| /* If-conversion support. |
| Copyright (C) 2000-2017 Free Software Foundation, Inc. |
| |
| 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 "cfghooks.h" |
| #include "df.h" |
| #include "memmodel.h" |
| #include "tm_p.h" |
| #include "expmed.h" |
| #include "optabs.h" |
| #include "regs.h" |
| #include "emit-rtl.h" |
| #include "recog.h" |
| |
| #include "cfgrtl.h" |
| #include "cfganal.h" |
| #include "cfgcleanup.h" |
| #include "expr.h" |
| #include "output.h" |
| #include "cfgloop.h" |
| #include "tree-pass.h" |
| #include "dbgcnt.h" |
| #include "shrink-wrap.h" |
| #include "rtl-iter.h" |
| #include "ifcvt.h" |
| #include "params.h" |
| |
| #ifndef MAX_CONDITIONAL_EXECUTE |
| #define MAX_CONDITIONAL_EXECUTE \ |
| (BRANCH_COST (optimize_function_for_speed_p (cfun), false) \ |
| + 1) |
| #endif |
| |
| #define IFCVT_MULTIPLE_DUMPS 1 |
| |
| #define NULL_BLOCK ((basic_block) NULL) |
| |
| /* True if after combine pass. */ |
| static bool ifcvt_after_combine; |
| |
| /* True if the target has the cbranchcc4 optab. */ |
| static bool have_cbranchcc4; |
| |
| /* # of IF-THEN or IF-THEN-ELSE blocks we looked at */ |
| static int num_possible_if_blocks; |
| |
| /* # of IF-THEN or IF-THEN-ELSE blocks were converted to conditional |
| execution. */ |
| static int num_updated_if_blocks; |
| |
| /* # of changes made. */ |
| static int num_true_changes; |
| |
| /* Whether conditional execution changes were made. */ |
| static int cond_exec_changed_p; |
| |
| /* Forward references. */ |
| static int count_bb_insns (const_basic_block); |
| static bool cheap_bb_rtx_cost_p (const_basic_block, profile_probability, int); |
| static rtx_insn *first_active_insn (basic_block); |
| static rtx_insn *last_active_insn (basic_block, int); |
| static rtx_insn *find_active_insn_before (basic_block, rtx_insn *); |
| static rtx_insn *find_active_insn_after (basic_block, rtx_insn *); |
| static basic_block block_fallthru (basic_block); |
| static rtx cond_exec_get_condition (rtx_insn *); |
| static rtx noce_get_condition (rtx_insn *, rtx_insn **, bool); |
| static int noce_operand_ok (const_rtx); |
| static void merge_if_block (ce_if_block *); |
| static int find_cond_trap (basic_block, edge, edge); |
| static basic_block find_if_header (basic_block, int); |
| static int block_jumps_and_fallthru_p (basic_block, basic_block); |
| static int noce_find_if_block (basic_block, edge, edge, int); |
| static int cond_exec_find_if_block (ce_if_block *); |
| static int find_if_case_1 (basic_block, edge, edge); |
| static int find_if_case_2 (basic_block, edge, edge); |
| static int dead_or_predicable (basic_block, basic_block, basic_block, |
| edge, int); |
| static void noce_emit_move_insn (rtx, rtx); |
| static rtx_insn *block_has_only_trap (basic_block); |
| |
| /* Count the number of non-jump active insns in BB. */ |
| |
| static int |
| count_bb_insns (const_basic_block bb) |
| { |
| int count = 0; |
| rtx_insn *insn = BB_HEAD (bb); |
| |
| while (1) |
| { |
| if (active_insn_p (insn) && !JUMP_P (insn)) |
| count++; |
| |
| if (insn == BB_END (bb)) |
| break; |
| insn = NEXT_INSN (insn); |
| } |
| |
| return count; |
| } |
| |
| /* Determine whether the total insn_cost on non-jump insns in |
| basic block BB is less than MAX_COST. This function returns |
| false if the cost of any instruction could not be estimated. |
| |
| The cost of the non-jump insns in BB is scaled by REG_BR_PROB_BASE |
| as those insns are being speculated. MAX_COST is scaled with SCALE |
| plus a small fudge factor. */ |
| |
| static bool |
| cheap_bb_rtx_cost_p (const_basic_block bb, |
| profile_probability prob, int max_cost) |
| { |
| int count = 0; |
| rtx_insn *insn = BB_HEAD (bb); |
| bool speed = optimize_bb_for_speed_p (bb); |
| int scale = prob.initialized_p () ? prob.to_reg_br_prob_base () |
| : REG_BR_PROB_BASE; |
| |
| /* Set scale to REG_BR_PROB_BASE to void the identical scaling |
| applied to insn_cost when optimizing for size. Only do |
| this after combine because if-conversion might interfere with |
| passes before combine. |
| |
| Use optimize_function_for_speed_p instead of the pre-defined |
| variable speed to make sure it is set to same value for all |
| basic blocks in one if-conversion transformation. */ |
| if (!optimize_function_for_speed_p (cfun) && ifcvt_after_combine) |
| scale = REG_BR_PROB_BASE; |
| /* Our branch probability/scaling factors are just estimates and don't |
| account for cases where we can get speculation for free and other |
| secondary benefits. So we fudge the scale factor to make speculating |
| appear a little more profitable when optimizing for performance. */ |
| else |
| scale += REG_BR_PROB_BASE / 8; |
| |
| |
| max_cost *= scale; |
| |
| while (1) |
| { |
| if (NONJUMP_INSN_P (insn)) |
| { |
| int cost = insn_cost (insn, speed) * REG_BR_PROB_BASE; |
| if (cost == 0) |
| return false; |
| |
| /* If this instruction is the load or set of a "stack" register, |
| such as a floating point register on x87, then the cost of |
| speculatively executing this insn may need to include |
| the additional cost of popping its result off of the |
| register stack. Unfortunately, correctly recognizing and |
| accounting for this additional overhead is tricky, so for |
| now we simply prohibit such speculative execution. */ |
| #ifdef STACK_REGS |
| { |
| rtx set = single_set (insn); |
| if (set && STACK_REG_P (SET_DEST (set))) |
| return false; |
| } |
| #endif |
| |
| count += cost; |
| if (count >= max_cost) |
| return false; |
| } |
| else if (CALL_P (insn)) |
| return false; |
| |
| if (insn == BB_END (bb)) |
| break; |
| insn = NEXT_INSN (insn); |
| } |
| |
| return true; |
| } |
| |
| /* Return the first non-jump active insn in the basic block. */ |
| |
| static rtx_insn * |
| first_active_insn (basic_block bb) |
| { |
| rtx_insn *insn = BB_HEAD (bb); |
| |
| if (LABEL_P (insn)) |
| { |
| if (insn == BB_END (bb)) |
| return NULL; |
| insn = NEXT_INSN (insn); |
| } |
| |
| while (NOTE_P (insn) || DEBUG_INSN_P (insn)) |
| { |
| if (insn == BB_END (bb)) |
| return NULL; |
| insn = NEXT_INSN (insn); |
| } |
| |
| if (JUMP_P (insn)) |
| return NULL; |
| |
| return insn; |
| } |
| |
| /* Return the last non-jump active (non-jump) insn in the basic block. */ |
| |
| static rtx_insn * |
| last_active_insn (basic_block bb, int skip_use_p) |
| { |
| rtx_insn *insn = BB_END (bb); |
| rtx_insn *head = BB_HEAD (bb); |
| |
| while (NOTE_P (insn) |
| || JUMP_P (insn) |
| || DEBUG_INSN_P (insn) |
| || (skip_use_p |
| && NONJUMP_INSN_P (insn) |
| && GET_CODE (PATTERN (insn)) == USE)) |
| { |
| if (insn == head) |
| return NULL; |
| insn = PREV_INSN (insn); |
| } |
| |
| if (LABEL_P (insn)) |
| return NULL; |
| |
| return insn; |
| } |
| |
| /* Return the active insn before INSN inside basic block CURR_BB. */ |
| |
| static rtx_insn * |
| find_active_insn_before (basic_block curr_bb, rtx_insn *insn) |
| { |
| if (!insn || insn == BB_HEAD (curr_bb)) |
| return NULL; |
| |
| while ((insn = PREV_INSN (insn)) != NULL_RTX) |
| { |
| if (NONJUMP_INSN_P (insn) || JUMP_P (insn) || CALL_P (insn)) |
| break; |
| |
| /* No other active insn all the way to the start of the basic block. */ |
| if (insn == BB_HEAD (curr_bb)) |
| return NULL; |
| } |
| |
| return insn; |
| } |
| |
| /* Return the active insn after INSN inside basic block CURR_BB. */ |
| |
| static rtx_insn * |
| find_active_insn_after (basic_block curr_bb, rtx_insn *insn) |
| { |
| if (!insn || insn == BB_END (curr_bb)) |
| return NULL; |
| |
| while ((insn = NEXT_INSN (insn)) != NULL_RTX) |
| { |
| if (NONJUMP_INSN_P (insn) || JUMP_P (insn) || CALL_P (insn)) |
| break; |
| |
| /* No other active insn all the way to the end of the basic block. */ |
| if (insn == BB_END (curr_bb)) |
| return NULL; |
| } |
| |
| return insn; |
| } |
| |
| /* Return the basic block reached by falling though the basic block BB. */ |
| |
| static basic_block |
| block_fallthru (basic_block bb) |
| { |
| edge e = find_fallthru_edge (bb->succs); |
| |
| return (e) ? e->dest : NULL_BLOCK; |
| } |
| |
| /* Return true if RTXs A and B can be safely interchanged. */ |
| |
| static bool |
| rtx_interchangeable_p (const_rtx a, const_rtx b) |
| { |
| if (!rtx_equal_p (a, b)) |
| return false; |
| |
| if (GET_CODE (a) != MEM) |
| return true; |
| |
| /* A dead type-unsafe memory reference is legal, but a live type-unsafe memory |
| reference is not. Interchanging a dead type-unsafe memory reference with |
| a live type-safe one creates a live type-unsafe memory reference, in other |
| words, it makes the program illegal. |
| We check here conservatively whether the two memory references have equal |
| memory attributes. */ |
| |
| return mem_attrs_eq_p (get_mem_attrs (a), get_mem_attrs (b)); |
| } |
| |
| |
| /* Go through a bunch of insns, converting them to conditional |
| execution format if possible. Return TRUE if all of the non-note |
| insns were processed. */ |
| |
| static int |
| cond_exec_process_insns (ce_if_block *ce_info ATTRIBUTE_UNUSED, |
| /* if block information */rtx_insn *start, |
| /* first insn to look at */rtx end, |
| /* last insn to look at */rtx test, |
| /* conditional execution test */profile_probability |
| prob_val, |
| /* probability of branch taken. */int mod_ok) |
| { |
| int must_be_last = FALSE; |
| rtx_insn *insn; |
| rtx xtest; |
| rtx pattern; |
| |
| if (!start || !end) |
| return FALSE; |
| |
| for (insn = start; ; insn = NEXT_INSN (insn)) |
| { |
| /* dwarf2out can't cope with conditional prologues. */ |
| if (NOTE_P (insn) && NOTE_KIND (insn) == NOTE_INSN_PROLOGUE_END) |
| return FALSE; |
| |
| if (NOTE_P (insn) || DEBUG_INSN_P (insn)) |
| goto insn_done; |
| |
| gcc_assert (NONJUMP_INSN_P (insn) || CALL_P (insn)); |
| |
| /* dwarf2out can't cope with conditional unwind info. */ |
| if (RTX_FRAME_RELATED_P (insn)) |
| return FALSE; |
| |
| /* Remove USE insns that get in the way. */ |
| if (reload_completed && GET_CODE (PATTERN (insn)) == USE) |
| { |
| /* ??? Ug. Actually unlinking the thing is problematic, |
| given what we'd have to coordinate with our callers. */ |
| SET_INSN_DELETED (insn); |
| goto insn_done; |
| } |
| |
| /* Last insn wasn't last? */ |
| if (must_be_last) |
| return FALSE; |
| |
| if (modified_in_p (test, insn)) |
| { |
| if (!mod_ok) |
| return FALSE; |
| must_be_last = TRUE; |
| } |
| |
| /* Now build the conditional form of the instruction. */ |
| pattern = PATTERN (insn); |
| xtest = copy_rtx (test); |
| |
| /* If this is already a COND_EXEC, rewrite the test to be an AND of the |
| two conditions. */ |
| if (GET_CODE (pattern) == COND_EXEC) |
| { |
| if (GET_MODE (xtest) != GET_MODE (COND_EXEC_TEST (pattern))) |
| return FALSE; |
| |
| xtest = gen_rtx_AND (GET_MODE (xtest), xtest, |
| COND_EXEC_TEST (pattern)); |
| pattern = COND_EXEC_CODE (pattern); |
| } |
| |
| pattern = gen_rtx_COND_EXEC (VOIDmode, xtest, pattern); |
| |
| /* If the machine needs to modify the insn being conditionally executed, |
| say for example to force a constant integer operand into a temp |
| register, do so here. */ |
| #ifdef IFCVT_MODIFY_INSN |
| IFCVT_MODIFY_INSN (ce_info, pattern, insn); |
| if (! pattern) |
| return FALSE; |
| #endif |
| |
| validate_change (insn, &PATTERN (insn), pattern, 1); |
| |
| if (CALL_P (insn) && prob_val.initialized_p ()) |
| validate_change (insn, ®_NOTES (insn), |
| gen_rtx_INT_LIST ((machine_mode) REG_BR_PROB, |
| prob_val.to_reg_br_prob_note (), |
| REG_NOTES (insn)), 1); |
| |
| insn_done: |
| if (insn == end) |
| break; |
| } |
| |
| return TRUE; |
| } |
| |
| /* Return the condition for a jump. Do not do any special processing. */ |
| |
| static rtx |
| cond_exec_get_condition (rtx_insn *jump) |
| { |
| rtx test_if, cond; |
| |
| if (any_condjump_p (jump)) |
| test_if = SET_SRC (pc_set (jump)); |
| else |
| return NULL_RTX; |
| cond = XEXP (test_if, 0); |
| |
| /* If this branches to JUMP_LABEL when the condition is false, |
| reverse the condition. */ |
| if (GET_CODE (XEXP (test_if, 2)) == LABEL_REF |
| && label_ref_label (XEXP (test_if, 2)) == JUMP_LABEL (jump)) |
| { |
| enum rtx_code rev = reversed_comparison_code (cond, jump); |
| if (rev == UNKNOWN) |
| return NULL_RTX; |
| |
| cond = gen_rtx_fmt_ee (rev, GET_MODE (cond), XEXP (cond, 0), |
| XEXP (cond, 1)); |
| } |
| |
| return cond; |
| } |
| |
| /* Given a simple IF-THEN or IF-THEN-ELSE block, attempt to convert it |
| to conditional execution. Return TRUE if we were successful at |
| converting the block. */ |
| |
| static int |
| cond_exec_process_if_block (ce_if_block * ce_info, |
| /* if block information */int do_multiple_p) |
| { |
| basic_block test_bb = ce_info->test_bb; /* last test block */ |
| basic_block then_bb = ce_info->then_bb; /* THEN */ |
| basic_block else_bb = ce_info->else_bb; /* ELSE or NULL */ |
| rtx test_expr; /* expression in IF_THEN_ELSE that is tested */ |
| rtx_insn *then_start; /* first insn in THEN block */ |
| rtx_insn *then_end; /* last insn + 1 in THEN block */ |
| rtx_insn *else_start = NULL; /* first insn in ELSE block or NULL */ |
| rtx_insn *else_end = NULL; /* last insn + 1 in ELSE block */ |
| int max; /* max # of insns to convert. */ |
| int then_mod_ok; /* whether conditional mods are ok in THEN */ |
| rtx true_expr; /* test for else block insns */ |
| rtx false_expr; /* test for then block insns */ |
| profile_probability true_prob_val;/* probability of else block */ |
| profile_probability false_prob_val;/* probability of then block */ |
| rtx_insn *then_last_head = NULL; /* Last match at the head of THEN */ |
| rtx_insn *else_last_head = NULL; /* Last match at the head of ELSE */ |
| rtx_insn *then_first_tail = NULL; /* First match at the tail of THEN */ |
| rtx_insn *else_first_tail = NULL; /* First match at the tail of ELSE */ |
| int then_n_insns, else_n_insns, n_insns; |
| enum rtx_code false_code; |
| rtx note; |
| |
| /* If test is comprised of && or || elements, and we've failed at handling |
| all of them together, just use the last test if it is the special case of |
| && elements without an ELSE block. */ |
| if (!do_multiple_p && ce_info->num_multiple_test_blocks) |
| { |
| if (else_bb || ! ce_info->and_and_p) |
| return FALSE; |
| |
| ce_info->test_bb = test_bb = ce_info->last_test_bb; |
| ce_info->num_multiple_test_blocks = 0; |
| ce_info->num_and_and_blocks = 0; |
| ce_info->num_or_or_blocks = 0; |
| } |
| |
| /* Find the conditional jump to the ELSE or JOIN part, and isolate |
| the test. */ |
| test_expr = cond_exec_get_condition (BB_END (test_bb)); |
| if (! test_expr) |
| return FALSE; |
| |
| /* If the conditional jump is more than just a conditional jump, |
| then we can not do conditional execution conversion on this block. */ |
| if (! onlyjump_p (BB_END (test_bb))) |
| return FALSE; |
| |
| /* Collect the bounds of where we're to search, skipping any labels, jumps |
| and notes at the beginning and end of the block. Then count the total |
| number of insns and see if it is small enough to convert. */ |
| then_start = first_active_insn (then_bb); |
| then_end = last_active_insn (then_bb, TRUE); |
| then_n_insns = ce_info->num_then_insns = count_bb_insns (then_bb); |
| n_insns = then_n_insns; |
| max = MAX_CONDITIONAL_EXECUTE; |
| |
| if (else_bb) |
| { |
| int n_matching; |
| |
| max *= 2; |
| else_start = first_active_insn (else_bb); |
| else_end = last_active_insn (else_bb, TRUE); |
| else_n_insns = ce_info->num_else_insns = count_bb_insns (else_bb); |
| n_insns += else_n_insns; |
| |
| /* Look for matching sequences at the head and tail of the two blocks, |
| and limit the range of insns to be converted if possible. */ |
| n_matching = flow_find_cross_jump (then_bb, else_bb, |
| &then_first_tail, &else_first_tail, |
| NULL); |
| if (then_first_tail == BB_HEAD (then_bb)) |
| then_start = then_end = NULL; |
| if (else_first_tail == BB_HEAD (else_bb)) |
| else_start = else_end = NULL; |
| |
| if (n_matching > 0) |
| { |
| if (then_end) |
| then_end = find_active_insn_before (then_bb, then_first_tail); |
| if (else_end) |
| else_end = find_active_insn_before (else_bb, else_first_tail); |
| n_insns -= 2 * n_matching; |
| } |
| |
| if (then_start |
| && else_start |
| && then_n_insns > n_matching |
| && else_n_insns > n_matching) |
| { |
| int longest_match = MIN (then_n_insns - n_matching, |
| else_n_insns - n_matching); |
| n_matching |
| = flow_find_head_matching_sequence (then_bb, else_bb, |
| &then_last_head, |
| &else_last_head, |
| longest_match); |
| |
| if (n_matching > 0) |
| { |
| rtx_insn *insn; |
| |
| /* We won't pass the insns in the head sequence to |
| cond_exec_process_insns, so we need to test them here |
| to make sure that they don't clobber the condition. */ |
| for (insn = BB_HEAD (then_bb); |
| insn != NEXT_INSN (then_last_head); |
| insn = NEXT_INSN (insn)) |
| if (!LABEL_P (insn) && !NOTE_P (insn) |
| && !DEBUG_INSN_P (insn) |
| && modified_in_p (test_expr, insn)) |
| return FALSE; |
| } |
| |
| if (then_last_head == then_end) |
| then_start = then_end = NULL; |
| if (else_last_head == else_end) |
| else_start = else_end = NULL; |
| |
| if (n_matching > 0) |
| { |
| if (then_start) |
| then_start = find_active_insn_after (then_bb, then_last_head); |
| if (else_start) |
| else_start = find_active_insn_after (else_bb, else_last_head); |
| n_insns -= 2 * n_matching; |
| } |
| } |
| } |
| |
| if (n_insns > max) |
| return FALSE; |
| |
| /* Map test_expr/test_jump into the appropriate MD tests to use on |
| the conditionally executed code. */ |
| |
| true_expr = test_expr; |
| |
| false_code = reversed_comparison_code (true_expr, BB_END (test_bb)); |
| if (false_code != UNKNOWN) |
| false_expr = gen_rtx_fmt_ee (false_code, GET_MODE (true_expr), |
| XEXP (true_expr, 0), XEXP (true_expr, 1)); |
| else |
| false_expr = NULL_RTX; |
| |
| #ifdef IFCVT_MODIFY_TESTS |
| /* If the machine description needs to modify the tests, such as setting a |
| conditional execution register from a comparison, it can do so here. */ |
| IFCVT_MODIFY_TESTS (ce_info, true_expr, false_expr); |
| |
| /* See if the conversion failed. */ |
| if (!true_expr || !false_expr) |
| goto fail; |
| #endif |
| |
| note = find_reg_note (BB_END (test_bb), REG_BR_PROB, NULL_RTX); |
| if (note) |
| { |
| true_prob_val = profile_probability::from_reg_br_prob_note (XINT (note, 0)); |
| false_prob_val = true_prob_val.invert (); |
| } |
| else |
| { |
| true_prob_val = profile_probability::uninitialized (); |
| false_prob_val = profile_probability::uninitialized (); |
| } |
| |
| /* If we have && or || tests, do them here. These tests are in the adjacent |
| blocks after the first block containing the test. */ |
| if (ce_info->num_multiple_test_blocks > 0) |
| { |
| basic_block bb = test_bb; |
| basic_block last_test_bb = ce_info->last_test_bb; |
| |
| if (! false_expr) |
| goto fail; |
| |
| do |
| { |
| rtx_insn *start, *end; |
| rtx t, f; |
| enum rtx_code f_code; |
| |
| bb = block_fallthru (bb); |
| start = first_active_insn (bb); |
| end = last_active_insn (bb, TRUE); |
| if (start |
| && ! cond_exec_process_insns (ce_info, start, end, false_expr, |
| false_prob_val, FALSE)) |
| goto fail; |
| |
| /* If the conditional jump is more than just a conditional jump, then |
| we can not do conditional execution conversion on this block. */ |
| if (! onlyjump_p (BB_END (bb))) |
| goto fail; |
| |
| /* Find the conditional jump and isolate the test. */ |
| t = cond_exec_get_condition (BB_END (bb)); |
| if (! t) |
| goto fail; |
| |
| f_code = reversed_comparison_code (t, BB_END (bb)); |
| if (f_code == UNKNOWN) |
| goto fail; |
| |
| f = gen_rtx_fmt_ee (f_code, GET_MODE (t), XEXP (t, 0), XEXP (t, 1)); |
| if (ce_info->and_and_p) |
| { |
| t = gen_rtx_AND (GET_MODE (t), true_expr, t); |
| f = gen_rtx_IOR (GET_MODE (t), false_expr, f); |
| } |
| else |
| { |
| t = gen_rtx_IOR (GET_MODE (t), true_expr, t); |
| f = gen_rtx_AND (GET_MODE (t), false_expr, f); |
| } |
| |
| /* If the machine description needs to modify the tests, such as |
| setting a conditional execution register from a comparison, it can |
| do so here. */ |
| #ifdef IFCVT_MODIFY_MULTIPLE_TESTS |
| IFCVT_MODIFY_MULTIPLE_TESTS (ce_info, bb, t, f); |
| |
| /* See if the conversion failed. */ |
| if (!t || !f) |
| goto fail; |
| #endif |
| |
| true_expr = t; |
| false_expr = f; |
| } |
| while (bb != last_test_bb); |
| } |
| |
| /* For IF-THEN-ELSE blocks, we don't allow modifications of the test |
| on then THEN block. */ |
| then_mod_ok = (else_bb == NULL_BLOCK); |
| |
| /* Go through the THEN and ELSE blocks converting the insns if possible |
| to conditional execution. */ |
| |
| if (then_end |
| && (! false_expr |
| || ! cond_exec_process_insns (ce_info, then_start, then_end, |
| false_expr, false_prob_val, |
| then_mod_ok))) |
| goto fail; |
| |
| if (else_bb && else_end |
| && ! cond_exec_process_insns (ce_info, else_start, else_end, |
| true_expr, true_prob_val, TRUE)) |
| goto fail; |
| |
| /* If we cannot apply the changes, fail. Do not go through the normal fail |
| processing, since apply_change_group will call cancel_changes. */ |
| if (! apply_change_group ()) |
| { |
| #ifdef IFCVT_MODIFY_CANCEL |
| /* Cancel any machine dependent changes. */ |
| IFCVT_MODIFY_CANCEL (ce_info); |
| #endif |
| return FALSE; |
| } |
| |
| #ifdef IFCVT_MODIFY_FINAL |
| /* Do any machine dependent final modifications. */ |
| IFCVT_MODIFY_FINAL (ce_info); |
| #endif |
| |
| /* Conversion succeeded. */ |
| if (dump_file) |
| fprintf (dump_file, "%d insn%s converted to conditional execution.\n", |
| n_insns, (n_insns == 1) ? " was" : "s were"); |
| |
| /* Merge the blocks! If we had matching sequences, make sure to delete one |
| copy at the appropriate location first: delete the copy in the THEN branch |
| for a tail sequence so that the remaining one is executed last for both |
| branches, and delete the copy in the ELSE branch for a head sequence so |
| that the remaining one is executed first for both branches. */ |
| if (then_first_tail) |
| { |
| rtx_insn *from = then_first_tail; |
| if (!INSN_P (from)) |
| from = find_active_insn_after (then_bb, from); |
| delete_insn_chain (from, get_last_bb_insn (then_bb), false); |
| } |
| if (else_last_head) |
| delete_insn_chain (first_active_insn (else_bb), else_last_head, false); |
| |
| merge_if_block (ce_info); |
| cond_exec_changed_p = TRUE; |
| return TRUE; |
| |
| fail: |
| #ifdef IFCVT_MODIFY_CANCEL |
| /* Cancel any machine dependent changes. */ |
| IFCVT_MODIFY_CANCEL (ce_info); |
| #endif |
| |
| cancel_changes (0); |
| return FALSE; |
| } |
| |
| static rtx noce_emit_store_flag (struct noce_if_info *, rtx, int, int); |
| static int noce_try_move (struct noce_if_info *); |
| static int noce_try_ifelse_collapse (struct noce_if_info *); |
| static int noce_try_store_flag (struct noce_if_info *); |
| static int noce_try_addcc (struct noce_if_info *); |
| static int noce_try_store_flag_constants (struct noce_if_info *); |
| static int noce_try_store_flag_mask (struct noce_if_info *); |
| static rtx noce_emit_cmove (struct noce_if_info *, rtx, enum rtx_code, rtx, |
| rtx, rtx, rtx); |
| static int noce_try_cmove (struct noce_if_info *); |
| static int noce_try_cmove_arith (struct noce_if_info *); |
| static rtx noce_get_alt_condition (struct noce_if_info *, rtx, rtx_insn **); |
| static int noce_try_minmax (struct noce_if_info *); |
| static int noce_try_abs (struct noce_if_info *); |
| static int noce_try_sign_mask (struct noce_if_info *); |
| |
| /* Return the comparison code for reversed condition for IF_INFO, |
| or UNKNOWN if reversing the condition is not possible. */ |
| |
| static inline enum rtx_code |
| noce_reversed_cond_code (struct noce_if_info *if_info) |
| { |
| if (if_info->rev_cond) |
| return GET_CODE (if_info->rev_cond); |
| return reversed_comparison_code (if_info->cond, if_info->jump); |
| } |
| |
| /* Return true if SEQ is a good candidate as a replacement for the |
| if-convertible sequence described in IF_INFO. |
| This is the default implementation that targets can override |
| through a target hook. */ |
| |
| bool |
| default_noce_conversion_profitable_p (rtx_insn *seq, |
| struct noce_if_info *if_info) |
| { |
| bool speed_p = if_info->speed_p; |
| |
| /* Cost up the new sequence. */ |
| unsigned int cost = seq_cost (seq, speed_p); |
| |
| if (cost <= if_info->original_cost) |
| return true; |
| |
| /* When compiling for size, we can make a reasonably accurately guess |
| at the size growth. When compiling for speed, use the maximum. */ |
| return speed_p && cost <= if_info->max_seq_cost; |
| } |
| |
| /* Helper function for noce_try_store_flag*. */ |
| |
| static rtx |
| noce_emit_store_flag (struct noce_if_info *if_info, rtx x, int reversep, |
| int normalize) |
| { |
| rtx cond = if_info->cond; |
| int cond_complex; |
| enum rtx_code code; |
| |
| cond_complex = (! general_operand (XEXP (cond, 0), VOIDmode) |
| || ! general_operand (XEXP (cond, 1), VOIDmode)); |
| |
| /* If earliest == jump, or when the condition is complex, try to |
| build the store_flag insn directly. */ |
| |
| if (cond_complex) |
| { |
| rtx set = pc_set (if_info->jump); |
| cond = XEXP (SET_SRC (set), 0); |
| if (GET_CODE (XEXP (SET_SRC (set), 2)) == LABEL_REF |
| && label_ref_label (XEXP (SET_SRC (set), 2)) == JUMP_LABEL (if_info->jump)) |
| reversep = !reversep; |
| if (if_info->then_else_reversed) |
| reversep = !reversep; |
| } |
| else if (reversep |
| && if_info->rev_cond |
| && general_operand (XEXP (if_info->rev_cond, 0), VOIDmode) |
| && general_operand (XEXP (if_info->rev_cond, 1), VOIDmode)) |
| { |
| cond = if_info->rev_cond; |
| reversep = false; |
| } |
| |
| if (reversep) |
| code = reversed_comparison_code (cond, if_info->jump); |
| else |
| code = GET_CODE (cond); |
| |
| if ((if_info->cond_earliest == if_info->jump || cond_complex) |
| && (normalize == 0 || STORE_FLAG_VALUE == normalize)) |
| { |
| rtx src = gen_rtx_fmt_ee (code, GET_MODE (x), XEXP (cond, 0), |
| XEXP (cond, 1)); |
| rtx set = gen_rtx_SET (x, src); |
| |
| start_sequence (); |
| rtx_insn *insn = emit_insn (set); |
| |
| if (recog_memoized (insn) >= 0) |
| { |
| rtx_insn *seq = get_insns (); |
| end_sequence (); |
| emit_insn (seq); |
| |
| if_info->cond_earliest = if_info->jump; |
| |
| return x; |
| } |
| |
| end_sequence (); |
| } |
| |
| /* Don't even try if the comparison operands or the mode of X are weird. */ |
| if (cond_complex || !SCALAR_INT_MODE_P (GET_MODE (x))) |
| return NULL_RTX; |
| |
| return emit_store_flag (x, code, XEXP (cond, 0), |
| XEXP (cond, 1), VOIDmode, |
| (code == LTU || code == LEU |
| || code == GEU || code == GTU), normalize); |
| } |
| |
| /* Emit instruction to move an rtx, possibly into STRICT_LOW_PART. |
| X is the destination/target and Y is the value to copy. */ |
| |
| static void |
| noce_emit_move_insn (rtx x, rtx y) |
| { |
| machine_mode outmode; |
| rtx outer, inner; |
| int bitpos; |
| |
| if (GET_CODE (x) != STRICT_LOW_PART) |
| { |
| rtx_insn *seq, *insn; |
| rtx target; |
| optab ot; |
| |
| start_sequence (); |
| /* Check that the SET_SRC is reasonable before calling emit_move_insn, |
| otherwise construct a suitable SET pattern ourselves. */ |
| insn = (OBJECT_P (y) || CONSTANT_P (y) || GET_CODE (y) == SUBREG) |
| ? emit_move_insn (x, y) |
| : emit_insn (gen_rtx_SET (x, y)); |
| seq = get_insns (); |
| end_sequence (); |
| |
| if (recog_memoized (insn) <= 0) |
| { |
| if (GET_CODE (x) == ZERO_EXTRACT) |
| { |
| rtx op = XEXP (x, 0); |
| unsigned HOST_WIDE_INT size = INTVAL (XEXP (x, 1)); |
| unsigned HOST_WIDE_INT start = INTVAL (XEXP (x, 2)); |
| |
| /* store_bit_field expects START to be relative to |
| BYTES_BIG_ENDIAN and adjusts this value for machines with |
| BITS_BIG_ENDIAN != BYTES_BIG_ENDIAN. In order to be able to |
| invoke store_bit_field again it is necessary to have the START |
| value from the first call. */ |
| if (BITS_BIG_ENDIAN != BYTES_BIG_ENDIAN) |
| { |
| if (MEM_P (op)) |
| start = BITS_PER_UNIT - start - size; |
| else |
| { |
| gcc_assert (REG_P (op)); |
| start = BITS_PER_WORD - start - size; |
| } |
| } |
| |
| gcc_assert (start < (MEM_P (op) ? BITS_PER_UNIT : BITS_PER_WORD)); |
| store_bit_field (op, size, start, 0, 0, GET_MODE (x), y, false); |
| return; |
| } |
| |
| switch (GET_RTX_CLASS (GET_CODE (y))) |
| { |
| case RTX_UNARY: |
| ot = code_to_optab (GET_CODE (y)); |
| if (ot) |
| { |
| start_sequence (); |
| target = expand_unop (GET_MODE (y), ot, XEXP (y, 0), x, 0); |
| if (target != NULL_RTX) |
| { |
| if (target != x) |
| emit_move_insn (x, target); |
| seq = get_insns (); |
| } |
| end_sequence (); |
| } |
| break; |
| |
| case RTX_BIN_ARITH: |
| case RTX_COMM_ARITH: |
| ot = code_to_optab (GET_CODE (y)); |
| if (ot) |
| { |
| start_sequence (); |
| target = expand_binop (GET_MODE (y), ot, |
| XEXP (y, 0), XEXP (y, 1), |
| x, 0, OPTAB_DIRECT); |
| if (target != NULL_RTX) |
| { |
| if (target != x) |
| emit_move_insn (x, target); |
| seq = get_insns (); |
| } |
| end_sequence (); |
| } |
| break; |
| |
| default: |
| break; |
| } |
| } |
| |
| emit_insn (seq); |
| return; |
| } |
| |
| outer = XEXP (x, 0); |
| inner = XEXP (outer, 0); |
| outmode = GET_MODE (outer); |
| bitpos = SUBREG_BYTE (outer) * BITS_PER_UNIT; |
| store_bit_field (inner, GET_MODE_BITSIZE (outmode), bitpos, |
| 0, 0, outmode, y, false); |
| } |
| |
| /* Return the CC reg if it is used in COND. */ |
| |
| static rtx |
| cc_in_cond (rtx cond) |
| { |
| if (have_cbranchcc4 && cond |
| && GET_MODE_CLASS (GET_MODE (XEXP (cond, 0))) == MODE_CC) |
| return XEXP (cond, 0); |
| |
| return NULL_RTX; |
| } |
| |
| /* Return sequence of instructions generated by if conversion. This |
| function calls end_sequence() to end the current stream, ensures |
| that the instructions are unshared, recognizable non-jump insns. |
| On failure, this function returns a NULL_RTX. */ |
| |
| static rtx_insn * |
| end_ifcvt_sequence (struct noce_if_info *if_info) |
| { |
| rtx_insn *insn; |
| rtx_insn *seq = get_insns (); |
| rtx cc = cc_in_cond (if_info->cond); |
| |
| set_used_flags (if_info->x); |
| set_used_flags (if_info->cond); |
| set_used_flags (if_info->a); |
| set_used_flags (if_info->b); |
| |
| for (insn = seq; insn; insn = NEXT_INSN (insn)) |
| set_used_flags (insn); |
| |
| unshare_all_rtl_in_chain (seq); |
| end_sequence (); |
| |
| /* Make sure that all of the instructions emitted are recognizable, |
| and that we haven't introduced a new jump instruction. |
| As an exercise for the reader, build a general mechanism that |
| allows proper placement of required clobbers. */ |
| for (insn = seq; insn; insn = NEXT_INSN (insn)) |
| if (JUMP_P (insn) |
| || recog_memoized (insn) == -1 |
| /* Make sure new generated code does not clobber CC. */ |
| || (cc && set_of (cc, insn))) |
| return NULL; |
| |
| return seq; |
| } |
| |
| /* Return true iff the then and else basic block (if it exists) |
| consist of a single simple set instruction. */ |
| |
| static bool |
| noce_simple_bbs (struct noce_if_info *if_info) |
| { |
| if (!if_info->then_simple) |
| return false; |
| |
| if (if_info->else_bb) |
| return if_info->else_simple; |
| |
| return true; |
| } |
| |
| /* Convert "if (a != b) x = a; else x = b" into "x = a" and |
| "if (a == b) x = a; else x = b" into "x = b". */ |
| |
| static int |
| noce_try_move (struct noce_if_info *if_info) |
| { |
| rtx cond = if_info->cond; |
| enum rtx_code code = GET_CODE (cond); |
| rtx y; |
| rtx_insn *seq; |
| |
| if (code != NE && code != EQ) |
| return FALSE; |
| |
| if (!noce_simple_bbs (if_info)) |
| return FALSE; |
| |
| /* This optimization isn't valid if either A or B could be a NaN |
| or a signed zero. */ |
| if (HONOR_NANS (if_info->x) |
| || HONOR_SIGNED_ZEROS (if_info->x)) |
| return FALSE; |
| |
| /* Check whether the operands of the comparison are A and in |
| either order. */ |
| if ((rtx_equal_p (if_info->a, XEXP (cond, 0)) |
| && rtx_equal_p (if_info->b, XEXP (cond, 1))) |
| || (rtx_equal_p (if_info->a, XEXP (cond, 1)) |
| && rtx_equal_p (if_info->b, XEXP (cond, 0)))) |
| { |
| if (!rtx_interchangeable_p (if_info->a, if_info->b)) |
| return FALSE; |
| |
| y = (code == EQ) ? if_info->a : if_info->b; |
| |
| /* Avoid generating the move if the source is the destination. */ |
| if (! rtx_equal_p (if_info->x, y)) |
| { |
| start_sequence (); |
| noce_emit_move_insn (if_info->x, y); |
| seq = end_ifcvt_sequence (if_info); |
| if (!seq) |
| return FALSE; |
| |
| emit_insn_before_setloc (seq, if_info->jump, |
| INSN_LOCATION (if_info->insn_a)); |
| } |
| if_info->transform_name = "noce_try_move"; |
| return TRUE; |
| } |
| return FALSE; |
| } |
| |
| /* Try forming an IF_THEN_ELSE (cond, b, a) and collapsing that |
| through simplify_rtx. Sometimes that can eliminate the IF_THEN_ELSE. |
| If that is the case, emit the result into x. */ |
| |
| static int |
| noce_try_ifelse_collapse (struct noce_if_info * if_info) |
| { |
| if (!noce_simple_bbs (if_info)) |
| return FALSE; |
| |
| machine_mode mode = GET_MODE (if_info->x); |
| rtx if_then_else = simplify_gen_ternary (IF_THEN_ELSE, mode, mode, |
| if_info->cond, if_info->b, |
| if_info->a); |
| |
| if (GET_CODE (if_then_else) == IF_THEN_ELSE) |
| return FALSE; |
| |
| rtx_insn *seq; |
| start_sequence (); |
| noce_emit_move_insn (if_info->x, if_then_else); |
| seq = end_ifcvt_sequence (if_info); |
| if (!seq) |
| return FALSE; |
| |
| emit_insn_before_setloc (seq, if_info->jump, |
| INSN_LOCATION (if_info->insn_a)); |
| |
| if_info->transform_name = "noce_try_ifelse_collapse"; |
| return TRUE; |
| } |
| |
| |
| /* Convert "if (test) x = 1; else x = 0". |
| |
| Only try 0 and STORE_FLAG_VALUE here. Other combinations will be |
| tried in noce_try_store_flag_constants after noce_try_cmove has had |
| a go at the conversion. */ |
| |
| static int |
| noce_try_store_flag (struct noce_if_info *if_info) |
| { |
| int reversep; |
| rtx target; |
| rtx_insn *seq; |
| |
| if (!noce_simple_bbs (if_info)) |
| return FALSE; |
| |
| if (CONST_INT_P (if_info->b) |
| && INTVAL (if_info->b) == STORE_FLAG_VALUE |
| && if_info->a == const0_rtx) |
| reversep = 0; |
| else if (if_info->b == const0_rtx |
| && CONST_INT_P (if_info->a) |
| && INTVAL (if_info->a) == STORE_FLAG_VALUE |
| && noce_reversed_cond_code (if_info) != UNKNOWN) |
| reversep = 1; |
| else |
| return FALSE; |
| |
| start_sequence (); |
| |
| target = noce_emit_store_flag (if_info, if_info->x, reversep, 0); |
| if (target) |
| { |
| if (target != if_info->x) |
| noce_emit_move_insn (if_info->x, target); |
| |
| seq = end_ifcvt_sequence (if_info); |
| if (! seq) |
| return FALSE; |
| |
| emit_insn_before_setloc (seq, if_info->jump, |
| INSN_LOCATION (if_info->insn_a)); |
| if_info->transform_name = "noce_try_store_flag"; |
| return TRUE; |
| } |
| else |
| { |
| end_sequence (); |
| return FALSE; |
| } |
| } |
| |
| |
| /* Convert "if (test) x = -A; else x = A" into |
| x = A; if (test) x = -x if the machine can do the |
| conditional negate form of this cheaply. |
| Try this before noce_try_cmove that will just load the |
| immediates into two registers and do a conditional select |
| between them. If the target has a conditional negate or |
| conditional invert operation we can save a potentially |
| expensive constant synthesis. */ |
| |
| static bool |
| noce_try_inverse_constants (struct noce_if_info *if_info) |
| { |
| if (!noce_simple_bbs (if_info)) |
| return false; |
| |
| if (!CONST_INT_P (if_info->a) |
| || !CONST_INT_P (if_info->b) |
| || !REG_P (if_info->x)) |
| return false; |
| |
| machine_mode mode = GET_MODE (if_info->x); |
| |
| HOST_WIDE_INT val_a = INTVAL (if_info->a); |
| HOST_WIDE_INT val_b = INTVAL (if_info->b); |
| |
| rtx cond = if_info->cond; |
| |
| rtx x = if_info->x; |
| rtx target; |
| |
| start_sequence (); |
| |
| rtx_code code; |
| if (val_b != HOST_WIDE_INT_MIN && val_a == -val_b) |
| code = NEG; |
| else if (val_a == ~val_b) |
| code = NOT; |
| else |
| { |
| end_sequence (); |
| return false; |
| } |
| |
| rtx tmp = gen_reg_rtx (mode); |
| noce_emit_move_insn (tmp, if_info->a); |
| |
| target = emit_conditional_neg_or_complement (x, code, mode, cond, tmp, tmp); |
| |
| if (target) |
| { |
| rtx_insn *seq = get_insns (); |
| |
| if (!seq) |
| { |
| end_sequence (); |
| return false; |
| } |
| |
| if (target != if_info->x) |
| noce_emit_move_insn (if_info->x, target); |
| |
| seq = end_ifcvt_sequence (if_info); |
| |
| if (!seq) |
| return false; |
| |
| emit_insn_before_setloc (seq, if_info->jump, |
| INSN_LOCATION (if_info->insn_a)); |
| if_info->transform_name = "noce_try_inverse_constants"; |
| return true; |
| } |
| |
| end_sequence (); |
| return false; |
| } |
| |
| |
| /* Convert "if (test) x = a; else x = b", for A and B constant. |
| Also allow A = y + c1, B = y + c2, with a common y between A |
| and B. */ |
| |
| static int |
| noce_try_store_flag_constants (struct noce_if_info *if_info) |
| { |
| rtx target; |
| rtx_insn *seq; |
| bool reversep; |
| HOST_WIDE_INT itrue, ifalse, diff, tmp; |
| int normalize; |
| bool can_reverse; |
| machine_mode mode = GET_MODE (if_info->x);; |
| rtx common = NULL_RTX; |
| |
| rtx a = if_info->a; |
| rtx b = if_info->b; |
| |
| /* Handle cases like x := test ? y + 3 : y + 4. */ |
| if (GET_CODE (a) == PLUS |
| && GET_CODE (b) == PLUS |
| && CONST_INT_P (XEXP (a, 1)) |
| && CONST_INT_P (XEXP (b, 1)) |
| && rtx_equal_p (XEXP (a, 0), XEXP (b, 0)) |
| /* Allow expressions that are not using the result or plain |
| registers where we handle overlap below. */ |
| && (REG_P (XEXP (a, 0)) |
| || (noce_operand_ok (XEXP (a, 0)) |
| && ! reg_overlap_mentioned_p (if_info->x, XEXP (a, 0))))) |
| { |
| common = XEXP (a, 0); |
| a = XEXP (a, 1); |
| b = XEXP (b, 1); |
| } |
| |
| if (!noce_simple_bbs (if_info)) |
| return FALSE; |
| |
| if (CONST_INT_P (a) |
| && CONST_INT_P (b)) |
| { |
| ifalse = INTVAL (a); |
| itrue = INTVAL (b); |
| bool subtract_flag_p = false; |
| |
| diff = (unsigned HOST_WIDE_INT) itrue - ifalse; |
| /* Make sure we can represent the difference between the two values. */ |
| if ((diff > 0) |
| != ((ifalse < 0) != (itrue < 0) ? ifalse < 0 : ifalse < itrue)) |
| return FALSE; |
| |
| diff = trunc_int_for_mode (diff, mode); |
| |
| can_reverse = noce_reversed_cond_code (if_info) != UNKNOWN; |
| reversep = false; |
| if (diff == STORE_FLAG_VALUE || diff == -STORE_FLAG_VALUE) |
| { |
| normalize = 0; |
| /* We could collapse these cases but it is easier to follow the |
| diff/STORE_FLAG_VALUE combinations when they are listed |
| explicitly. */ |
| |
| /* test ? 3 : 4 |
| => 4 + (test != 0). */ |
| if (diff < 0 && STORE_FLAG_VALUE < 0) |
| reversep = false; |
| /* test ? 4 : 3 |
| => can_reverse | 4 + (test == 0) |
| !can_reverse | 3 - (test != 0). */ |
| else if (diff > 0 && STORE_FLAG_VALUE < 0) |
| { |
| reversep = can_reverse; |
| subtract_flag_p = !can_reverse; |
| /* If we need to subtract the flag and we have PLUS-immediate |
| A and B then it is unlikely to be beneficial to play tricks |
| here. */ |
| if (subtract_flag_p && common) |
| return FALSE; |
| } |
| /* test ? 3 : 4 |
| => can_reverse | 3 + (test == 0) |
| !can_reverse | 4 - (test != 0). */ |
| else if (diff < 0 && STORE_FLAG_VALUE > 0) |
| { |
| reversep = can_reverse; |
| subtract_flag_p = !can_reverse; |
| /* If we need to subtract the flag and we have PLUS-immediate |
| A and B then it is unlikely to be beneficial to play tricks |
| here. */ |
| if (subtract_flag_p && common) |
| return FALSE; |
| } |
| /* test ? 4 : 3 |
| => 4 + (test != 0). */ |
| else if (diff > 0 && STORE_FLAG_VALUE > 0) |
| reversep = false; |
| else |
| gcc_unreachable (); |
| } |
| /* Is this (cond) ? 2^n : 0? */ |
| else if (ifalse == 0 && pow2p_hwi (itrue) |
| && STORE_FLAG_VALUE == 1) |
| normalize = 1; |
| /* Is this (cond) ? 0 : 2^n? */ |
| else if (itrue == 0 && pow2p_hwi (ifalse) && can_reverse |
| && STORE_FLAG_VALUE == 1) |
| { |
| normalize = 1; |
| reversep = true; |
| } |
| /* Is this (cond) ? -1 : x? */ |
| else if (itrue == -1 |
| && STORE_FLAG_VALUE == -1) |
| normalize = -1; |
| /* Is this (cond) ? x : -1? */ |
| else if (ifalse == -1 && can_reverse |
| && STORE_FLAG_VALUE == -1) |
| { |
| normalize = -1; |
| reversep = true; |
| } |
| else |
| return FALSE; |
| |
| if (reversep) |
| { |
| std::swap (itrue, ifalse); |
| diff = trunc_int_for_mode (-(unsigned HOST_WIDE_INT) diff, mode); |
| } |
| |
| start_sequence (); |
| |
| /* If we have x := test ? x + 3 : x + 4 then move the original |
| x out of the way while we store flags. */ |
| if (common && rtx_equal_p (common, if_info->x)) |
| { |
| common = gen_reg_rtx (mode); |
| noce_emit_move_insn (common, if_info->x); |
| } |
| |
| target = noce_emit_store_flag (if_info, if_info->x, reversep, normalize); |
| if (! target) |
| { |
| end_sequence (); |
| return FALSE; |
| } |
| |
| /* if (test) x = 3; else x = 4; |
| => x = 3 + (test == 0); */ |
| if (diff == STORE_FLAG_VALUE || diff == -STORE_FLAG_VALUE) |
| { |
| /* Add the common part now. This may allow combine to merge this |
| with the store flag operation earlier into some sort of conditional |
| increment/decrement if the target allows it. */ |
| if (common) |
| target = expand_simple_binop (mode, PLUS, |
| target, common, |
| target, 0, OPTAB_WIDEN); |
| |
| /* Always use ifalse here. It should have been swapped with itrue |
| when appropriate when reversep is true. */ |
| target = expand_simple_binop (mode, subtract_flag_p ? MINUS : PLUS, |
| gen_int_mode (ifalse, mode), target, |
| if_info->x, 0, OPTAB_WIDEN); |
| } |
| /* Other cases are not beneficial when the original A and B are PLUS |
| expressions. */ |
| else if (common) |
| { |
| end_sequence (); |
| return FALSE; |
| } |
| /* if (test) x = 8; else x = 0; |
| => x = (test != 0) << 3; */ |
| else if (ifalse == 0 && (tmp = exact_log2 (itrue)) >= 0) |
| { |
| target = expand_simple_binop (mode, ASHIFT, |
| target, GEN_INT (tmp), if_info->x, 0, |
| OPTAB_WIDEN); |
| } |
| |
| /* if (test) x = -1; else x = b; |
| => x = -(test != 0) | b; */ |
| else if (itrue == -1) |
| { |
| target = expand_simple_binop (mode, IOR, |
| target, gen_int_mode (ifalse, mode), |
| if_info->x, 0, OPTAB_WIDEN); |
| } |
| else |
| { |
| end_sequence (); |
| return FALSE; |
| } |
| |
| if (! target) |
| { |
| end_sequence (); |
| return FALSE; |
| } |
| |
| if (target != if_info->x) |
| noce_emit_move_insn (if_info->x, target); |
| |
| seq = end_ifcvt_sequence (if_info); |
| if (!seq || !targetm.noce_conversion_profitable_p (seq, if_info)) |
| return FALSE; |
| |
| emit_insn_before_setloc (seq, if_info->jump, |
| INSN_LOCATION (if_info->insn_a)); |
| if_info->transform_name = "noce_try_store_flag_constants"; |
| |
| return TRUE; |
| } |
| |
| return FALSE; |
| } |
| |
| /* Convert "if (test) foo++" into "foo += (test != 0)", and |
| similarly for "foo--". */ |
| |
| static int |
| noce_try_addcc (struct noce_if_info *if_info) |
| { |
| rtx target; |
| rtx_insn *seq; |
| int subtract, normalize; |
| |
| if (!noce_simple_bbs (if_info)) |
| return FALSE; |
| |
| if (GET_CODE (if_info->a) == PLUS |
| && rtx_equal_p (XEXP (if_info->a, 0), if_info->b) |
| && noce_reversed_cond_code (if_info) != UNKNOWN) |
| { |
| rtx cond = if_info->rev_cond; |
| enum rtx_code code; |
| |
| if (cond == NULL_RTX) |
| { |
| cond = if_info->cond; |
| code = reversed_comparison_code (cond, if_info->jump); |
| } |
| else |
| code = GET_CODE (cond); |
| |
| /* First try to use addcc pattern. */ |
| if (general_operand (XEXP (cond, 0), VOIDmode) |
| && general_operand (XEXP (cond, 1), VOIDmode)) |
| { |
| start_sequence (); |
| target = emit_conditional_add (if_info->x, code, |
| XEXP (cond, 0), |
| XEXP (cond, 1), |
| VOIDmode, |
| if_info->b, |
| XEXP (if_info->a, 1), |
| GET_MODE (if_info->x), |
| (code == LTU || code == GEU |
| || code == LEU || code == GTU)); |
| if (target) |
| { |
| if (target != if_info->x) |
| noce_emit_move_insn (if_info->x, target); |
| |
| seq = end_ifcvt_sequence (if_info); |
| if (!seq || !targetm.noce_conversion_profitable_p (seq, if_info)) |
| return FALSE; |
| |
| emit_insn_before_setloc (seq, if_info->jump, |
| INSN_LOCATION (if_info->insn_a)); |
| if_info->transform_name = "noce_try_addcc"; |
| |
| return TRUE; |
| } |
| end_sequence (); |
| } |
| |
| /* If that fails, construct conditional increment or decrement using |
| setcc. We're changing a branch and an increment to a comparison and |
| an ADD/SUB. */ |
| if (XEXP (if_info->a, 1) == const1_rtx |
| || XEXP (if_info->a, 1) == constm1_rtx) |
| { |
| start_sequence (); |
| if (STORE_FLAG_VALUE == INTVAL (XEXP (if_info->a, 1))) |
| subtract = 0, normalize = 0; |
| else if (-STORE_FLAG_VALUE == INTVAL (XEXP (if_info->a, 1))) |
| subtract = 1, normalize = 0; |
| else |
| subtract = 0, normalize = INTVAL (XEXP (if_info->a, 1)); |
| |
| |
| target = noce_emit_store_flag (if_info, |
| gen_reg_rtx (GET_MODE (if_info->x)), |
| 1, normalize); |
| |
| if (target) |
| target = expand_simple_binop (GET_MODE (if_info->x), |
| subtract ? MINUS : PLUS, |
| if_info->b, target, if_info->x, |
| 0, OPTAB_WIDEN); |
| if (target) |
| { |
| if (target != if_info->x) |
| noce_emit_move_insn (if_info->x, target); |
| |
| seq = end_ifcvt_sequence (if_info); |
| if (!seq || !targetm.noce_conversion_profitable_p (seq, if_info)) |
| return FALSE; |
| |
| emit_insn_before_setloc (seq, if_info->jump, |
| INSN_LOCATION (if_info->insn_a)); |
| if_info->transform_name = "noce_try_addcc"; |
| return TRUE; |
| } |
| end_sequence (); |
| } |
| } |
| |
| return FALSE; |
| } |
| |
| /* Convert "if (test) x = 0;" to "x &= -(test == 0);" */ |
| |
| static int |
| noce_try_store_flag_mask (struct noce_if_info *if_info) |
| { |
| rtx target; |
| rtx_insn *seq; |
| int reversep; |
| |
| if (!noce_simple_bbs (if_info)) |
| return FALSE; |
| |
| reversep = 0; |
| |
| if ((if_info->a == const0_rtx |
| && rtx_equal_p (if_info->b, if_info->x)) |
| || ((reversep = (noce_reversed_cond_code (if_info) != UNKNOWN)) |
| && if_info->b == const0_rtx |
| && rtx_equal_p (if_info->a, if_info->x))) |
| { |
| start_sequence (); |
| target = noce_emit_store_flag (if_info, |
| gen_reg_rtx (GET_MODE (if_info->x)), |
| reversep, -1); |
| if (target) |
| target = expand_simple_binop (GET_MODE (if_info->x), AND, |
| if_info->x, |
| target, if_info->x, 0, |
| OPTAB_WIDEN); |
| |
| if (target) |
| { |
| if (target != if_info->x) |
| noce_emit_move_insn (if_info->x, target); |
| |
| seq = end_ifcvt_sequence (if_info); |
| if (!seq || !targetm.noce_conversion_profitable_p (seq, if_info)) |
| return FALSE; |
| |
| emit_insn_before_setloc (seq, if_info->jump, |
| INSN_LOCATION (if_info->insn_a)); |
| if_info->transform_name = "noce_try_store_flag_mask"; |
| |
| return TRUE; |
| } |
| |
| end_sequence (); |
| } |
| |
| return FALSE; |
| } |
| |
| /* Helper function for noce_try_cmove and noce_try_cmove_arith. */ |
| |
| static rtx |
| noce_emit_cmove (struct noce_if_info *if_info, rtx x, enum rtx_code code, |
| rtx cmp_a, rtx cmp_b, rtx vfalse, rtx vtrue) |
| { |
| rtx target ATTRIBUTE_UNUSED; |
| int unsignedp ATTRIBUTE_UNUSED; |
| |
| /* If earliest == jump, try to build the cmove insn directly. |
| This is helpful when combine has created some complex condition |
| (like for alpha's cmovlbs) that we can't hope to regenerate |
| through the normal interface. */ |
| |
| if (if_info->cond_earliest == if_info->jump) |
| { |
| rtx cond = gen_rtx_fmt_ee (code, GET_MODE (if_info->cond), cmp_a, cmp_b); |
| rtx if_then_else = gen_rtx_IF_THEN_ELSE (GET_MODE (x), |
| cond, vtrue, vfalse); |
| rtx set = gen_rtx_SET (x, if_then_else); |
| |
| start_sequence (); |
| rtx_insn *insn = emit_insn (set); |
| |
| if (recog_memoized (insn) >= 0) |
| { |
| rtx_insn *seq = get_insns (); |
| end_sequence (); |
| emit_insn (seq); |
| |
| return x; |
| } |
| |
| end_sequence (); |
| } |
| |
| /* Don't even try if the comparison operands are weird |
| except that the target supports cbranchcc4. */ |
| if (! general_operand (cmp_a, GET_MODE (cmp_a)) |
| || ! general_operand (cmp_b, GET_MODE (cmp_b))) |
| { |
| if (!have_cbranchcc4 |
| || GET_MODE_CLASS (GET_MODE (cmp_a)) != MODE_CC |
| || cmp_b != const0_rtx) |
| return NULL_RTX; |
| } |
| |
| unsignedp = (code == LTU || code == GEU |
| || code == LEU || code == GTU); |
| |
| target = emit_conditional_move (x, code, cmp_a, cmp_b, VOIDmode, |
| vtrue, vfalse, GET_MODE (x), |
| unsignedp); |
| if (target) |
| return target; |
| |
| /* We might be faced with a situation like: |
| |
| x = (reg:M TARGET) |
| vtrue = (subreg:M (reg:N VTRUE) BYTE) |
| vfalse = (subreg:M (reg:N VFALSE) BYTE) |
| |
| We can't do a conditional move in mode M, but it's possible that we |
| could do a conditional move in mode N instead and take a subreg of |
| the result. |
| |
| If we can't create new pseudos, though, don't bother. */ |
| if (reload_completed) |
| return NULL_RTX; |
| |
| if (GET_CODE (vtrue) == SUBREG && GET_CODE (vfalse) == SUBREG) |
| { |
| rtx reg_vtrue = SUBREG_REG (vtrue); |
| rtx reg_vfalse = SUBREG_REG (vfalse); |
| unsigned int byte_vtrue = SUBREG_BYTE (vtrue); |
| unsigned int byte_vfalse = SUBREG_BYTE (vfalse); |
| rtx promoted_target; |
| |
| if (GET_MODE (reg_vtrue) != GET_MODE (reg_vfalse) |
| || byte_vtrue != byte_vfalse |
| || (SUBREG_PROMOTED_VAR_P (vtrue) |
| != SUBREG_PROMOTED_VAR_P (vfalse)) |
| || (SUBREG_PROMOTED_GET (vtrue) |
| != SUBREG_PROMOTED_GET (vfalse))) |
| return NULL_RTX; |
| |
| promoted_target = gen_reg_rtx (GET_MODE (reg_vtrue)); |
| |
| target = emit_conditional_move (promoted_target, code, cmp_a, cmp_b, |
| VOIDmode, reg_vtrue, reg_vfalse, |
| GET_MODE (reg_vtrue), unsignedp); |
| /* Nope, couldn't do it in that mode either. */ |
| if (!target) |
| return NULL_RTX; |
| |
| target = gen_rtx_SUBREG (GET_MODE (vtrue), promoted_target, byte_vtrue); |
| SUBREG_PROMOTED_VAR_P (target) = SUBREG_PROMOTED_VAR_P (vtrue); |
| SUBREG_PROMOTED_SET (target, SUBREG_PROMOTED_GET (vtrue)); |
| emit_move_insn (x, target); |
| return x; |
| } |
| else |
| return NULL_RTX; |
| } |
| |
| /* Try only simple constants and registers here. More complex cases |
| are handled in noce_try_cmove_arith after noce_try_store_flag_arith |
| has had a go at it. */ |
| |
| static int |
| noce_try_cmove (struct noce_if_info *if_info) |
| { |
| enum rtx_code code; |
| rtx target; |
| rtx_insn *seq; |
| |
| if (!noce_simple_bbs (if_info)) |
| return FALSE; |
| |
| if ((CONSTANT_P (if_info->a) || register_operand (if_info->a, VOIDmode)) |
| && (CONSTANT_P (if_info->b) || register_operand (if_info->b, VOIDmode))) |
| { |
| start_sequence (); |
| |
| code = GET_CODE (if_info->cond); |
| target = noce_emit_cmove (if_info, if_info->x, code, |
| XEXP (if_info->cond, 0), |
| XEXP (if_info->cond, 1), |
| if_info->a, if_info->b); |
| |
| if (target) |
| { |
| if (target != if_info->x) |
| noce_emit_move_insn (if_info->x, target); |
| |
| seq = end_ifcvt_sequence (if_info); |
| if (!seq || !targetm.noce_conversion_profitable_p (seq, if_info)) |
| return FALSE; |
| |
| emit_insn_before_setloc (seq, if_info->jump, |
| INSN_LOCATION (if_info->insn_a)); |
| if_info->transform_name = "noce_try_cmove"; |
| |
| return TRUE; |
| } |
| /* If both a and b are constants try a last-ditch transformation: |
| if (test) x = a; else x = b; |
| => x = (-(test != 0) & (b - a)) + a; |
| Try this only if the target-specific expansion above has failed. |
| The target-specific expander may want to generate sequences that |
| we don't know about, so give them a chance before trying this |
| approach. */ |
| else if (!targetm.have_conditional_execution () |
| && CONST_INT_P (if_info->a) && CONST_INT_P (if_info->b)) |
| { |
| machine_mode mode = GET_MODE (if_info->x); |
| HOST_WIDE_INT ifalse = INTVAL (if_info->a); |
| HOST_WIDE_INT itrue = INTVAL (if_info->b); |
| rtx target = noce_emit_store_flag (if_info, if_info->x, false, -1); |
| if (!target) |
| { |
| end_sequence (); |
| return FALSE; |
| } |
| |
| HOST_WIDE_INT diff = (unsigned HOST_WIDE_INT) itrue - ifalse; |
| /* Make sure we can represent the difference |
| between the two values. */ |
| if ((diff > 0) |
| != ((ifalse < 0) != (itrue < 0) ? ifalse < 0 : ifalse < itrue)) |
| { |
| end_sequence (); |
| return FALSE; |
| } |
| |
| diff = trunc_int_for_mode (diff, mode); |
| target = expand_simple_binop (mode, AND, |
| target, gen_int_mode (diff, mode), |
| if_info->x, 0, OPTAB_WIDEN); |
| if (target) |
| target = expand_simple_binop (mode, PLUS, |
| target, gen_int_mode (ifalse, mode), |
| if_info->x, 0, OPTAB_WIDEN); |
| if (target) |
| { |
| if (target != if_info->x) |
| noce_emit_move_insn (if_info->x, target); |
| |
| seq = end_ifcvt_sequence (if_info); |
| if (!seq || !targetm.noce_conversion_profitable_p (seq, if_info)) |
| return FALSE; |
| |
| emit_insn_before_setloc (seq, if_info->jump, |
| INSN_LOCATION (if_info->insn_a)); |
| if_info->transform_name = "noce_try_cmove"; |
| return TRUE; |
| } |
| else |
| { |
| end_sequence (); |
| return FALSE; |
| } |
| } |
| else |
| end_sequence (); |
| } |
| |
| return FALSE; |
| } |
| |
| /* Return true if X contains a conditional code mode rtx. */ |
| |
| static bool |
| contains_ccmode_rtx_p (rtx x) |
| { |
| subrtx_iterator::array_type array; |
| FOR_EACH_SUBRTX (iter, array, x, ALL) |
| if (GET_MODE_CLASS (GET_MODE (*iter)) == MODE_CC) |
| return true; |
| |
| return false; |
| } |
| |
| /* Helper for bb_valid_for_noce_process_p. Validate that |
| the rtx insn INSN is a single set that does not set |
| the conditional register CC and is in general valid for |
| if-conversion. */ |
| |
| static bool |
| insn_valid_noce_process_p (rtx_insn *insn, rtx cc) |
| { |
| if (!insn |
| || !NONJUMP_INSN_P (insn) |
| || (cc && set_of (cc, insn))) |
| return false; |
| |
| rtx sset = single_set (insn); |
| |
| /* Currently support only simple single sets in test_bb. */ |
| if (!sset |
| || !noce_operand_ok (SET_DEST (sset)) |
| || contains_ccmode_rtx_p (SET_DEST (sset)) |
| || !noce_operand_ok (SET_SRC (sset))) |
| return false; |
| |
| return true; |
| } |
| |
| |
| /* Return true iff the registers that the insns in BB_A set do not get |
| used in BB_B. If TO_RENAME is non-NULL then it is a location that will be |
| renamed later by the caller and so conflicts on it should be ignored |
| in this function. */ |
| |
| static bool |
| bbs_ok_for_cmove_arith (basic_block bb_a, basic_block bb_b, rtx to_rename) |
| { |
| rtx_insn *a_insn; |
| bitmap bba_sets = BITMAP_ALLOC (®_obstack); |
| |
| df_ref def; |
| df_ref use; |
| |
| FOR_BB_INSNS (bb_a, a_insn) |
| { |
| if (!active_insn_p (a_insn)) |
| continue; |
| |
| rtx sset_a = single_set (a_insn); |
| |
| if (!sset_a) |
| { |
| BITMAP_FREE (bba_sets); |
| return false; |
| } |
| /* Record all registers that BB_A sets. */ |
| FOR_EACH_INSN_DEF (def, a_insn) |
| if (!(to_rename && DF_REF_REG (def) == to_rename)) |
| bitmap_set_bit (bba_sets, DF_REF_REGNO (def)); |
| } |
| |
| rtx_insn *b_insn; |
| |
| FOR_BB_INSNS (bb_b, b_insn) |
| { |
| if (!active_insn_p (b_insn)) |
| continue; |
| |
| rtx sset_b = single_set (b_insn); |
| |
| if (!sset_b) |
| { |
| BITMAP_FREE (bba_sets); |
| return false; |
| } |
| |
| /* Make sure this is a REG and not some instance |
| of ZERO_EXTRACT or SUBREG or other dangerous stuff. |
| If we have a memory destination then we have a pair of simple |
| basic blocks performing an operation of the form [addr] = c ? a : b. |
| bb_valid_for_noce_process_p will have ensured that these are |
| the only stores present. In that case [addr] should be the location |
| to be renamed. Assert that the callers set this up properly. */ |
| if (MEM_P (SET_DEST (sset_b))) |
| gcc_assert (rtx_equal_p (SET_DEST (sset_b), to_rename)); |
| else if (!REG_P (SET_DEST (sset_b))) |
| { |
| BITMAP_FREE (bba_sets); |
| return false; |
| } |
| |
| /* If the insn uses a reg set in BB_A return false. */ |
| FOR_EACH_INSN_USE (use, b_insn) |
| { |
| if (bitmap_bit_p (bba_sets, DF_REF_REGNO (use))) |
| { |
| BITMAP_FREE (bba_sets); |
| return false; |
| } |
| } |
| |
| } |
| |
| BITMAP_FREE (bba_sets); |
| return true; |
| } |
| |
| /* Emit copies of all the active instructions in BB except the last. |
| This is a helper for noce_try_cmove_arith. */ |
| |
| static void |
| noce_emit_all_but_last (basic_block bb) |
| { |
| rtx_insn *last = last_active_insn (bb, FALSE); |
| rtx_insn *insn; |
| FOR_BB_INSNS (bb, insn) |
| { |
| if (insn != last && active_insn_p (insn)) |
| { |
| rtx_insn *to_emit = as_a <rtx_insn *> (copy_rtx (insn)); |
| |
| emit_insn (PATTERN (to_emit)); |
| } |
| } |
| } |
| |
| /* Helper for noce_try_cmove_arith. Emit the pattern TO_EMIT and return |
| the resulting insn or NULL if it's not a valid insn. */ |
| |
| static rtx_insn * |
| noce_emit_insn (rtx to_emit) |
| { |
| gcc_assert (to_emit); |
| rtx_insn *insn = emit_insn (to_emit); |
| |
| if (recog_memoized (insn) < 0) |
| return NULL; |
| |
| return insn; |
| } |
| |
| /* Helper for noce_try_cmove_arith. Emit a copy of the insns up to |
| and including the penultimate one in BB if it is not simple |
| (as indicated by SIMPLE). Then emit LAST_INSN as the last |
| insn in the block. The reason for that is that LAST_INSN may |
| have been modified by the preparation in noce_try_cmove_arith. */ |
| |
| static bool |
| noce_emit_bb (rtx last_insn, basic_block bb, bool simple) |
| { |
| if (bb && !simple) |
| noce_emit_all_but_last (bb); |
| |
| if (last_insn && !noce_emit_insn (last_insn)) |
| return false; |
| |
| return true; |
| } |
| |
| /* Try more complex cases involving conditional_move. */ |
| |
| static int |
| noce_try_cmove_arith (struct noce_if_info *if_info) |
| { |
| rtx a = if_info->a; |
| rtx b = if_info->b; |
| rtx x = if_info->x; |
| rtx orig_a, orig_b; |
| rtx_insn *insn_a, *insn_b; |
| bool a_simple = if_info->then_simple; |
| bool b_simple = if_info->else_simple; |
| basic_block then_bb = if_info->then_bb; |
| basic_block else_bb = if_info->else_bb; |
| rtx target; |
| int is_mem = 0; |
| enum rtx_code code; |
| rtx cond = if_info->cond; |
| rtx_insn *ifcvt_seq; |
| |
| /* A conditional move from two memory sources is equivalent to a |
| conditional on their addresses followed by a load. Don't do this |
| early because it'll screw alias analysis. Note that we've |
| already checked for no side effects. */ |
| if (cse_not_expected |
| && MEM_P (a) && MEM_P (b) |
| && MEM_ADDR_SPACE (a) == MEM_ADDR_SPACE (b)) |
| { |
| machine_mode address_mode = get_address_mode (a); |
| |
| a = XEXP (a, 0); |
| b = XEXP (b, 0); |
| x = gen_reg_rtx (address_mode); |
| is_mem = 1; |
| } |
| |
| /* ??? We could handle this if we knew that a load from A or B could |
| not trap or fault. This is also true if we've already loaded |
| from the address along the path from ENTRY. */ |
| else if (may_trap_or_fault_p (a) || may_trap_or_fault_p (b)) |
| return FALSE; |
| |
| /* if (test) x = a + b; else x = c - d; |
| => y = a + b; |
| x = c - d; |
| if (test) |
| x = y; |
| */ |
| |
| code = GET_CODE (cond); |
| insn_a = if_info->insn_a; |
| insn_b = if_info->insn_b; |
| |
| machine_mode x_mode = GET_MODE (x); |
| |
| if (!can_conditionally_move_p (x_mode)) |
| return FALSE; |
| |
| /* Possibly rearrange operands to make things come out more natural. */ |
| if (noce_reversed_cond_code (if_info) != UNKNOWN) |
| { |
| int reversep = 0; |
| if (rtx_equal_p (b, x)) |
| reversep = 1; |
| else if (general_operand (b, GET_MODE (b))) |
| reversep = 1; |
| |
| if (reversep) |
| { |
| if (if_info->rev_cond) |
| { |
| cond = if_info->rev_cond; |
| code = GET_CODE (cond); |
| } |
| else |
| code = reversed_comparison_code (cond, if_info->jump); |
| std::swap (a, b); |
| std::swap (insn_a, insn_b); |
| std::swap (a_simple, b_simple); |
| std::swap (then_bb, else_bb); |
| } |
| } |
| |
| if (then_bb && else_bb |
| && (!bbs_ok_for_cmove_arith (then_bb, else_bb, if_info->orig_x) |
| || !bbs_ok_for_cmove_arith (else_bb, then_bb, if_info->orig_x))) |
| return FALSE; |
| |
| start_sequence (); |
| |
| /* If one of the blocks is empty then the corresponding B or A value |
| came from the test block. The non-empty complex block that we will |
| emit might clobber the register used by B or A, so move it to a pseudo |
| first. */ |
| |
| rtx tmp_a = NULL_RTX; |
| rtx tmp_b = NULL_RTX; |
| |
| if (b_simple || !else_bb) |
| tmp_b = gen_reg_rtx (x_mode); |
| |
| if (a_simple || !then_bb) |
| tmp_a = gen_reg_rtx (x_mode); |
| |
| orig_a = a; |
| orig_b = b; |
| |
| rtx emit_a = NULL_RTX; |
| rtx emit_b = NULL_RTX; |
| rtx_insn *tmp_insn = NULL; |
| bool modified_in_a = false; |
| bool modified_in_b = false; |
| /* If either operand is complex, load it into a register first. |
| The best way to do this is to copy the original insn. In this |
| way we preserve any clobbers etc that the insn may have had. |
| This is of course not possible in the IS_MEM case. */ |
| |
| if (! general_operand (a, GET_MODE (a)) || tmp_a) |
| { |
| |
| if (is_mem) |
| { |
| rtx reg = gen_reg_rtx (GET_MODE (a)); |
| emit_a = gen_rtx_SET (reg, a); |
| } |
| else |
| { |
| if (insn_a) |
| { |
| a = tmp_a ? tmp_a : gen_reg_rtx (GET_MODE (a)); |
| |
| rtx_insn *copy_of_a = as_a <rtx_insn *> (copy_rtx (insn_a)); |
| rtx set = single_set (copy_of_a); |
| SET_DEST (set) = a; |
| |
| emit_a = PATTERN (copy_of_a); |
| } |
| else |
| { |
| rtx tmp_reg = tmp_a ? tmp_a : gen_reg_rtx (GET_MODE (a)); |
| emit_a = gen_rtx_SET (tmp_reg, a); |
| a = tmp_reg; |
| } |
| } |
| } |
| |
| if (! general_operand (b, GET_MODE (b)) || tmp_b) |
| { |
| if (is_mem) |
| { |
| rtx reg = gen_reg_rtx (GET_MODE (b)); |
| emit_b = gen_rtx_SET (reg, b); |
| } |
| else |
| { |
| if (insn_b) |
| { |
| b = tmp_b ? tmp_b : gen_reg_rtx (GET_MODE (b)); |
| rtx_insn *copy_of_b = as_a <rtx_insn *> (copy_rtx (insn_b)); |
| rtx set = single_set (copy_of_b); |
| |
| SET_DEST (set) = b; |
| emit_b = PATTERN (copy_of_b); |
| } |
| else |
| { |
| rtx tmp_reg = tmp_b ? tmp_b : gen_reg_rtx (GET_MODE (b)); |
| emit_b = gen_rtx_SET (tmp_reg, b); |
| b = tmp_reg; |
| } |
| } |
| } |
| |
| modified_in_a = emit_a != NULL_RTX && modified_in_p (orig_b, emit_a); |
| if (tmp_b && then_bb) |
| { |
| FOR_BB_INSNS (then_bb, tmp_insn) |
| /* Don't check inside insn_a. We will have changed it to emit_a |
| with a destination that doesn't conflict. */ |
| if (!(insn_a && tmp_insn == insn_a) |
| && modified_in_p (orig_b, tmp_insn)) |
| { |
| modified_in_a = true; |
| break; |
| } |
| |
| } |
| |
| modified_in_b = emit_b != NULL_RTX && modified_in_p (orig_a, emit_b); |
| if (tmp_a && else_bb) |
| { |
| FOR_BB_INSNS (else_bb, tmp_insn) |
| /* Don't check inside insn_b. We will have changed it to emit_b |
| with a destination that doesn't conflict. */ |
| if (!(insn_b && tmp_insn == insn_b) |
| && modified_in_p (orig_a, tmp_insn)) |
| { |
| modified_in_b = true; |
| break; |
| } |
| } |
| |
| /* If insn to set up A clobbers any registers B depends on, try to |
| swap insn that sets up A with the one that sets up B. If even |
| that doesn't help, punt. */ |
| if (modified_in_a && !modified_in_b) |
| { |
| if (!noce_emit_bb (emit_b, else_bb, b_simple)) |
| goto end_seq_and_fail; |
| |
| if (!noce_emit_bb (emit_a, then_bb, a_simple)) |
| goto end_seq_and_fail; |
| } |
| else if (!modified_in_a) |
| { |
| if (!noce_emit_bb (emit_a, then_bb, a_simple)) |
| goto end_seq_and_fail; |
| |
| if (!noce_emit_bb (emit_b, else_bb, b_simple)) |
| goto end_seq_and_fail; |
| } |
| else |
| goto end_seq_and_fail; |
| |
| target = noce_emit_cmove (if_info, x, code, XEXP (cond, 0), XEXP (cond, 1), |
| a, b); |
| |
| if (! target) |
| goto end_seq_and_fail; |
| |
| /* If we're handling a memory for above, emit the load now. */ |
| if (is_mem) |
| { |
| rtx mem = gen_rtx_MEM (GET_MODE (if_info->x), target); |
| |
| /* Copy over flags as appropriate. */ |
| if (MEM_VOLATILE_P (if_info->a) || MEM_VOLATILE_P (if_info->b)) |
| MEM_VOLATILE_P (mem) = 1; |
| if (MEM_ALIAS_SET (if_info->a) == MEM_ALIAS_SET (if_info->b)) |
| set_mem_alias_set (mem, MEM_ALIAS_SET (if_info->a)); |
| set_mem_align (mem, |
| MIN (MEM_ALIGN (if_info->a), MEM_ALIGN (if_info->b))); |
| |
| gcc_assert (MEM_ADDR_SPACE (if_info->a) == MEM_ADDR_SPACE (if_info->b)); |
| set_mem_addr_space (mem, MEM_ADDR_SPACE (if_info->a)); |
| |
| noce_emit_move_insn (if_info->x, mem); |
| } |
| else if (target != x) |
| noce_emit_move_insn (x, target); |
| |
| ifcvt_seq = end_ifcvt_sequence (if_info); |
| if (!ifcvt_seq || !targetm.noce_conversion_profitable_p (ifcvt_seq, if_info)) |
| return FALSE; |
| |
| emit_insn_before_setloc (ifcvt_seq, if_info->jump, |
| INSN_LOCATION (if_info->insn_a)); |
| if_info->transform_name = "noce_try_cmove_arith"; |
| return TRUE; |
| |
| end_seq_and_fail: |
| end_sequence (); |
| return FALSE; |
| } |
| |
| /* For most cases, the simplified condition we found is the best |
| choice, but this is not the case for the min/max/abs transforms. |
| For these we wish to know that it is A or B in the condition. */ |
| |
| static rtx |
| noce_get_alt_condition (struct noce_if_info *if_info, rtx target, |
| rtx_insn **earliest) |
| { |
| rtx cond, set; |
| rtx_insn *insn; |
| int reverse; |
| |
| /* If target is already mentioned in the known condition, return it. */ |
| if (reg_mentioned_p (target, if_info->cond)) |
| { |
| *earliest = if_info->cond_earliest; |
| return if_info->cond; |
| } |
| |
| set = pc_set (if_info->jump); |
| cond = XEXP (SET_SRC (set), 0); |
| reverse |
| = GET_CODE (XEXP (SET_SRC (set), 2)) == LABEL_REF |
| && label_ref_label (XEXP (SET_SRC (set), 2)) == JUMP_LABEL (if_info->jump); |
| if (if_info->then_else_reversed) |
| reverse = !reverse; |
| |
| /* If we're looking for a constant, try to make the conditional |
| have that constant in it. There are two reasons why it may |
| not have the constant we want: |
| |
| 1. GCC may have needed to put the constant in a register, because |
| the target can't compare directly against that constant. For |
| this case, we look for a SET immediately before the comparison |
| that puts a constant in that register. |
| |
| 2. GCC may have canonicalized the conditional, for example |
| replacing "if x < 4" with "if x <= 3". We can undo that (or |
| make equivalent types of changes) to get the constants we need |
| if they're off by one in the right direction. */ |
| |
| if (CONST_INT_P (target)) |
| { |
| enum rtx_code code = GET_CODE (if_info->cond); |
| rtx op_a = XEXP (if_info->cond, 0); |
| rtx op_b = XEXP (if_info->cond, 1); |
| rtx_insn *prev_insn; |
| |
| /* First, look to see if we put a constant in a register. */ |
| prev_insn = prev_nonnote_insn (if_info->cond_earliest); |
| if (prev_insn |
| && BLOCK_FOR_INSN (prev_insn) |
| == BLOCK_FOR_INSN (if_info->cond_earliest) |
| && INSN_P (prev_insn) |
| && GET_CODE (PATTERN (prev_insn)) == SET) |
| { |
| rtx src = find_reg_equal_equiv_note (prev_insn); |
| if (!src) |
| src = SET_SRC (PATTERN (prev_insn)); |
| if (CONST_INT_P (src)) |
| { |
| if (rtx_equal_p (op_a, SET_DEST (PATTERN (prev_insn)))) |
| op_a = src; |
| else if (rtx_equal_p (op_b, SET_DEST (PATTERN (prev_insn)))) |
| op_b = src; |
| |
| if (CONST_INT_P (op_a)) |
| { |
| std::swap (op_a, op_b); |
| code = swap_condition (code); |
| } |
| } |
| } |
| |
| /* Now, look to see if we can get the right constant by |
| adjusting the conditional. */ |
| if (CONST_INT_P (op_b)) |
| { |
| HOST_WIDE_INT desired_val = INTVAL (target); |
| HOST_WIDE_INT actual_val = INTVAL (op_b); |
| |
| switch (code) |
| { |
| case LT: |
| if (desired_val != HOST_WIDE_INT_MAX |
| && actual_val == desired_val + 1) |
| { |
| code = LE; |
| op_b = GEN_INT (desired_val); |
| } |
| break; |
| case LE: |
| if (desired_val != HOST_WIDE_INT_MIN |
| && actual_val == desired_val - 1) |
| { |
| code = LT; |
| op_b = GEN_INT (desired_val); |
| } |
| break; |
| case GT: |
| if (desired_val != HOST_WIDE_INT_MIN |
| && actual_val == desired_val - 1) |
| { |
| code = GE; |
| op_b = GEN_INT (desired_val); |
| } |
| break; |
| case GE: |
| if (desired_val != HOST_WIDE_INT_MAX |
| && actual_val == desired_val + 1) |
| { |
| code = GT; |
| op_b = GEN_INT (desired_val); |
| } |
| break; |
| default: |
| break; |
| } |
| } |
| |
| /* If we made any changes, generate a new conditional that is |
| equivalent to what we started with, but has the right |
| constants in it. */ |
| if (code != GET_CODE (if_info->cond) |
| || op_a != XEXP (if_info->cond, 0) |
| || op_b != XEXP (if_info->cond, 1)) |
| { |
| cond = gen_rtx_fmt_ee (code, GET_MODE (cond), op_a, op_b); |
| *earliest = if_info->cond_earliest; |
| return cond; |
| } |
| } |
| |
| cond = canonicalize_condition (if_info->jump, cond, reverse, |
| earliest, target, have_cbranchcc4, true); |
| if (! cond || ! reg_mentioned_p (target, cond)) |
| return NULL; |
| |
| /* We almost certainly searched back to a different place. |
| Need to re-verify correct lifetimes. */ |
| |
| /* X may not be mentioned in the range (cond_earliest, jump]. */ |
| for (insn = if_info->jump; insn != *earliest; insn = PREV_INSN (insn)) |
| if (INSN_P (insn) && reg_overlap_mentioned_p (if_info->x, PATTERN (insn))) |
| return NULL; |
| |
| /* A and B may not be modified in the range [cond_earliest, jump). */ |
| for (insn = *earliest; insn != if_info->jump; insn = NEXT_INSN (insn)) |
| if (INSN_P (insn) |
| && (modified_in_p (if_info->a, insn) |
| || modified_in_p (if_info->b, insn))) |
| return NULL; |
| |
| return cond; |
| } |
| |
| /* Convert "if (a < b) x = a; else x = b;" to "x = min(a, b);", etc. */ |
| |
| static int |
| noce_try_minmax (struct noce_if_info *if_info) |
| { |
| rtx cond, target; |
| rtx_insn *earliest, *seq; |
| enum rtx_code code, op; |
| int unsignedp; |
| |
| if (!noce_simple_bbs (if_info)) |
| return FALSE; |
| |
| /* ??? Reject modes with NaNs or signed zeros since we don't know how |
| they will be resolved with an SMIN/SMAX. It wouldn't be too hard |
| to get the target to tell us... */ |
| if (HONOR_SIGNED_ZEROS (if_info->x) |
| || HONOR_NANS (if_info->x)) |
| return FALSE; |
| |
| cond = noce_get_alt_condition (if_info, if_info->a, &earliest); |
| if (!cond) |
| return FALSE; |
| |
| /* Verify the condition is of the form we expect, and canonicalize |
| the comparison code. */ |
| code = GET_CODE (cond); |
| if (rtx_equal_p (XEXP (cond, 0), if_info->a)) |
| { |
| if (! rtx_equal_p (XEXP (cond, 1), if_info->b)) |
| return FALSE; |
| } |
| else if (rtx_equal_p (XEXP (cond, 1), if_info->a)) |
| { |
| if (! rtx_equal_p (XEXP (cond, 0), if_info->b)) |
| return FALSE; |
| code = swap_condition (code); |
| } |
| else |
| return FALSE; |
| |
| /* Determine what sort of operation this is. Note that the code is for |
| a taken branch, so the code->operation mapping appears backwards. */ |
| switch (code) |
| { |
| case LT: |
| case LE: |
| case UNLT: |
| case UNLE: |
| op = SMAX; |
| unsignedp = 0; |
| break; |
| case GT: |
| case GE: |
| case UNGT: |
| case UNGE: |
| op = SMIN; |
| unsignedp = 0; |
| break; |
| case LTU: |
| case LEU: |
| op = UMAX; |
| unsignedp = 1; |
| break; |
| case GTU: |
| case GEU: |
| op = UMIN; |
| unsignedp = 1; |
| break; |
| default: |
| return FALSE; |
| } |
| |
| start_sequence (); |
| |
| target = expand_simple_binop (GET_MODE (if_info->x), op, |
| if_info->a, if_info->b, |
| if_info->x, unsignedp, OPTAB_WIDEN); |
| if (! target) |
| { |
| end_sequence (); |
| return FALSE; |
| } |
| if (target != if_info->x) |
| noce_emit_move_insn (if_info->x, target); |
| |
| seq = end_ifcvt_sequence (if_info); |
| if (!seq) |
| return FALSE; |
| |
| emit_insn_before_setloc (seq, if_info->jump, INSN_LOCATION (if_info->insn_a)); |
| if_info->cond = cond; |
| if_info->cond_earliest = earliest; |
| if_info->rev_cond = NULL_RTX; |
| if_info->transform_name = "noce_try_minmax"; |
| |
| return TRUE; |
| } |
| |
| /* Convert "if (a < 0) x = -a; else x = a;" to "x = abs(a);", |
| "if (a < 0) x = ~a; else x = a;" to "x = one_cmpl_abs(a);", |
| etc. */ |
| |
| static int |
| noce_try_abs (struct noce_if_info *if_info) |
| { |
| rtx cond, target, a, b, c; |
| rtx_insn *earliest, *seq; |
| int negate; |
| bool one_cmpl = false; |
| |
| if (!noce_simple_bbs (if_info)) |
| return FALSE; |
| |
| /* Reject modes with signed zeros. */ |
| if (HONOR_SIGNED_ZEROS (if_info->x)) |
| return FALSE; |
| |
| /* Recognize A and B as constituting an ABS or NABS. The canonical |
| form is a branch around the negation, taken when the object is the |
| first operand of a comparison against 0 that evaluates to true. */ |
| a = if_info->a; |
| b = if_info->b; |
| if (GET_CODE (a) == NEG && rtx_equal_p (XEXP (a, 0), b)) |
| negate = 0; |
| else if (GET_CODE (b) == NEG && rtx_equal_p (XEXP (b, 0), a)) |
| { |
| std::swap (a, b); |
| negate = 1; |
| } |
| else if (GET_CODE (a) == NOT && rtx_equal_p (XEXP (a, 0), b)) |
| { |
| negate = 0; |
| one_cmpl = true; |
| } |
| else if (GET_CODE (b) == NOT && rtx_equal_p (XEXP (b, 0), a)) |
| { |
| std::swap (a, b); |
| negate = 1; |
| one_cmpl = true; |
| } |
| else |
| return FALSE; |
| |
| cond = noce_get_alt_condition (if_info, b, &earliest); |
| if (!cond) |
| return FALSE; |
| |
| /* Verify the condition is of the form we expect. */ |
| if (rtx_equal_p (XEXP (cond, 0), b)) |
| c = XEXP (cond, 1); |
| else if (rtx_equal_p (XEXP (cond, 1), b)) |
| { |
| c = XEXP (cond, 0); |
| negate = !negate; |
| } |
| else |
| return FALSE; |
| |
| /* Verify that C is zero. Search one step backward for a |
| REG_EQUAL note or a simple source if necessary. */ |
| if (REG_P (c)) |
| { |
| rtx set; |
| rtx_insn *insn = prev_nonnote_insn (earliest); |
| if (insn |
| && BLOCK_FOR_INSN (insn) == BLOCK_FOR_INSN (earliest) |
| && (set = single_set (insn)) |
| && rtx_equal_p (SET_DEST (set), c)) |
| { |
| rtx note = find_reg_equal_equiv_note (insn); |
| if (note) |
| c = XEXP (note, 0); |
| else |
| c = SET_SRC (set); |
| } |
| else |
| return FALSE; |
| } |
| if (MEM_P (c) |
| && GET_CODE (XEXP (c, 0)) == SYMBOL_REF |
| && CONSTANT_POOL_ADDRESS_P (XEXP (c, 0))) |
| c = get_pool_constant (XEXP (c, 0)); |
| |
| /* Work around funny ideas get_condition has wrt canonicalization. |
| Note that these rtx constants are known to be CONST_INT, and |
| therefore imply integer comparisons. |
| The one_cmpl case is more complicated, as we want to handle |
| only x < 0 ? ~x : x or x >= 0 ? x : ~x to one_cmpl_abs (x) |
| and x < 0 ? x : ~x or x >= 0 ? ~x : x to ~one_cmpl_abs (x), |
| but not other cases (x > -1 is equivalent of x >= 0). */ |
| if (c == constm1_rtx && GET_CODE (cond) == GT) |
| ; |
| else if (c == const1_rtx && GET_CODE (cond) == LT) |
| { |
| if (one_cmpl) |
| return FALSE; |
| } |
| else if (c == CONST0_RTX (GET_MODE (b))) |
| { |
| if (one_cmpl |
| && GET_CODE (cond) != GE |
| && GET_CODE (cond) != LT) |
| return FALSE; |
| } |
| else |
| return FALSE; |
| |
| /* Determine what sort of operation this is. */ |
| switch (GET_CODE (cond)) |
| { |
| case LT: |
| case LE: |
| case UNLT: |
| case UNLE: |
| negate = !negate; |
| break; |
| case GT: |
| case GE: |
| case UNGT: |
| case UNGE: |
| break; |
| default: |
| return FALSE; |
| } |
| |
| start_sequence (); |
| if (one_cmpl) |
| target = expand_one_cmpl_abs_nojump (GET_MODE (if_info->x), b, |
| if_info->x); |
| else |
| target = expand_abs_nojump (GET_MODE (if_info->x), b, if_info->x, 1); |
| |
| /* ??? It's a quandary whether cmove would be better here, especially |
| for integers. Perhaps combine will clean things up. */ |
| if (target && negate) |
| { |
| if (one_cmpl) |
| target = expand_simple_unop (GET_MODE (target), NOT, target, |
| if_info->x, 0); |
| else |
| target = expand_simple_unop (GET_MODE (target), NEG, target, |
| if_info->x, 0); |
| } |
| |
| if (! target) |
| { |
| end_sequence (); |
| return FALSE; |
| } |
| |
| if (target != if_info->x) |
| noce_emit_move_insn (if_info->x, target); |
| |
| seq = end_ifcvt_sequence (if_info); |
| if (!seq) |
| return FALSE; |
| |
| emit_insn_before_setloc (seq, if_info->jump, INSN_LOCATION (if_info->insn_a)); |
| if_info->cond = cond; |
| if_info->cond_earliest = earliest; |
| if_info->rev_cond = NULL_RTX; |
| if_info->transform_name = "noce_try_abs"; |
| |
| return TRUE; |
| } |
| |
| /* Convert "if (m < 0) x = b; else x = 0;" to "x = (m >> C) & b;". */ |
| |
| static int |
| noce_try_sign_mask (struct noce_if_info *if_info) |
| { |
| rtx cond, t, m, c; |
| rtx_insn *seq; |
| machine_mode mode; |
| enum rtx_code code; |
| bool t_unconditional; |
| |
| if (!noce_simple_bbs (if_info)) |
| return FALSE; |
| |
| cond = if_info->cond; |
| code = GET_CODE (cond); |
| m = XEXP (cond, 0); |
| c = XEXP (cond, 1); |
| |
| t = NULL_RTX; |
| if (if_info->a == const0_rtx) |
| { |
| if ((code == LT && c == const0_rtx) |
| || (code == LE && c == constm1_rtx)) |
| t = if_info->b; |
| } |
| else if (if_info->b == const0_rtx) |
| { |
| if ((code == GE && c == const0_rtx) |
| || (code == GT && c == constm1_rtx)) |
| t = if_info->a; |
| } |
| |
| if (! t || side_effects_p (t)) |
| return FALSE; |
| |
| /* We currently don't handle different modes. */ |
| mode = GET_MODE (t); |
| if (GET_MODE (m) != mode) |
| return FALSE; |
| |
| /* This is only profitable if T is unconditionally executed/evaluated in the |
| original insn sequence or T is cheap. The former happens if B is the |
| non-zero (T) value and if INSN_B was taken from TEST_BB, or there was no |
| INSN_B which can happen for e.g. conditional stores to memory. For the |
| cost computation use the block TEST_BB where the evaluation will end up |
| after the transformation. */ |
| t_unconditional = |
| (t == if_info->b |
| && (if_info->insn_b == NULL_RTX |
| || BLOCK_FOR_INSN (if_info->insn_b) == if_info->test_bb)); |
| if (!(t_unconditional |
| || (set_src_cost (t, mode, if_info->speed_p) |
| < COSTS_N_INSNS (2)))) |
| return FALSE; |
| |
| start_sequence (); |
| /* Use emit_store_flag to generate "m < 0 ? -1 : 0" instead of expanding |
| "(signed) m >> 31" directly. This benefits targets with specialized |
| insns to obtain the signmask, but still uses ashr_optab otherwise. */ |
| m = emit_store_flag (gen_reg_rtx (mode), LT, m, const0_rtx, mode, 0, -1); |
| t = m ? expand_binop (mode, and_optab, m, t, NULL_RTX, 0, OPTAB_DIRECT) |
| : NULL_RTX; |
| |
| if (!t) |
| { |
| end_sequence (); |
| return FALSE; |
| } |
| |
| noce_emit_move_insn (if_info->x, t); |
| |
| seq = end_ifcvt_sequence (if_info); |
| if (!seq) |
| return FALSE; |
| |
| emit_insn_before_setloc (seq, if_info->jump, INSN_LOCATION (if_info->insn_a)); |
| if_info->transform_name = "noce_try_sign_mask"; |
| |
| return TRUE; |
| } |
| |
| |
| /* Optimize away "if (x & C) x |= C" and similar bit manipulation |
| transformations. */ |
| |
| static int |
| noce_try_bitop (struct noce_if_info *if_info) |
| { |
| rtx cond, x, a, result; |
| rtx_insn *seq; |
| scalar_int_mode mode; |
| enum rtx_code code; |
| int bitnum; |
| |
| x = if_info->x; |
| cond = if_info->cond; |
| code = GET_CODE (cond); |
| |
| /* Check for an integer operation. */ |
| if (!is_a <scalar_int_mode> (GET_MODE (x), &mode)) |
| return FALSE; |
| |
| if (!noce_simple_bbs (if_info)) |
| return FALSE; |
| |
| /* Check for no else condition. */ |
| if (! rtx_equal_p (x, if_info->b)) |
| return FALSE; |
| |
| /* Check for a suitable condition. */ |
| if (code != NE && code != EQ) |
| return FALSE; |
| if (XEXP (cond, 1) != const0_rtx) |
| return FALSE; |
| cond = XEXP (cond, 0); |
| |
| /* ??? We could also handle AND here. */ |
| if (GET_CODE (cond) == ZERO_EXTRACT) |
| { |
| if (XEXP (cond, 1) != const1_rtx |
| || !CONST_INT_P (XEXP (cond, 2)) |
| || ! rtx_equal_p (x, XEXP (cond, 0))) |
| return FALSE; |
| bitnum = INTVAL (XEXP (cond, 2)); |
| if (BITS_BIG_ENDIAN) |
| bitnum = GET_MODE_BITSIZE (mode) - 1 - bitnum; |
| if (bitnum < 0 || bitnum >= HOST_BITS_PER_WIDE_INT) |
| return FALSE; |
| } |
| else |
| return FALSE; |
| |
| a = if_info->a; |
| if (GET_CODE (a) == IOR || GET_CODE (a) == XOR) |
| { |
| /* Check for "if (X & C) x = x op C". */ |
| if (! rtx_equal_p (x, XEXP (a, 0)) |
| || !CONST_INT_P (XEXP (a, 1)) |
| || (INTVAL (XEXP (a, 1)) & GET_MODE_MASK (mode)) |
| != HOST_WIDE_INT_1U << bitnum) |
| return FALSE; |
| |
| /* if ((x & C) == 0) x |= C; is transformed to x |= C. */ |
| /* if ((x & C) != 0) x |= C; is transformed to nothing. */ |
| if (GET_CODE (a) == IOR) |
| result = (code == NE) ? a : NULL_RTX; |
| else if (code == NE) |
| { |
| /* if ((x & C) == 0) x ^= C; is transformed to x |= C. */ |
| result = gen_int_mode (HOST_WIDE_INT_1 << bitnum, mode); |
| result = simplify_gen_binary (IOR, mode, x, result); |
| } |
| else |
| { |
| /* if ((x & C) != 0) x ^= C; is transformed to x &= ~C. */ |
| result = gen_int_mode (~(HOST_WIDE_INT_1 << bitnum), mode); |
| result = simplify_gen_binary (AND, mode, x, result); |
| } |
| } |
| else if (GET_CODE (a) == AND) |
| { |
| /* Check for "if (X & C) x &= ~C". */ |
| if (! rtx_equal_p (x, XEXP (a, 0)) |
| || !CONST_INT_P (XEXP (a, 1)) |
| || (INTVAL (XEXP (a, 1)) & GET_MODE_MASK (mode)) |
| != (~(HOST_WIDE_INT_1 << bitnum) & GET_MODE_MASK (mode))) |
| return FALSE; |
| |
| /* if ((x & C) == 0) x &= ~C; is transformed to nothing. */ |
| /* if ((x & C) != 0) x &= ~C; is transformed to x &= ~C. */ |
| result = (code == EQ) ? a : NULL_RTX; |
| } |
| else |
| return FALSE; |
| |
| if (result) |
| { |
| start_sequence (); |
| noce_emit_move_insn (x, result); |
| seq = end_ifcvt_sequence (if_info); |
| if (!seq) |
| return FALSE; |
| |
| emit_insn_before_setloc (seq, if_info->jump, |
| INSN_LOCATION (if_info->insn_a)); |
| } |
| if_info->transform_name = "noce_try_bitop"; |
| return TRUE; |
| } |
| |
| |
| /* Similar to get_condition, only the resulting condition must be |
| valid at JUMP, instead of at EARLIEST. |
| |
| If THEN_ELSE_REVERSED is true, the fallthrough does not go to the |
| THEN block of the caller, and we have to reverse the condition. */ |
| |
| static rtx |
| noce_get_condition (rtx_insn *jump, rtx_insn **earliest, bool then_else_reversed) |
| { |
| rtx cond, set, tmp; |
| bool reverse; |
| |
| if (! any_condjump_p (jump)) |
| return NULL_RTX; |
| |
| set = pc_set (jump); |
| |
| /* If this branches to JUMP_LABEL when the condition is false, |
| reverse the condition. */ |
| reverse = (GET_CODE (XEXP (SET_SRC (set), 2)) == LABEL_REF |
| && label_ref_label (XEXP (SET_SRC (set), 2)) == JUMP_LABEL (jump)); |
| |
| /* We may have to reverse because the caller's if block is not canonical, |
| i.e. the THEN block isn't the fallthrough block for the TEST block |
| (see find_if_header). */ |
| if (then_else_reversed) |
| reverse = !reverse; |
| |
| /* If the condition variable is a register and is MODE_INT, accept it. */ |
| |
| cond = XEXP (SET_SRC (set), 0); |
| tmp = XEXP (cond, 0); |
| if (REG_P (tmp) && GET_MODE_CLASS (GET_MODE (tmp)) == MODE_INT |
| && (GET_MODE (tmp) != BImode |
| || !targetm.small_register_classes_for_mode_p (BImode))) |
| { |
| *earliest = jump; |
| |
| if (reverse) |
| cond = gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond)), |
| GET_MODE (cond), tmp, XEXP (cond, 1)); |
| return cond; |
| } |
| |
| /* Otherwise, fall back on canonicalize_condition to do the dirty |
| work of manipulating MODE_CC values and COMPARE rtx codes. */ |
| tmp = canonicalize_condition (jump, cond, reverse, earliest, |
| NULL_RTX, have_cbranchcc4, true); |
| |
| /* We don't handle side-effects in the condition, like handling |
| REG_INC notes and making sure no duplicate conditions are emitted. */ |
| if (tmp != NULL_RTX && side_effects_p (tmp)) |
| return NULL_RTX; |
| |
| return tmp; |
| } |
| |
| /* Return true if OP is ok for if-then-else processing. */ |
| |
| static int |
| noce_operand_ok (const_rtx op) |
| { |
| if (side_effects_p (op)) |
| return FALSE; |
| |
| /* We special-case memories, so handle any of them with |
| no address side effects. */ |
| if (MEM_P (op)) |
| return ! side_effects_p (XEXP (op, 0)); |
| |
| return ! may_trap_p (op); |
| } |
| |
| /* Return true iff basic block TEST_BB is valid for noce if-conversion. |
| The condition used in this if-conversion is in COND. |
| In practice, check that TEST_BB ends with a single set |
| x := a and all previous computations |
| in TEST_BB don't produce any values that are live after TEST_BB. |
| In other words, all the insns in TEST_BB are there only |
| to compute a value for x. Add the rtx cost of the insns |
| in TEST_BB to COST. Record whether TEST_BB is a single simple |
| set instruction in SIMPLE_P. */ |
| |
| static bool |
| bb_valid_for_noce_process_p (basic_block test_bb, rtx cond, |
| unsigned int *cost, bool *simple_p) |
| { |
| if (!test_bb) |
| return false; |
| |
| rtx_insn *last_insn = last_active_insn (test_bb, FALSE); |
| rtx last_set = NULL_RTX; |
| |
| rtx cc = cc_in_cond (cond); |
| |
| if (!insn_valid_noce_process_p (last_insn, cc)) |
| return false; |
| last_set = single_set (last_insn); |
| |
| rtx x = SET_DEST (last_set); |
| rtx_insn *first_insn = first_active_insn (test_bb); |
| rtx first_set = single_set (first_insn); |
| |
| if (!first_set) |
| return false; |
| |
| /* We have a single simple set, that's okay. */ |
| bool speed_p = optimize_bb_for_speed_p (test_bb); |
| |
| if (first_insn == last_insn) |
| { |
| *simple_p = noce_operand_ok (SET_DEST (first_set)); |
| *cost += pattern_cost (first_set, speed_p); |
| return *simple_p; |
| } |
| |
| rtx_insn *prev_last_insn = PREV_INSN (last_insn); |
| gcc_assert (prev_last_insn); |
| |
| /* For now, disallow setting x multiple times in test_bb. */ |
| if (REG_P (x) && reg_set_between_p (x, first_insn, prev_last_insn)) |
| return false; |
| |
| bitmap test_bb_temps = BITMAP_ALLOC (®_obstack); |
| |
| /* The regs that are live out of test_bb. */ |
| bitmap test_bb_live_out = df_get_live_out (test_bb); |
| |
| int potential_cost = pattern_cost (last_set, speed_p); |
| rtx_insn *insn; |
| FOR_BB_INSNS (test_bb, insn) |
| { |
| if (insn != last_insn) |
| { |
| if (!active_insn_p (insn)) |
| continue; |
| |
| if (!insn_valid_noce_process_p (insn, cc)) |
| goto free_bitmap_and_fail; |
| |
| rtx sset = single_set (insn); |
| gcc_assert (sset); |
| |
| if (contains_mem_rtx_p (SET_SRC (sset)) |
| || !REG_P (SET_DEST (sset)) |
| || reg_overlap_mentioned_p (SET_DEST (sset), cond)) |
| goto free_bitmap_and_fail; |
| |
| potential_cost += pattern_cost (sset, speed_p); |
| bitmap_set_bit (test_bb_temps, REGNO (SET_DEST (sset))); |
| } |
| } |
| |
| /* If any of the intermediate results in test_bb are live after test_bb |
| then fail. */ |
| if (bitmap_intersect_p (test_bb_live_out, test_bb_temps)) |
| goto free_bitmap_and_fail; |
| |
| BITMAP_FREE (test_bb_temps); |
| *cost += potential_cost; |
| *simple_p = false; |
| return true; |
| |
| free_bitmap_and_fail: |
| BITMAP_FREE (test_bb_temps); |
| return false; |
| } |
| |
| /* We have something like: |
| |
| if (x > y) |
| { i = a; j = b; k = c; } |
| |
| Make it: |
| |
| tmp_i = (x > y) ? a : i; |
| tmp_j = (x > y) ? b : j; |
| tmp_k = (x > y) ? c : k; |
| i = tmp_i; |
| j = tmp_j; |
| k = tmp_k; |
| |
| Subsequent passes are expected to clean up the extra moves. |
| |
| Look for special cases such as writes to one register which are |
| read back in another SET, as might occur in a swap idiom or |
| similar. |
| |
| These look like: |
| |
| if (x > y) |
| i = a; |
| j = i; |
| |
| Which we want to rewrite to: |
| |
| tmp_i = (x > y) ? a : i; |
| tmp_j = (x > y) ? tmp_i : j; |
| i = tmp_i; |
| j = tmp_j; |
| |
| We can catch these when looking at (SET x y) by keeping a list of the |
| registers we would have targeted before if-conversion and looking back |
| through it for an overlap with Y. If we find one, we rewire the |
| conditional set to use the temporary we introduced earlier. |
| |
| IF_INFO contains the useful information about the block structure and |
| jump instructions. */ |
| |
| static int |
| noce_convert_multiple_sets (struct noce_if_info *if_info) |
| { |
| basic_block test_bb = if_info->test_bb; |
| basic_block then_bb = if_info->then_bb; |
| basic_block join_bb = if_info->join_bb; |
| rtx_insn *jump = if_info->jump; |
| rtx_insn *cond_earliest; |
| rtx_insn *insn; |
| |
| start_sequence (); |
| |
| /* Decompose the condition attached to the jump. */ |
| rtx cond = noce_get_condition (jump, &cond_earliest, false); |
| rtx x = XEXP (cond, 0); |
| rtx y = XEXP (cond, 1); |
| rtx_code cond_code = GET_CODE (cond); |
| |
| /* The true targets for a conditional move. */ |
| auto_vec<rtx> targets; |
| /* The temporaries introduced to allow us to not consider register |
| overlap. */ |
| auto_vec<rtx> temporaries; |
| /* The insns we've emitted. */ |
| auto_vec<rtx_insn *> unmodified_insns; |
| int count = 0; |
| |
| FOR_BB_INSNS (then_bb, insn) |
| { |
| /* Skip over non-insns. */ |
| if (!active_insn_p (insn)) |
| continue; |
| |
| rtx set = single_set (insn); |
| gcc_checking_assert (set); |
| |
| rtx target = SET_DEST (set); |
| rtx temp = gen_reg_rtx (GET_MODE (target)); |
| rtx new_val = SET_SRC (set); |
| rtx old_val = target; |
| |
| /* If we were supposed to read from an earlier write in this block, |
| we've changed the register allocation. Rewire the read. While |
| we are looking, also try to catch a swap idiom. */ |
| for (int i = count - 1; i >= 0; --i) |
| if (reg_overlap_mentioned_p (new_val, targets[i])) |
| { |
| /* Catch a "swap" style idiom. */ |
| if (find_reg_note (insn, REG_DEAD, new_val) != NULL_RTX) |
| /* The write to targets[i] is only live until the read |
| here. As the condition codes match, we can propagate |
| the set to here. */ |
| new_val = SET_SRC (single_set (unmodified_insns[i])); |
| else |
| new_val = temporaries[i]; |
| break; |
| } |
| |
| /* If we had a non-canonical conditional jump (i.e. one where |
| the fallthrough is to the "else" case) we need to reverse |
| the conditional select. */ |
| if (if_info->then_else_reversed) |
| std::swap (old_val, new_val); |
| |
| |
| /* We allow simple lowpart register subreg SET sources in |
| bb_ok_for_noce_convert_multiple_sets. Be careful when processing |
| sequences like: |
| (set (reg:SI r1) (reg:SI r2)) |
| (set (reg:HI r3) (subreg:HI (r1))) |
| For the second insn new_val or old_val (r1 in this example) will be |
| taken from the temporaries and have the wider mode which will not |
| match with the mode of the other source of the conditional move, so |
| we'll end up trying to emit r4:HI = cond ? (r1:SI) : (r3:HI). |
| Wrap the two cmove operands into subregs if appropriate to prevent |
| that. */ |
| if (GET_MODE (new_val) != GET_MODE (temp)) |
| { |
| machine_mode src_mode = GET_MODE (new_val); | <