p (PATTERN (insn))) |
| SET_INSN_VOLATILE (insn); |
| |
| /* A SET that makes space on the stack cannot be dead. |
| (Such SETs occur only for allocating variable-size data, |
| so they will always have a PLUS or MINUS according to the |
| direction of stack growth.) |
| Even if this function never uses this stack pointer value, |
| signal handlers do! */ |
| else if (code1 == INSN && GET_CODE (PATTERN (insn)) == SET |
| && SET_DEST (PATTERN (insn)) == stack_pointer_rtx |
| #ifdef STACK_GROWS_DOWNWARD |
| && GET_CODE (SET_SRC (PATTERN (insn))) == MINUS |
| #else |
| && GET_CODE (SET_SRC (PATTERN (insn))) == PLUS |
| #endif |
| && XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx) |
| SET_INSN_VOLATILE (insn); |
| |
| /* Delete (in effect) any obvious no-op moves. */ |
| else if (noop_move_p (insn)) |
| { |
| PUT_CODE (insn, NOTE); |
| NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED; |
| NOTE_SOURCE_FILE (insn) = 0; |
| } |
| } |
| |
| /* Check if insn modifies the stack pointer. */ |
| if ( current_function_sp_is_unchanging |
| && GET_RTX_CLASS (GET_CODE (insn)) == 'i') |
| note_stores (PATTERN (insn), notice_stack_pointer_modification); |
| } |
| } |
| |
| /* Mark those regs which are needed at the end of the function as live |
| at the end of the last basic block. */ |
| static void |
| mark_regs_live_at_end (set) |
| regset set; |
| { |
| int i; |
| |
| /* If exiting needs the right stack value, consider the stack pointer |
| live at the end of the function. */ |
| if (! EXIT_IGNORE_STACK |
| || (! FRAME_POINTER_REQUIRED |
| && ! current_function_calls_alloca |
| && flag_omit_frame_pointer) |
| || current_function_sp_is_unchanging) |
| { |
| SET_REGNO_REG_SET (set, STACK_POINTER_REGNUM); |
| } |
| |
| /* Mark the frame pointer if needed at the end of the function. If |
| we end up eliminating it, it will be removed from the live list |
| of each basic block by reload. */ |
| |
| if (! reload_completed || frame_pointer_needed) |
| { |
| SET_REGNO_REG_SET (set, FRAME_POINTER_REGNUM); |
| #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM |
| /* If they are different, also mark the hard frame pointer as live */ |
| SET_REGNO_REG_SET (set, HARD_FRAME_POINTER_REGNUM); |
| #endif |
| } |
| |
| /* Mark all global registers, and all registers used by the epilogue |
| as being live at the end of the function since they may be |
| referenced by our caller. */ |
| for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
| if (global_regs[i] |
| #ifdef EPILOGUE_USES |
| || EPILOGUE_USES (i) |
| #endif |
| ) |
| SET_REGNO_REG_SET (set, i); |
| |
| /* ??? Mark function return value here rather than as uses. */ |
| } |
| |
| /* Determine which registers are live at the start of each |
| basic block of the function whose first insn is F. |
| NREGS is the number of registers used in F. |
| We allocate the vector basic_block_live_at_start |
| and the regsets that it points to, and fill them with the data. |
| regset_size and regset_bytes are also set here. */ |
| |
| static void |
| life_analysis_1 (f, nregs, remove_dead_code) |
| rtx f; |
| int nregs; |
| int remove_dead_code; |
| { |
| int first_pass; |
| int changed; |
| register int i; |
| char save_regs_ever_live[FIRST_PSEUDO_REGISTER]; |
| regset *new_live_at_end; |
| |
| struct obstack flow_obstack; |
| |
| gcc_obstack_init (&flow_obstack); |
| |
| max_regno = nregs; |
| |
| /* Allocate and zero out many data structures |
| that will record the data from lifetime analysis. */ |
| |
| allocate_reg_life_data (); |
| allocate_bb_life_data (); |
| |
| reg_next_use = (rtx *) alloca (nregs * sizeof (rtx)); |
| memset (reg_next_use, 0, nregs * sizeof (rtx)); |
| |
| /* Set up regset-vectors used internally within this function. |
| Their meanings are documented above, with their declarations. */ |
| |
| new_live_at_end = (regset *) alloca ((n_basic_blocks + 1) * sizeof (regset)); |
| init_regset_vector (new_live_at_end, n_basic_blocks + 1, &flow_obstack); |
| |
| /* Stick these vectors into the AUX field of the basic block, so that |
| we don't have to keep going through the index. */ |
| |
| for (i = 0; i < n_basic_blocks; ++i) |
| BASIC_BLOCK (i)->aux = new_live_at_end[i]; |
| ENTRY_BLOCK_PTR->aux = new_live_at_end[i]; |
| |
| /* Assume that the stack pointer is unchanging if alloca hasn't been used. |
| This will be cleared by record_volatile_insns if it encounters an insn |
| which modifies the stack pointer. */ |
| current_function_sp_is_unchanging = !current_function_calls_alloca; |
| |
| record_volatile_insns (f); |
| |
| if (n_basic_blocks > 0) |
| { |
| regset theend; |
| register edge e; |
| |
| theend = EXIT_BLOCK_PTR->global_live_at_start; |
| mark_regs_live_at_end (theend); |
| |
| /* Propogate this exit data to each of EXIT's predecessors. */ |
| for (e = EXIT_BLOCK_PTR->pred; e ; e = e->pred_next) |
| { |
| COPY_REG_SET (e->src->global_live_at_end, theend); |
| COPY_REG_SET ((regset) e->src->aux, theend); |
| } |
| } |
| |
| /* The post-reload life analysis have (on a global basis) the same registers |
| live as was computed by reload itself. |
| |
| Otherwise elimination offsets and such may be incorrect. |
| |
| Reload will make some registers as live even though they do not appear |
| in the rtl. */ |
| if (reload_completed) |
| memcpy (save_regs_ever_live, regs_ever_live, sizeof (regs_ever_live)); |
| memset (regs_ever_live, 0, sizeof regs_ever_live); |
| |
| /* Propagate life info through the basic blocks |
| around the graph of basic blocks. |
| |
| This is a relaxation process: each time a new register |
| is live at the end of the basic block, we must scan the block |
| to determine which registers are, as a consequence, live at the beginning |
| of that block. These registers must then be marked live at the ends |
| of all the blocks that can transfer control to that block. |
| The process continues until it reaches a fixed point. */ |
| |
| first_pass = 1; |
| changed = 1; |
| while (changed) |
| { |
| changed = 0; |
| for (i = n_basic_blocks - 1; i >= 0; i--) |
| { |
| basic_block bb = BASIC_BLOCK (i); |
| int consider = first_pass; |
| int must_rescan = first_pass; |
| register int j; |
| |
| if (!first_pass) |
| { |
| /* Set CONSIDER if this block needs thinking about at all |
| (that is, if the regs live now at the end of it |
| are not the same as were live at the end of it when |
| we last thought about it). |
| Set must_rescan if it needs to be thought about |
| instruction by instruction (that is, if any additional |
| reg that is live at the end now but was not live there before |
| is one of the significant regs of this basic block). */ |
| |
| EXECUTE_IF_AND_COMPL_IN_REG_SET |
| ((regset) bb->aux, bb->global_live_at_end, 0, j, |
| { |
| consider = 1; |
| if (REGNO_REG_SET_P (bb->local_set, j)) |
| { |
| must_rescan = 1; |
| goto done; |
| } |
| }); |
| done: |
| if (! consider) |
| continue; |
| } |
| |
| /* The live_at_start of this block may be changing, |
| so another pass will be required after this one. */ |
| changed = 1; |
| |
| if (! must_rescan) |
| { |
| /* No complete rescan needed; |
| just record those variables newly known live at end |
| as live at start as well. */ |
| IOR_AND_COMPL_REG_SET (bb->global_live_at_start, |
| (regset) bb->aux, |
| bb->global_live_at_end); |
| |
| IOR_AND_COMPL_REG_SET (bb->global_live_at_end, |
| (regset) bb->aux, |
| bb->global_live_at_end); |
| } |
| else |
| { |
| /* Update the basic_block_live_at_start |
| by propagation backwards through the block. */ |
| COPY_REG_SET (bb->global_live_at_end, (regset) bb->aux); |
| COPY_REG_SET (bb->global_live_at_start, |
| bb->global_live_at_end); |
| propagate_block (bb->global_live_at_start, |
| bb->head, bb->end, 0, |
| first_pass ? bb->local_set : (regset) 0, |
| i, remove_dead_code); |
| } |
| |
| /* Update the new_live_at_end's of the block's predecessors. */ |
| { |
| register edge e; |
| |
| for (e = bb->pred; e ; e = e->pred_next) |
| IOR_REG_SET ((regset) e->src->aux, bb->global_live_at_start); |
| } |
| |
| #ifdef USE_C_ALLOCA |
| alloca (0); |
| #endif |
| } |
| first_pass = 0; |
| } |
| |
| /* The only pseudos that are live at the beginning of the function are |
| those that were not set anywhere in the function. local-alloc doesn't |
| know how to handle these correctly, so mark them as not local to any |
| one basic block. */ |
| |
| if (n_basic_blocks > 0) |
| EXECUTE_IF_SET_IN_REG_SET (BASIC_BLOCK (0)->global_live_at_start, |
| FIRST_PSEUDO_REGISTER, i, |
| { |
| REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; |
| }); |
| |
| /* Now the life information is accurate. Make one more pass over each |
| basic block to delete dead stores, create autoincrement addressing |
| and record how many times each register is used, is set, or dies. */ |
| |
| for (i = 0; i < n_basic_blocks; i++) |
| { |
| basic_block bb = BASIC_BLOCK (i); |
| |
| /* We start with global_live_at_end to determine which stores are |
| dead. This process is destructive, and we wish to preserve the |
| contents of global_live_at_end for posterity. Fortunately, |
| new_live_at_end, due to the way we converged on a solution, |
| contains a duplicate of global_live_at_end that we can kill. */ |
| propagate_block ((regset) bb->aux, bb->head, bb->end, 1, (regset) 0, i, remove_dead_code); |
| |
| #ifdef USE_C_ALLOCA |
| alloca (0); |
| #endif |
| } |
| |
| /* We have a problem with any pseudoreg that lives across the setjmp. |
| ANSI says that if a user variable does not change in value between |
| the setjmp and the longjmp, then the longjmp preserves it. This |
| includes longjmp from a place where the pseudo appears dead. |
| (In principle, the value still exists if it is in scope.) |
| If the pseudo goes in a hard reg, some other value may occupy |
| that hard reg where this pseudo is dead, thus clobbering the pseudo. |
| Conclusion: such a pseudo must not go in a hard reg. */ |
| EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp, |
| FIRST_PSEUDO_REGISTER, i, |
| { |
| if (regno_reg_rtx[i] != 0) |
| { |
| REG_LIVE_LENGTH (i) = -1; |
| REG_BASIC_BLOCK (i) = -1; |
| } |
| }); |
| |
| /* Restore regs_ever_live that was provided by reload. */ |
| if (reload_completed) |
| memcpy (regs_ever_live, save_regs_ever_live, sizeof (regs_ever_live)); |
| |
| free_regset_vector (new_live_at_end, n_basic_blocks); |
| obstack_free (&flow_obstack, NULL_PTR); |
| |
| for (i = 0; i < n_basic_blocks; ++i) |
| BASIC_BLOCK (i)->aux = NULL; |
| ENTRY_BLOCK_PTR->aux = NULL; |
| } |
| |
| /* Subroutines of life analysis. */ |
| |
| /* Allocate the permanent data structures that represent the results |
| of life analysis. Not static since used also for stupid life analysis. */ |
| |
| void |
| allocate_bb_life_data () |
| { |
| register int i; |
| |
| for (i = 0; i < n_basic_blocks; i++) |
| { |
| basic_block bb = BASIC_BLOCK (i); |
| |
| bb->local_set = OBSTACK_ALLOC_REG_SET (function_obstack); |
| bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (function_obstack); |
| bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (function_obstack); |
| } |
| |
| ENTRY_BLOCK_PTR->global_live_at_end |
| = OBSTACK_ALLOC_REG_SET (function_obstack); |
| EXIT_BLOCK_PTR->global_live_at_start |
| = OBSTACK_ALLOC_REG_SET (function_obstack); |
| |
| regs_live_at_setjmp = OBSTACK_ALLOC_REG_SET (function_obstack); |
| } |
| |
| void |
| allocate_reg_life_data () |
| { |
| int i; |
| |
| /* Recalculate the register space, in case it has grown. Old style |
| vector oriented regsets would set regset_{size,bytes} here also. */ |
| allocate_reg_info (max_regno, FALSE, FALSE); |
| |
| /* Because both reg_scan and flow_analysis want to set up the REG_N_SETS |
| information, explicitly reset it here. The allocation should have |
| already happened on the previous reg_scan pass. Make sure in case |
| some more registers were allocated. */ |
| for (i = 0; i < max_regno; i++) |
| REG_N_SETS (i) = 0; |
| } |
| |
| /* Make each element of VECTOR point at a regset. The vector has |
| NELTS elements, and space is allocated from the ALLOC_OBSTACK |
| obstack. */ |
| |
| static void |
| init_regset_vector (vector, nelts, alloc_obstack) |
| regset *vector; |
| int nelts; |
| struct obstack *alloc_obstack; |
| { |
| register int i; |
| |
| for (i = 0; i < nelts; i++) |
| { |
| vector[i] = OBSTACK_ALLOC_REG_SET (alloc_obstack); |
| CLEAR_REG_SET (vector[i]); |
| } |
| } |
| |
| /* Release any additional space allocated for each element of VECTOR point |
| other than the regset header itself. The vector has NELTS elements. */ |
| |
| void |
| free_regset_vector (vector, nelts) |
| regset *vector; |
| int nelts; |
| { |
| register int i; |
| |
| for (i = 0; i < nelts; i++) |
| FREE_REG_SET (vector[i]); |
| } |
| |
| /* Compute the registers live at the beginning of a basic block |
| from those live at the end. |
| |
| When called, OLD contains those live at the end. |
| On return, it contains those live at the beginning. |
| FIRST and LAST are the first and last insns of the basic block. |
| |
| FINAL is nonzero if we are doing the final pass which is not |
| for computing the life info (since that has already been done) |
| but for acting on it. On this pass, we delete dead stores, |
| set up the logical links and dead-variables lists of instructions, |
| and merge instructions for autoincrement and autodecrement addresses. |
| |
| SIGNIFICANT is nonzero only the first time for each basic block. |
| If it is nonzero, it points to a regset in which we store |
| a 1 for each register that is set within the block. |
| |
| BNUM is the number of the basic block. */ |
| |
| static void |
| propagate_block (old, first, last, final, significant, bnum, remove_dead_code) |
| register regset old; |
| rtx first; |
| rtx last; |
| int final; |
| regset significant; |
| int bnum; |
| int remove_dead_code; |
| { |
| register rtx insn; |
| rtx prev; |
| regset live; |
| regset dead; |
| |
| /* Find the loop depth for this block. Ignore loop level changes in the |
| middle of the basic block -- for register allocation purposes, the |
| important uses will be in the blocks wholely contained within the loop |
| not in the loop pre-header or post-trailer. */ |
| loop_depth = BASIC_BLOCK (bnum)->loop_depth; |
| |
| dead = ALLOCA_REG_SET (); |
| live = ALLOCA_REG_SET (); |
| |
| cc0_live = 0; |
| mem_set_list = NULL_RTX; |
| |
| if (final) |
| { |
| register int i; |
| |
| /* Process the regs live at the end of the block. |
| Mark them as not local to any one basic block. */ |
| EXECUTE_IF_SET_IN_REG_SET (old, 0, i, |
| { |
| REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; |
| }); |
| } |
| |
| /* Scan the block an insn at a time from end to beginning. */ |
| |
| for (insn = last; ; insn = prev) |
| { |
| prev = PREV_INSN (insn); |
| |
| if (GET_CODE (insn) == NOTE) |
| { |
| /* If this is a call to `setjmp' et al, |
| warn if any non-volatile datum is live. */ |
| |
| if (final && NOTE_LINE_NUMBER (insn) == NOTE_INSN_SETJMP) |
| IOR_REG_SET (regs_live_at_setjmp, old); |
| } |
| |
| /* Update the life-status of regs for this insn. |
| First DEAD gets which regs are set in this insn |
| then LIVE gets which regs are used in this insn. |
| Then the regs live before the insn |
| are those live after, with DEAD regs turned off, |
| and then LIVE regs turned on. */ |
| |
| else if (GET_RTX_CLASS (GET_CODE (insn)) == 'i') |
| { |
| register int i; |
| rtx note = find_reg_note (insn, REG_RETVAL, NULL_RTX); |
| int insn_is_dead = 0; |
| int libcall_is_dead = 0; |
| |
| if (remove_dead_code) |
| { |
| insn_is_dead = (insn_dead_p (PATTERN (insn), old, 0, REG_NOTES (insn)) |
| /* Don't delete something that refers to volatile storage! */ |
| && ! INSN_VOLATILE (insn)); |
| libcall_is_dead = (insn_is_dead && note != 0 |
| && libcall_dead_p (PATTERN (insn), old, note, insn)); |
| } |
| |
| /* If an instruction consists of just dead store(s) on final pass, |
| "delete" it by turning it into a NOTE of type NOTE_INSN_DELETED. |
| We could really delete it with delete_insn, but that |
| can cause trouble for first or last insn in a basic block. */ |
| if (final && insn_is_dead) |
| { |
| PUT_CODE (insn, NOTE); |
| NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED; |
| NOTE_SOURCE_FILE (insn) = 0; |
| |
| /* CC0 is now known to be dead. Either this insn used it, |
| in which case it doesn't anymore, or clobbered it, |
| so the next insn can't use it. */ |
| cc0_live = 0; |
| |
| /* If this insn is copying the return value from a library call, |
| delete the entire library call. */ |
| if (libcall_is_dead) |
| { |
| rtx first = XEXP (note, 0); |
| rtx p = insn; |
| while (INSN_DELETED_P (first)) |
| first = NEXT_INSN (first); |
| while (p != first) |
| { |
| p = PREV_INSN (p); |
| PUT_CODE (p, NOTE); |
| NOTE_LINE_NUMBER (p) = NOTE_INSN_DELETED; |
| NOTE_SOURCE_FILE (p) = 0; |
| } |
| } |
| goto flushed; |
| } |
| |
| CLEAR_REG_SET (dead); |
| CLEAR_REG_SET (live); |
| |
| /* See if this is an increment or decrement that can be |
| merged into a following memory address. */ |
| #ifdef AUTO_INC_DEC |
| { |
| register rtx x = single_set (insn); |
| |
| /* Does this instruction increment or decrement a register? */ |
| if (!reload_completed |
| && final && x != 0 |
| && GET_CODE (SET_DEST (x)) == REG |
| && (GET_CODE (SET_SRC (x)) == PLUS |
| || GET_CODE (SET_SRC (x)) == MINUS) |
| && XEXP (SET_SRC (x), 0) == SET_DEST (x) |
| && GET_CODE (XEXP (SET_SRC (x), 1)) == CONST_INT |
| /* Ok, look for a following memory ref we can combine with. |
| If one is found, change the memory ref to a PRE_INC |
| or PRE_DEC, cancel this insn, and return 1. |
| Return 0 if nothing has been done. */ |
| && try_pre_increment_1 (insn)) |
| goto flushed; |
| } |
| #endif /* AUTO_INC_DEC */ |
| |
| /* If this is not the final pass, and this insn is copying the |
| value of a library call and it's dead, don't scan the |
| insns that perform the library call, so that the call's |
| arguments are not marked live. */ |
| if (libcall_is_dead) |
| { |
| /* Mark the dest reg as `significant'. */ |
| mark_set_regs (old, dead, PATTERN (insn), NULL_RTX, significant); |
| |
| insn = XEXP (note, 0); |
| prev = PREV_INSN (insn); |
| } |
| else if (GET_CODE (PATTERN (insn)) == SET |
| && SET_DEST (PATTERN (insn)) == stack_pointer_rtx |
| && GET_CODE (SET_SRC (PATTERN (insn))) == PLUS |
| && XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx |
| && GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 1)) == CONST_INT) |
| /* We have an insn to pop a constant amount off the stack. |
| (Such insns use PLUS regardless of the direction of the stack, |
| and any insn to adjust the stack by a constant is always a pop.) |
| These insns, if not dead stores, have no effect on life. */ |
| ; |
| else |
| { |
| /* Any regs live at the time of a call instruction |
| must not go in a register clobbered by calls. |
| Find all regs now live and record this for them. */ |
| |
| if (GET_CODE (insn) == CALL_INSN && final) |
| EXECUTE_IF_SET_IN_REG_SET (old, 0, i, |
| { |
| REG_N_CALLS_CROSSED (i)++; |
| }); |
| |
| /* LIVE gets the regs used in INSN; |
| DEAD gets those set by it. Dead insns don't make anything |
| live. */ |
| |
| mark_set_regs (old, dead, PATTERN (insn), |
| final ? insn : NULL_RTX, significant); |
| |
| /* If an insn doesn't use CC0, it becomes dead since we |
| assume that every insn clobbers it. So show it dead here; |
| mark_used_regs will set it live if it is referenced. */ |
| cc0_live = 0; |
| |
| if (! insn_is_dead) |
| mark_used_regs (old, live, PATTERN (insn), final, insn); |
| |
| /* Sometimes we may have inserted something before INSN (such as |
| a move) when we make an auto-inc. So ensure we will scan |
| those insns. */ |
| #ifdef AUTO_INC_DEC |
| prev = PREV_INSN (insn); |
| #endif |
| |
| if (! insn_is_dead && GET_CODE (insn) == CALL_INSN) |
| { |
| register int i; |
| |
| rtx note; |
| |
| for (note = CALL_INSN_FUNCTION_USAGE (insn); |
| note; |
| note = XEXP (note, 1)) |
| if (GET_CODE (XEXP (note, 0)) == USE) |
| mark_used_regs (old, live, SET_DEST (XEXP (note, 0)), |
| final, insn); |
| |
| /* Each call clobbers all call-clobbered regs that are not |
| global or fixed. Note that the function-value reg is a |
| call-clobbered reg, and mark_set_regs has already had |
| a chance to handle it. */ |
| |
| for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
| if (call_used_regs[i] && ! global_regs[i] |
| && ! fixed_regs[i]) |
| SET_REGNO_REG_SET (dead, i); |
| |
| /* The stack ptr is used (honorarily) by a CALL insn. */ |
| SET_REGNO_REG_SET (live, STACK_POINTER_REGNUM); |
| |
| /* Calls may also reference any of the global registers, |
| so they are made live. */ |
| for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
| if (global_regs[i]) |
| mark_used_regs (old, live, |
| gen_rtx_REG (reg_raw_mode[i], i), |
| final, insn); |
| |
| /* Calls also clobber memory. */ |
| mem_set_list = NULL_RTX; |
| } |
| |
| /* Update OLD for the registers used or set. */ |
| AND_COMPL_REG_SET (old, dead); |
| IOR_REG_SET (old, live); |
| |
| } |
| |
| /* On final pass, update counts of how many insns each reg is live |
| at. */ |
| if (final) |
| EXECUTE_IF_SET_IN_REG_SET (old, 0, i, |
| { REG_LIVE_LENGTH (i)++; }); |
| } |
| flushed: ; |
| if (insn == first) |
| break; |
| } |
| |
| FREE_REG_SET (dead); |
| FREE_REG_SET (live); |
| } |
| |
| /* Return 1 if X (the body of an insn, or part of it) is just dead stores |
| (SET expressions whose destinations are registers dead after the insn). |
| NEEDED is the regset that says which regs are alive after the insn. |
| |
| Unless CALL_OK is non-zero, an insn is needed if it contains a CALL. |
| |
| If X is the entire body of an insn, NOTES contains the reg notes |
| pertaining to the insn. */ |
| |
| static int |
| insn_dead_p (x, needed, call_ok, notes) |
| rtx x; |
| regset needed; |
| int call_ok; |
| rtx notes ATTRIBUTE_UNUSED; |
| { |
| enum rtx_code code = GET_CODE (x); |
| |
| #ifdef AUTO_INC_DEC |
| /* If flow is invoked after reload, we must take existing AUTO_INC |
| expresions into account. */ |
| if (reload_completed) |
| { |
| for ( ; notes; notes = XEXP (notes, 1)) |
| { |
| if (REG_NOTE_KIND (notes) == REG_INC) |
| { |
| int regno = REGNO (XEXP (notes, 0)); |
| |
| /* Don't delete insns to set global regs. */ |
| if ((regno < FIRST_PSEUDO_REGISTER && global_regs[regno]) |
| || REGNO_REG_SET_P (needed, regno)) |
| return 0; |
| } |
| } |
| } |
| #endif |
| |
| /* If setting something that's a reg or part of one, |
| see if that register's altered value will be live. */ |
| |
| if (code == SET) |
| { |
| rtx r = SET_DEST (x); |
| |
| /* A SET that is a subroutine call cannot be dead. */ |
| if (! call_ok && GET_CODE (SET_SRC (x)) == CALL) |
| return 0; |
| |
| #ifdef HAVE_cc0 |
| if (GET_CODE (r) == CC0) |
| return ! cc0_live; |
| #endif |
| |
| if (GET_CODE (r) == MEM && ! MEM_VOLATILE_P (r)) |
| { |
| rtx temp; |
| /* Walk the set of memory locations we are currently tracking |
| and see if one is an identical match to this memory location. |
| If so, this memory write is dead (remember, we're walking |
| backwards from the end of the block to the start. */ |
| temp = mem_set_list; |
| while (temp) |
| { |
| if (rtx_equal_p (XEXP (temp, 0), r)) |
| return 1; |
| temp = XEXP (temp, 1); |
| } |
| } |
| |
| while (GET_CODE (r) == SUBREG || GET_CODE (r) == STRICT_LOW_PART |
| || GET_CODE (r) == ZERO_EXTRACT) |
| r = SUBREG_REG (r); |
| |
| if (GET_CODE (r) == REG) |
| { |
| int regno = REGNO (r); |
| |
| /* Don't delete insns to set global regs. */ |
| if ((regno < FIRST_PSEUDO_REGISTER && global_regs[regno]) |
| /* Make sure insns to set frame pointer aren't deleted. */ |
| || (regno == FRAME_POINTER_REGNUM |
| && (! reload_completed || frame_pointer_needed)) |
| #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM |
| || (regno == HARD_FRAME_POINTER_REGNUM |
| && (! reload_completed || frame_pointer_needed)) |
| #endif |
| #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM |
| /* Make sure insns to set arg pointer are never deleted |
| (if the arg pointer isn't fixed, there will be a USE for |
| it, so we can treat it normally). */ |
| || (regno == ARG_POINTER_REGNUM && fixed_regs[regno]) |
| #endif |
| || REGNO_REG_SET_P (needed, regno)) |
| return 0; |
| |
| /* If this is a hard register, verify that subsequent words are |
| not needed. */ |
| if (regno < FIRST_PSEUDO_REGISTER) |
| { |
| int n = HARD_REGNO_NREGS (regno, GET_MODE (r)); |
| |
| while (--n > 0) |
| if (REGNO_REG_SET_P (needed, regno+n)) |
| return 0; |
| } |
| |
| return 1; |
| } |
| } |
| |
| /* If performing several activities, |
| insn is dead if each activity is individually dead. |
| Also, CLOBBERs and USEs can be ignored; a CLOBBER or USE |
| that's inside a PARALLEL doesn't make the insn worth keeping. */ |
| else if (code == PARALLEL) |
| { |
| int i = XVECLEN (x, 0); |
| |
| for (i--; i >= 0; i--) |
| if (GET_CODE (XVECEXP (x, 0, i)) != CLOBBER |
| && GET_CODE (XVECEXP (x, 0, i)) != USE |
| && ! insn_dead_p (XVECEXP (x, 0, i), needed, call_ok, NULL_RTX)) |
| return 0; |
| |
| return 1; |
| } |
| |
| /* A CLOBBER of a pseudo-register that is dead serves no purpose. That |
| is not necessarily true for hard registers. */ |
| else if (code == CLOBBER && GET_CODE (XEXP (x, 0)) == REG |
| && REGNO (XEXP (x, 0)) >= FIRST_PSEUDO_REGISTER |
| && ! REGNO_REG_SET_P (needed, REGNO (XEXP (x, 0)))) |
| return 1; |
| |
| /* We do not check other CLOBBER or USE here. An insn consisting of just |
| a CLOBBER or just a USE should not be deleted. */ |
| return 0; |
| } |
| |
| /* If X is the pattern of the last insn in a libcall, and assuming X is dead, |
| return 1 if the entire library call is dead. |
| This is true if X copies a register (hard or pseudo) |
| and if the hard return reg of the call insn is dead. |
| (The caller should have tested the destination of X already for death.) |
| |
| If this insn doesn't just copy a register, then we don't |
| have an ordinary libcall. In that case, cse could not have |
| managed to substitute the source for the dest later on, |
| so we can assume the libcall is dead. |
| |
| NEEDED is the bit vector of pseudoregs live before this insn. |
| NOTE is the REG_RETVAL note of the insn. INSN is the insn itself. */ |
| |
| static int |
| libcall_dead_p (x, needed, note, insn) |
| rtx x; |
| regset needed; |
| rtx note; |
| rtx insn; |
| { |
| register RTX_CODE code = GET_CODE (x); |
| |
| if (code == SET) |
| { |
| register rtx r = SET_SRC (x); |
| if (GET_CODE (r) == REG) |
| { |
| rtx call = XEXP (note, 0); |
| rtx call_pat; |
| register int i; |
| |
| /* Find the call insn. */ |
| while (call != insn && GET_CODE (call) != CALL_INSN) |
| call = NEXT_INSN (call); |
| |
| /* If there is none, do nothing special, |
| since ordinary death handling can understand these insns. */ |
| if (call == insn) |
| return 0; |
| |
| /* See if the hard reg holding the value is dead. |
| If this is a PARALLEL, find the call within it. */ |
| call_pat = PATTERN (call); |
| if (GET_CODE (call_pat) == PARALLEL) |
| { |
| for (i = XVECLEN (call_pat, 0) - 1; i >= 0; i--) |
| if (GET_CODE (XVECEXP (call_pat, 0, i)) == SET |
| && GET_CODE (SET_SRC (XVECEXP (call_pat, 0, i))) == CALL) |
| break; |
| |
| /* This may be a library call that is returning a value |
| via invisible pointer. Do nothing special, since |
| ordinary death handling can understand these insns. */ |
| if (i < 0) |
| return 0; |
| |
| call_pat = XVECEXP (call_pat, 0, i); |
| } |
| |
| return insn_dead_p (call_pat, needed, 1, REG_NOTES (call)); |
| } |
| } |
| return 1; |
| } |
| |
| /* Return 1 if register REGNO was used before it was set, i.e. if it is |
| live at function entry. Don't count global register variables, variables |
| in registers that can be used for function arg passing, or variables in |
| fixed hard registers. */ |
| |
| int |
| regno_uninitialized (regno) |
| int regno; |
| { |
| if (n_basic_blocks == 0 |
| || (regno < FIRST_PSEUDO_REGISTER |
| && (global_regs[regno] |
| || fixed_regs[regno] |
| || FUNCTION_ARG_REGNO_P (regno)))) |
| return 0; |
| |
| return REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno); |
| } |
| |
| /* 1 if register REGNO was alive at a place where `setjmp' was called |
| and was set more than once or is an argument. |
| Such regs may be clobbered by `longjmp'. */ |
| |
| int |
| regno_clobbered_at_setjmp (regno) |
| int regno; |
| { |
| if (n_basic_blocks == 0) |
| return 0; |
| |
| return ((REG_N_SETS (regno) > 1 |
| || REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno)) |
| && REGNO_REG_SET_P (regs_live_at_setjmp, regno)); |
| } |
| |
| /* INSN references memory, possibly using autoincrement addressing modes. |
| Find any entries on the mem_set_list that need to be invalidated due |
| to an address change. */ |
| static void |
| invalidate_mems_from_autoinc (insn) |
| rtx insn; |
| { |
| rtx note = REG_NOTES (insn); |
| for (note = REG_NOTES (insn); note; note = XEXP (note, 1)) |
| { |
| if (REG_NOTE_KIND (note) == REG_INC) |
| { |
| rtx temp = mem_set_list; |
| rtx prev = NULL_RTX; |
| |
| while (temp) |
| { |
| if (reg_overlap_mentioned_p (XEXP (note, 0), XEXP (temp, 0))) |
| { |
| /* Splice temp out of list. */ |
| if (prev) |
| XEXP (prev, 1) = XEXP (temp, 1); |
| else |
| mem_set_list = XEXP (temp, 1); |
| } |
| else |
| prev = temp; |
| temp = XEXP (temp, 1); |
| } |
| } |
| } |
| } |
| |
| /* Process the registers that are set within X. |
| Their bits are set to 1 in the regset DEAD, |
| because they are dead prior to this insn. |
| |
| If INSN is nonzero, it is the insn being processed |
| and the fact that it is nonzero implies this is the FINAL pass |
| in propagate_block. In this case, various info about register |
| usage is stored, LOG_LINKS fields of insns are set up. */ |
| |
| static void |
| mark_set_regs (needed, dead, x, insn, significant) |
| regset needed; |
| regset dead; |
| rtx x; |
| rtx insn; |
| regset significant; |
| { |
| register RTX_CODE code = GET_CODE (x); |
| |
| if (code == SET || code == CLOBBER) |
| mark_set_1 (needed, dead, x, insn, significant); |
| else if (code == PARALLEL) |
| { |
| register int i; |
| for (i = XVECLEN (x, 0) - 1; i >= 0; i--) |
| { |
| code = GET_CODE (XVECEXP (x, 0, i)); |
| if (code == SET || code == CLOBBER) |
| mark_set_1 (needed, dead, XVECEXP (x, 0, i), insn, significant); |
| } |
| } |
| } |
| |
| /* Process a single SET rtx, X. */ |
| |
| static void |
| mark_set_1 (needed, dead, x, insn, significant) |
| regset needed; |
| regset dead; |
| rtx x; |
| rtx insn; |
| regset significant; |
| { |
| register int regno; |
| register rtx reg = SET_DEST (x); |
| |
| /* Some targets place small structures in registers for |
| return values of functions. We have to detect this |
| case specially here to get correct flow information. */ |
| if (GET_CODE (reg) == PARALLEL |
| && GET_MODE (reg) == BLKmode) |
| { |
| register int i; |
| |
| for (i = XVECLEN (reg, 0) - 1; i >= 0; i--) |
| mark_set_1 (needed, dead, XVECEXP (reg, 0, i), insn, significant); |
| return; |
| } |
| |
| /* Modifying just one hardware register of a multi-reg value |
| or just a byte field of a register |
| does not mean the value from before this insn is now dead. |
| But it does mean liveness of that register at the end of the block |
| is significant. |
| |
| Within mark_set_1, however, we treat it as if the register is |
| indeed modified. mark_used_regs will, however, also treat this |
| register as being used. Thus, we treat these insns as setting a |
| new value for the register as a function of its old value. This |
| cases LOG_LINKS to be made appropriately and this will help combine. */ |
| |
| while (GET_CODE (reg) == SUBREG || GET_CODE (reg) == ZERO_EXTRACT |
| || GET_CODE (reg) == SIGN_EXTRACT |
| || GET_CODE (reg) == STRICT_LOW_PART) |
| reg = XEXP (reg, 0); |
| |
| /* If this set is a MEM, then it kills any aliased writes. |
| If this set is a REG, then it kills any MEMs which use the reg. */ |
| if (GET_CODE (reg) == MEM |
| || GET_CODE (reg) == REG) |
| { |
| rtx temp = mem_set_list; |
| rtx prev = NULL_RTX; |
| |
| while (temp) |
| { |
| if ((GET_CODE (reg) == MEM |
| && output_dependence (XEXP (temp, 0), reg)) |
| || (GET_CODE (reg) == REG |
| && reg_overlap_mentioned_p (reg, XEXP (temp, 0)))) |
| { |
| /* Splice this entry out of the list. */ |
| if (prev) |
| XEXP (prev, 1) = XEXP (temp, 1); |
| else |
| mem_set_list = XEXP (temp, 1); |
| } |
| else |
| prev = temp; |
| temp = XEXP (temp, 1); |
| } |
| } |
| |
| /* If the memory reference had embedded side effects (autoincrement |
| address modes. Then we may need to kill some entries on the |
| memory set list. */ |
| if (insn && GET_CODE (reg) == MEM) |
| invalidate_mems_from_autoinc (insn); |
| |
| if (GET_CODE (reg) == MEM && ! side_effects_p (reg) |
| /* We do not know the size of a BLKmode store, so we do not track |
| them for redundant store elimination. */ |
| && GET_MODE (reg) != BLKmode |
| /* There are no REG_INC notes for SP, so we can't assume we'll see |
| everything that invalidates it. To be safe, don't eliminate any |
| stores though SP; none of them should be redundant anyway. */ |
| && ! reg_mentioned_p (stack_pointer_rtx, reg)) |
| mem_set_list = gen_rtx_EXPR_LIST (VOIDmode, reg, mem_set_list); |
| |
| if (GET_CODE (reg) == REG |
| && (regno = REGNO (reg), ! (regno == FRAME_POINTER_REGNUM |
| && (! reload_completed || frame_pointer_needed))) |
| #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM |
| && ! (regno == HARD_FRAME_POINTER_REGNUM |
| && (! reload_completed || frame_pointer_needed)) |
| #endif |
| #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM |
| && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno]) |
| #endif |
| && ! (regno < FIRST_PSEUDO_REGISTER && global_regs[regno])) |
| /* && regno != STACK_POINTER_REGNUM) -- let's try without this. */ |
| { |
| int some_needed = REGNO_REG_SET_P (needed, regno); |
| int some_not_needed = ! some_needed; |
| |
| /* Mark it as a significant register for this basic block. */ |
| if (significant) |
| SET_REGNO_REG_SET (significant, regno); |
| |
| /* Mark it as dead before this insn. */ |
| SET_REGNO_REG_SET (dead, regno); |
| |
| /* A hard reg in a wide mode may really be multiple registers. |
| If so, mark all of them just like the first. */ |
| if (regno < FIRST_PSEUDO_REGISTER) |
| { |
| int n; |
| |
| /* Nothing below is needed for the stack pointer; get out asap. |
| Eg, log links aren't needed, since combine won't use them. */ |
| if (regno == STACK_POINTER_REGNUM) |
| return; |
| |
| n = HARD_REGNO_NREGS (regno, GET_MODE (reg)); |
| while (--n > 0) |
| { |
| int regno_n = regno + n; |
| int needed_regno = REGNO_REG_SET_P (needed, regno_n); |
| if (significant) |
| SET_REGNO_REG_SET (significant, regno_n); |
| |
| SET_REGNO_REG_SET (dead, regno_n); |
| some_needed |= needed_regno; |
| some_not_needed |= ! needed_regno; |
| } |
| } |
| /* Additional data to record if this is the final pass. */ |
| if (insn) |
| { |
| register rtx y = reg_next_use[regno]; |
| register int blocknum = BLOCK_NUM (insn); |
| |
| /* If this is a hard reg, record this function uses the reg. */ |
| |
| if (regno < FIRST_PSEUDO_REGISTER) |
| { |
| register int i; |
| int endregno = regno + HARD_REGNO_NREGS (regno, GET_MODE (reg)); |
| |
| for (i = regno; i < endregno; i++) |
| { |
| /* The next use is no longer "next", since a store |
| intervenes. */ |
| reg_next_use[i] = 0; |
| |
| regs_ever_live[i] = 1; |
| REG_N_SETS (i)++; |
| } |
| } |
| else |
| { |
| /* The next use is no longer "next", since a store |
| intervenes. */ |
| reg_next_use[regno] = 0; |
| |
| /* Keep track of which basic blocks each reg appears in. */ |
| |
| if (REG_BASIC_BLOCK (regno) == REG_BLOCK_UNKNOWN) |
| REG_BASIC_BLOCK (regno) = blocknum; |
| else if (REG_BASIC_BLOCK (regno) != blocknum) |
| REG_BASIC_BLOCK (regno) = REG_BLOCK_GLOBAL; |
| |
| /* Count (weighted) references, stores, etc. This counts a |
| register twice if it is modified, but that is correct. */ |
| REG_N_SETS (regno)++; |
| |
| REG_N_REFS (regno) += loop_depth; |
| |
| /* The insns where a reg is live are normally counted |
| elsewhere, but we want the count to include the insn |
| where the reg is set, and the normal counting mechanism |
| would not count it. */ |
| REG_LIVE_LENGTH (regno)++; |
| } |
| |
| if (! some_not_needed) |
| { |
| /* Make a logical link from the next following insn |
| that uses this register, back to this insn. |
| The following insns have already been processed. |
| |
| We don't build a LOG_LINK for hard registers containing |
| in ASM_OPERANDs. If these registers get replaced, |
| we might wind up changing the semantics of the insn, |
| even if reload can make what appear to be valid assignments |
| later. */ |
| if (y && (BLOCK_NUM (y) == blocknum) |
| && (regno >= FIRST_PSEUDO_REGISTER |
| || asm_noperands (PATTERN (y)) < 0)) |
| LOG_LINKS (y) |
| = gen_rtx_INSN_LIST (VOIDmode, insn, LOG_LINKS (y)); |
| } |
| else if (! some_needed) |
| { |
| /* Note that dead stores have already been deleted when possible |
| If we get here, we have found a dead store that cannot |
| be eliminated (because the same insn does something useful). |
| Indicate this by marking the reg being set as dying here. */ |
| REG_NOTES (insn) |
| = gen_rtx_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn)); |
| REG_N_DEATHS (REGNO (reg))++; |
| } |
| else |
| { |
| /* This is a case where we have a multi-word hard register |
| and some, but not all, of the words of the register are |
| needed in subsequent insns. Write REG_UNUSED notes |
| for those parts that were not needed. This case should |
| be rare. */ |
| |
| int i; |
| |
| for (i = HARD_REGNO_NREGS (regno, GET_MODE (reg)) - 1; |
| i >= 0; i--) |
| if (!REGNO_REG_SET_P (needed, regno + i)) |
| REG_NOTES (insn) |
| = gen_rtx_EXPR_LIST (REG_UNUSED, |
| gen_rtx_REG (reg_raw_mode[regno + i], |
| regno + i), |
| REG_NOTES (insn)); |
| } |
| } |
| } |
| else if (GET_CODE (reg) == REG) |
| reg_next_use[regno] = 0; |
| |
| /* If this is the last pass and this is a SCRATCH, show it will be dying |
| here and count it. */ |
| else if (GET_CODE (reg) == SCRATCH && insn != 0) |
| { |
| REG_NOTES (insn) |
| = gen_rtx_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn)); |
| } |
| } |
| |
| #ifdef AUTO_INC_DEC |
| |
| /* X is a MEM found in INSN. See if we can convert it into an auto-increment |
| reference. */ |
| |
| static void |
| find_auto_inc (needed, x, insn) |
| regset needed; |
| rtx x; |
| rtx insn; |
| { |
| rtx addr = XEXP (x, 0); |
| HOST_WIDE_INT offset = 0; |
| rtx set; |
| |
| /* Here we detect use of an index register which might be good for |
| postincrement, postdecrement, preincrement, or predecrement. */ |
| |
| if (GET_CODE (addr) == PLUS && GET_CODE (XEXP (addr, 1)) == CONST_INT) |
| offset = INTVAL (XEXP (addr, 1)), addr = XEXP (addr, 0); |
| |
| if (GET_CODE (addr) == REG) |
| { |
| register rtx y; |
| register int size = GET_MODE_SIZE (GET_MODE (x)); |
| rtx use; |
| rtx incr; |
| int regno = REGNO (addr); |
| |
| /* Is the next use an increment that might make auto-increment? */ |
| if ((incr = reg_next_use[regno]) != 0 |
| && (set = single_set (incr)) != 0 |
| && GET_CODE (set) == SET |
| && BLOCK_NUM (incr) == BLOCK_NUM (insn) |
| /* Can't add side effects to jumps; if reg is spilled and |
| reloaded, there's no way to store back the altered value. */ |
| && GET_CODE (insn) != JUMP_INSN |
| && (y = SET_SRC (set), GET_CODE (y) == PLUS) |
| && XEXP (y, 0) == addr |
| && GET_CODE (XEXP (y, 1)) == CONST_INT |
| && ((HAVE_POST_INCREMENT |
| && (INTVAL (XEXP (y, 1)) == size && offset == 0)) |
| || (HAVE_POST_DECREMENT |
| && (INTVAL (XEXP (y, 1)) == - size && offset == 0)) |
| || (HAVE_PRE_INCREMENT |
| && (INTVAL (XEXP (y, 1)) == size && offset == size)) |
| || (HAVE_PRE_DECREMENT |
| && (INTVAL (XEXP (y, 1)) == - size && offset == - size))) |
| /* Make sure this reg appears only once in this insn. */ |
| && (use = find_use_as_address (PATTERN (insn), addr, offset), |
| use != 0 && use != (rtx) 1)) |
| { |
| rtx q = SET_DEST (set); |
| enum rtx_code inc_code = (INTVAL (XEXP (y, 1)) == size |
| ? (offset ? PRE_INC : POST_INC) |
| : (offset ? PRE_DEC : POST_DEC)); |
| |
| if (dead_or_set_p (incr, addr)) |
| { |
| /* This is the simple case. Try to make the auto-inc. If |
| we can't, we are done. Otherwise, we will do any |
| needed updates below. */ |
| if (! validate_change (insn, &XEXP (x, 0), |
| gen_rtx_fmt_e (inc_code, Pmode, addr), |
| 0)) |
| return; |
| } |
| else if (GET_CODE (q) == REG |
| /* PREV_INSN used here to check the semi-open interval |
| [insn,incr). */ |
| && ! reg_used_between_p (q, PREV_INSN (insn), incr) |
| /* We must also check for sets of q as q may be |
| a call clobbered hard register and there may |
| be a call between PREV_INSN (insn) and incr. */ |
| && ! reg_set_between_p (q, PREV_INSN (insn), incr)) |
| { |
| /* We have *p followed sometime later by q = p+size. |
| Both p and q must be live afterward, |
| and q is not used between INSN and its assignment. |
| Change it to q = p, ...*q..., q = q+size. |
| Then fall into the usual case. */ |
| rtx insns, temp; |
| basic_block bb; |
| |
| start_sequence (); |
| emit_move_insn (q, addr); |
| insns = get_insns (); |
| end_sequence (); |
| |
| bb = BLOCK_FOR_INSN (insn); |
| for (temp = insns; temp; temp = NEXT_INSN (temp)) |
| set_block_for_insn (temp, bb); |
| |
| /* If we can't make the auto-inc, or can't make the |
| replacement into Y, exit. There's no point in making |
| the change below if we can't do the auto-inc and doing |
| so is not correct in the pre-inc case. */ |
| |
| validate_change (insn, &XEXP (x, 0), |
| gen_rtx_fmt_e (inc_code, Pmode, q), |
| 1); |
| validate_change (incr, &XEXP (y, 0), q, 1); |
| if (! apply_change_group ()) |
| return; |
| |
| /* We now know we'll be doing this change, so emit the |
| new insn(s) and do the updates. */ |
| emit_insns_before (insns, insn); |
| |
| if (BLOCK_FOR_INSN (insn)->head == insn) |
| BLOCK_FOR_INSN (insn)->head = insns; |
| |
| /* INCR will become a NOTE and INSN won't contain a |
| use of ADDR. If a use of ADDR was just placed in |
| the insn before INSN, make that the next use. |
| Otherwise, invalidate it. */ |
| if (GET_CODE (PREV_INSN (insn)) == INSN |
| && GET_CODE (PATTERN (PREV_INSN (insn))) == SET |
| && SET_SRC (PATTERN (PREV_INSN (insn))) == addr) |
| reg_next_use[regno] = PREV_INSN (insn); |
| else |
| reg_next_use[regno] = 0; |
| |
| addr = q; |
| regno = REGNO (q); |
| |
| /* REGNO is now used in INCR which is below INSN, but |
| it previously wasn't live here. If we don't mark |
| it as needed, we'll put a REG_DEAD note for it |
| on this insn, which is incorrect. */ |
| SET_REGNO_REG_SET (needed, regno); |
| |
| /* If there are any calls between INSN and INCR, show |
| that REGNO now crosses them. */ |
| for (temp = insn; temp != incr; temp = NEXT_INSN (temp)) |
| if (GET_CODE (temp) == CALL_INSN) |
| REG_N_CALLS_CROSSED (regno)++; |
| } |
| else |
| return; |
| |
| /* If we haven't returned, it means we were able to make the |
| auto-inc, so update the status. First, record that this insn |
| has an implicit side effect. */ |
| |
| REG_NOTES (insn) |
| = gen_rtx_EXPR_LIST (REG_INC, addr, REG_NOTES (insn)); |
| |
| /* Modify the old increment-insn to simply copy |
| the already-incremented value of our register. */ |
| if (! validate_change (incr, &SET_SRC (set), addr, 0)) |
| abort (); |
| |
| /* If that makes it a no-op (copying the register into itself) delete |
| it so it won't appear to be a "use" and a "set" of this |
| register. */ |
| if (SET_DEST (set) == addr) |
| { |
| PUT_CODE (incr, NOTE); |
| NOTE_LINE_NUMBER (incr) = NOTE_INSN_DELETED; |
| NOTE_SOURCE_FILE (incr) = 0; |
| } |
| |
| if (regno >= FIRST_PSEUDO_REGISTER) |
| { |
| /* Count an extra reference to the reg. When a reg is |
| incremented, spilling it is worse, so we want to make |
| that less likely. */ |
| REG_N_REFS (regno) += loop_depth; |
| |
| /* Count the increment as a setting of the register, |
| even though it isn't a SET in rtl. */ |
| REG_N_SETS (regno)++; |
| } |
| } |
| } |
| } |
| #endif /* AUTO_INC_DEC */ |
| |
| /* Scan expression X and store a 1-bit in LIVE for each reg it uses. |
| This is done assuming the registers needed from X |
| are those that have 1-bits in NEEDED. |
| |
| On the final pass, FINAL is 1. This means try for autoincrement |
| and count the uses and deaths of each pseudo-reg. |
| |
| INSN is the containing instruction. If INSN is dead, this function is not |
| called. */ |
| |
| static void |
| mark_used_regs (needed, live, x, final, insn) |
| regset needed; |
| regset live; |
| rtx x; |
| int final; |
| rtx insn; |
| { |
| register RTX_CODE code; |
| register int regno; |
| int i; |
| |
| retry: |
| code = GET_CODE (x); |
| switch (code) |
| { |
| case LABEL_REF: |
| case SYMBOL_REF: |
| case CONST_INT: |
| case CONST: |
| case CONST_DOUBLE: |
| case PC: |
| case ADDR_VEC: |
| case ADDR_DIFF_VEC: |
| return; |
| |
| #ifdef HAVE_cc0 |
| case CC0: |
| cc0_live = 1; |
| return; |
| #endif |
| |
| case CLOBBER: |
| /* If we are clobbering a MEM, mark any registers inside the address |
| as being used. */ |
| if (GET_CODE (XEXP (x, 0)) == MEM) |
| mark_used_regs (needed, live, XEXP (XEXP (x, 0), 0), final, insn); |
| return; |
| |
| case MEM: |
| /* Invalidate the data for the last MEM stored, but only if MEM is |
| something that can be stored into. */ |
| if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF |
| && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0))) |
| ; /* needn't clear the memory set list */ |
| else |
| { |
| rtx temp = mem_set_list; |
| rtx prev = NULL_RTX; |
| |
| while (temp) |
| { |
| if (anti_dependence (XEXP (temp, 0), x)) |
| { |
| /* Splice temp out of the list. */ |
| if (prev) |
| XEXP (prev, 1) = XEXP (temp, 1); |
| else |
| mem_set_list = XEXP (temp, 1); |
| } |
| else |
| prev = temp; |
| temp = XEXP (temp, 1); |
| } |
| } |
| |
| /* If the memory reference had embedded side effects (autoincrement |
| address modes. Then we may need to kill some entries on the |
| memory set list. */ |
| if (insn) |
| invalidate_mems_from_autoinc (insn); |
| |
| #ifdef AUTO_INC_DEC |
| if (final) |
| find_auto_inc (needed, x, insn); |
| #endif |
| break; |
| |
| case SUBREG: |
| if (GET_CODE (SUBREG_REG (x)) == REG |
| && REGNO (SUBREG_REG (x)) >= FIRST_PSEUDO_REGISTER |
| && (GET_MODE_SIZE (GET_MODE (x)) |
| != GET_MODE_SIZE (GET_MODE (SUBREG_REG (x))))) |
| REG_CHANGES_SIZE (REGNO (SUBREG_REG (x))) = 1; |
| |
| /* While we're here, optimize this case. */ |
| x = SUBREG_REG (x); |
| |
| /* In case the SUBREG is not of a register, don't optimize */ |
| if (GET_CODE (x) != REG) |
| { |
| mark_used_regs (needed, live, x, final, insn); |
| return; |
| } |
| |
| /* ... fall through ... */ |
| |
| case REG: |
| /* See a register other than being set |
| => mark it as needed. */ |
| |
| regno = REGNO (x); |
| { |
| int some_needed = REGNO_REG_SET_P (needed, regno); |
| int some_not_needed = ! some_needed; |
| |
| SET_REGNO_REG_SET (live, regno); |
| |
| /* A hard reg in a wide mode may really be multiple registers. |
| If so, mark all of them just like the first. */ |
| if (regno < FIRST_PSEUDO_REGISTER) |
| { |
| int n; |
| |
| /* For stack ptr or fixed arg pointer, |
| nothing below can be necessary, so waste no more time. */ |
| if (regno == STACK_POINTER_REGNUM |
| #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM |
| || (regno == HARD_FRAME_POINTER_REGNUM |
| && (! reload_completed || frame_pointer_needed)) |
| #endif |
| #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM |
| || (regno == ARG_POINTER_REGNUM && fixed_regs[regno]) |
| #endif |
| || (regno == FRAME_POINTER_REGNUM |
| && (! reload_completed || frame_pointer_needed))) |
| { |
| /* If this is a register we are going to try to eliminate, |
| don't mark it live here. If we are successful in |
| eliminating it, it need not be live unless it is used for |
| pseudos, in which case it will have been set live when |
| it was allocated to the pseudos. If the register will not |
| be eliminated, reload will set it live at that point. */ |
| |
| if (! TEST_HARD_REG_BIT (elim_reg_set, regno)) |
| regs_ever_live[regno] = 1; |
| return; |
| } |
| /* No death notes for global register variables; |
| their values are live after this function exits. */ |
| if (global_regs[regno]) |
| { |
| if (final) |
| reg_next_use[regno] = insn; |
| return; |
| } |
| |
| n = HARD_REGNO_NREGS (regno, GET_MODE (x)); |
| while (--n > 0) |
| { |
| int regno_n = regno + n; |
| int needed_regno = REGNO_REG_SET_P (needed, regno_n); |
| |
| SET_REGNO_REG_SET (live, regno_n); |
| some_needed |= needed_regno; |
| some_not_needed |= ! needed_regno; |
| } |
| } |
| if (final) |
| { |
| /* Record where each reg is used, so when the reg |
| is set we know the next insn that uses it. */ |
| |
| reg_next_use[regno] = insn; |
| |
| if (regno < FIRST_PSEUDO_REGISTER) |
| { |
| /* If a hard reg is being used, |
| record that this function does use it. */ |
| |
| i = HARD_REGNO_NREGS (regno, GET_MODE (x)); |
| if (i == 0) |
| i = 1; |
| do |
| regs_ever_live[regno + --i] = 1; |
| while (i > 0); |
| } |
| else |
| { |
| /* Keep track of which basic block each reg appears in. */ |
| |
| register int blocknum = BLOCK_NUM (insn); |
| |
| if (REG_BASIC_BLOCK (regno) == REG_BLOCK_UNKNOWN) |
| REG_BASIC_BLOCK (regno) = blocknum; |
| else if (REG_BASIC_BLOCK (regno) != blocknum) |
| REG_BASIC_BLOCK (regno) = REG_BLOCK_GLOBAL; |
| |
| /* Count (weighted) number of uses of each reg. */ |
| |
| REG_N_REFS (regno) += loop_depth; |
| } |
| |
| /* Record and count the insns in which a reg dies. |
| If it is used in this insn and was dead below the insn |
| then it dies in this insn. If it was set in this insn, |
| we do not make a REG_DEAD note; likewise if we already |
| made such a note. */ |
| |
| if (some_not_needed |
| && ! dead_or_set_p (insn, x) |
| #if 0 |
| && (regno >= FIRST_PSEUDO_REGISTER || ! fixed_regs[regno]) |
| #endif |
| ) |
| { |
| /* Check for the case where the register dying partially |
| overlaps the register set by this insn. */ |
| if (regno < FIRST_PSEUDO_REGISTER |
| && HARD_REGNO_NREGS (regno, GET_MODE (x)) > 1) |
| { |
| int n = HARD_REGNO_NREGS (regno, GET_MODE (x)); |
| while (--n >= 0) |
| some_needed |= dead_or_set_regno_p (insn, regno + n); |
| } |
| |
| /* If none of the words in X is needed, make a REG_DEAD |
| note. Otherwise, we must make partial REG_DEAD notes. */ |
| if (! some_needed) |
| { |
| REG_NOTES (insn) |
| = gen_rtx_EXPR_LIST (REG_DEAD, x, REG_NOTES (insn)); |
| REG_N_DEATHS (regno)++; |
| } |
| else |
| { |
| int i; |
| |
| /* Don't make a REG_DEAD note for a part of a register |
| that is set in the insn. */ |
| |
| for (i = HARD_REGNO_NREGS (regno, GET_MODE (x)) - 1; |
| i >= 0; i--) |
| if (!REGNO_REG_SET_P (needed, regno + i) |
| && ! dead_or_set_regno_p (insn, regno + i)) |
| REG_NOTES (insn) |
| = gen_rtx_EXPR_LIST (REG_DEAD, |
| gen_rtx_REG (reg_raw_mode[regno + i], |
| regno + i), |
| REG_NOTES (insn)); |
| } |
| } |
| } |
| } |
| return; |
| |
| case SET: |
| { |
| register rtx testreg = SET_DEST (x); |
| int mark_dest = 0; |
| |
| /* If storing into MEM, don't show it as being used. But do |
| show the address as being used. */ |
| if (GET_CODE (testreg) == MEM) |
| { |
| #ifdef AUTO_INC_DEC |
| if (final) |
| find_auto_inc (needed, testreg, insn); |
| #endif |
| mark_used_regs (needed, live, XEXP (testreg, 0), final, insn); |
| mark_used_regs (needed, live, SET_SRC (x), final, insn); |
| return; |
| } |
| |
| /* Storing in STRICT_LOW_PART is like storing in a reg |
| in that this SET might be dead, so ignore it in TESTREG. |
| but in some other ways it is like using the reg. |
| |
| Storing in a SUBREG or a bit field is like storing the entire |
| register in that if the register's value is not used |
| then this SET is not needed. */ |
| while (GET_CODE (testreg) == STRICT_LOW_PART |
| || GET_CODE (testreg) == ZERO_EXTRACT |
| || GET_CODE (testreg) == SIGN_EXTRACT |
| || GET_CODE (testreg) == SUBREG) |
| { |
| if (GET_CODE (testreg) == SUBREG |
| && GET_CODE (SUBREG_REG (testreg)) == REG |
| && REGNO (SUBREG_REG (testreg)) >= FIRST_PSEUDO_REGISTER |
| && (GET_MODE_SIZE (GET_MODE (testreg)) |
| != GET_MODE_SIZE (GET_MODE (SUBREG_REG (testreg))))) |
| REG_CHANGES_SIZE (REGNO (SUBREG_REG (testreg))) = 1; |
| |
| /* Modifying a single register in an alternate mode |
| does not use any of the old value. But these other |
| ways of storing in a register do use the old value. */ |
| if (GET_CODE (testreg) == SUBREG |
| && !(REG_SIZE (SUBREG_REG (testreg)) > REG_SIZE (testreg))) |
| ; |
| else |
| mark_dest = 1; |
| |
| testreg = XEXP (testreg, 0); |
| } |
| |
| /* If this is a store into a register, |
| recursively scan the value being stored. */ |
| |
| if ((GET_CODE (testreg) == PARALLEL |
| && GET_MODE (testreg) == BLKmode) |
| || (GET_CODE (testreg) == REG |
| && (regno = REGNO (testreg), ! (regno == FRAME_POINTER_REGNUM |
| && (! reload_completed || frame_pointer_needed))) |
| #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM |
| && ! (regno == HARD_FRAME_POINTER_REGNUM |
| && (! reload_completed || frame_pointer_needed)) |
| #endif |
| #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM |
| && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno]) |
| #endif |
| )) |
| /* We used to exclude global_regs here, but that seems wrong. |
| Storing in them is like storing in mem. */ |
| { |
| mark_used_regs (needed, live, SET_SRC (x), final, insn); |
| if (mark_dest) |
| mark_used_regs (needed, live, SET_DEST (x), final, insn); |
| return; |
| } |
| } |
| break; |
| |
| case RETURN: |
| /* If exiting needs the right stack value, consider this insn as |
| using the stack pointer. In any event, consider it as using |
| all global registers and all registers used by return. */ |
| if (! EXIT_IGNORE_STACK |
| || (! FRAME_POINTER_REQUIRED |
| && ! current_function_calls_alloca |
| && flag_omit_frame_pointer) |
| || current_function_sp_is_unchanging) |
| SET_REGNO_REG_SET (live, STACK_POINTER_REGNUM); |
| |
| for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
| if (global_regs[i] |
| #ifdef EPILOGUE_USES |
| || EPILOGUE_USES (i) |
| #endif |
| ) |
| SET_REGNO_REG_SET (live, i); |
| break; |
| |
| case ASM_OPERANDS: |
| case UNSPEC_VOLATILE: |
| case TRAP_IF: |
| case ASM_INPUT: |
| { |
| /* Traditional and volatile asm instructions must be considered to use |
| and clobber all hard registers, all pseudo-registers and all of |
| memory. So must TRAP_IF and UNSPEC_VOLATILE operations. |
| |
| Consider for instance a volatile asm that changes the fpu rounding |
| mode. An insn should not be moved across this even if it only uses |
| pseudo-regs because it might give an incorrectly rounded result. |
| |
| ?!? Unfortunately, marking all hard registers as live causes massive |
| problems for the register allocator and marking all pseudos as live |
| creates mountains of uninitialized variable warnings. |
| |
| So for now, just clear the memory set list and mark any regs |
| we can find in ASM_OPERANDS as used. */ |
| if (code != ASM_OPERANDS || MEM_VOLATILE_P (x)) |
| mem_set_list = NULL_RTX; |
| |
| /* For all ASM_OPERANDS, we must traverse the vector of input operands. |
| We can not just fall through here since then we would be confused |
| by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate |
| traditional asms unlike their normal usage. */ |
| if (code == ASM_OPERANDS) |
| { |
| int j; |
| |
| for (j = 0; j < ASM_OPERANDS_INPUT_LENGTH (x); j++) |
| mark_used_regs (needed, live, ASM_OPERANDS_INPUT (x, j), |
| final, insn); |
| } |
| break; |
| } |
| |
| |
| default: |
| break; |
| } |
| |
| /* Recursively scan the operands of this expression. */ |
| |
| { |
| register char *fmt = GET_RTX_FORMAT (code); |
| register int i; |
| |
| for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) |
| { |
| if (fmt[i] == 'e') |
| { |
| /* Tail recursive case: save a function call level. */ |
| if (i == 0) |
| { |
| x = XEXP (x, 0); |
| goto retry; |
| } |
| mark_used_regs (needed, live, XEXP (x, i), final, insn); |
| } |
| else if (fmt[i] == 'E') |
| { |
| register int j; |
| for (j = 0; j < XVECLEN (x, i); j++) |
| mark_used_regs (needed, live, XVECEXP (x, i, j), final, insn); |
| } |
| } |
| } |
| } |
| |
| #ifdef AUTO_INC_DEC |
| |
| static int |
| try_pre_increment_1 (insn) |
| rtx insn; |
| { |
| /* Find the next use of this reg. If in same basic block, |
| make it do pre-increment or pre-decrement if appropriate. */ |
| rtx x = single_set (insn); |
| HOST_WIDE_INT amount = ((GET_CODE (SET_SRC (x)) == PLUS ? 1 : -1) |
| * INTVAL (XEXP (SET_SRC (x), 1))); |
| int regno = REGNO (SET_DEST (x)); |
| rtx y = reg_next_use[regno]; |
| if (y != 0 |
| && BLOCK_NUM (y) == BLOCK_NUM (insn) |
| /* Don't do this if the reg dies, or gets set in y; a standard addressing |
| mode would be better. */ |
| && ! dead_or_set_p (y, SET_DEST (x)) |
| && try_pre_increment (y, SET_DEST (x), amount)) |
| { |
| /* We have found a suitable auto-increment |
| and already changed insn Y to do it. |
| So flush this increment-instruction. */ |
| PUT_CODE (insn, NOTE); |
| NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED; |
| NOTE_SOURCE_FILE (insn) = 0; |
| /* Count a reference to this reg for the increment |
| insn we are deleting. When a reg is incremented. |
| spilling it is worse, so we want to make that |
| less likely. */ |
| if (regno >= FIRST_PSEUDO_REGISTER) |
| { |
| REG_N_REFS (regno) += loop_depth; |
| REG_N_SETS (regno)++; |
| } |
| return 1; |
| } |
| return 0; |
| } |
| |
| /* Try to change INSN so that it does pre-increment or pre-decrement |
| addressing on register REG in order to add AMOUNT to REG. |
| AMOUNT is negative for pre-decrement. |
| Returns 1 if the change could be made. |
| This checks all about the validity of the result of modifying INSN. */ |
| |
| static int |
| try_pre_increment (insn, reg, amount) |
| rtx insn, reg; |
| HOST_WIDE_INT amount; |
| { |
| register rtx use; |
| |
| /* Nonzero if we can try to make a pre-increment or pre-decrement. |
| For example, addl $4,r1; movl (r1),... can become movl +(r1),... */ |
| int pre_ok = 0; |
| /* Nonzero if we can try to make a post-increment or post-decrement. |
| For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,... |
| It is possible for both PRE_OK and POST_OK to be nonzero if the machine |
| supports both pre-inc and post-inc, or both pre-dec and post-dec. */ |
| int post_ok = 0; |
| |
| /* Nonzero if the opportunity actually requires post-inc or post-dec. */ |
| int do_post = 0; |
| |
| /* From the sign of increment, see which possibilities are conceivable |
| on this target machine. */ |
| if (HAVE_PRE_INCREMENT && amount > 0) |
| pre_ok = 1; |
| if (HAVE_POST_INCREMENT && amount > 0) |
| post_ok = 1; |
| |
| if (HAVE_PRE_DECREMENT && amount < 0) |
| pre_ok = 1; |
| if (HAVE_POST_DECREMENT && amount < 0) |
| post_ok = 1; |
| |
| if (! (pre_ok || post_ok)) |
| return 0; |
| |
| /* It is not safe to add a side effect to a jump insn |
| because if the incremented register is spilled and must be reloaded |
| there would be no way to store the incremented value back in memory. */ |
| |
| if (GET_CODE (insn) == JUMP_INSN) |
| return 0; |
| |
| use = 0; |
| if (pre_ok) |
| use = find_use_as_address (PATTERN (insn), reg, 0); |
| if (post_ok && (use == 0 || use == (rtx) 1)) |
| { |
| use = find_use_as_address (PATTERN (insn), reg, -amount); |
| do_post = 1; |
| } |
| |
| if (use == 0 || use == (rtx) 1) |
| return 0; |
| |
| if (GET_MODE_SIZE (GET_MODE (use)) != (amount > 0 ? amount : - amount)) |
| return 0; |
| |
| /* See if this combination of instruction and addressing mode exists. */ |
| if (! validate_change (insn, &XEXP (use, 0), |
| gen_rtx_fmt_e (amount > 0 |
| ? (do_post ? POST_INC : PRE_INC) |
| : (do_post ? POST_DEC : PRE_DEC), |
| Pmode, reg), 0)) |
| return 0; |
| |
| /* Record that this insn now has an implicit side effect on X. */ |
| REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_INC, reg, REG_NOTES (insn)); |
| return 1; |
| } |
| |
| #endif /* AUTO_INC_DEC */ |
| |
| /* Find the place in the rtx X where REG is used as a memory address. |
| Return the MEM rtx that so uses it. |
| If PLUSCONST is nonzero, search instead for a memory address equivalent to |
| (plus REG (const_int PLUSCONST)). |
| |
| If such an address does not appear, return 0. |
| If REG appears more than once, or is used other than in such an address, |
| return (rtx)1. */ |
| |
| rtx |
| find_use_as_address (x, reg, plusconst) |
| register rtx x; |
| rtx reg; |
| HOST_WIDE_INT plusconst; |
| { |
| enum rtx_code code = GET_CODE (x); |
| char *fmt = GET_RTX_FORMAT (code); |
| register int i; |
| register rtx value = 0; |
| register rtx tem; |
| |
| if (code == MEM && XEXP (x, 0) == reg && plusconst == 0) |
| return x; |
| |
| if (code == MEM && GET_CODE (XEXP (x, 0)) == PLUS |
| && XEXP (XEXP (x, 0), 0) == reg |
| && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT |
| && INTVAL (XEXP (XEXP (x, 0), 1)) == plusconst) |
| return x; |
| |
| if (code == SIGN_EXTRACT || code == ZERO_EXTRACT) |
| { |
| /* If REG occurs inside a MEM used in a bit-field reference, |
| that is unacceptable. */ |
| if (find_use_as_address (XEXP (x, 0), reg, 0) != 0) |
| return (rtx) (HOST_WIDE_INT) 1; |
| } |
| |
| if (x == reg) |
| return (rtx) (HOST_WIDE_INT) 1; |
| |
| for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) |
| { |
| if (fmt[i] == 'e') |
| { |
| tem = find_use_as_address (XEXP (x, i), reg, plusconst); |
| if (value == 0) |
| value = tem; |
| else if (tem != 0) |
| return (rtx) (HOST_WIDE_INT) 1; |
| } |
| if (fmt[i] == 'E') |
| { |
| register int j; |
| for (j = XVECLEN (x, i) - 1; j >= 0; j--) |
| { |
| tem = find_use_as_address (XVECEXP (x, i, j), reg, plusconst); |
| if (value == 0) |
| value = tem; |
| else if (tem != 0) |
| return (rtx) (HOST_WIDE_INT) 1; |
| } |
| } |
| } |
| |
| return value; |
| } |
| |
| /* Write information about registers and basic blocks into FILE. |
| This is part of making a debugging dump. */ |
| |
| void |
| dump_flow_info (file) |
| FILE *file; |
| { |
| register int i; |
| static char *reg_class_names[] = REG_CLASS_NAMES; |
| |
| fprintf (file, "%d registers.\n", max_regno); |
| for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++) |
| if (REG_N_REFS (i)) |
| { |
| enum reg_class class, altclass; |
| fprintf (file, "\nRegister %d used %d times across %d insns", |
| i, REG_N_REFS (i), REG_LIVE_LENGTH (i)); |
| if (REG_BASIC_BLOCK (i) >= 0) |
| fprintf (file, " in block %d", REG_BASIC_BLOCK (i)); |
| if (REG_N_SETS (i)) |
| fprintf (file, "; set %d time%s", REG_N_SETS (i), |
| (REG_N_SETS (i) == 1) ? "" : "s"); |
| if (REG_USERVAR_P (regno_reg_rtx[i])) |
| fprintf (file, "; user var"); |
| if (REG_N_DEATHS (i) != 1) |
| fprintf (file, "; dies in %d places", REG_N_DEATHS (i)); |
| if (REG_N_CALLS_CROSSED (i) == 1) |
| fprintf (file, "; crosses 1 call"); |
| else if (REG_N_CALLS_CROSSED (i)) |
| fprintf (file, "; crosses %d calls", REG_N_CALLS_CROSSED (i)); |
| if (PSEUDO_REGNO_BYTES (i) != UNITS_PER_WORD) |
| fprintf (file, "; %d bytes", PSEUDO_REGNO_BYTES (i)); |
| class = reg_preferred_class (i); |
| altclass = reg_alternate_class (i); |
| if (class != GENERAL_REGS || altclass != ALL_REGS) |
| { |
| if (altclass == ALL_REGS || class == ALL_REGS) |
| fprintf (file, "; pref %s", reg_class_names[(int) class]); |
| else if (altclass == NO_REGS) |
| fprintf (file, "; %s or none", reg_class_names[(int) class]); |
| else |
| fprintf (file, "; pref %s, else %s", |
| reg_class_names[(int) class], |
| reg_class_names[(int) altclass]); |
| } |
| if (REGNO_POINTER_FLAG (i)) |
| fprintf (file, "; pointer"); |
| fprintf (file, ".\n"); |
| } |
| |
| fprintf (file, "\n%d basic blocks.\n", n_basic_blocks); |
| for (i = 0; i < n_basic_blocks; i++) |
| { |
| register basic_block bb = BASIC_BLOCK (i); |
| register int regno; |
| register edge e; |
| |
| fprintf (file, "\nBasic block %d: first insn %d, last %d.\n", |
| i, INSN_UID (bb->head), INSN_UID (bb->end)); |
| |
| fprintf (file, "Predecessors: "); |
| for (e = bb->pred; e ; e = e->pred_next) |
| dump_edge_info (file, e, 0); |
| |
| fprintf (file, "\nSuccessors: "); |
| for (e = bb->succ; e ; e = e->succ_next) |
| dump_edge_info (file, e, 1); |
| |
| fprintf (file, "\nRegisters live at start:"); |
| if (bb->global_live_at_start) |
| { |
| for (regno = 0; regno < max_regno; regno++) |
| if (REGNO_REG_SET_P (bb->global_live_at_start, regno)) |
| fprintf (file, " %d", regno); |
| } |
| else |
| fprintf (file, " n/a"); |
| |
| fprintf (file, "\nRegisters live at end:"); |
| if (bb->global_live_at_end) |
| { |
| for (regno = 0; regno < max_regno; regno++) |
| if (REGNO_REG_SET_P (bb->global_live_at_end, regno)) |
| fprintf (file, " %d", regno); |
| } |
| else |
| fprintf (file, " n/a"); |
| |
| putc('\n', file); |
| } |
| |
| putc('\n', file); |
| } |
| |
| static void |
| dump_edge_info (file, e, do_succ) |
| FILE *file; |
| edge e; |
| int do_succ; |
| { |
| basic_block side = (do_succ ? e->dest : e->src); |
| |
| if (side == ENTRY_BLOCK_PTR) |
| fputs (" ENTRY", file); |
| else if (side == EXIT_BLOCK_PTR) |
| fputs (" EXIT", file); |
| else |
| fprintf (file, " %d", side->index); |
| |
| if (e->flags) |
| { |
| static char * bitnames[] = { |
| "fallthru", "crit", "ab", "abcall", "eh", "fake" |
| }; |
| int comma = 0; |
| int i, flags = e->flags; |
| |
| fputc (' ', file); |
| fputc ('(', file); |
| for (i = 0; flags; i++) |
| if (flags & (1 << i)) |
| { |
| flags &= ~(1 << i); |
| |
| if (comma) |
| fputc (',', file); |
| if (i < (int)(sizeof (bitnames) / sizeof (*bitnames))) |
| fputs (bitnames[i], file); |
| else |
| fprintf (file, "%d", i); |
| comma = 1; |
| } |
| fputc (')', file); |
| } |
| } |
| |
| |
| /* Like print_rtl, but also print out live information for the start of each |
| basic block. */ |
| |
| void |
| print_rtl_with_bb (outf, rtx_first) |
| FILE *outf; |
| rtx rtx_first; |
| { |
| register rtx tmp_rtx; |
| |
| if (rtx_first == 0) |
| fprintf (outf, "(nil)\n"); |
| else |
| { |
| int i; |
| enum bb_state { NOT_IN_BB, IN_ONE_BB, IN_MULTIPLE_BB }; |
| int max_uid = get_max_uid (); |
| basic_block *start = (basic_block *) |
| alloca (max_uid * sizeof (basic_block)); |
| basic_block *end = (basic_block *) |
| alloca (max_uid * sizeof (basic_block)); |
| enum bb_state *in_bb_p = (enum bb_state *) |
| alloca (max_uid * sizeof (enum bb_state)); |
| |
| memset (start, 0, max_uid * sizeof (basic_block)); |
| memset (end, 0, max_uid * sizeof (basic_block)); |
| memset (in_bb_p, 0, max_uid * sizeof (enum bb_state)); |
| |
| for (i = n_basic_blocks - 1; i >= 0; i--) |
| { |
| basic_block bb = BASIC_BLOCK (i); |
| rtx x; |
| |
| start[INSN_UID (bb->head)] = bb; |
| end[INSN_UID (bb->end)] = bb; |
| for (x = bb->head; x != NULL_RTX; x = NEXT_INSN (x)) |
| { |
| enum bb_state state = IN_MULTIPLE_BB; |
| if (in_bb_p[INSN_UID(x)] == NOT_IN_BB) |
| state = IN_ONE_BB; |
| in_bb_p[INSN_UID(x)] = state; |
| |
| if (x == bb->end) |
| break; |
| } |
| } |
| |
| for (tmp_rtx = rtx_first; NULL != tmp_rtx; tmp_rtx = NEXT_INSN (tmp_rtx)) |
| { |
| int did_output; |
| basic_block bb; |
| |
| if ((bb = start[INSN_UID (tmp_rtx)]) != NULL) |
| { |
| fprintf (outf, ";; Start of basic block %d, registers live:", |
| bb->index); |
| |
| EXECUTE_IF_SET_IN_REG_SET (bb->global_live_at_start, 0, i, |
| { |
| fprintf (outf, " %d", i); |
| if (i < FIRST_PSEUDO_REGISTER) |
| fprintf (outf, " [%s]", |
| reg_names[i]); |
| }); |
| putc ('\n', outf); |
| } |
| |
| if (in_bb_p[INSN_UID(tmp_rtx)] == NOT_IN_BB |
| && GET_CODE (tmp_rtx) != NOTE |
| && GET_CODE (tmp_rtx) != BARRIER |
| && ! obey_regdecls) |
| fprintf (outf, ";; Insn is not within a basic block\n"); |
| else if (in_bb_p[INSN_UID(tmp_rtx)] == IN_MULTIPLE_BB) |
| fprintf (outf, ";; Insn is in multiple basic blocks\n"); |
| |
| did_output = print_rtl_single (outf, tmp_rtx); |
| |
| if ((bb = end[INSN_UID (tmp_rtx)]) != NULL) |
| fprintf (outf, ";; End of basic block %d\n", bb->index); |
| |
| if (did_output) |
| putc ('\n', outf); |
| } |
| } |
| } |
| |
| |
| /* Integer list support. */ |
| |
| /* Allocate a node from list *HEAD_PTR. */ |
| |
| static int_list_ptr |
| alloc_int_list_node (head_ptr) |
| int_list_block **head_ptr; |
| { |
| struct int_list_block *first_blk = *head_ptr; |
| |
| if (first_blk == NULL || first_blk->nodes_left <= 0) |
| { |
| first_blk = (struct int_list_block *) xmalloc (sizeof (struct int_list_block)); |
| first_blk->nodes_left = INT_LIST_NODES_IN_BLK; |
| first_blk->next = *head_ptr; |
| *head_ptr = first_blk; |
| } |
| |
| first_blk->nodes_left--; |
| return &first_blk->nodes[first_blk->nodes_left]; |
| } |
| |
| /* Pointer to head of predecessor/successor block list. */ |
| static int_list_block *pred_int_list_blocks; |
| |
| /* Add a new node to integer list LIST with value VAL. |
| LIST is a pointer to a list object to allow for different implementations. |
| If *LIST is initially NULL, the list is empty. |
| The caller must not care whether the element is added to the front or |
| to the end of the list (to allow for different implementations). */ |
| |
| static int_list_ptr |
| add_int_list_node (blk_list, list, val) |
| int_list_block **blk_list; |
| int_list **list; |
| int val; |
| { |
| int_list_ptr p = alloc_int_list_node (blk_list); |
| |
| p->val = val; |
| p->next = *list; |
| *list = p; |
| return p; |
| } |
| |
| /* Free the blocks of lists at BLK_LIST. */ |
| |
| void |
| free_int_list (blk_list) |
| int_list_block **blk_list; |
| { |
| int_list_block *p, *next; |
| |
| for (p = *blk_list; p != NULL; p = next) |
| { |
| next = p->next; |
| free (p); |
| } |
| |
| /* Mark list as empty for the next function we compile. */ |
| *blk_list = NULL; |
| } |
| |
| /* Predecessor/successor computation. */ |
| |
| /* Mark PRED_BB a precessor of SUCC_BB, |
| and conversely SUCC_BB a successor of PRED_BB. */ |
| |
| static void |
| add_pred_succ (pred_bb, succ_bb, s_preds, s_succs, num_preds, num_succs) |
| int pred_bb; |
| int succ_bb; |
| int_list_ptr *s_preds; |
| int_list_ptr *s_succs; |
| int *num_preds; |
| int *num_succs; |
| { |
| if (succ_bb != EXIT_BLOCK) |
| { |
| add_int_list_node (&pred_int_list_blocks, &s_preds[succ_bb], pred_bb); |
| num_preds[succ_bb]++; |
| } |
| if (pred_bb != ENTRY_BLOCK) |
| { |
| add_int_list_node (&pred_int_list_blocks, &s_succs[pred_bb], succ_bb); |
| num_succs[pred_bb]++; |
| } |
| } |
| |
| /* Convert edge lists into pred/succ lists for backward compatibility. */ |
| |
| void |
| compute_preds_succs (s_preds, s_succs, num_preds, num_succs) |
| int_list_ptr *s_preds; |
| int_list_ptr *s_succs; |
| int *num_preds; |
| int *num_succs; |
| { |
| int i, n = n_basic_blocks; |
| edge e; |
| |
| memset (s_preds, 0, n_basic_blocks * sizeof (int_list_ptr)); |
| memset (s_succs, 0, n_basic_blocks * sizeof (int_list_ptr)); |
| memset (num_preds, 0, n_basic_blocks * sizeof (int)); |
| memset (num_succs, 0, n_basic_blocks * sizeof (int)); |
| |
| for (i = 0; i < n; ++i) |
| { |
| basic_block bb = BASIC_BLOCK (i); |
| |
| for (e = bb->succ; e ; e = e->succ_next) |
| add_pred_succ (i, e->dest->index, s_preds, s_succs, |
| num_preds, num_succs); |
| } |
| |
| for (e = ENTRY_BLOCK_PTR->succ; e ; e = e->succ_next) |
| add_pred_succ (ENTRY_BLOCK, e->dest->index, s_preds, s_succs, |
| num_preds, num_succs); |
| } |
| |
| void |
| dump_bb_data (file, preds, succs, live_info) |
| FILE *file; |
| int_list_ptr *preds; |
| int_list_ptr *succs; |
| int live_info; |
| { |
| int bb; |
| int_list_ptr p; |
| |
| fprintf (file, "BB data\n\n"); |
| for (bb = 0; bb < n_basic_blocks; bb++) |
| { |
| fprintf (file, "BB %d, start %d, end %d\n", bb, |
| INSN_UID (BLOCK_HEAD (bb)), INSN_UID (BLOCK_END (bb))); |
| fprintf (file, " preds:"); |
| for (p = preds[bb]; p != NULL; p = p->next) |
| { |
| int pred_bb = INT_LIST_VAL (p); |
| if (pred_bb == ENTRY_BLOCK) |
| fprintf (file, " entry"); |
| else |
| fprintf (file, " %d", pred_bb); |
| } |
| fprintf (file, "\n"); |
| fprintf (file, " succs:"); |
| for (p = succs[bb]; p != NULL; p = p->next) |
| { |
| int succ_bb = INT_LIST_VAL (p); |
| if (succ_bb == EXIT_BLOCK) |
| fprintf (file, " exit"); |
| else |
| fprintf (file, " %d", succ_bb); |
| } |
| if (live_info) |
| { |
| int regno; |
| fprintf (file, "\nRegisters live at start:"); |
| for (regno = 0; regno < max_regno; regno++) |
| if (REGNO_REG_SET_P (BASIC_BLOCK (bb)->global_live_at_start, regno)) |
| fprintf (file, " %d", regno); |
| fprintf (file, "\n"); |
| } |
| fprintf (file, "\n"); |
| } |
| fprintf (file, "\n"); |
| } |
| |
| /* Free basic block data storage. */ |
| |
| void |
| free_bb_mem () |
| { |
| free_int_list (&pred_int_list_blocks); |
| } |
| |
| /* Compute dominator relationships. */ |
| void |
| compute_dominators (dominators, post_dominators, s_preds, s_succs) |
| sbitmap *dominators; |
| sbitmap *post_dominators; |
| int_list_ptr *s_preds; |
| int_list_ptr *s_succs; |
| { |
| int bb, changed, passes; |
| sbitmap *temp_bitmap; |
| |
| temp_bitmap = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks); |
| sbitmap_vector_ones (dominators, n_basic_blocks); |
| sbitmap_vector_ones (post_dominators, n_basic_blocks); |
| sbitmap_vector_zero (temp_bitmap, n_basic_blocks); |
| |
| sbitmap_zero (dominators[0]); |
| SET_BIT (dominators[0], 0); |
| |
| sbitmap_zero (post_dominators[n_basic_blocks - 1]); |
| SET_BIT (post_dominators[n_basic_blocks - 1], 0); |
| |
| passes = 0; |
| changed = 1; |
| while (changed) |
| { |
| changed = 0; |
| for (bb = 1; bb < n_basic_blocks; bb++) |
| { |
| sbitmap_intersect_of_predecessors (temp_bitmap[bb], dominators, |
| bb, s_preds); |
| SET_BIT (temp_bitmap[bb], bb); |
| changed |= sbitmap_a_and_b (dominators[bb], |
| dominators[bb], |
| temp_bitmap[bb]); |
| sbitmap_intersect_of_successors (temp_bitmap[bb], post_dominators, |
| bb, s_succs); |
| SET_BIT (temp_bitmap[bb], bb); |
| changed |= sbitmap_a_and_b (post_dominators[bb], |
| post_dominators[bb], |
| temp_bitmap[bb]); |
| } |
| passes++; |
| } |
| |
| free (temp_bitmap); |
| } |
| |
| /* Given DOMINATORS, compute the immediate dominators into IDOM. */ |
| |
| void |
| compute_immediate_dominators (idom, dominators) |
| int *idom; |
| sbitmap *dominators; |
| { |
| sbitmap *tmp; |
| int b; |
| |
| tmp = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks); |
| |
| /* Begin with tmp(n) = dom(n) - { n }. */ |
| for (b = n_basic_blocks; --b >= 0; ) |
| { |
| sbitmap_copy (tmp[b], dominators[b]); |
| RESET_BIT (tmp[b], b); |
| } |
| |
| /* Subtract out all of our dominator's dominators. */ |
| for (b = n_basic_blocks; --b >= 0; ) |
| { |
| sbitmap tmp_b = tmp[b]; |
| int s; |
| |
| for (s = n_basic_blocks; --s >= 0; ) |
| if (TEST_BIT (tmp_b, s)) |
| sbitmap_difference (tmp_b, tmp_b, tmp[s]); |
| } |
| |
| /* Find the one bit set in the bitmap and put it in the output array. */ |
| for (b = n_basic_blocks; --b >= 0; ) |
| { |
| int t; |
| EXECUTE_IF_SET_IN_SBITMAP (tmp[b], 0, t, { idom[b] = t; }); |
| } |
| |
| sbitmap_vector_free (tmp); |
| } |
| |
| /* Count for a single SET rtx, X. */ |
| |
| static void |
| count_reg_sets_1 (x) |
| rtx x; |
| { |
| register int regno; |
| register rtx reg = SET_DEST (x); |
| |
| /* Find the register that's set/clobbered. */ |
| while (GET_CODE (reg) == SUBREG || GET_CODE (reg) == ZERO_EXTRACT |
| || GET_CODE (reg) == SIGN_EXTRACT |
| || GET_CODE (reg) == STRICT_LOW_PART) |
| reg = XEXP (reg, 0); |
| |
| if (GET_CODE (reg) == PARALLEL |
| && GET_MODE (reg) == BLKmode) |
| { |
| register int i; |
| for (i = XVECLEN (reg, 0) - 1; i >= 0; i--) |
| count_reg_sets_1 (XVECEXP (reg, 0, i)); |
| return; |
| } |
| |
| if (GET_CODE (reg) == REG) |
| { |
| regno = REGNO (reg); |
| if (regno >= FIRST_PSEUDO_REGISTER) |
| { |
| /* Count (weighted) references, stores, etc. This counts a |
| register twice if it is modified, but that is correct. */ |
| REG_N_SETS (regno)++; |
| |
| REG_N_REFS (regno) += loop_depth; |
| } |
| } |
| } |
| |
| /* Increment REG_N_SETS for each SET or CLOBBER found in X; also increment |
| REG_N_REFS by the current loop depth for each SET or CLOBBER found. */ |
| |
| static void |
| count_reg_sets (x) |
| rtx x; |
| { |
| register RTX_CODE code = GET_CODE (x); |
| |
| if (code == SET || code == CLOBBER) |
| count_reg_sets_1 (x); |
| else if (code == PARALLEL) |
| { |
| register int i; |
| for (i = XVECLEN (x, 0) - 1; i >= 0; i--) |
| { |
| code = GET_CODE (XVECEXP (x, 0, i)); |
| if (code == SET || code == CLOBBER) |
| count_reg_sets_1 (XVECEXP (x, 0, i)); |
| } |
| } |
| } |
| |
| /* Increment REG_N_REFS by the current loop depth each register reference |
| found in X. */ |
| |
| static void |
| count_reg_references (x) |
| rtx x; |
| { |
| register RTX_CODE code; |
| |
| retry: |
| code = GET_CODE (x); |
| switch (code) |
| { |
| case LABEL_REF: |
| case SYMBOL_REF: |
| case CONST_INT: |
| case CONST: |
| case CONST_DOUBLE: |
| case PC: |
| case ADDR_VEC: |
| case ADDR_DIFF_VEC: |
| case ASM_INPUT: |
| return; |
| |
| #ifdef HAVE_cc0 |
| case CC0: |
| return; |
| #endif |
| |
| case CLOBBER: |
| /* If we are clobbering a MEM, mark any registers inside the address |
| as being used. */ |
| if (GET_CODE (XEXP (x, 0)) == MEM) |
| count_reg_references (XEXP (XEXP (x, 0), 0)); |
| return; |
| |
| case SUBREG: |
| /* While we're here, optimize this case. */ |
| x = SUBREG_REG (x); |
| |
| /* In case the SUBREG is not of a register, don't optimize */ |
| if (GET_CODE (x) != REG) |
| { |
| count_reg_references (x); |
| return; |
| } |
| |
| /* ... fall through ... */ |
| |
| case REG: |
| if (REGNO (x) >= FIRST_PSEUDO_REGISTER) |
| REG_N_REFS (REGNO (x)) += loop_depth; |
| return; |
| |
| case SET: |
| { |
| register rtx testreg = SET_DEST (x); |
| int mark_dest = 0; |
| |
| /* If storing into MEM, don't show it as being used. But do |
| show the address as being used. */ |
| if (GET_CODE (testreg) == MEM) |
| { |
| count_reg_references (XEXP (testreg, 0)); |
| count_reg_references (SET_SRC (x)); |
| return; |
| } |
| |
| /* Storing in STRICT_LOW_PART is like storing in a reg |
| in that this SET might be dead, so ignore it in TESTREG. |
| but in some other ways it is like using the reg. |
| |
| Storing in a SUBREG or a bit field is like storing the entire |
| register in that if the register's value is not used |
| then this SET is not needed. */ |
| while (GET_CODE (testreg) == STRICT_LOW_PART |
| || GET_CODE (testreg) == ZERO_EXTRACT |
| || GET_CODE (testreg) == SIGN_EXTRACT |
| || GET_CODE (testreg) == SUBREG) |
| { |
| /* Modifying a single register in an alternate mode |
| does not use any of the old value. But these other |
| ways of storing in a register do use the old value. */ |
| if (GET_CODE (testreg) == SUBREG |
| && !(REG_SIZE (SUBREG_REG (testreg)) > REG_SIZE (testreg))) |
| ; |
| else |
| mark_dest = 1; |
| |
| testreg = XEXP (testreg, 0); |
| } |
| |
| /* If this is a store into a register, |
| recursively scan the value being stored. */ |
| |
| if ((GET_CODE (testreg) == PARALLEL |
| && GET_MODE (testreg) == BLKmode) |
| || GET_CODE (testreg) == REG) |
| { |
| count_reg_references (SET_SRC (x)); |
| if (mark_dest) |
| count_reg_references (SET_DEST (x)); |
| return; |
| } |
| } |
| break; |
| |
| default: |
| break; |
| } |
| |
| /* Recursively scan the operands of this expression. */ |
| |
| { |
| register char *fmt = GET_RTX_FORMAT (code); |
| register int i; |
| |
| for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) |
| { |
| if (fmt[i] == 'e') |
| { |
| /* Tail recursive case: save a function call level. */ |
| if (i == 0) |
| { |
| x = XEXP (x, 0); |
| goto retry; |
| } |
| count_reg_references (XEXP (x, i)); |
| } |
| else if (fmt[i] == 'E') |
| { |
| register int j; |
| for (j = 0; j < XVECLEN (x, i); j++) |
| count_reg_references (XVECEXP (x, i, j)); |
| } |
| } |
| } |
| } |
| |
| /* Recompute register set/reference counts immediately prior to register |
| allocation. |
| |
| This avoids problems with set/reference counts changing to/from values |
| which have special meanings to the register allocators. |
| |
| Additionally, the reference counts are the primary component used by the |
| register allocators to prioritize pseudos for allocation to hard regs. |
| More accurate reference counts generally lead to better register allocation. |
| |
| F is the first insn to be scanned. |
| LOOP_STEP denotes how much loop_depth should be incremented per |
| loop nesting level in order to increase the ref count more for references |
| in a loop. |
| |
| It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and |
| possibly other information which is used by the register allocators. */ |
| |
| void |
| recompute_reg_usage (f, loop_step) |
| rtx f; |
| int loop_step; |
| { |
| rtx insn; |
| int i, max_reg; |
| |
| /* Clear out the old data. */ |
| max_reg = max_reg_num (); |
| for (i = FIRST_PSEUDO_REGISTER; i < max_reg; i++) |
| { |
| REG_N_SETS (i) = 0; |
| REG_N_REFS (i) = 0; |
| } |
| |
| /* Scan each insn in the chain and count how many times each register is |
| set/used. */ |
| loop_depth = 1; |
| for (insn = f; insn; insn = NEXT_INSN (insn)) |
| { |
| /* Keep track of loop depth. */ |
| if (GET_CODE (insn) == NOTE) |
| { |
| /* Look for loop boundaries. */ |
| if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END) |
| loop_depth -= loop_step; |
| else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG) |
| loop_depth += loop_step; |
| |
| /* If we have LOOP_DEPTH == 0, there has been a bookkeeping error. |
| Abort now rather than setting register status incorrectly. */ |
| if (loop_depth == 0) |
| abort (); |
| } |
| else if (GET_RTX_CLASS (GET_CODE (insn)) == 'i') |
| { |
| rtx links; |
| |
| /* This call will increment REG_N_SETS for each SET or CLOBBER |
| of a register in INSN. It will also increment REG_N_REFS |
| by the loop depth for each set of a register in INSN. */ |
| count_reg_sets (PATTERN (insn)); |
| |
| /* count_reg_sets does not detect autoincrement address modes, so |
| detect them here by looking at the notes attached to INSN. */ |
| for (links = REG_NOTES (insn); links; links = XEXP (links, 1)) |
| { |
| if (REG_NOTE_KIND (links) == REG_INC) |
| /* Count (weighted) references, stores, etc. This counts a |
| register twice if it is modified, but that is correct. */ |
| REG_N_SETS (REGNO (XEXP (links, 0)))++; |
| } |
| |
| /* This call will increment REG_N_REFS by the current loop depth for |
| each reference to a register in INSN. */ |
| count_reg_references (PATTERN (insn)); |
| |
| /* count_reg_references will not include counts for arguments to |
| function calls, so detect them here by examining the |
| CALL_INSN_FUNCTION_USAGE data. */ |
| if (GET_CODE (insn) == CALL_INSN) |
| { |
| rtx note; |
| |
| for (note = CALL_INSN_FUNCTION_USAGE (insn); |
| note; |
| note = XEXP (note, 1)) |
| if (GET_CODE (XEXP (note, 0)) == USE) |
| count_reg_references (SET_DEST (XEXP (note, 0))); |
| } |
| } |
| } |
| } |
| |
| /* Record INSN's block as BB. */ |
| |
| void |
| set_block_for_insn (insn, bb) |
| rtx insn; |
| basic_block bb; |
| { |
| size_t uid = INSN_UID (insn); |
| if (uid >= basic_block_for_insn->num_elements) |
| { |
| int new_size; |
| |
| /* Add one-eighth the size so we don't keep calling xrealloc. */ |
| new_size = uid + (uid + 7) / 8; |
| |
| VARRAY_GROW (basic_block_for_insn, new_size); |
| } |
| VARRAY_BB (basic_block_for_insn, uid) = bb; |
| } |
| |
| /* Record INSN's block number as BB. */ |
| /* ??? This has got to go. */ |
| |
| void |
| set_block_num (insn, bb) |
| rtx insn; |
| int bb; |
| { |
| set_block_for_insn (insn, BASIC_BLOCK (bb)); |
| } |
| |
| /* Verify the CFG consistency. This function check some CFG invariants and |
| aborts when something is wrong. Hope that this function will help to |
| convert many optimization passes to preserve CFG consistent. |
| |
| Currently it does following checks: |
| |
| - test head/end pointers |
| - overlapping of basic blocks |
| - edge list corectness |
| - headers of basic blocks (the NOTE_INSN_BASIC_BLOCK note) |
| - tails of basic blocks (ensure that boundary is necesary) |
| - scans body of the basic block for JUMP_INSN, CODE_LABEL |
| and NOTE_INSN_BASIC_BLOCK |
| - check that all insns are in the basic blocks |
| (except the switch handling code, barriers and notes) |
| |
| In future it can be extended check a lot of other stuff as well |
| (reachability of basic blocks, life information, etc. etc.). */ |
| |
| void |
| verify_flow_info () |
| { |
| const int max_uid = get_max_uid (); |
| const rtx rtx_first = get_insns (); |
| basic_block *bb_info; |
| rtx x; |
| int i; |
| |
| bb_info = (basic_block *) alloca (max_uid * sizeof (basic_block)); |
| memset (bb_info, 0, max_uid * sizeof (basic_block)); |
| |
| /* First pass check head/end pointers and set bb_info array used by |
| later passes. */ |
| for (i = n_basic_blocks - 1; i >= 0; i--) |
| { |
| basic_block bb = BASIC_BLOCK (i); |
| |
| /* Check the head pointer and make sure that it is pointing into |
| insn list. */ |
| for (x = rtx_first; x != NULL_RTX; x = NEXT_INSN (x)) |
| if (x == bb->head) |
| break; |
| if (!x) |
| { |
| fatal ("verify_flow_info: Head insn %d for block %d not found in the insn stream.\n", |
| INSN_UID (bb->head), bb->index); |
| } |
| |
| /* Check the end pointer and make sure that it is pointing into |
| insn list. */ |
| for (x = bb->head; x != NULL_RTX; x = NEXT_INSN (x)) |
| { |
| if (bb_info[INSN_UID (x)] != NULL) |
| { |
| fatal ("verify_flow_info: Insn %d is in multiple basic blocks (%d and %d)", |
| INSN_UID (x), bb->index, bb_info[INSN_UID (x)]->index); |
| } |
| bb_info[INSN_UID (x)] = bb; |
| |
| if (x == bb->end) |
| break; |
| } |
| if (!x) |
| { |
| fatal ("verify_flow_info: End insn %d for block %d not found in the insn stream.\n", |
| INSN_UID (bb->end), bb->index); |
| } |
| } |
| |
| /* Now check the basic blocks (boundaries etc.) */ |
| for (i = n_basic_blocks - 1; i >= 0; i--) |
| { |
| basic_block bb = BASIC_BLOCK (i); |
| /* Check corectness of edge lists */ |
| edge e; |
| |
| e = bb->succ; |
| while (e) |
| { |
| if (e->src != bb) |
| { |
| fprintf (stderr, "verify_flow_info: Basic block %d succ edge is corrupted\n", |
| bb->index); |
| fprintf (stderr, "Predecessor: "); |
| dump_edge_info (stderr, e, 0); |
| fprintf (stderr, "\nSuccessor: "); |
| dump_edge_info (stderr, e, 1); |
| fflush (stderr); |
| abort (); |
| } |
| if (e->dest != EXIT_BLOCK_PTR) |
| { |
| edge e2 = e->dest->pred; |
| while (e2 && e2 != e) |
| e2 = e2->pred_next; |
| if (!e2) |
| { |
| fatal ("verify_flow_info: Basic block %i edge lists are corrupted\n", |
| bb->index); |
| } |
| } |
| e = e->succ_next; |
| } |
| |
| e = bb->pred; |
| while (e) |
| { |
| if (e->dest != bb) |
| { |
| fprintf (stderr, "verify_flow_info: Basic block %d pred edge is corrupted\n", |
| bb->index); |
| fprintf (stderr, "Predecessor: "); |
| dump_edge_info (stderr, e, 0); |
| fprintf (stderr, "\nSuccessor: "); |
| dump_edge_info (stderr, e, 1); |
| fflush (stderr); |
| abort (); |
| } |
| if (e->src != ENTRY_BLOCK_PTR) |
| { |
| edge e2 = e->src->succ; |
| while (e2 && e2 != e) |
| e2 = e2->succ_next; |
| if (!e2) |
| { |
| fatal ("verify_flow_info: Basic block %i edge lists are corrupted\n", |
| bb->index); |
| } |
| } |
| e = e->pred_next; |
| } |
| |
| /* OK pointers are correct. Now check the header of basic |
| block. It ought to contain optional CODE_LABEL followed |
| by NOTE_BASIC_BLOCK. */ |
| x = bb->head; |
| if (GET_CODE (x) == CODE_LABEL) |
| { |
| if (bb->end == x) |
| { |
| fatal ("verify_flow_info: Basic block contains only CODE_LABEL and no NOTE_INSN_BASIC_BLOCK note\n"); |
| } |
| x = NEXT_INSN (x); |
| } |
| if (GET_CODE (x) != NOTE |
| || NOTE_LINE_NUMBER (x) != NOTE_INSN_BASIC_BLOCK |
| || NOTE_BASIC_BLOCK (x) != bb) |
| { |
| fatal ("verify_flow_info: NOTE_INSN_BASIC_BLOCK is missing for block %d\n", |
| bb->index); |
| } |
| |
| if (bb->end == x) |
| { |
| /* Do checks for empty blocks here */ |
| } |
| else |
| { |
| x = NEXT_INSN (x); |
| while (x) |
| { |
| if (GET_CODE (x) == NOTE |
| && NOTE_LINE_NUMBER (x) == NOTE_INSN_BASIC_BLOCK) |
| { |
| fatal ("verify_flow_info: NOTE_INSN_BASIC_BLOCK %d in the middle of basic block %d\n", |
| INSN_UID (x), bb->index); |
| } |
| |
| if (x == bb->end) |
| break; |
| |
| if (GET_CODE (x) == JUMP_INSN |
| || GET_CODE (x) == CODE_LABEL |
| || GET_CODE (x) == BARRIER) |
| { |
| fatal_insn ("verify_flow_info: Incorrect insn in the middle of basic block %d\n", |
| x, bb->index); |
| } |
| |
| x = NEXT_INSN (x); |
| } |
| } |
| } |
| |
| x = rtx_first; |
| while (x) |
| { |
| if (!bb_info[INSN_UID (x)]) |
| { |
| switch (GET_CODE (x)) |
| { |
| case BARRIER: |
| case NOTE: |
| break; |
| |
| case CODE_LABEL: |
| /* An addr_vec is placed outside any block block. */ |
| if (NEXT_INSN (x) |
| && GET_CODE (NEXT_INSN (x)) == JUMP_INSN |
| && (GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_DIFF_VEC |
| || GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_VEC)) |
| { |
| x = NEXT_INSN (x); |
| } |
| |
| /* But in any case, non-deletable labels can appear anywhere. */ |
| break; |
| |
| default: |
| fatal_insn ("verify_flow_info: Insn outside basic block\n", x); |
| } |
| } |
| |
| x = NEXT_INSN (x); |
| } |
| } |