Hi all,
Since vpermq is really slow, we should avoid using it when it is
the only instruction could be used for ix86_expand_vecop_qihi2.
Bootstrapped and regtested on x86_64-pc-linux-gnu. Ok for trunk?
Thx,
Haochen
gcc/ChangeLog:
PR target/115069
* config/i386/i386-expand.cc (ix86_expand_vecop_qihi2):
Do not enable the optimization when AVX512BW is not enabled.
---
gcc/config/i386/i386-expand.cc | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/gcc/config/i386/i386-expand.cc b/gcc/config/i386/i386-expand.cc
index a6132911e6a..f24c800bb4f 100644
--- a/gcc/config/i386/i386-expand.cc
+++ b/gcc/config/i386/i386-expand.cc
@@ -24323,6 +24323,11 @@ ix86_expand_vecop_qihi2 (enum rtx_code code, rtx dest,
rtx op1, rtx op2)
bool op2vec = GET_MODE_CLASS (GET_MODE (op2)) == MODE_VECTOR_INT;
bool uns_p = code != ASHIFTRT;
+ /* vpermq is slow and we should not fall into the optimization when
+ it is the only instruction to be selected. */
+ if (!TARGET_AVX512BW)
+ return false;
+
if ((qimode == V16QImode && !TARGET_AVX2)
|| (qimode == V32QImode && (!TARGET_AVX512BW || !TARGET_EVEX512))
/* There are no V64HImode instructions. */
--
2.31.1
