https://gcc.gnu.org/g:d826f7945609046f922732b138fb90795d5b1985
commit r15-313-gd826f7945609046f922732b138fb90795d5b1985
Author: konglin1 <lingling.k...@intel.com>
Date: Wed May 8 15:46:10 2024 +0800
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.
Diff:
---
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);
