From d400fda3a8c3330f77eb9d51874f5482d3819a9f Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Wed, 31 Oct 2018 09:42:39 +0000 Subject: [PATCH] aarch64: Improve cas generation Do not zero-extend the input to the cas for subword operations; instead, use the appropriate zero-extending compare insns. Correct the predicates and constraints for immediate expected operand. * config/aarch64/aarch64.c (aarch64_gen_compare_reg_maybe_ze): New. (aarch64_split_compare_and_swap): Use it. (aarch64_expand_compare_and_swap): Likewise. Remove convert_modes; test oldval against the proper predicate. * config/aarch64/atomics.md (@atomic_compare_and_swap): Use nonmemory_operand for expected. (cas_short_expected_pred): New. (@aarch64_compare_and_swap): Use it; use "rn" not "rI" to match. (@aarch64_compare_and_swap): Use "rn" not "rI" for expected. * config/aarch64/predicates.md (aarch64_plushi_immediate): New. (aarch64_plushi_operand): New. From-SVN: r265657 --- gcc/ChangeLog | 12 ++++++ gcc/config/aarch64/aarch64.c | 88 ++++++++++++++++++++++++---------------- gcc/config/aarch64/atomics.md | 19 +++++---- gcc/config/aarch64/predicates.md | 12 ++++++ 4 files changed, 87 insertions(+), 44 deletions(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 3c764c5..0938370 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,5 +1,17 @@ 2018-10-31 Richard Henderson + * config/aarch64/aarch64.c (aarch64_gen_compare_reg_maybe_ze): New. + (aarch64_split_compare_and_swap): Use it. + (aarch64_expand_compare_and_swap): Likewise. Remove convert_modes; + test oldval against the proper predicate. + * config/aarch64/atomics.md (@atomic_compare_and_swap): + Use nonmemory_operand for expected. + (cas_short_expected_pred): New. + (@aarch64_compare_and_swap): Use it; use "rn" not "rI" to match. + (@aarch64_compare_and_swap): Use "rn" not "rI" for expected. + * config/aarch64/predicates.md (aarch64_plushi_immediate): New. + (aarch64_plushi_operand): New. + * config/aarch64/aarch64.c (aarch64_expand_compare_and_swap): Force oldval into the rval register for TARGET_LSE; emit the compare during initial expansion so that it may be deleted if unused. diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c index 9d53cf9..7beda54 100644 --- a/gcc/config/aarch64/aarch64.c +++ b/gcc/config/aarch64/aarch64.c @@ -1614,6 +1614,33 @@ aarch64_gen_compare_reg (RTX_CODE code, rtx x, rtx y) return cc_reg; } +/* Similarly, but maybe zero-extend Y if Y_MODE < SImode. */ + +static rtx +aarch64_gen_compare_reg_maybe_ze (RTX_CODE code, rtx x, rtx y, + machine_mode y_mode) +{ + if (y_mode == E_QImode || y_mode == E_HImode) + { + if (CONST_INT_P (y)) + y = GEN_INT (INTVAL (y) & GET_MODE_MASK (y_mode)); + else + { + rtx t, cc_reg; + machine_mode cc_mode; + + t = gen_rtx_ZERO_EXTEND (SImode, y); + t = gen_rtx_COMPARE (CC_SWPmode, t, x); + cc_mode = CC_SWPmode; + cc_reg = gen_rtx_REG (cc_mode, CC_REGNUM); + emit_set_insn (cc_reg, t); + return cc_reg; + } + } + + return aarch64_gen_compare_reg (code, x, y); +} + /* Build the SYMBOL_REF for __tls_get_addr. */ static GTY(()) rtx tls_get_addr_libfunc; @@ -14575,8 +14602,8 @@ aarch64_emit_unlikely_jump (rtx insn) void aarch64_expand_compare_and_swap (rtx operands[]) { - rtx bval, rval, mem, oldval, newval, is_weak, mod_s, mod_f, x; - machine_mode mode, cmp_mode; + rtx bval, rval, mem, oldval, newval, is_weak, mod_s, mod_f, x, cc_reg; + machine_mode mode, r_mode; bval = operands[0]; rval = operands[1]; @@ -14587,36 +14614,19 @@ aarch64_expand_compare_and_swap (rtx operands[]) mod_s = operands[6]; mod_f = operands[7]; mode = GET_MODE (mem); - cmp_mode = mode; /* Normally the succ memory model must be stronger than fail, but in the unlikely event of fail being ACQUIRE and succ being RELEASE we need to promote succ to ACQ_REL so that we don't lose the acquire semantics. */ - if (is_mm_acquire (memmodel_from_int (INTVAL (mod_f))) && is_mm_release (memmodel_from_int (INTVAL (mod_s)))) mod_s = GEN_INT (MEMMODEL_ACQ_REL); - switch (mode) + r_mode = mode; + if (mode == QImode || mode == HImode) { - case E_QImode: - case E_HImode: - /* For short modes, we're going to perform the comparison in SImode, - so do the zero-extension now. */ - cmp_mode = SImode; - rval = gen_reg_rtx (SImode); - oldval = convert_modes (SImode, mode, oldval, true); - /* Fall through. */ - - case E_SImode: - case E_DImode: - /* Force the value into a register if needed. */ - if (!aarch64_plus_operand (oldval, mode)) - oldval = force_reg (cmp_mode, oldval); - break; - - default: - gcc_unreachable (); + r_mode = SImode; + rval = gen_reg_rtx (r_mode); } if (TARGET_LSE) @@ -14624,26 +14634,32 @@ aarch64_expand_compare_and_swap (rtx operands[]) /* The CAS insn requires oldval and rval overlap, but we need to have a copy of oldval saved across the operation to tell if the operation is successful. */ - if (mode == QImode || mode == HImode) - rval = copy_to_mode_reg (SImode, gen_lowpart (SImode, oldval)); - else if (reg_overlap_mentioned_p (rval, oldval)) - rval = copy_to_mode_reg (mode, oldval); + if (reg_overlap_mentioned_p (rval, oldval)) + rval = copy_to_mode_reg (r_mode, oldval); else - emit_move_insn (rval, oldval); + emit_move_insn (rval, gen_lowpart (r_mode, oldval)); + emit_insn (gen_aarch64_compare_and_swap_lse (mode, rval, mem, newval, mod_s)); - aarch64_gen_compare_reg (EQ, rval, oldval); + cc_reg = aarch64_gen_compare_reg_maybe_ze (NE, rval, oldval, mode); } else - emit_insn (gen_aarch64_compare_and_swap (mode, rval, mem, oldval, newval, - is_weak, mod_s, mod_f)); + { + /* The oldval predicate varies by mode. Test it and force to reg. */ + insn_code code = code_for_aarch64_compare_and_swap (mode); + if (!insn_data[code].operand[2].predicate (oldval, mode)) + oldval = force_reg (mode, oldval); - if (mode == QImode || mode == HImode) + emit_insn (GEN_FCN (code) (rval, mem, oldval, newval, + is_weak, mod_s, mod_f)); + cc_reg = gen_rtx_REG (CCmode, CC_REGNUM); + } + + if (r_mode != mode) rval = gen_lowpart (mode, rval); emit_move_insn (operands[1], rval); - x = gen_rtx_REG (CCmode, CC_REGNUM); - x = gen_rtx_EQ (SImode, x, const0_rtx); + x = gen_rtx_EQ (SImode, cc_reg, const0_rtx); emit_insn (gen_rtx_SET (bval, x)); } @@ -14758,10 +14774,10 @@ aarch64_split_compare_and_swap (rtx operands[]) } else { - cond = aarch64_gen_compare_reg (NE, rval, oldval); + cond = aarch64_gen_compare_reg_maybe_ze (NE, rval, oldval, mode); x = gen_rtx_NE (VOIDmode, cond, const0_rtx); x = gen_rtx_IF_THEN_ELSE (VOIDmode, x, - gen_rtx_LABEL_REF (Pmode, label2), pc_rtx); + gen_rtx_LABEL_REF (Pmode, label2), pc_rtx); aarch64_emit_unlikely_jump (gen_rtx_SET (pc_rtx, x)); } diff --git a/gcc/config/aarch64/atomics.md b/gcc/config/aarch64/atomics.md index 2266085..e44301b 100644 --- a/gcc/config/aarch64/atomics.md +++ b/gcc/config/aarch64/atomics.md @@ -24,8 +24,8 @@ [(match_operand:SI 0 "register_operand" "") ;; bool out (match_operand:ALLI 1 "register_operand" "") ;; val out (match_operand:ALLI 2 "aarch64_sync_memory_operand" "") ;; memory - (match_operand:ALLI 3 "general_operand" "") ;; expected - (match_operand:ALLI 4 "aarch64_reg_or_zero" "") ;; desired + (match_operand:ALLI 3 "nonmemory_operand" "") ;; expected + (match_operand:ALLI 4 "aarch64_reg_or_zero" "") ;; desired (match_operand:SI 5 "const_int_operand") ;; is_weak (match_operand:SI 6 "const_int_operand") ;; mod_s (match_operand:SI 7 "const_int_operand")] ;; mod_f @@ -36,19 +36,22 @@ } ) +(define_mode_attr cas_short_expected_pred + [(QI "aarch64_reg_or_imm") (HI "aarch64_plushi_operand")]) + (define_insn_and_split "@aarch64_compare_and_swap" [(set (reg:CC CC_REGNUM) ;; bool out (unspec_volatile:CC [(const_int 0)] UNSPECV_ATOMIC_CMPSW)) - (set (match_operand:SI 0 "register_operand" "=&r") ;; val out + (set (match_operand:SI 0 "register_operand" "=&r") ;; val out (zero_extend:SI (match_operand:SHORT 1 "aarch64_sync_memory_operand" "+Q"))) ;; memory (set (match_dup 1) (unspec_volatile:SHORT - [(match_operand:SI 2 "aarch64_plus_operand" "rI") ;; expected + [(match_operand:SHORT 2 "" "rn") ;; expected (match_operand:SHORT 3 "aarch64_reg_or_zero" "rZ") ;; desired - (match_operand:SI 4 "const_int_operand") ;; is_weak - (match_operand:SI 5 "const_int_operand") ;; mod_s - (match_operand:SI 6 "const_int_operand")] ;; mod_f + (match_operand:SI 4 "const_int_operand") ;; is_weak + (match_operand:SI 5 "const_int_operand") ;; mod_s + (match_operand:SI 6 "const_int_operand")] ;; mod_f UNSPECV_ATOMIC_CMPSW)) (clobber (match_scratch:SI 7 "=&r"))] "" @@ -68,7 +71,7 @@ (match_operand:GPI 1 "aarch64_sync_memory_operand" "+Q")) ;; memory (set (match_dup 1) (unspec_volatile:GPI - [(match_operand:GPI 2 "aarch64_plus_operand" "rI") ;; expect + [(match_operand:GPI 2 "aarch64_plus_operand" "rn") ;; expect (match_operand:GPI 3 "aarch64_reg_or_zero" "rZ") ;; desired (match_operand:SI 4 "const_int_operand") ;; is_weak (match_operand:SI 5 "const_int_operand") ;; mod_s diff --git a/gcc/config/aarch64/predicates.md b/gcc/config/aarch64/predicates.md index 5b08b03..4c75eff 100644 --- a/gcc/config/aarch64/predicates.md +++ b/gcc/config/aarch64/predicates.md @@ -114,6 +114,18 @@ (ior (match_operand 0 "register_operand") (match_operand 0 "aarch64_plus_immediate"))) +(define_predicate "aarch64_plushi_immediate" + (match_code "const_int") +{ + HOST_WIDE_INT val = INTVAL (op); + /* The HImode value must be zero-extendable to an SImode plus_operand. */ + return ((val & 0xfff) == val || sext_hwi (val & 0xf000, 16) == val); +}) + +(define_predicate "aarch64_plushi_operand" + (ior (match_operand 0 "register_operand") + (match_operand 0 "aarch64_plushi_immediate"))) + (define_predicate "aarch64_pluslong_immediate" (and (match_code "const_int") (match_test "(INTVAL (op) < 0xffffff && INTVAL (op) > -0xffffff)"))) -- 2.7.4