From e9ebb86799fd77cdd5351078230c114a90e66066 Mon Sep 17 00:00:00 2001 From: Robin Dapp Date: Wed, 27 Nov 2019 13:53:40 +0100 Subject: [PATCH] ifcvt/optabs: Allow using a CC comparison for emit_conditional_move. Currently we only ever call emit_conditional_move with the comparison (as well as its comparands) we got from the jump. Thus, backends are going to emit a CC comparison for every conditional move that is being generated instead of re-using the existing CC. This, combined with emitting temporaries for each conditional move, causes sky-high costs for conditional moves. This patch allows to re-use a CC so the costing situation is improved a bit. gcc/ChangeLog: * rtl.h (struct rtx_comparison): New struct that holds an rtx comparison. * config/rs6000/rs6000.cc (rs6000_emit_minmax): Use struct instead of single parameters. (rs6000_emit_swsqrt): Likewise. * expmed.cc (expand_sdiv_pow2): Likewise. (emit_store_flag): Likewise. * expr.cc (expand_cond_expr_using_cmove): Likewise. (expand_expr_real_2): Likewise. * ifcvt.cc (noce_emit_cmove): Add compare and reversed compare parameters. * optabs.cc (emit_conditional_move_1): New function. (expand_doubleword_shift_condmove): Use struct. (emit_conditional_move): Use struct and allow to call directly without going through preparation steps. * optabs.h (emit_conditional_move): Use struct. --- gcc/config/rs6000/rs6000.cc | 6 +- gcc/expmed.cc | 8 +-- gcc/expr.cc | 10 ++-- gcc/ifcvt.cc | 45 ++++++++------ gcc/optabs.cc | 140 +++++++++++++++++++++++++++++++++----------- gcc/optabs.h | 4 +- gcc/rtl.h | 11 +++- 7 files changed, 157 insertions(+), 67 deletions(-) diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc index d37775e..0882ecb 100644 --- a/gcc/config/rs6000/rs6000.cc +++ b/gcc/config/rs6000/rs6000.cc @@ -16373,10 +16373,10 @@ rs6000_emit_minmax (rtx dest, enum rtx_code code, rtx op0, rtx op1) c = GEU; if (code == SMAX || code == UMAX) - target = emit_conditional_move (dest, c, op0, op1, mode, + target = emit_conditional_move (dest, { c, op0, op1, mode }, op0, op1, mode, 0); else - target = emit_conditional_move (dest, c, op0, op1, mode, + target = emit_conditional_move (dest, { c, op0, op1, mode }, op1, op0, mode, 0); gcc_assert (target); if (target != dest) @@ -22769,7 +22769,7 @@ rs6000_emit_swsqrt (rtx dst, rtx src, bool recip) if (mode == SFmode) { - rtx target = emit_conditional_move (e, GT, src, zero, mode, + rtx target = emit_conditional_move (e, { GT, src, zero, mode }, e, zero, mode, 0); if (target != e) emit_move_insn (e, target); diff --git a/gcc/expmed.cc b/gcc/expmed.cc index 7150058..80a16ce 100644 --- a/gcc/expmed.cc +++ b/gcc/expmed.cc @@ -4124,8 +4124,8 @@ expand_sdiv_pow2 (scalar_int_mode mode, rtx op0, HOST_WIDE_INT d) temp = force_reg (mode, temp); /* Construct "temp2 = (temp2 < 0) ? temp : temp2". */ - temp2 = emit_conditional_move (temp2, LT, temp2, const0_rtx, - mode, temp, temp2, mode, 0); + temp2 = emit_conditional_move (temp2, { LT, temp2, const0_rtx, mode }, + temp, temp2, mode, 0); if (temp2) { rtx_insn *seq = get_insns (); @@ -6127,10 +6127,10 @@ emit_store_flag (rtx target, enum rtx_code code, rtx op0, rtx op1, return 0; if (and_them) - tem = emit_conditional_move (target, code, op0, op1, mode, + tem = emit_conditional_move (target, { code, op0, op1, mode }, tem, const0_rtx, GET_MODE (tem), 0); else - tem = emit_conditional_move (target, code, op0, op1, mode, + tem = emit_conditional_move (target, { code, op0, op1, mode }, trueval, tem, GET_MODE (tem), 0); if (tem == 0) diff --git a/gcc/expr.cc b/gcc/expr.cc index 4324b18..35e4029 100644 --- a/gcc/expr.cc +++ b/gcc/expr.cc @@ -8824,8 +8824,9 @@ expand_cond_expr_using_cmove (tree treeop0 ATTRIBUTE_UNUSED, op2 = gen_lowpart (mode, op2); /* Try to emit the conditional move. */ - insn = emit_conditional_move (temp, comparison_code, - op00, op01, comparison_mode, + insn = emit_conditional_move (temp, + { comparison_code, op00, op01, + comparison_mode }, op1, op2, mode, unsignedp); @@ -9716,8 +9717,9 @@ expand_expr_real_2 (sepops ops, rtx target, machine_mode tmode, start_sequence (); /* Try to emit the conditional move. */ - insn = emit_conditional_move (target, comparison_code, - op0, cmpop1, mode, + insn = emit_conditional_move (target, + { comparison_code, + op0, cmpop1, mode }, op0, op1, mode, unsignedp); diff --git a/gcc/ifcvt.cc b/gcc/ifcvt.cc index 27e4294..7c81738 100644 --- a/gcc/ifcvt.cc +++ b/gcc/ifcvt.cc @@ -772,7 +772,7 @@ 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); + rtx, rtx, rtx, rtx = NULL, rtx = NULL); 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 **); @@ -1711,7 +1711,8 @@ noce_try_store_flag_mask (struct noce_if_info *if_info) 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 cmp_a, rtx cmp_b, rtx vfalse, rtx vtrue, rtx cc_cmp, + rtx rev_cc_cmp) { rtx target ATTRIBUTE_UNUSED; int unsignedp ATTRIBUTE_UNUSED; @@ -1743,23 +1744,30 @@ noce_emit_cmove (struct noce_if_info *if_info, rtx x, enum rtx_code code, 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 (cc_cmp != NULL_RTX && rev_cc_cmp != NULL_RTX) + target = emit_conditional_move (x, cc_cmp, rev_cc_cmp, + vtrue, vfalse, GET_MODE (x)); + else + { + /* 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; + } + + target = emit_conditional_move (x, { code, cmp_a, cmp_b, VOIDmode }, + vtrue, vfalse, GET_MODE (x), + unsignedp); + } + if (target) return target; @@ -1795,8 +1803,9 @@ noce_emit_cmove (struct noce_if_info *if_info, rtx x, enum rtx_code code, 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, + 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) diff --git a/gcc/optabs.cc b/gcc/optabs.cc index 5f759d5..2486e14 100644 --- a/gcc/optabs.cc +++ b/gcc/optabs.cc @@ -52,6 +52,8 @@ static void prepare_float_lib_cmp (rtx, rtx, enum rtx_code, rtx *, static rtx expand_unop_direct (machine_mode, optab, rtx, rtx, int); static void emit_libcall_block_1 (rtx_insn *, rtx, rtx, rtx, bool); +static rtx emit_conditional_move_1 (rtx, rtx, rtx, rtx, machine_mode); + /* Debug facility for use in GDB. */ void debug_optab_libfuncs (void); @@ -624,12 +626,13 @@ expand_doubleword_shift_condmove (scalar_int_mode op1_mode, optab binoptab, /* Select between them. Do the INTO half first because INTO_SUPERWORD might be the current value of OUTOF_TARGET. */ - if (!emit_conditional_move (into_target, cmp_code, cmp1, cmp2, op1_mode, + if (!emit_conditional_move (into_target, { cmp_code, cmp1, cmp2, op1_mode }, into_target, into_superword, word_mode, false)) return false; if (outof_target != 0) - if (!emit_conditional_move (outof_target, cmp_code, cmp1, cmp2, op1_mode, + if (!emit_conditional_move (outof_target, + { cmp_code, cmp1, cmp2, op1_mode }, outof_target, outof_superword, word_mode, false)) return false; @@ -4851,8 +4854,8 @@ emit_indirect_jump (rtx loc) is not supported. */ rtx -emit_conditional_move (rtx target, enum rtx_code code, rtx op0, rtx op1, - machine_mode cmode, rtx op2, rtx op3, +emit_conditional_move (rtx target, struct rtx_comparison comp, + rtx op2, rtx op3, machine_mode mode, int unsignedp) { rtx comparison; @@ -4874,31 +4877,33 @@ emit_conditional_move (rtx target, enum rtx_code code, rtx op0, rtx op1, /* If one operand is constant, make it the second one. Only do this if the other operand is not constant as well. */ - if (swap_commutative_operands_p (op0, op1)) + if (swap_commutative_operands_p (comp.op0, comp.op1)) { - std::swap (op0, op1); - code = swap_condition (code); + std::swap (comp.op0, comp.op1); + comp.code = swap_condition (comp.code); } /* get_condition will prefer to generate LT and GT even if the old comparison was against zero, so undo that canonicalization here since comparisons against zero are cheaper. */ - if (code == LT && op1 == const1_rtx) - code = LE, op1 = const0_rtx; - else if (code == GT && op1 == constm1_rtx) - code = GE, op1 = const0_rtx; - if (cmode == VOIDmode) - cmode = GET_MODE (op0); + if (comp.code == LT && comp.op1 == const1_rtx) + comp.code = LE, comp.op1 = const0_rtx; + else if (comp.code == GT && comp.op1 == constm1_rtx) + comp.code = GE, comp.op1 = const0_rtx; - enum rtx_code orig_code = code; + if (comp.mode == VOIDmode) + comp.mode = GET_MODE (comp.op0); + + enum rtx_code orig_code = comp.code; bool swapped = false; if (swap_commutative_operands_p (op2, op3) - && ((reversed = reversed_comparison_code_parts (code, op0, op1, NULL)) - != UNKNOWN)) + && ((reversed = + reversed_comparison_code_parts (comp.code, comp.op0, comp.op1, NULL)) + != UNKNOWN)) { std::swap (op2, op3); - code = reversed; + comp.code = reversed; swapped = true; } @@ -4915,8 +4920,10 @@ emit_conditional_move (rtx target, enum rtx_code code, rtx op0, rtx op1, for (int pass = 0; ; pass++) { - code = unsignedp ? unsigned_condition (code) : code; - comparison = simplify_gen_relational (code, VOIDmode, cmode, op0, op1); + comp.code = unsignedp ? unsigned_condition (comp.code) : comp.code; + comparison = + simplify_gen_relational (comp.code, VOIDmode, + comp.mode, comp.op0, comp.op1); /* We can get const0_rtx or const_true_rtx in some circumstances. Just punt and let the caller figure out how best to deal with this @@ -4927,24 +4934,16 @@ emit_conditional_move (rtx target, enum rtx_code code, rtx op0, rtx op1, save_pending_stack_adjust (&save); last = get_last_insn (); do_pending_stack_adjust (); - machine_mode cmpmode = cmode; + machine_mode cmpmode = comp.mode; prepare_cmp_insn (XEXP (comparison, 0), XEXP (comparison, 1), GET_CODE (comparison), NULL_RTX, unsignedp, OPTAB_WIDEN, &comparison, &cmpmode); if (comparison) { - class expand_operand ops[4]; - - create_output_operand (&ops[0], target, mode); - create_fixed_operand (&ops[1], comparison); - create_input_operand (&ops[2], op2, mode); - create_input_operand (&ops[3], op3, mode); - if (maybe_expand_insn (icode, 4, ops)) - { - if (ops[0].value != target) - convert_move (target, ops[0].value, false); - return target; - } + rtx res = emit_conditional_move_1 (target, comparison, + op2, op3, mode); + if (res != NULL_RTX) + return res; } delete_insns_since (last); restore_pending_stack_adjust (&save); @@ -4956,17 +4955,88 @@ emit_conditional_move (rtx target, enum rtx_code code, rtx op0, rtx op1, /* If the preferred op2/op3 order is not usable, retry with other operand order, perhaps it will expand successfully. */ if (swapped) - code = orig_code; - else if ((reversed = reversed_comparison_code_parts (orig_code, op0, op1, + comp.code = orig_code; + else if ((reversed = + reversed_comparison_code_parts (orig_code, comp.op0, comp.op1, NULL)) != UNKNOWN) - code = reversed; + comp.code = reversed; else return NULL_RTX; std::swap (op2, op3); } } +/* Helper function that, in addition to COMPARISON, also tries + the reversed REV_COMPARISON with swapped OP2 and OP3. As opposed + to when we pass the specific constituents of a comparison, no + additional insns are emitted for it. It might still be necessary + to emit more than one insn for the final conditional move, though. */ + +rtx +emit_conditional_move (rtx target, rtx comparison, rtx rev_comparison, + rtx op2, rtx op3, machine_mode mode) +{ + rtx res = emit_conditional_move_1 (target, comparison, op2, op3, mode); + + if (res != NULL_RTX) + return res; + + return emit_conditional_move_1 (target, rev_comparison, op3, op2, mode); +} + +/* Helper for emitting a conditional move. */ + +static rtx +emit_conditional_move_1 (rtx target, rtx comparison, + rtx op2, rtx op3, machine_mode mode) +{ + enum insn_code icode; + + if (comparison == NULL_RTX || !COMPARISON_P (comparison)) + return NULL_RTX; + + /* If the two source operands are identical, that's just a move. + As the comparison comes in non-canonicalized, we must make + sure not to discard any possible side effects. If there are + side effects, just let the target handle it. */ + if (!side_effects_p (comparison) && rtx_equal_p (op2, op3)) + { + if (!target) + target = gen_reg_rtx (mode); + + emit_move_insn (target, op3); + return target; + } + + if (mode == VOIDmode) + mode = GET_MODE (op2); + + icode = direct_optab_handler (movcc_optab, mode); + + if (icode == CODE_FOR_nothing) + return NULL_RTX; + + if (!target) + target = gen_reg_rtx (mode); + + class expand_operand ops[4]; + + create_output_operand (&ops[0], target, mode); + create_fixed_operand (&ops[1], comparison); + create_input_operand (&ops[2], op2, mode); + create_input_operand (&ops[3], op3, mode); + + if (maybe_expand_insn (icode, 4, ops)) + { + if (ops[0].value != target) + convert_move (target, ops[0].value, false); + return target; + } + + return NULL_RTX; +} + /* Emit a conditional negate or bitwise complement using the negcc or notcc optabs if available. Return NULL_RTX if such operations diff --git a/gcc/optabs.h b/gcc/optabs.h index 2d98ad6..cfd7c74 100644 --- a/gcc/optabs.h +++ b/gcc/optabs.h @@ -279,8 +279,8 @@ extern void emit_indirect_jump (rtx); #endif /* Emit a conditional move operation. */ -rtx emit_conditional_move (rtx, enum rtx_code, rtx, rtx, machine_mode, - rtx, rtx, machine_mode, int); +rtx emit_conditional_move (rtx, rtx_comparison, rtx, rtx, machine_mode, int); +rtx emit_conditional_move (rtx, rtx, rtx, rtx, rtx, machine_mode); /* Emit a conditional negate or bitwise complement operation. */ rtx emit_conditional_neg_or_complement (rtx, rtx_code, machine_mode, rtx, diff --git a/gcc/rtl.h b/gcc/rtl.h index 648f9b8..9df2fab 100644 --- a/gcc/rtl.h +++ b/gcc/rtl.h @@ -4604,7 +4604,16 @@ word_register_operation_p (const_rtx x) return true; } } - + +/* Holds an rtx comparison to simplify passing many parameters pertaining to a + single comparison. */ + +struct rtx_comparison { + rtx_code code; + rtx op0, op1; + machine_mode mode; +}; + /* gtype-desc.cc. */ extern void gt_ggc_mx (rtx &); extern void gt_pch_nx (rtx &); -- 2.7.4