| /* Discovery of auto-inc and auto-dec instructions. |
| Copyright (C) 2006-2020 Free Software Foundation, Inc. |
| Contributed by Kenneth Zadeck <zadeck@naturalbridge.com> |
| |
| This file is part of GCC. |
| |
| GCC 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 3, or (at your option) any later |
| version. |
| |
| GCC 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 GCC; see the file COPYING3. If not see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include "config.h" |
| #include "system.h" |
| #include "coretypes.h" |
| #include "backend.h" |
| #include "target.h" |
| #include "rtl.h" |
| #include "tree.h" |
| #include "predict.h" |
| #include "df.h" |
| #include "insn-config.h" |
| #include "memmodel.h" |
| #include "emit-rtl.h" |
| #include "recog.h" |
| #include "cfgrtl.h" |
| #include "expr.h" |
| #include "tree-pass.h" |
| #include "dbgcnt.h" |
| #include "print-rtl.h" |
| #include "valtrack.h" |
| |
| /* This pass was originally removed from flow.c. However there is |
| almost nothing that remains of that code. |
| |
| There are (4) basic forms that are matched: |
| |
| (1) FORM_PRE_ADD |
| a <- b + c |
| ... |
| *a |
| |
| becomes |
| |
| a <- b |
| ... |
| *(a += c) pre |
| |
| or, alternately, |
| |
| a <- b + c |
| ... |
| *b |
| |
| becomes |
| |
| a <- b |
| ... |
| *(a += c) post |
| |
| This uses a post-add, but it's handled as FORM_PRE_ADD because |
| the "increment" insn appears before the memory access. |
| |
| |
| (2) FORM_PRE_INC |
| a += c |
| ... |
| *a |
| |
| becomes |
| |
| ... |
| *(a += c) pre |
| |
| |
| (3) FORM_POST_ADD |
| *a |
| ... |
| b <- a + c |
| |
| (For this case to be true, b must not be assigned or used between |
| the *a and the assignment to b. B must also be a Pmode reg.) |
| |
| becomes |
| |
| b <- a |
| *(b += c) post |
| ... |
| |
| |
| (4) FORM_POST_INC |
| *a |
| ... |
| a <- a + c |
| |
| becomes |
| |
| *(a += c) post |
| ... |
| |
| |
| There are three types of values of c. |
| |
| 1) c is a constant equal to the width of the value being accessed by |
| the pointer. This is useful for machines that have |
| HAVE_PRE_INCREMENT, HAVE_POST_INCREMENT, HAVE_PRE_DECREMENT or |
| HAVE_POST_DECREMENT defined. |
| |
| 2) c is a constant not equal to the width of the value being accessed |
| by the pointer. This is useful for machines that have |
| HAVE_PRE_MODIFY_DISP, HAVE_POST_MODIFY_DISP defined. |
| |
| 3) c is a register. This is useful for machines that have |
| HAVE_PRE_MODIFY_REG, HAVE_POST_MODIFY_REG |
| |
| The is one special case: if a already had an offset equal to it +- |
| its width and that offset is equal to -c when the increment was |
| before the ref or +c if the increment was after the ref, then if we |
| can do the combination but switch the pre/post bit. */ |
| |
| |
| enum form |
| { |
| FORM_PRE_ADD, |
| FORM_PRE_INC, |
| FORM_POST_ADD, |
| FORM_POST_INC, |
| FORM_last |
| }; |
| |
| /* The states of the second operands of mem refs and inc insns. If no |
| second operand of the mem_ref was found, it is assumed to just be |
| ZERO. SIZE is the size of the mode accessed in the memref. The |
| ANY is used for constants that are not +-size or 0. REG is used if |
| the forms are reg1 + reg2. */ |
| |
| enum inc_state |
| { |
| INC_ZERO, /* == 0 */ |
| INC_NEG_SIZE, /* == +size */ |
| INC_POS_SIZE, /* == -size */ |
| INC_NEG_ANY, /* == some -constant */ |
| INC_POS_ANY, /* == some +constant */ |
| INC_REG, /* == some register */ |
| INC_last |
| }; |
| |
| /* The eight forms that pre/post inc/dec can take. */ |
| enum gen_form |
| { |
| NOTHING, |
| SIMPLE_PRE_INC, /* ++size */ |
| SIMPLE_POST_INC, /* size++ */ |
| SIMPLE_PRE_DEC, /* --size */ |
| SIMPLE_POST_DEC, /* size-- */ |
| DISP_PRE, /* ++con */ |
| DISP_POST, /* con++ */ |
| REG_PRE, /* ++reg */ |
| REG_POST /* reg++ */ |
| }; |
| |
| /* Tmp mem rtx for use in cost modeling. */ |
| static rtx mem_tmp; |
| |
| static enum inc_state |
| set_inc_state (HOST_WIDE_INT val, poly_int64 size) |
| { |
| if (val == 0) |
| return INC_ZERO; |
| if (val < 0) |
| return known_eq (val, -size) ? INC_NEG_SIZE : INC_NEG_ANY; |
| else |
| return known_eq (val, size) ? INC_POS_SIZE : INC_POS_ANY; |
| } |
| |
| /* The DECISION_TABLE that describes what form, if any, the increment |
| or decrement will take. It is a three dimensional table. The first |
| index is the type of constant or register found as the second |
| operand of the inc insn. The second index is the type of constant |
| or register found as the second operand of the memory reference (if |
| no second operand exists, 0 is used). The third index is the form |
| and location (relative to the mem reference) of inc insn. */ |
| |
| static bool initialized = false; |
| static enum gen_form decision_table[INC_last][INC_last][FORM_last]; |
| |
| static void |
| init_decision_table (void) |
| { |
| enum gen_form value; |
| |
| if (HAVE_PRE_INCREMENT || HAVE_PRE_MODIFY_DISP) |
| { |
| /* Prefer the simple form if both are available. */ |
| value = (HAVE_PRE_INCREMENT) ? SIMPLE_PRE_INC : DISP_PRE; |
| |
| decision_table[INC_POS_SIZE][INC_ZERO][FORM_PRE_ADD] = value; |
| decision_table[INC_POS_SIZE][INC_ZERO][FORM_PRE_INC] = value; |
| |
| decision_table[INC_POS_SIZE][INC_POS_SIZE][FORM_POST_ADD] = value; |
| decision_table[INC_POS_SIZE][INC_POS_SIZE][FORM_POST_INC] = value; |
| } |
| |
| if (HAVE_POST_INCREMENT || HAVE_POST_MODIFY_DISP) |
| { |
| /* Prefer the simple form if both are available. */ |
| value = (HAVE_POST_INCREMENT) ? SIMPLE_POST_INC : DISP_POST; |
| |
| decision_table[INC_POS_SIZE][INC_ZERO][FORM_POST_ADD] = value; |
| decision_table[INC_POS_SIZE][INC_ZERO][FORM_POST_INC] = value; |
| |
| decision_table[INC_POS_SIZE][INC_NEG_SIZE][FORM_PRE_ADD] = value; |
| decision_table[INC_POS_SIZE][INC_NEG_SIZE][FORM_PRE_INC] = value; |
| } |
| |
| if (HAVE_PRE_DECREMENT || HAVE_PRE_MODIFY_DISP) |
| { |
| /* Prefer the simple form if both are available. */ |
| value = (HAVE_PRE_DECREMENT) ? SIMPLE_PRE_DEC : DISP_PRE; |
| |
| decision_table[INC_NEG_SIZE][INC_ZERO][FORM_PRE_ADD] = value; |
| decision_table[INC_NEG_SIZE][INC_ZERO][FORM_PRE_INC] = value; |
| |
| decision_table[INC_NEG_SIZE][INC_NEG_SIZE][FORM_POST_ADD] = value; |
| decision_table[INC_NEG_SIZE][INC_NEG_SIZE][FORM_POST_INC] = value; |
| } |
| |
| if (HAVE_POST_DECREMENT || HAVE_POST_MODIFY_DISP) |
| { |
| /* Prefer the simple form if both are available. */ |
| value = (HAVE_POST_DECREMENT) ? SIMPLE_POST_DEC : DISP_POST; |
| |
| decision_table[INC_NEG_SIZE][INC_ZERO][FORM_POST_ADD] = value; |
| decision_table[INC_NEG_SIZE][INC_ZERO][FORM_POST_INC] = value; |
| |
| decision_table[INC_NEG_SIZE][INC_POS_SIZE][FORM_PRE_ADD] = value; |
| decision_table[INC_NEG_SIZE][INC_POS_SIZE][FORM_PRE_INC] = value; |
| } |
| |
| if (HAVE_PRE_MODIFY_DISP) |
| { |
| decision_table[INC_POS_ANY][INC_ZERO][FORM_PRE_ADD] = DISP_PRE; |
| decision_table[INC_POS_ANY][INC_ZERO][FORM_PRE_INC] = DISP_PRE; |
| |
| decision_table[INC_POS_ANY][INC_POS_ANY][FORM_POST_ADD] = DISP_PRE; |
| decision_table[INC_POS_ANY][INC_POS_ANY][FORM_POST_INC] = DISP_PRE; |
| |
| decision_table[INC_NEG_ANY][INC_ZERO][FORM_PRE_ADD] = DISP_PRE; |
| decision_table[INC_NEG_ANY][INC_ZERO][FORM_PRE_INC] = DISP_PRE; |
| |
| decision_table[INC_NEG_ANY][INC_NEG_ANY][FORM_POST_ADD] = DISP_PRE; |
| decision_table[INC_NEG_ANY][INC_NEG_ANY][FORM_POST_INC] = DISP_PRE; |
| } |
| |
| if (HAVE_POST_MODIFY_DISP) |
| { |
| decision_table[INC_POS_ANY][INC_ZERO][FORM_POST_ADD] = DISP_POST; |
| decision_table[INC_POS_ANY][INC_ZERO][FORM_POST_INC] = DISP_POST; |
| |
| decision_table[INC_POS_ANY][INC_NEG_ANY][FORM_PRE_ADD] = DISP_POST; |
| decision_table[INC_POS_ANY][INC_NEG_ANY][FORM_PRE_INC] = DISP_POST; |
| |
| decision_table[INC_NEG_ANY][INC_ZERO][FORM_POST_ADD] = DISP_POST; |
| decision_table[INC_NEG_ANY][INC_ZERO][FORM_POST_INC] = DISP_POST; |
| |
| decision_table[INC_NEG_ANY][INC_POS_ANY][FORM_PRE_ADD] = DISP_POST; |
| decision_table[INC_NEG_ANY][INC_POS_ANY][FORM_PRE_INC] = DISP_POST; |
| } |
| |
| /* This is much simpler than the other cases because we do not look |
| for the reg1-reg2 case. Note that we do not have a INC_POS_REG |
| and INC_NEG_REG states. Most of the use of such states would be |
| on a target that had an R1 - R2 update address form. |
| |
| There is the remote possibility that you could also catch a = a + |
| b; *(a - b) as a postdecrement of (a + b). However, it is |
| unclear if *(a - b) would ever be generated on a machine that did |
| not have that kind of addressing mode. The IA-64 and RS6000 will |
| not do this, and I cannot speak for any other. If any |
| architecture does have an a-b update for, these cases should be |
| added. */ |
| if (HAVE_PRE_MODIFY_REG) |
| { |
| decision_table[INC_REG][INC_ZERO][FORM_PRE_ADD] = REG_PRE; |
| decision_table[INC_REG][INC_ZERO][FORM_PRE_INC] = REG_PRE; |
| |
| decision_table[INC_REG][INC_REG][FORM_POST_ADD] = REG_PRE; |
| decision_table[INC_REG][INC_REG][FORM_POST_INC] = REG_PRE; |
| } |
| |
| if (HAVE_POST_MODIFY_REG) |
| { |
| decision_table[INC_REG][INC_ZERO][FORM_POST_ADD] = REG_POST; |
| decision_table[INC_REG][INC_ZERO][FORM_POST_INC] = REG_POST; |
| } |
| |
| initialized = true; |
| } |
| |
| /* Parsed fields of an inc insn of the form "reg_res = reg0+reg1" or |
| "reg_res = reg0+c". */ |
| |
| static struct inc_insn |
| { |
| rtx_insn *insn; /* The insn being parsed. */ |
| rtx pat; /* The pattern of the insn. */ |
| bool reg1_is_const; /* True if reg1 is const, false if reg1 is a reg. */ |
| enum form form; |
| rtx reg_res; |
| rtx reg0; |
| rtx reg1; |
| enum inc_state reg1_state;/* The form of the const if reg1 is a const. */ |
| HOST_WIDE_INT reg1_val;/* Value if reg1 is const. */ |
| } inc_insn; |
| |
| |
| /* Dump the parsed inc insn to FILE. */ |
| |
| static void |
| dump_inc_insn (FILE *file) |
| { |
| const char *f = ((inc_insn.form == FORM_PRE_ADD) |
| || (inc_insn.form == FORM_PRE_INC)) ? "pre" : "post"; |
| |
| dump_insn_slim (file, inc_insn.insn); |
| |
| switch (inc_insn.form) |
| { |
| case FORM_PRE_ADD: |
| case FORM_POST_ADD: |
| if (inc_insn.reg1_is_const) |
| fprintf (file, "found %s add(%d) r[%d]=r[%d]+%d\n", |
| f, INSN_UID (inc_insn.insn), |
| REGNO (inc_insn.reg_res), |
| REGNO (inc_insn.reg0), (int) inc_insn.reg1_val); |
| else |
| fprintf (file, "found %s add(%d) r[%d]=r[%d]+r[%d]\n", |
| f, INSN_UID (inc_insn.insn), |
| REGNO (inc_insn.reg_res), |
| REGNO (inc_insn.reg0), REGNO (inc_insn.reg1)); |
| break; |
| |
| case FORM_PRE_INC: |
| case FORM_POST_INC: |
| if (inc_insn.reg1_is_const) |
| fprintf (file, "found %s inc(%d) r[%d]+=%d\n", |
| f, INSN_UID (inc_insn.insn), |
| REGNO (inc_insn.reg_res), (int) inc_insn.reg1_val); |
| else |
| fprintf (file, "found %s inc(%d) r[%d]+=r[%d]\n", |
| f, INSN_UID (inc_insn.insn), |
| REGNO (inc_insn.reg_res), REGNO (inc_insn.reg1)); |
| break; |
| |
| default: |
| break; |
| } |
| } |
| |
| |
| /* Parsed fields of a mem ref of the form "*(reg0+reg1)" or "*(reg0+c)". */ |
| |
| static struct mem_insn |
| { |
| rtx_insn *insn; /* The insn being parsed. */ |
| rtx pat; /* The pattern of the insn. */ |
| rtx *mem_loc; /* The address of the field that holds the mem */ |
| /* that is to be replaced. */ |
| bool reg1_is_const; /* True if reg1 is const, false if reg1 is a reg. */ |
| rtx reg0; |
| rtx reg1; /* This is either a reg or a const depending on |
| reg1_is_const. */ |
| enum inc_state reg1_state;/* The form of the const if reg1 is a const. */ |
| HOST_WIDE_INT reg1_val;/* Value if reg1 is const. */ |
| } mem_insn; |
| |
| |
| /* Dump the parsed mem insn to FILE. */ |
| |
| static void |
| dump_mem_insn (FILE *file) |
| { |
| dump_insn_slim (file, mem_insn.insn); |
| |
| if (mem_insn.reg1_is_const) |
| fprintf (file, "found mem(%d) *(r[%d]+%d)\n", |
| INSN_UID (mem_insn.insn), |
| REGNO (mem_insn.reg0), (int) mem_insn.reg1_val); |
| else |
| fprintf (file, "found mem(%d) *(r[%d]+r[%d])\n", |
| INSN_UID (mem_insn.insn), |
| REGNO (mem_insn.reg0), REGNO (mem_insn.reg1)); |
| } |
| |
| |
| /* The following three arrays contain pointers to instructions. They |
| are indexed by REGNO. At any point in the basic block where we are |
| looking these three arrays contain, respectively, the next insn |
| that uses REGNO, the next inc or add insn that uses REGNO and the |
| next insn that sets REGNO. |
| |
| The arrays are not cleared when we move from block to block so |
| whenever an insn is retrieved from these arrays, it's block number |
| must be compared with the current block. |
| */ |
| |
| static rtx_insn **reg_next_debug_use = NULL; |
| static rtx_insn **reg_next_use = NULL; |
| static rtx_insn **reg_next_inc_use = NULL; |
| static rtx_insn **reg_next_def = NULL; |
| |
| |
| /* Move dead note that match PATTERN to TO_INSN from FROM_INSN. We do |
| not really care about moving any other notes from the inc or add |
| insn. Moving the REG_EQUAL and REG_EQUIV is clearly wrong and it |
| does not appear that there are any other kinds of relevant notes. */ |
| |
| static void |
| move_dead_notes (rtx_insn *to_insn, rtx_insn *from_insn, rtx pattern) |
| { |
| rtx note; |
| rtx next_note; |
| rtx prev_note = NULL; |
| |
| for (note = REG_NOTES (from_insn); note; note = next_note) |
| { |
| next_note = XEXP (note, 1); |
| |
| if ((REG_NOTE_KIND (note) == REG_DEAD) |
| && pattern == XEXP (note, 0)) |
| { |
| XEXP (note, 1) = REG_NOTES (to_insn); |
| REG_NOTES (to_insn) = note; |
| if (prev_note) |
| XEXP (prev_note, 1) = next_note; |
| else |
| REG_NOTES (from_insn) = next_note; |
| } |
| else prev_note = note; |
| } |
| } |
| |
| /* Change mem_insn.mem_loc so that uses NEW_ADDR which has an |
| increment of INC_REG. To have reached this point, the change is a |
| legitimate one from a dataflow point of view. The only questions |
| are is this a valid change to the instruction and is this a |
| profitable change to the instruction. */ |
| |
| static bool |
| attempt_change (rtx new_addr, rtx inc_reg) |
| { |
| /* There are four cases: For the two cases that involve an add |
| instruction, we are going to have to delete the add and insert a |
| mov. We are going to assume that the mov is free. This is |
| fairly early in the backend and there are a lot of opportunities |
| for removing that move later. In particular, there is the case |
| where the move may be dead, this is what dead code elimination |
| passes are for. The two cases where we have an inc insn will be |
| handled mov free. */ |
| |
| basic_block bb = BLOCK_FOR_INSN (mem_insn.insn); |
| rtx_insn *mov_insn = NULL; |
| int regno; |
| rtx mem = *mem_insn.mem_loc; |
| machine_mode mode = GET_MODE (mem); |
| int align = MEM_ALIGN (mem); |
| rtx new_mem; |
| int old_cost = 0; |
| int new_cost = 0; |
| bool speed = optimize_bb_for_speed_p (bb); |
| |
| PUT_MODE (mem_tmp, mode); |
| XEXP (mem_tmp, 0) = new_addr; |
| set_mem_align (mem_tmp, align); |
| |
| old_cost = (set_src_cost (mem, mode, speed) |
| + set_rtx_cost (PATTERN (inc_insn.insn), speed)); |
| |
| new_cost = set_src_cost (mem_tmp, mode, speed); |
| |
| /* In the FORM_PRE_ADD and FORM_POST_ADD cases we emit an extra move |
| whose cost we should account for. */ |
| if (inc_insn.form == FORM_PRE_ADD |
| || inc_insn.form == FORM_POST_ADD) |
| { |
| start_sequence (); |
| emit_move_insn (inc_insn.reg_res, inc_insn.reg0); |
| mov_insn = get_insns (); |
| end_sequence (); |
| new_cost += seq_cost (mov_insn, speed); |
| } |
| |
| /* The first item of business is to see if this is profitable. */ |
| if (old_cost < new_cost) |
| { |
| if (dump_file) |
| fprintf (dump_file, "cost failure old=%d new=%d\n", old_cost, new_cost); |
| return false; |
| } |
| |
| /* Jump through a lot of hoops to keep the attributes up to date. We |
| do not want to call one of the change address variants that take |
| an offset even though we know the offset in many cases. These |
| assume you are changing where the address is pointing by the |
| offset. */ |
| new_mem = replace_equiv_address_nv (mem, new_addr); |
| if (! validate_change (mem_insn.insn, mem_insn.mem_loc, new_mem, 0)) |
| { |
| if (dump_file) |
| fprintf (dump_file, "validation failure\n"); |
| return false; |
| } |
| |
| /* From here to the end of the function we are committed to the |
| change, i.e. nothing fails. Generate any necessary movs, move |
| any regnotes, and fix up the reg_next_{use,inc_use,def}. */ |
| switch (inc_insn.form) |
| { |
| case FORM_PRE_ADD: |
| /* Replace the addition with a move. Do it at the location of |
| the addition since the operand of the addition may change |
| before the memory reference. */ |
| gcc_assert (mov_insn); |
| emit_insn_before (mov_insn, inc_insn.insn); |
| regno = REGNO (inc_insn.reg0); |
| /* ??? Could REGNO possibly be used in MEM_INSN other than in |
| the MEM address, and still die there, so that move_dead_notes |
| would incorrectly move the note? */ |
| if (reg_next_use[regno] == mem_insn.insn) |
| move_dead_notes (mov_insn, mem_insn.insn, inc_insn.reg0); |
| else |
| move_dead_notes (mov_insn, inc_insn.insn, inc_insn.reg0); |
| |
| regno = REGNO (inc_insn.reg_res); |
| if (reg_next_debug_use && reg_next_debug_use[regno] |
| && BLOCK_FOR_INSN (reg_next_debug_use[regno]) == bb) |
| { |
| rtx adjres = gen_rtx_PLUS (GET_MODE (inc_insn.reg_res), |
| inc_insn.reg_res, inc_insn.reg1); |
| if (dump_file) |
| fprintf (dump_file, "adjusting debug insns\n"); |
| propagate_for_debug (PREV_INSN (reg_next_debug_use[regno]), |
| mem_insn.insn, |
| inc_insn.reg_res, adjres, bb); |
| reg_next_debug_use[regno] = NULL; |
| } |
| reg_next_def[regno] = mov_insn; |
| reg_next_use[regno] = NULL; |
| |
| regno = REGNO (inc_insn.reg0); |
| if (reg_next_debug_use && reg_next_debug_use[regno] |
| && BLOCK_FOR_INSN (reg_next_debug_use[regno]) == bb |
| && find_reg_note (mov_insn, REG_DEAD, inc_insn.reg0)) |
| { |
| if (dump_file) |
| fprintf (dump_file, "remapping debug insns\n"); |
| propagate_for_debug (PREV_INSN (reg_next_debug_use[regno]), |
| mem_insn.insn, |
| inc_insn.reg0, inc_insn.reg_res, bb); |
| reg_next_debug_use[regno] = NULL; |
| } |
| reg_next_use[regno] = mov_insn; |
| df_recompute_luids (bb); |
| break; |
| |
| case FORM_POST_INC: |
| regno = REGNO (inc_insn.reg_res); |
| if (reg_next_debug_use && reg_next_debug_use[regno] |
| && BLOCK_FOR_INSN (reg_next_debug_use[regno]) == bb) |
| { |
| rtx adjres = gen_rtx_MINUS (GET_MODE (inc_insn.reg_res), |
| inc_insn.reg_res, inc_insn.reg1); |
| if (dump_file) |
| fprintf (dump_file, "adjusting debug insns\n"); |
| propagate_for_debug (PREV_INSN (reg_next_debug_use[regno]), |
| inc_insn.insn, |
| inc_insn.reg_res, adjres, bb); |
| reg_next_debug_use[regno] = NULL; |
| } |
| if (reg_next_use[regno] == reg_next_inc_use[regno]) |
| reg_next_inc_use[regno] = NULL; |
| |
| /* Fallthru. */ |
| case FORM_PRE_INC: |
| regno = REGNO (inc_insn.reg_res); |
| /* Despite the fall-through, we won't run this twice: we'll have |
| already cleared reg_next_debug_use[regno] before falling |
| through. */ |
| if (reg_next_debug_use && reg_next_debug_use[regno] |
| && BLOCK_FOR_INSN (reg_next_debug_use[regno]) == bb) |
| { |
| rtx adjres = gen_rtx_PLUS (GET_MODE (inc_insn.reg_res), |
| inc_insn.reg_res, inc_insn.reg1); |
| if (dump_file) |
| fprintf (dump_file, "adjusting debug insns\n"); |
| propagate_for_debug (PREV_INSN (reg_next_debug_use[regno]), |
| mem_insn.insn, |
| inc_insn.reg_res, adjres, bb); |
| if (DF_INSN_LUID (mem_insn.insn) |
| < DF_INSN_LUID (reg_next_debug_use[regno])) |
| reg_next_debug_use[regno] = NULL; |
| } |
| reg_next_def[regno] = mem_insn.insn; |
| reg_next_use[regno] = NULL; |
| |
| break; |
| |
| case FORM_POST_ADD: |
| gcc_assert (mov_insn); |
| emit_insn_before (mov_insn, mem_insn.insn); |
| move_dead_notes (mov_insn, inc_insn.insn, inc_insn.reg0); |
| |
| /* Do not move anything to the mov insn because the instruction |
| pointer for the main iteration has not yet hit that. It is |
| still pointing to the mem insn. */ |
| regno = REGNO (inc_insn.reg_res); |
| /* The pseudo is now set earlier, so it must have been dead in |
| that range, and dead registers cannot be referenced in debug |
| insns. */ |
| gcc_assert (!(reg_next_debug_use && reg_next_debug_use[regno] |
| && BLOCK_FOR_INSN (reg_next_debug_use[regno]) == bb)); |
| reg_next_def[regno] = mem_insn.insn; |
| reg_next_use[regno] = NULL; |
| |
| regno = REGNO (inc_insn.reg0); |
| if (reg_next_debug_use && reg_next_debug_use[regno] |
| && BLOCK_FOR_INSN (reg_next_debug_use[regno]) == bb |
| && find_reg_note (mov_insn, REG_DEAD, inc_insn.reg0)) |
| { |
| if (dump_file) |
| fprintf (dump_file, "remapping debug insns\n"); |
| propagate_for_debug (PREV_INSN (reg_next_debug_use[regno]), |
| inc_insn.insn, |
| inc_insn.reg0, inc_insn.reg_res, bb); |
| reg_next_debug_use[regno] = NULL; |
| } |
| reg_next_use[regno] = mem_insn.insn; |
| if ((reg_next_use[regno] == reg_next_inc_use[regno]) |
| || (reg_next_inc_use[regno] == inc_insn.insn)) |
| reg_next_inc_use[regno] = NULL; |
| df_recompute_luids (bb); |
| break; |
| |
| case FORM_last: |
| default: |
| gcc_unreachable (); |
| } |
| |
| if (!inc_insn.reg1_is_const) |
| { |
| regno = REGNO (inc_insn.reg1); |
| reg_next_use[regno] = mem_insn.insn; |
| if ((reg_next_use[regno] == reg_next_inc_use[regno]) |
| || (reg_next_inc_use[regno] == inc_insn.insn)) |
| reg_next_inc_use[regno] = NULL; |
| } |
| |
| delete_insn (inc_insn.insn); |
| |
| if (dump_file && mov_insn) |
| { |
| fprintf (dump_file, "inserting mov "); |
| dump_insn_slim (dump_file, mov_insn); |
| } |
| |
| /* Record that this insn has an implicit side effect. */ |
| add_reg_note (mem_insn.insn, REG_INC, inc_reg); |
| |
| if (dump_file) |
| { |
| fprintf (dump_file, "****success "); |
| dump_insn_slim (dump_file, mem_insn.insn); |
| } |
| |
| return true; |
| } |
| |
| |
| /* Try to combine the instruction in INC_INSN with the instruction in |
| MEM_INSN. First the form is determined using the DECISION_TABLE |
| and the results of parsing the INC_INSN and the MEM_INSN. |
| Assuming the form is ok, a prototype new address is built which is |
| passed to ATTEMPT_CHANGE for final processing. */ |
| |
| static bool |
| try_merge (void) |
| { |
| enum gen_form gen_form; |
| rtx mem = *mem_insn.mem_loc; |
| rtx inc_reg = inc_insn.form == FORM_POST_ADD ? |
| inc_insn.reg_res : mem_insn.reg0; |
| |
| /* The width of the mem being accessed. */ |
| poly_int64 size = GET_MODE_SIZE (GET_MODE (mem)); |
| rtx_insn *last_insn = NULL; |
| machine_mode reg_mode = GET_MODE (inc_reg); |
| |
| switch (inc_insn.form) |
| { |
| case FORM_PRE_ADD: |
| case FORM_PRE_INC: |
| last_insn = mem_insn.insn; |
| break; |
| case FORM_POST_INC: |
| case FORM_POST_ADD: |
| last_insn = inc_insn.insn; |
| break; |
| case FORM_last: |
| default: |
| gcc_unreachable (); |
| } |
| |
| /* Cannot handle auto inc of the stack. */ |
| if (inc_reg == stack_pointer_rtx) |
| { |
| if (dump_file) |
| fprintf (dump_file, "cannot inc stack %d failure\n", REGNO (inc_reg)); |
| return false; |
| } |
| |
| /* Look to see if the inc register is dead after the memory |
| reference. If it is, do not do the combination. */ |
| if (find_regno_note (last_insn, REG_DEAD, REGNO (inc_reg))) |
| { |
| if (dump_file) |
| fprintf (dump_file, "dead failure %d\n", REGNO (inc_reg)); |
| return false; |
| } |
| |
| mem_insn.reg1_state = (mem_insn.reg1_is_const) |
| ? set_inc_state (mem_insn.reg1_val, size) : INC_REG; |
| inc_insn.reg1_state = (inc_insn.reg1_is_const) |
| ? set_inc_state (inc_insn.reg1_val, size) : INC_REG; |
| |
| /* Now get the form that we are generating. */ |
| gen_form = decision_table |
| [inc_insn.reg1_state][mem_insn.reg1_state][inc_insn.form]; |
| |
| if (dbg_cnt (auto_inc_dec) == false) |
| return false; |
| |
| switch (gen_form) |
| { |
| default: |
| case NOTHING: |
| return false; |
| |
| case SIMPLE_PRE_INC: /* ++size */ |
| if (dump_file) |
| fprintf (dump_file, "trying SIMPLE_PRE_INC\n"); |
| return attempt_change (gen_rtx_PRE_INC (reg_mode, inc_reg), inc_reg); |
| |
| case SIMPLE_POST_INC: /* size++ */ |
| if (dump_file) |
| fprintf (dump_file, "trying SIMPLE_POST_INC\n"); |
| return attempt_change (gen_rtx_POST_INC (reg_mode, inc_reg), inc_reg); |
| |
| case SIMPLE_PRE_DEC: /* --size */ |
| if (dump_file) |
| fprintf (dump_file, "trying SIMPLE_PRE_DEC\n"); |
| return attempt_change (gen_rtx_PRE_DEC (reg_mode, inc_reg), inc_reg); |
| |
| case SIMPLE_POST_DEC: /* size-- */ |
| if (dump_file) |
| fprintf (dump_file, "trying SIMPLE_POST_DEC\n"); |
| return attempt_change (gen_rtx_POST_DEC (reg_mode, inc_reg), inc_reg); |
| |
| case DISP_PRE: /* ++con */ |
| if (dump_file) |
| fprintf (dump_file, "trying DISP_PRE\n"); |
| return attempt_change (gen_rtx_PRE_MODIFY (reg_mode, |
| inc_reg, |
| gen_rtx_PLUS (reg_mode, |
| inc_reg, |
| inc_insn.reg1)), |
| inc_reg); |
| |
| case DISP_POST: /* con++ */ |
| if (dump_file) |
| fprintf (dump_file, "trying POST_DISP\n"); |
| return attempt_change (gen_rtx_POST_MODIFY (reg_mode, |
| inc_reg, |
| gen_rtx_PLUS (reg_mode, |
| inc_reg, |
| inc_insn.reg1)), |
| inc_reg); |
| |
| case REG_PRE: /* ++reg */ |
| if (dump_file) |
| fprintf (dump_file, "trying PRE_REG\n"); |
| return attempt_change (gen_rtx_PRE_MODIFY (reg_mode, |
| inc_reg, |
| gen_rtx_PLUS (reg_mode, |
| inc_reg, |
| inc_insn.reg1)), |
| inc_reg); |
| |
| case REG_POST: /* reg++ */ |
| if (dump_file) |
| fprintf (dump_file, "trying POST_REG\n"); |
| return attempt_change (gen_rtx_POST_MODIFY (reg_mode, |
| inc_reg, |
| gen_rtx_PLUS (reg_mode, |
| inc_reg, |
| inc_insn.reg1)), |
| inc_reg); |
| } |
| } |
| |
| /* Return the next insn that uses (if reg_next_use is passed in |
| NEXT_ARRAY) or defines (if reg_next_def is passed in NEXT_ARRAY) |
| REGNO in BB. */ |
| |
| static rtx_insn * |
| get_next_ref (int regno, basic_block bb, rtx_insn **next_array) |
| { |
| rtx_insn *insn = next_array[regno]; |
| |
| /* Lazy about cleaning out the next_arrays. */ |
| if (insn && BLOCK_FOR_INSN (insn) != bb) |
| { |
| next_array[regno] = NULL; |
| insn = NULL; |
| } |
| |
| return insn; |
| } |
| |
| |
| /* Return true if INSN is of a form "a = b op c" where a and b are |
| regs. op is + if c is a reg and +|- if c is a const. Fill in |
| INC_INSN with what is found. |
| |
| This function is called in two contexts, if BEFORE_MEM is true, |
| this is called for each insn in the basic block. If BEFORE_MEM is |
| false, it is called for the instruction in the block that uses the |
| index register for some memory reference that is currently being |
| processed. */ |
| |
| static bool |
| parse_add_or_inc (rtx_insn *insn, bool before_mem) |
| { |
| rtx pat = single_set (insn); |
| if (!pat) |
| return false; |
| |
| /* Result must be single reg. */ |
| if (!REG_P (SET_DEST (pat))) |
| return false; |
| |
| if ((GET_CODE (SET_SRC (pat)) != PLUS) |
| && (GET_CODE (SET_SRC (pat)) != MINUS)) |
| return false; |
| |
| if (!REG_P (XEXP (SET_SRC (pat), 0))) |
| return false; |
| |
| inc_insn.insn = insn; |
| inc_insn.pat = pat; |
| inc_insn.reg_res = SET_DEST (pat); |
| inc_insn.reg0 = XEXP (SET_SRC (pat), 0); |
| |
| /* Block any auto increment of the frame pointer since it expands into |
| an addition and cannot be removed by copy propagation. */ |
| if (inc_insn.reg0 == frame_pointer_rtx) |
| return false; |
| |
| if (rtx_equal_p (inc_insn.reg_res, inc_insn.reg0)) |
| inc_insn.form = before_mem ? FORM_PRE_INC : FORM_POST_INC; |
| else |
| inc_insn.form = before_mem ? FORM_PRE_ADD : FORM_POST_ADD; |
| |
| if (CONST_INT_P (XEXP (SET_SRC (pat), 1))) |
| { |
| /* Process a = b + c where c is a const. */ |
| inc_insn.reg1_is_const = true; |
| if (GET_CODE (SET_SRC (pat)) == PLUS) |
| { |
| inc_insn.reg1 = XEXP (SET_SRC (pat), 1); |
| inc_insn.reg1_val = INTVAL (inc_insn.reg1); |
| } |
| else |
| { |
| inc_insn.reg1_val = -INTVAL (XEXP (SET_SRC (pat), 1)); |
| inc_insn.reg1 = GEN_INT (inc_insn.reg1_val); |
| } |
| return true; |
| } |
| else if ((HAVE_PRE_MODIFY_REG || HAVE_POST_MODIFY_REG) |
| && (REG_P (XEXP (SET_SRC (pat), 1))) |
| && GET_CODE (SET_SRC (pat)) == PLUS) |
| { |
| /* Process a = b + c where c is a reg. */ |
| inc_insn.reg1 = XEXP (SET_SRC (pat), 1); |
| inc_insn.reg1_is_const = false; |
| |
| if (inc_insn.form == FORM_PRE_INC |
| || inc_insn.form == FORM_POST_INC) |
| return true; |
| else if (rtx_equal_p (inc_insn.reg_res, inc_insn.reg1)) |
| { |
| /* Reverse the two operands and turn *_ADD into *_INC since |
| a = c + a. */ |
| std::swap (inc_insn.reg0, inc_insn.reg1); |
| inc_insn.form = before_mem ? FORM_PRE_INC : FORM_POST_INC; |
| return true; |
| } |
| else |
| return true; |
| } |
| |
| return false; |
| } |
| |
| |
| /* A recursive function that checks all of the mem uses in |
| ADDRESS_OF_X to see if any single one of them is compatible with |
| what has been found in inc_insn. To avoid accidental matches, we |
| will only find MEMs with FINDREG, be it inc_insn.reg_res, be it |
| inc_insn.reg0. |
| |
| -1 is returned for success. 0 is returned if nothing was found and |
| 1 is returned for failure. */ |
| |
| static int |
| find_address (rtx *address_of_x, rtx findreg) |
| { |
| rtx x = *address_of_x; |
| enum rtx_code code = GET_CODE (x); |
| const char *const fmt = GET_RTX_FORMAT (code); |
| int i; |
| int value = 0; |
| int tem; |
| |
| if (code == MEM && findreg == inc_insn.reg_res |
| && rtx_equal_p (XEXP (x, 0), inc_insn.reg_res)) |
| { |
| /* Match with *reg_res. */ |
| mem_insn.mem_loc = address_of_x; |
| mem_insn.reg0 = inc_insn.reg_res; |
| mem_insn.reg1_is_const = true; |
| mem_insn.reg1_val = 0; |
| mem_insn.reg1 = GEN_INT (0); |
| return -1; |
| } |
| if (code == MEM && inc_insn.reg1_is_const && inc_insn.reg0 |
| && findreg == inc_insn.reg0 |
| && rtx_equal_p (XEXP (x, 0), inc_insn.reg0)) |
| { |
| /* Match with *reg0, assumed to be equivalent to |
| *(reg_res - reg1_val); callers must check whether this is the case. */ |
| mem_insn.mem_loc = address_of_x; |
| mem_insn.reg0 = inc_insn.reg_res; |
| mem_insn.reg1_is_const = true; |
| mem_insn.reg1_val = -inc_insn.reg1_val; |
| mem_insn.reg1 = GEN_INT (mem_insn.reg1_val); |
| return -1; |
| } |
| if (code == MEM && findreg == inc_insn.reg_res |
| && GET_CODE (XEXP (x, 0)) == PLUS |
| && rtx_equal_p (XEXP (XEXP (x, 0), 0), inc_insn.reg_res)) |
| { |
| rtx b = XEXP (XEXP (x, 0), 1); |
| mem_insn.mem_loc = address_of_x; |
| mem_insn.reg0 = inc_insn.reg_res; |
| mem_insn.reg1 = b; |
| mem_insn.reg1_is_const = inc_insn.reg1_is_const; |
| if (CONST_INT_P (b)) |
| { |
| /* Match with *(reg0 + reg1) where reg1 is a const. */ |
| HOST_WIDE_INT val = INTVAL (b); |
| if (inc_insn.reg1_is_const |
| && (inc_insn.reg1_val == val || inc_insn.reg1_val == -val)) |
| { |
| mem_insn.reg1_val = val; |
| return -1; |
| } |
| } |
| else if (!inc_insn.reg1_is_const |
| && rtx_equal_p (inc_insn.reg1, b)) |
| /* Match with *(reg0 + reg1). */ |
| return -1; |
| } |
| |
| if (code == SIGN_EXTRACT || code == ZERO_EXTRACT) |
| { |
| /* If REG occurs inside a MEM used in a bit-field reference, |
| that is unacceptable. */ |
| if (find_address (&XEXP (x, 0), findreg)) |
| return 1; |
| } |
| |
| if (x == inc_insn.reg_res) |
| return 1; |
| |
| /* Time for some deep diving. */ |
| for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) |
| { |
| if (fmt[i] == 'e') |
| { |
| tem = find_address (&XEXP (x, i), findreg); |
| /* If this is the first use, let it go so the rest of the |
| insn can be checked. */ |
| if (value == 0) |
| value = tem; |
| else if (tem != 0) |
| /* More than one match was found. */ |
| return 1; |
| } |
| else if (fmt[i] == 'E') |
| { |
| int j; |
| for (j = XVECLEN (x, i) - 1; j >= 0; j--) |
| { |
| tem = find_address (&XVECEXP (x, i, j), findreg); |
| /* If this is the first use, let it go so the rest of |
| the insn can be checked. */ |
| if (value == 0) |
| value = tem; |
| else if (tem != 0) |
| /* More than one match was found. */ |
| return 1; |
| } |
| } |
| } |
| return value; |
| } |
| |
| /* Once a suitable mem reference has been found and the MEM_INSN |
| structure has been filled in, FIND_INC is called to see if there is |
| a suitable add or inc insn that follows the mem reference and |
| determine if it is suitable to merge. |
| |
| In the case where the MEM_INSN has two registers in the reference, |
| this function may be called recursively. The first time looking |
| for an add of the first register, and if that fails, looking for an |
| add of the second register. The FIRST_TRY parameter is used to |
| only allow the parameters to be reversed once. */ |
| |
| static bool |
| find_inc (bool first_try) |
| { |
| rtx_insn *insn; |
| basic_block bb = BLOCK_FOR_INSN (mem_insn.insn); |
| rtx_insn *other_insn; |
| df_ref def; |
| |
| /* Make sure this reg appears only once in this insn. */ |
| if (count_occurrences (PATTERN (mem_insn.insn), mem_insn.reg0, 1) != 1) |
| { |
| if (dump_file) |
| fprintf (dump_file, "mem count failure\n"); |
| return false; |
| } |
| |
| if (dump_file) |
| dump_mem_insn (dump_file); |
| |
| /* Find the next use that is an inc. */ |
| insn = get_next_ref (REGNO (mem_insn.reg0), |
| BLOCK_FOR_INSN (mem_insn.insn), |
| reg_next_inc_use); |
| if (!insn) |
| return false; |
| |
| /* Even though we know the next use is an add or inc because it came |
| from the reg_next_inc_use, we must still reparse. */ |
| if (!parse_add_or_inc (insn, false)) |
| { |
| /* Next use was not an add. Look for one extra case. It could be |
| that we have: |
| |
| *(a + b) |
| ...= a; |
| ...= b + a |
| |
| if we reverse the operands in the mem ref we would |
| find this. Only try it once though. */ |
| if (first_try && !mem_insn.reg1_is_const) |
| { |
| std::swap (mem_insn.reg0, mem_insn.reg1); |
| return find_inc (false); |
| } |
| else |
| return false; |
| } |
| |
| /* Need to assure that none of the operands of the inc instruction are |
| assigned to by the mem insn. */ |
| FOR_EACH_INSN_DEF (def, mem_insn.insn) |
| { |
| unsigned int regno = DF_REF_REGNO (def); |
| if ((regno == REGNO (inc_insn.reg0)) |
| || (regno == REGNO (inc_insn.reg_res))) |
| { |
| if (dump_file) |
| fprintf (dump_file, "inc conflicts with store failure.\n"); |
| return false; |
| } |
| if (!inc_insn.reg1_is_const && (regno == REGNO (inc_insn.reg1))) |
| { |
| if (dump_file) |
| fprintf (dump_file, "inc conflicts with store failure.\n"); |
| return false; |
| } |
| } |
| |
| if (dump_file) |
| dump_inc_insn (dump_file); |
| |
| if (inc_insn.form == FORM_POST_ADD) |
| { |
| /* Make sure that there is no insn that assigns to inc_insn.res |
| between the mem_insn and the inc_insn. */ |
| rtx_insn *other_insn = get_next_ref (REGNO (inc_insn.reg_res), |
| BLOCK_FOR_INSN (mem_insn.insn), |
| reg_next_def); |
| if (other_insn != inc_insn.insn) |
| { |
| if (dump_file) |
| fprintf (dump_file, |
| "result of add is assigned to between mem and inc insns.\n"); |
| return false; |
| } |
| |
| other_insn = get_next_ref (REGNO (inc_insn.reg_res), |
| BLOCK_FOR_INSN (mem_insn.insn), |
| reg_next_use); |
| if (other_insn |
| && (other_insn != inc_insn.insn) |
| && (DF_INSN_LUID (inc_insn.insn) > DF_INSN_LUID (other_insn))) |
| { |
| if (dump_file) |
| fprintf (dump_file, |
| "result of add is used between mem and inc insns.\n"); |
| return false; |
| } |
| |
| /* For the post_add to work, the result_reg of the inc must not be |
| used in the mem insn since this will become the new index |
| register. */ |
| if (reg_overlap_mentioned_p (inc_insn.reg_res, PATTERN (mem_insn.insn))) |
| { |
| if (dump_file) |
| fprintf (dump_file, "base reg replacement failure.\n"); |
| return false; |
| } |
| } |
| |
| if (mem_insn.reg1_is_const) |
| { |
| if (mem_insn.reg1_val == 0) |
| { |
| if (!inc_insn.reg1_is_const) |
| { |
| /* The mem looks like *r0 and the rhs of the add has two |
| registers. */ |
| int luid = DF_INSN_LUID (inc_insn.insn); |
| if (inc_insn.form == FORM_POST_ADD) |
| { |
| /* The trick is that we are not going to increment r0, |
| we are going to increment the result of the add insn. |
| For this trick to be correct, the result reg of |
| the inc must be a valid addressing reg. */ |
| addr_space_t as = MEM_ADDR_SPACE (*mem_insn.mem_loc); |
| if (GET_MODE (inc_insn.reg_res) |
| != targetm.addr_space.address_mode (as)) |
| { |
| if (dump_file) |
| fprintf (dump_file, "base reg mode failure.\n"); |
| return false; |
| } |
| |
| /* We also need to make sure that the next use of |
| inc result is after the inc. */ |
| other_insn |
| = get_next_ref (REGNO (inc_insn.reg1), bb, reg_next_use); |
| if (other_insn && luid > DF_INSN_LUID (other_insn)) |
| return false; |
| |
| if (!rtx_equal_p (mem_insn.reg0, inc_insn.reg0)) |
| std::swap (inc_insn.reg0, inc_insn.reg1); |
| } |
| |
| other_insn |
| = get_next_ref (REGNO (inc_insn.reg1), bb, reg_next_def); |
| if (other_insn && luid > DF_INSN_LUID (other_insn)) |
| return false; |
| } |
| } |
| /* Both the inc/add and the mem have a constant. Need to check |
| that the constants are ok. */ |
| else if ((mem_insn.reg1_val != inc_insn.reg1_val) |
| && (mem_insn.reg1_val != -inc_insn.reg1_val)) |
| return false; |
| } |
| else |
| { |
| /* The mem insn is of the form *(a + b) where a and b are both |
| regs. It may be that in order to match the add or inc we |
| need to treat it as if it was *(b + a). It may also be that |
| the add is of the form a + c where c does not match b and |
| then we just abandon this. */ |
| |
| int luid = DF_INSN_LUID (inc_insn.insn); |
| rtx_insn *other_insn; |
| |
| /* Make sure this reg appears only once in this insn. */ |
| if (count_occurrences (PATTERN (mem_insn.insn), mem_insn.reg1, 1) != 1) |
| return false; |
| |
| if (inc_insn.form == FORM_POST_ADD) |
| { |
| /* For this trick to be correct, the result reg of the inc |
| must be a valid addressing reg. */ |
| addr_space_t as = MEM_ADDR_SPACE (*mem_insn.mem_loc); |
| if (GET_MODE (inc_insn.reg_res) |
| != targetm.addr_space.address_mode (as)) |
| { |
| if (dump_file) |
| fprintf (dump_file, "base reg mode failure.\n"); |
| return false; |
| } |
| |
| if (rtx_equal_p (mem_insn.reg0, inc_insn.reg0)) |
| { |
| if (!rtx_equal_p (mem_insn.reg1, inc_insn.reg1)) |
| { |
| /* See comment above on find_inc (false) call. */ |
| if (first_try) |
| { |
| std::swap (mem_insn.reg0, mem_insn.reg1); |
| return find_inc (false); |
| } |
| else |
| return false; |
| } |
| |
| /* Need to check that there are no assignments to b |
| before the add insn. */ |
| other_insn |
| = get_next_ref (REGNO (inc_insn.reg1), bb, reg_next_def); |
| if (other_insn && luid > DF_INSN_LUID (other_insn)) |
| return false; |
| /* All ok for the next step. */ |
| } |
| else |
| { |
| /* We know that mem_insn.reg0 must equal inc_insn.reg1 |
| or else we would not have found the inc insn. */ |
| std::swap (mem_insn.reg0, mem_insn.reg1); |
| if (!rtx_equal_p (mem_insn.reg0, inc_insn.reg0)) |
| { |
| /* See comment above on find_inc (false) call. */ |
| if (first_try) |
| return find_inc (false); |
| else |
| return false; |
| } |
| /* To have gotten here know that. |
| *(b + a) |
| |
| ... = (b + a) |
| |
| We also know that the lhs of the inc is not b or a. We |
| need to make sure that there are no assignments to b |
| between the mem ref and the inc. */ |
| |
| other_insn |
| = get_next_ref (REGNO (inc_insn.reg0), bb, reg_next_def); |
| if (other_insn && luid > DF_INSN_LUID (other_insn)) |
| return false; |
| } |
| |
| /* Need to check that the next use of the add result is later than |
| add insn since this will be the reg incremented. */ |
| other_insn |
| = get_next_ref (REGNO (inc_insn.reg_res), bb, reg_next_use); |
| if (other_insn && luid > DF_INSN_LUID (other_insn)) |
| return false; |
| } |
| else /* FORM_POST_INC. There is less to check here because we |
| know that operands must line up. */ |
| { |
| if (!rtx_equal_p (mem_insn.reg1, inc_insn.reg1)) |
| /* See comment above on find_inc (false) call. */ |
| { |
| if (first_try) |
| { |
| std::swap (mem_insn.reg0, mem_insn.reg1); |
| return find_inc (false); |
| } |
| else |
| return false; |
| } |
| |
| /* To have gotten here know that. |
| *(a + b) |
| |
| ... = (a + b) |
| |
| We also know that the lhs of the inc is not b. We need to make |
| sure that there are no assignments to b between the mem ref and |
| the inc. */ |
| other_insn |
| = get_next_ref (REGNO (inc_insn.reg1), bb, reg_next_def); |
| if (other_insn && luid > DF_INSN_LUID (other_insn)) |
| return false; |
| } |
| } |
| |
| if (inc_insn.form == FORM_POST_INC) |
| { |
| other_insn |
| = get_next_ref (REGNO (inc_insn.reg0), bb, reg_next_use); |
| /* When we found inc_insn, we were looking for the |
| next add or inc, not the next insn that used the |
| reg. Because we are going to increment the reg |
| in this form, we need to make sure that there |
| were no intervening uses of reg. */ |
| if (inc_insn.insn != other_insn) |
| return false; |
| } |
| |
| return try_merge (); |
| } |
| |
| |
| /* A recursive function that walks ADDRESS_OF_X to find all of the mem |
| uses in pat that could be used as an auto inc or dec. It then |
| calls FIND_INC for each one. */ |
| |
| static bool |
| find_mem (rtx *address_of_x) |
| { |
| rtx x = *address_of_x; |
| enum rtx_code code = GET_CODE (x); |
| const char *const fmt = GET_RTX_FORMAT (code); |
| int i; |
| |
| if (code == MEM && REG_P (XEXP (x, 0))) |
| { |
| /* Match with *reg0. */ |
| mem_insn.mem_loc = address_of_x; |
| mem_insn.reg0 = XEXP (x, 0); |
| mem_insn.reg1_is_const = true; |
| mem_insn.reg1_val = 0; |
| mem_insn.reg1 = GEN_INT (0); |
| if (find_inc (true)) |
| return true; |
| } |
| if (code == MEM && GET_CODE (XEXP (x, 0)) == PLUS |
| && REG_P (XEXP (XEXP (x, 0), 0))) |
| { |
| rtx reg1 = XEXP (XEXP (x, 0), 1); |
| mem_insn.mem_loc = address_of_x; |
| mem_insn.reg0 = XEXP (XEXP (x, 0), 0); |
| mem_insn.reg1 = reg1; |
| if (CONST_INT_P (reg1)) |
| { |
| mem_insn.reg1_is_const = true; |
| /* Match with *(reg0 + c) where c is a const. */ |
| mem_insn.reg1_val = INTVAL (reg1); |
| if (find_inc (true)) |
| return true; |
| } |
| else if (REG_P (reg1)) |
| { |
| /* Match with *(reg0 + reg1). */ |
| mem_insn.reg1_is_const = false; |
| if (find_inc (true)) |
| return true; |
| } |
| } |
| |
| if (code == SIGN_EXTRACT || code == ZERO_EXTRACT) |
| { |
| /* If REG occurs inside a MEM used in a bit-field reference, |
| that is unacceptable. */ |
| return false; |
| } |
| |
| /* Time for some deep diving. */ |
| for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) |
| { |
| if (fmt[i] == 'e') |
| { |
| if (find_mem (&XEXP (x, i))) |
| return true; |
| } |
| else if (fmt[i] == 'E') |
| { |
| int j; |
| for (j = XVECLEN (x, i) - 1; j >= 0; j--) |
| if (find_mem (&XVECEXP (x, i, j))) |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| |
| /* Try to combine all incs and decs by constant values with memory |
| references in BB. */ |
| |
| static void |
| merge_in_block (int max_reg, basic_block bb) |
| { |
| rtx_insn *insn; |
| rtx_insn *curr; |
| int success_in_block = 0; |
| |
| if (dump_file) |
| fprintf (dump_file, "\n\nstarting bb %d\n", bb->index); |
| |
| FOR_BB_INSNS_REVERSE_SAFE (bb, insn, curr) |
| { |
| bool insn_is_add_or_inc = true; |
| |
| if (!NONDEBUG_INSN_P (insn)) |
| { |
| if (DEBUG_BIND_INSN_P (insn)) |
| { |
| df_insn_info *insn_info = DF_INSN_INFO_GET (insn); |
| df_ref use; |
| |
| if (dump_file) |
| dump_insn_slim (dump_file, insn); |
| |
| FOR_EACH_INSN_INFO_USE (use, insn_info) |
| reg_next_debug_use[DF_REF_REGNO (use)] = insn; |
| } |
| continue; |
| } |
| |
| /* Reload should handle auto-inc within a jump correctly, while LRA |
| is known to have issues with autoinc. */ |
| if (JUMP_P (insn) && targetm.lra_p ()) |
| continue; |
| |
| if (dump_file) |
| dump_insn_slim (dump_file, insn); |
| |
| /* Does this instruction increment or decrement a register? */ |
| if (parse_add_or_inc (insn, true)) |
| { |
| int regno = REGNO (inc_insn.reg_res); |
| /* Cannot handle case where there are three separate regs |
| before a mem ref. Too many moves would be needed to be |
| profitable. */ |
| if ((inc_insn.form == FORM_PRE_INC) || inc_insn.reg1_is_const) |
| { |
| mem_insn.insn = get_next_ref (regno, bb, reg_next_use); |
| if (mem_insn.insn) |
| { |
| bool ok = true; |
| if (!inc_insn.reg1_is_const) |
| { |
| /* We are only here if we are going to try a |
| HAVE_*_MODIFY_REG type transformation. c is a |
| reg and we must sure that the path from the |
| inc_insn to the mem_insn.insn is both def and use |
| clear of c because the inc insn is going to move |
| into the mem_insn.insn. */ |
| int luid = DF_INSN_LUID (mem_insn.insn); |
| rtx_insn *other_insn |
| = get_next_ref (REGNO (inc_insn.reg1), bb, reg_next_use); |
| |
| if (other_insn && luid > DF_INSN_LUID (other_insn)) |
| ok = false; |
| |
| other_insn |
| = get_next_ref (REGNO (inc_insn.reg1), bb, reg_next_def); |
| |
| if (other_insn && luid > DF_INSN_LUID (other_insn)) |
| ok = false; |
| } |
| |
| if (dump_file) |
| dump_inc_insn (dump_file); |
| |
| if (ok && find_address (&PATTERN (mem_insn.insn), |
| inc_insn.reg_res) == -1) |
| { |
| if (dump_file) |
| dump_mem_insn (dump_file); |
| if (try_merge ()) |
| { |
| success_in_block++; |
| insn_is_add_or_inc = false; |
| } |
| } |
| } |
| |
| if (insn_is_add_or_inc |
| /* find_address will only recognize an address |
| with a reg0 that's not reg_res when |
| reg1_is_const, so cut it off early if we |
| already know it won't match. */ |
| && inc_insn.reg1_is_const |
| && inc_insn.reg0 |
| && inc_insn.reg0 != inc_insn.reg_res) |
| { |
| /* If we identified an inc_insn that uses two |
| different pseudos, it's of the form |
| |
| (set reg_res (plus reg0 reg1)) |
| |
| where reg1 is a constant (*). |
| |
| The next use of reg_res was not identified by |
| find_address as a mem_insn that we could turn |
| into auto-inc, so see if we find a suitable |
| MEM in the next use of reg0, as long as it's |
| before any subsequent use of reg_res: |
| |
| ... (mem (... reg0 ...)) ... |
| |
| ... reg_res ... |
| |
| In this case, we can turn the plus into a |
| copy, and the reg0 in the MEM address into a |
| post_inc of reg_res: |
| |
| (set reg_res reg0) |
| |
| ... (mem (... (post_add reg_res reg1) ...)) ... |
| |
| reg_res will then have the correct value at |
| subsequent uses, and reg0 will remain |
| unchanged. |
| |
| (*) We could support non-const reg1, but then |
| we'd have to check that reg1 remains |
| unchanged all the way to the modified MEM, |
| and we'd have to extend find_address to |
| represent a non-const negated reg1. */ |
| regno = REGNO (inc_insn.reg0); |
| rtx_insn *reg0_use = get_next_ref (regno, bb, |
| reg_next_use); |
| |
| /* Give up if the next use of reg0 is after the next |
| use of reg_res (same insn is ok; we might have |
| found a MEM with reg_res before, and that failed, |
| but now we try reg0, which might work), or defs |
| of reg_res (same insn is not ok, we'd introduce |
| another def in the same insn) or reg0. */ |
| if (reg0_use) |
| { |
| int luid = DF_INSN_LUID (reg0_use); |
| |
| /* It might seem pointless to introduce an |
| auto-inc if there's no subsequent use of |
| reg_res (i.e., mem_insn.insn == NULL), but |
| the next use might be in the next iteration |
| of a loop, and it won't hurt if we make the |
| change even if it's not needed. */ |
| if (mem_insn.insn |
| && luid > DF_INSN_LUID (mem_insn.insn)) |
| reg0_use = NULL; |
| |
| rtx_insn *other_insn |
| = get_next_ref (REGNO (inc_insn.reg_res), bb, |
| reg_next_def); |
| |
| if (other_insn && luid >= DF_INSN_LUID (other_insn)) |
| reg0_use = NULL; |
| |
| other_insn |
| = get_next_ref (REGNO (inc_insn.reg0), bb, |
| reg_next_def); |
| |
| if (other_insn && luid > DF_INSN_LUID (other_insn)) |
| reg0_use = NULL; |
| } |
| |
| mem_insn.insn = reg0_use; |
| |
| if (mem_insn.insn |
| && find_address (&PATTERN (mem_insn.insn), |
| inc_insn.reg0) == -1) |
| { |
| if (dump_file) |
| dump_mem_insn (dump_file); |
| if (try_merge ()) |
| { |
| success_in_block++; |
| insn_is_add_or_inc = false; |
| } |
| } |
| } |
| } |
| } |
| else |
| { |
| insn_is_add_or_inc = false; |
| /* We can't use auto inc/dec for bare USEs and CLOBBERs, |
| since they aren't supposed to generate any code. */ |
| rtx_code code = GET_CODE (PATTERN (insn)); |
| if (code != USE && code != CLOBBER) |
| { |
| mem_insn.insn = insn; |
| if (find_mem (&PATTERN (insn))) |
| success_in_block++; |
| } |
| } |
| |
| /* If the inc insn was merged with a mem, the inc insn is gone |
| and there is noting to update. */ |
| if (df_insn_info *insn_info = DF_INSN_INFO_GET (insn)) |
| { |
| df_ref def, use; |
| |
| /* Need to update next use. */ |
| FOR_EACH_INSN_INFO_DEF (def, insn_info) |
| { |
| if (reg_next_debug_use) |
| reg_next_debug_use[DF_REF_REGNO (def)] = NULL; |
| reg_next_use[DF_REF_REGNO (def)] = NULL; |
| reg_next_inc_use[DF_REF_REGNO (def)] = NULL; |
| reg_next_def[DF_REF_REGNO (def)] = insn; |
| } |
| |
| FOR_EACH_INSN_INFO_USE (use, insn_info) |
| { |
| if (reg_next_debug_use) |
| /* This may seem surprising, but we know we may only |
| modify the value of a REG between an insn and the |
| next nondebug use thereof. Any debug uses after |
| the next nondebug use can be left alone, the REG |
| will hold the expected value there. */ |
| reg_next_debug_use[DF_REF_REGNO (use)] = NULL; |
| reg_next_use[DF_REF_REGNO (use)] = insn; |
| if (insn_is_add_or_inc) |
| reg_next_inc_use[DF_REF_REGNO (use)] = insn; |
| else |
| reg_next_inc_use[DF_REF_REGNO (use)] = NULL; |
| } |
| } |
| else if (dump_file) |
| fprintf (dump_file, "skipping update of deleted insn %d\n", |
| INSN_UID (insn)); |
| } |
| |
| /* If we were successful, try again. There may have been several |
| opportunities that were interleaved. This is rare but |
| gcc.c-torture/compile/pr17273.c actually exhibits this. */ |
| if (success_in_block) |
| { |
| /* In this case, we must clear these vectors since the trick of |
| testing if the stale insn in the block will not work. */ |
| if (reg_next_debug_use) |
| memset (reg_next_debug_use, 0, max_reg * sizeof (rtx)); |
| memset (reg_next_use, 0, max_reg * sizeof (rtx)); |
| memset (reg_next_inc_use, 0, max_reg * sizeof (rtx)); |
| memset (reg_next_def, 0, max_reg * sizeof (rtx)); |
| df_recompute_luids (bb); |
| merge_in_block (max_reg, bb); |
| } |
| } |
| |
| /* Discover auto-inc auto-dec instructions. */ |
| |
| namespace { |
| |
| const pass_data pass_data_inc_dec = |
| { |
| RTL_PASS, /* type */ |
| "auto_inc_dec", /* name */ |
| OPTGROUP_NONE, /* optinfo_flags */ |
| TV_AUTO_INC_DEC, /* tv_id */ |
| 0, /* properties_required */ |
| 0, /* properties_provided */ |
| 0, /* properties_destroyed */ |
| 0, /* todo_flags_start */ |
| TODO_df_finish, /* todo_flags_finish */ |
| }; |
| |
| class pass_inc_dec : public rtl_opt_pass |
| { |
| public: |
| pass_inc_dec (gcc::context *ctxt) |
| : rtl_opt_pass (pass_data_inc_dec, ctxt) |
| {} |
| |
| /* opt_pass methods: */ |
| virtual bool gate (function *) |
| { |
| if (!AUTO_INC_DEC) |
| return false; |
| |
| return (optimize > 0 && flag_auto_inc_dec); |
| } |
| |
| |
| unsigned int execute (function *); |
| |
| }; // class pass_inc_dec |
| |
| unsigned int |
| pass_inc_dec::execute (function *fun ATTRIBUTE_UNUSED) |
| { |
| if (!AUTO_INC_DEC) |
| return 0; |
| |
| basic_block bb; |
| int max_reg = max_reg_num (); |
| |
| if (!initialized) |
| init_decision_table (); |
| |
| mem_tmp = gen_rtx_MEM (Pmode, NULL_RTX); |
| |
| df_note_add_problem (); |
| df_analyze (); |
| |
| if (MAY_HAVE_DEBUG_BIND_INSNS) |
| reg_next_debug_use = XCNEWVEC (rtx_insn *, max_reg); |
| else |
| /* An earlier function may have had debug binds. */ |
| reg_next_debug_use = NULL; |
| reg_next_use = XCNEWVEC (rtx_insn *, max_reg); |
| reg_next_inc_use = XCNEWVEC (rtx_insn *, max_reg); |
| reg_next_def = XCNEWVEC (rtx_insn *, max_reg); |
| FOR_EACH_BB_FN (bb, fun) |
| merge_in_block (max_reg, bb); |
| |
| free (reg_next_debug_use); |
| free (reg_next_use); |
| free (reg_next_inc_use); |
| free (reg_next_def); |
| |
| mem_tmp = NULL; |
| |
| return 0; |
| } |
| |
| } // anon namespace |
| |
| rtl_opt_pass * |
| make_pass_inc_dec (gcc::context *ctxt) |
| { |
| return new pass_inc_dec (ctxt); |
| } |