diff options
Diffstat (limited to 'gcc/ifcvt.cc')
| -rw-r--r-- | gcc/ifcvt.cc | 243 |
1 files changed, 105 insertions, 138 deletions
diff --git a/gcc/ifcvt.cc b/gcc/ifcvt.cc index f496a46e..3e25f30 100644 --- a/gcc/ifcvt.cc +++ b/gcc/ifcvt.cc @@ -98,14 +98,10 @@ static bool dead_or_predicable (basic_block, basic_block, basic_block, edge, bool); static void noce_emit_move_insn (rtx, rtx); static rtx_insn *block_has_only_trap (basic_block); -static void need_cmov_or_rewire (basic_block, hash_set<rtx_insn *> *, - hash_map<rtx_insn *, int> *); +static void init_noce_multiple_sets_info (basic_block, + auto_delete_vec<noce_multiple_sets_info> &); static bool noce_convert_multiple_sets_1 (struct noce_if_info *, - hash_set<rtx_insn *> *, - hash_map<rtx_insn *, int> *, - auto_vec<rtx> *, - auto_vec<rtx> *, - auto_vec<rtx_insn *> *, int *); + auto_delete_vec<noce_multiple_sets_info> &, int *); /* Count the number of non-jump active insns in BB. */ @@ -3487,24 +3483,13 @@ noce_convert_multiple_sets (struct noce_if_info *if_info) rtx x = XEXP (cond, 0); rtx y = XEXP (cond, 1); - /* 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; - - hash_set<rtx_insn *> need_no_cmov; - hash_map<rtx_insn *, int> rewired_src; - - need_cmov_or_rewire (then_bb, &need_no_cmov, &rewired_src); + auto_delete_vec<noce_multiple_sets_info> insn_info; + init_noce_multiple_sets_info (then_bb, insn_info); int last_needs_comparison = -1; bool ok = noce_convert_multiple_sets_1 - (if_info, &need_no_cmov, &rewired_src, &targets, &temporaries, - &unmodified_insns, &last_needs_comparison); + (if_info, insn_info, &last_needs_comparison); if (!ok) return false; @@ -3519,8 +3504,7 @@ noce_convert_multiple_sets (struct noce_if_info *if_info) end_sequence (); start_sequence (); ok = noce_convert_multiple_sets_1 - (if_info, &need_no_cmov, &rewired_src, &targets, &temporaries, - &unmodified_insns, &last_needs_comparison); + (if_info, insn_info, &last_needs_comparison); /* Actually we should not fail anymore if we reached here, but better still check. */ if (!ok) @@ -3529,12 +3513,12 @@ noce_convert_multiple_sets (struct noce_if_info *if_info) /* We must have seen some sort of insn to insert, otherwise we were given an empty BB to convert, and we can't handle that. */ - gcc_assert (!unmodified_insns.is_empty ()); + gcc_assert (!insn_info.is_empty ()); /* Now fixup the assignments. */ - for (unsigned i = 0; i < targets.length (); i++) - if (targets[i] != temporaries[i]) - noce_emit_move_insn (targets[i], temporaries[i]); + for (unsigned i = 0; i < insn_info.length (); i++) + if (insn_info[i]->target != insn_info[i]->temporary) + noce_emit_move_insn (insn_info[i]->target, insn_info[i]->temporary); /* Actually emit the sequence if it isn't too expensive. */ rtx_insn *seq = get_insns (); @@ -3549,10 +3533,10 @@ noce_convert_multiple_sets (struct noce_if_info *if_info) set_used_flags (insn); /* Mark all our temporaries and targets as used. */ - for (unsigned i = 0; i < targets.length (); i++) + for (unsigned i = 0; i < insn_info.length (); i++) { - set_used_flags (temporaries[i]); - set_used_flags (targets[i]); + set_used_flags (insn_info[i]->temporary); + set_used_flags (insn_info[i]->target); } set_used_flags (cond); @@ -3571,7 +3555,7 @@ noce_convert_multiple_sets (struct noce_if_info *if_info) return false; emit_insn_before_setloc (seq, if_info->jump, - INSN_LOCATION (unmodified_insns.last ())); + INSN_LOCATION (insn_info.last ()->unmodified_insn)); /* Clean up THEN_BB and the edges in and out of it. */ remove_edge (find_edge (test_bb, join_bb)); @@ -3592,20 +3576,12 @@ noce_convert_multiple_sets (struct noce_if_info *if_info) return true; } -/* This goes through all relevant insns of IF_INFO->then_bb and tries to - create conditional moves. In case a simple move sufficis the insn - should be listed in NEED_NO_CMOV. The rewired-src cases should be - specified via REWIRED_SRC. TARGETS, TEMPORARIES and UNMODIFIED_INSNS - are specified and used in noce_convert_multiple_sets and should be passed - to this function.. */ +/* This goes through all relevant insns of IF_INFO->then_bb and tries to create + conditional moves. Information for the insns is kept in INSN_INFO. */ static bool noce_convert_multiple_sets_1 (struct noce_if_info *if_info, - hash_set<rtx_insn *> *need_no_cmov, - hash_map<rtx_insn *, int> *rewired_src, - auto_vec<rtx> *targets, - auto_vec<rtx> *temporaries, - auto_vec<rtx_insn *> *unmodified_insns, + auto_delete_vec<noce_multiple_sets_info> &insn_info, int *last_needs_comparison) { basic_block then_bb = if_info->then_bb; @@ -3624,11 +3600,6 @@ noce_convert_multiple_sets_1 (struct noce_if_info *if_info, rtx_insn *insn; int count = 0; - - targets->truncate (0); - temporaries->truncate (0); - unmodified_insns->truncate (0); - bool second_try = *last_needs_comparison != -1; FOR_BB_INSNS (then_bb, insn) @@ -3637,6 +3608,8 @@ noce_convert_multiple_sets_1 (struct noce_if_info *if_info, if (!active_insn_p (insn)) continue; + noce_multiple_sets_info *info = insn_info[count]; + rtx set = single_set (insn); gcc_checking_assert (set); @@ -3644,9 +3617,12 @@ noce_convert_multiple_sets_1 (struct noce_if_info *if_info, rtx temp; rtx new_val = SET_SRC (set); - if (int *ii = rewired_src->get (insn)) - new_val = simplify_replace_rtx (new_val, (*targets)[*ii], - (*temporaries)[*ii]); + + int i, ii; + FOR_EACH_VEC_ELT (info->rewired_src, i, ii) + new_val = simplify_replace_rtx (new_val, insn_info[ii]->target, + insn_info[ii]->temporary); + rtx old_val = target; /* As we are transforming @@ -3687,7 +3663,7 @@ noce_convert_multiple_sets_1 (struct noce_if_info *if_info, /* We have identified swap-style idioms before. A normal set will need to be a cmov while the first instruction of a swap-style idiom can be a regular move. This helps with costing. */ - bool need_cmov = !need_no_cmov->contains (insn); + bool need_cmov = info->need_cmov; /* If we had a non-canonical conditional jump (i.e. one where the fallthrough is to the "else" case) we need to reverse @@ -3842,9 +3818,10 @@ noce_convert_multiple_sets_1 (struct noce_if_info *if_info, /* Bookkeeping. */ count++; - targets->safe_push (target); - temporaries->safe_push (temp_dest); - unmodified_insns->safe_push (insn); + + info->target = target; + info->temporary = temp_dest; + info->unmodified_insn = insn; } /* Even if we did not actually need the comparison, we want to make sure @@ -3852,11 +3829,84 @@ noce_convert_multiple_sets_1 (struct noce_if_info *if_info, if (*last_needs_comparison == -1) *last_needs_comparison = 0; - return true; } +/* Find local swap-style idioms in BB and mark the first insn (1) + that is only a temporary as not needing a conditional move as + it is going to be dead afterwards anyway. + + (1) int tmp = a; + a = b; + b = tmp; + + ifcvt + --> + + tmp = a; + a = cond ? b : a_old; + b = cond ? tmp : b_old; + + Additionally, store the index of insns like (2) when a subsequent + SET reads from their destination. + + (2) int c = a; + int d = c; + + ifcvt + --> + c = cond ? a : c_old; + d = cond ? d : c; // Need to use c rather than c_old here. +*/ + +static void +init_noce_multiple_sets_info (basic_block bb, + auto_delete_vec<noce_multiple_sets_info> &insn_info) +{ + rtx_insn *insn; + int count = 0; + auto_vec<rtx> dests; + bitmap bb_live_out = df_get_live_out (bb); + + /* Iterate over all SETs, storing the destinations in DEST. + - If we encounter a previously changed register, + rewire the read to the original source. + - If we encounter a SET that writes to a destination + that is not live after this block then the register + does not need to be moved conditionally. */ + FOR_BB_INSNS (bb, insn) + { + if (!active_insn_p (insn)) + continue; + + noce_multiple_sets_info *info = new noce_multiple_sets_info; + info->target = NULL_RTX; + info->temporary = NULL_RTX; + info->unmodified_insn = NULL; + insn_info.safe_push (info); + + rtx set = single_set (insn); + gcc_checking_assert (set); + + rtx src = SET_SRC (set); + rtx dest = SET_DEST (set); + + gcc_checking_assert (REG_P (dest)); + info->need_cmov = bitmap_bit_p (bb_live_out, REGNO (dest)); + + /* Check if the current SET's source is the same + as any previously seen destination. + This is quadratic but the number of insns in BB + is bounded by PARAM_MAX_RTL_IF_CONVERSION_INSNS. */ + for (int i = count - 1; i >= 0; --i) + if (reg_mentioned_p (dests[i], src)) + insn_info[count]->rewired_src.safe_push (i); + + dests.safe_push (dest); + count++; + } +} /* Return true iff basic block TEST_BB is suitable for conversion to a series of conditional moves. Also check that we have more than one @@ -4326,89 +4376,6 @@ check_cond_move_block (basic_block bb, return true; } -/* Find local swap-style idioms in BB and mark the first insn (1) - that is only a temporary as not needing a conditional move as - it is going to be dead afterwards anyway. - - (1) int tmp = a; - a = b; - b = tmp; - - ifcvt - --> - - tmp = a; - a = cond ? b : a_old; - b = cond ? tmp : b_old; - - Additionally, store the index of insns like (2) when a subsequent - SET reads from their destination. - - (2) int c = a; - int d = c; - - ifcvt - --> - - c = cond ? a : c_old; - d = cond ? d : c; // Need to use c rather than c_old here. -*/ - -static void -need_cmov_or_rewire (basic_block bb, - hash_set<rtx_insn *> *need_no_cmov, - hash_map<rtx_insn *, int> *rewired_src) -{ - rtx_insn *insn; - int count = 0; - auto_vec<rtx_insn *> insns; - auto_vec<rtx> dests; - - /* Iterate over all SETs, storing the destinations - in DEST. - - If we hit a SET that reads from a destination - that we have seen before and the corresponding register - is dead afterwards, the register does not need to be - moved conditionally. - - If we encounter a previously changed register, - rewire the read to the original source. */ - FOR_BB_INSNS (bb, insn) - { - rtx set, src, dest; - - if (!active_insn_p (insn)) - continue; - - set = single_set (insn); - if (set == NULL_RTX) - continue; - - src = SET_SRC (set); - if (SUBREG_P (src)) - src = SUBREG_REG (src); - dest = SET_DEST (set); - - /* Check if the current SET's source is the same - as any previously seen destination. - This is quadratic but the number of insns in BB - is bounded by PARAM_MAX_RTL_IF_CONVERSION_INSNS. */ - if (REG_P (src)) - for (int i = count - 1; i >= 0; --i) - if (reg_overlap_mentioned_p (src, dests[i])) - { - if (find_reg_note (insn, REG_DEAD, src) != NULL_RTX) - need_no_cmov->add (insns[i]); - else - rewired_src->put (insn, i); - } - - insns.safe_push (insn); - dests.safe_push (dest); - - count++; - } -} - /* Given a basic block BB suitable for conditional move conversion, a condition COND, and pointer maps THEN_VALS and ELSE_VALS containing the register values depending on COND, emit the insns in the block as |