From 0fe4fca4e1a5e06a270127dd80bb753d4dda61c6 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Thu, 15 Sep 2016 15:16:00 +0200 Subject: [PATCH] tcg: try sti when moving a constant into a dead memory temp This comes from free from unifying tcg_reg_alloc_mov and tcg_reg_alloc_movi's handling of TEMP_VAL_CONST. It triggers often on moves to cc_dst, such as the following translation of "sub $0x3c,%esp": before: after: subl $0x3c,%ebp subl $0x3c,%ebp movl %ebp,0x10(%r14) movl %ebp,0x10(%r14) movl $0x3c,%ebx movl $0x3c,0x2c(%r14) movl %ebx,0x2c(%r14) Signed-off-by: Paolo Bonzini Message-Id: <1473945360-13663-1-git-send-email-pbonzini@redhat.com> Reviewed-by: Richard Henderson Signed-off-by: Paolo Bonzini --- tcg/tcg.c | 56 +++++++++++++++++++++++++++---------------------------- 1 file changed, 27 insertions(+), 29 deletions(-) diff --git a/tcg/tcg.c b/tcg/tcg.c index c450c6273b..2d3e498bc2 100644 --- a/tcg/tcg.c +++ b/tcg/tcg.c @@ -2097,15 +2097,9 @@ static void tcg_reg_alloc_bb_end(TCGContext *s, TCGRegSet allocated_regs) save_globals(s, allocated_regs); } -static void tcg_reg_alloc_movi(TCGContext *s, const TCGArg *args, - TCGLifeData arg_life) +static void tcg_reg_alloc_do_movi(TCGContext *s, TCGTemp *ots, + tcg_target_ulong val, TCGLifeData arg_life) { - TCGTemp *ots; - tcg_target_ulong val; - - ots = &s->temps[args[0]]; - val = args[1]; - if (ots->fixed_reg) { /* For fixed registers, we do not do any constant propagation. */ tcg_out_movi(s, ots->type, ots->reg, val); @@ -2126,6 +2120,15 @@ static void tcg_reg_alloc_movi(TCGContext *s, const TCGArg *args, } } +static void tcg_reg_alloc_movi(TCGContext *s, const TCGArg *args, + TCGLifeData arg_life) +{ + TCGTemp *ots = &s->temps[args[0]]; + tcg_target_ulong val = args[1]; + + tcg_reg_alloc_do_movi(s, ots, val, arg_life); +} + static void tcg_reg_alloc_mov(TCGContext *s, const TCGOpDef *def, const TCGArg *args, TCGLifeData arg_life) { @@ -2141,21 +2144,29 @@ static void tcg_reg_alloc_mov(TCGContext *s, const TCGOpDef *def, otype = ots->type; itype = ts->type; - /* If the source value is not in a register, and we're going to be - forced to have it in a register in order to perform the copy, - then copy the SOURCE value into its own register first. That way - we don't have to reload SOURCE the next time it is used. */ - if (((NEED_SYNC_ARG(0) || ots->fixed_reg) && ts->val_type != TEMP_VAL_REG) - || ts->val_type == TEMP_VAL_MEM) { + if (ts->val_type == TEMP_VAL_CONST) { + /* propagate constant or generate sti */ + tcg_target_ulong val = ts->val; + if (IS_DEAD_ARG(1)) { + temp_dead(s, ts); + } + tcg_reg_alloc_do_movi(s, ots, val, arg_life); + return; + } + + /* If the source value is in memory we're going to be forced + to have it in a register in order to perform the copy. Copy + the SOURCE value into its own register first, that way we + don't have to reload SOURCE the next time it is used. */ + if (ts->val_type == TEMP_VAL_MEM) { temp_load(s, ts, tcg_target_available_regs[itype], allocated_regs); } + tcg_debug_assert(ts->val_type == TEMP_VAL_REG); if (IS_DEAD_ARG(0) && !ots->fixed_reg) { /* mov to a non-saved dead register makes no sense (even with liveness analysis disabled). */ tcg_debug_assert(NEED_SYNC_ARG(0)); - /* The code above should have moved the temp to a register. */ - tcg_debug_assert(ts->val_type == TEMP_VAL_REG); if (!ots->mem_allocated) { temp_allocate_frame(s, args[0]); } @@ -2164,20 +2175,7 @@ static void tcg_reg_alloc_mov(TCGContext *s, const TCGOpDef *def, temp_dead(s, ts); } temp_dead(s, ots); - } else if (ts->val_type == TEMP_VAL_CONST) { - /* propagate constant */ - if (ots->val_type == TEMP_VAL_REG) { - s->reg_to_temp[ots->reg] = NULL; - } - ots->val_type = TEMP_VAL_CONST; - ots->val = ts->val; - if (IS_DEAD_ARG(1)) { - temp_dead(s, ts); - } } else { - /* The code in the first if block should have moved the - temp to a register. */ - tcg_debug_assert(ts->val_type == TEMP_VAL_REG); if (IS_DEAD_ARG(1) && !ts->fixed_reg && !ots->fixed_reg) { /* the mov can be suppressed */ if (ots->val_type == TEMP_VAL_REG) {