From d826f7945609046f922732b138fb90795d5b1985 Mon Sep 17 00:00:00 2001 From: konglin1 Date: Wed, 8 May 2024 15:46:10 +0800 Subject: [PATCH] x86: Fix cmov cost model issue [PR109549] (if_then_else:SI (eq (reg:CCZ 17 flags) (const_int 0 [0])) (reg/v:SI 101 [ e ]) (reg:SI 102)) The cost is 8 for the rtx, the cost for (eq (reg:CCZ 17 flags) (const_int 0 [0])) is 4, but this is just an operator do not need to compute it's cost in cmov. gcc/ChangeLog: PR target/109549 * config/i386/i386.cc (ix86_rtx_costs): The XEXP (x, 0) for cmov is an operator do not need to compute cost. gcc/testsuite/ChangeLog: * gcc.target/i386/cmov6.c: Fixed. --- gcc/config/i386/i386.cc | 2 +- gcc/testsuite/gcc.target/i386/cmov6.c | 5 +---- 2 files changed, 2 insertions(+), 5 deletions(-) diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc index e58335adc8f0..c2df4ab91ee9 100644 --- a/gcc/config/i386/i386.cc +++ b/gcc/config/i386/i386.cc @@ -22237,7 +22237,7 @@ ix86_rtx_costs (rtx x, machine_mode mode, int outer_code_i, int opno, { /* cmov. */ *total = COSTS_N_INSNS (1); - if (!REG_P (XEXP (x, 0))) + if (!COMPARISON_P (XEXP (x, 0)) && !REG_P (XEXP (x, 0))) *total += rtx_cost (XEXP (x, 0), mode, code, 0, speed); if (!REG_P (XEXP (x, 1))) *total += rtx_cost (XEXP (x, 1), mode, code, 1, speed); diff --git a/gcc/testsuite/gcc.target/i386/cmov6.c b/gcc/testsuite/gcc.target/i386/cmov6.c index 5111c8a90995..535326e4c2a3 100644 --- a/gcc/testsuite/gcc.target/i386/cmov6.c +++ b/gcc/testsuite/gcc.target/i386/cmov6.c @@ -1,9 +1,6 @@ /* { dg-do compile } */ /* { dg-options "-O2 -march=k8" } */ -/* if-converting this sequence would require two cmov - instructions and seems to always cost more independent - of the TUNE_ONE_IF_CONV setting. */ -/* { dg-final { scan-assembler-not "cmov\[^6\]" } } */ +/* { dg-final { scan-assembler "cmov\[^6\]" } } */ /* Verify that blocks are converted to conditional moves. */ extern int bar (int, int); -- 2.47.3