From b7e560deb37e38fb224a0cf108e15df4a717167a Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Thu, 19 Sep 2019 14:36:33 +0000 Subject: [PATCH] aarch64: Tidy aarch64_split_compare_and_swap With aarch64_track_speculation, we had extra code to do exactly what the !strong_zero_p path already did. The rest is reducing code duplication. * config/aarch64/aarch64 (aarch64_split_compare_and_swap): Disable strong_zero_p for aarch64_track_speculation; unify some code paths; use aarch64_gen_compare_reg instead of open-coding. From-SVN: r275966 --- gcc/ChangeLog | 4 +++ gcc/config/aarch64/aarch64.c | 50 ++++++++++-------------------------- 2 files changed, 18 insertions(+), 36 deletions(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index d8749b9b2e0..cef3a6e2b6d 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -16,6 +16,10 @@ (aarch64_store_exclusive_pair): New. * config/aarch64/iterators.md (JUST_TI): New. + * config/aarch64/aarch64 (aarch64_split_compare_and_swap): Disable + strong_zero_p for aarch64_track_speculation; unify some code paths; + use aarch64_gen_compare_reg instead of open-coding. + 2019-09-19 Feng Xue * ipa-fnsummary.c (set_cond_stmt_execution_predicate): Do not compute diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c index a5c4f55627d..b937514e6f8 100644 --- a/gcc/config/aarch64/aarch64.c +++ b/gcc/config/aarch64/aarch64.c @@ -16955,13 +16955,11 @@ aarch64_emit_post_barrier (enum memmodel model) void aarch64_split_compare_and_swap (rtx operands[]) { - rtx rval, mem, oldval, newval, scratch; + rtx rval, mem, oldval, newval, scratch, x, model_rtx; machine_mode mode; bool is_weak; rtx_code_label *label1, *label2; - rtx x, cond; enum memmodel model; - rtx model_rtx; rval = operands[0]; mem = operands[1]; @@ -16982,7 +16980,8 @@ aarch64_split_compare_and_swap (rtx operands[]) CBNZ scratch, .label1 .label2: CMP rval, 0. */ - bool strong_zero_p = !is_weak && oldval == const0_rtx && mode != TImode; + bool strong_zero_p = (!is_weak && !aarch64_track_speculation && + oldval == const0_rtx && mode != TImode); label1 = NULL; if (!is_weak) @@ -16995,35 +16994,20 @@ aarch64_split_compare_and_swap (rtx operands[]) /* The initial load can be relaxed for a __sync operation since a final barrier will be emitted to stop code hoisting. */ if (is_mm_sync (model)) - aarch64_emit_load_exclusive (mode, rval, mem, - GEN_INT (MEMMODEL_RELAXED)); + aarch64_emit_load_exclusive (mode, rval, mem, GEN_INT (MEMMODEL_RELAXED)); else aarch64_emit_load_exclusive (mode, rval, mem, model_rtx); if (strong_zero_p) - { - if (aarch64_track_speculation) - { - /* Emit an explicit compare instruction, so that we can correctly - track the condition codes. */ - rtx cc_reg = aarch64_gen_compare_reg (NE, rval, const0_rtx); - x = gen_rtx_NE (GET_MODE (cc_reg), cc_reg, const0_rtx); - } - else - x = gen_rtx_NE (VOIDmode, rval, const0_rtx); - - x = gen_rtx_IF_THEN_ELSE (VOIDmode, x, - gen_rtx_LABEL_REF (Pmode, label2), pc_rtx); - aarch64_emit_unlikely_jump (gen_rtx_SET (pc_rtx, x)); - } + x = gen_rtx_NE (VOIDmode, rval, const0_rtx); else { - 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); - aarch64_emit_unlikely_jump (gen_rtx_SET (pc_rtx, x)); + rtx cc_reg = aarch64_gen_compare_reg_maybe_ze (NE, rval, oldval, mode); + x = gen_rtx_NE (VOIDmode, cc_reg, const0_rtx); } + x = gen_rtx_IF_THEN_ELSE (VOIDmode, x, + gen_rtx_LABEL_REF (Pmode, label2), pc_rtx); + aarch64_emit_unlikely_jump (gen_rtx_SET (pc_rtx, x)); aarch64_emit_store_exclusive (mode, scratch, mem, newval, model_rtx); @@ -17044,22 +17028,16 @@ aarch64_split_compare_and_swap (rtx operands[]) aarch64_emit_unlikely_jump (gen_rtx_SET (pc_rtx, x)); } else - { - cond = gen_rtx_REG (CCmode, CC_REGNUM); - x = gen_rtx_COMPARE (CCmode, scratch, const0_rtx); - emit_insn (gen_rtx_SET (cond, x)); - } + aarch64_gen_compare_reg (NE, scratch, const0_rtx); emit_label (label2); + /* If we used a CBNZ in the exchange loop emit an explicit compare with RVAL to set the condition flags. If this is not used it will be removed by later passes. */ if (strong_zero_p) - { - cond = gen_rtx_REG (CCmode, CC_REGNUM); - x = gen_rtx_COMPARE (CCmode, rval, const0_rtx); - emit_insn (gen_rtx_SET (cond, x)); - } + aarch64_gen_compare_reg (NE, rval, const0_rtx); + /* Emit any final barrier needed for a __sync operation. */ if (is_mm_sync (model)) aarch64_emit_post_barrier (model); -- 2.30.2