From: Richard Henderson <richard.henderson@linaro.org>
To: qemu-devel@nongnu.org
Cc: zhiwei_liu@linux.alibaba.com, tangtiancheng.ttc@alibaba-inc.com,
liwei1518@gmail.com, bmeng.cn@gmail.com
Subject: [PATCH 06/12] tcg/optimize: Fold movcond with true and false values identical
Date: Sat, 7 Sep 2024 19:26:26 -0700 [thread overview]
Message-ID: <20240908022632.459477-7-richard.henderson@linaro.org> (raw)
In-Reply-To: <20240908022632.459477-1-richard.henderson@linaro.org>
Fold "x = cond ? y : y" to "x = y".
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
tcg/optimize.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/tcg/optimize.c b/tcg/optimize.c
index ba16ec27e2..cf311790e0 100644
--- a/tcg/optimize.c
+++ b/tcg/optimize.c
@@ -1851,6 +1851,11 @@ static bool fold_movcond(OptContext *ctx, TCGOp *op)
{
int i;
+ /* If true and false values are the same, eliminate the cmp. */
+ if (args_are_copies(op->args[3], op->args[4])) {
+ return tcg_opt_gen_mov(ctx, op, op->args[0], op->args[3]);
+ }
+
/*
* Canonicalize the "false" input reg to match the destination reg so
* that the tcg backend can implement a "move if true" operation.
--
2.43.0
next prev parent reply other threads:[~2024-09-08 2:29 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-09-08 2:26 [PATCH 00/12] tcg: Improve support for cmpsel_vec Richard Henderson
2024-09-08 2:26 ` [PATCH 01/12] tcg: Fix iteration step in 32-bit gvec operation Richard Henderson
2024-09-10 6:57 ` Philippe Mathieu-Daudé
2024-09-10 14:46 ` Richard Henderson
2024-09-08 2:26 ` [PATCH 02/12] tcg: Export vec_gen_6 Richard Henderson
2024-09-10 6:57 ` Philippe Mathieu-Daudé
2024-09-08 2:26 ` [PATCH 03/12] tcg/i386: Split out tcg_out_vex_modrm_type Richard Henderson
2024-09-10 6:59 ` Philippe Mathieu-Daudé
2024-09-08 2:26 ` [PATCH 04/12] tcg/i386: Do not expand cmp_vec early Richard Henderson
2024-09-08 2:26 ` [PATCH 05/12] tcg/i386: Do not expand cmpsel_vec early Richard Henderson
2024-09-08 2:26 ` Richard Henderson [this message]
2024-09-10 7:00 ` [PATCH 06/12] tcg/optimize: Fold movcond with true and false values identical Philippe Mathieu-Daudé
2024-09-08 2:26 ` [PATCH 07/12] tcg/optimize: Optimize cmp_vec and cmpsel_vec Richard Henderson
2024-09-08 2:26 ` [PATCH 08/12] tcg/optimize: Optimize bitsel_vec Richard Henderson
2024-09-08 2:26 ` [PATCH 09/12] tcg/i386: Optimize cmpsel with constant 0 arguments Richard Henderson
2024-09-08 2:26 ` [PATCH 10/12] tcg/i386: Implement cmp_vec with avx512 insns Richard Henderson
2024-09-08 2:26 ` [PATCH 11/12] tcg/i386: Add predicate parameters to tcg_out_evex_opc Richard Henderson
2024-09-10 7:04 ` Philippe Mathieu-Daudé
2024-09-08 2:26 ` [PATCH 12/12] tcg/i386: Implement cmpsel_vec with avx512 insns Richard Henderson
2024-09-09 23:37 ` [PATCH 00/12] tcg: Improve support for cmpsel_vec Richard Henderson
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