Hi,
(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.

Bootstrapped and regtested on x86_64-pc-linux-gnu.
OK for trunk?

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 
4d6b2b98761..59b4ce3bfbf 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 5111c8a9099..535326e4c2a 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);
--
2.31.1

Reply via email to