From 73a167cfa225d5ee7092d41596b9fea1719898ff Mon Sep 17 00:00:00 2001 From: Haochen Jiang Date: Tue, 21 May 2024 14:10:43 +0800 Subject: i386: Disable ix86_expand_vecop_qihi2 when !TARGET_AVX512BW Since vpermq is really slow, we should avoid using it for permutation when vpmovwb is not available (needs AVX512BW) for ix86_expand_vecop_qihi2 and fall back to ix86_expand_vecop_qihi. 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/testsuite/ChangeLog: PR target/115069 * gcc.target/i386/pr115069.c: New. --- gcc/config/i386/i386-expand.cc | 7 +++++++ gcc/testsuite/gcc.target/i386/pr115069.c | 9 +++++++++ 2 files changed, 16 insertions(+) create mode 100644 gcc/testsuite/gcc.target/i386/pr115069.c diff --git a/gcc/config/i386/i386-expand.cc b/gcc/config/i386/i386-expand.cc index 7142c0a..ec402a7 100644 --- a/gcc/config/i386/i386-expand.cc +++ b/gcc/config/i386/i386-expand.cc @@ -24188,6 +24188,13 @@ 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; + /* Without VPMOVWB (provided by AVX512BW ISA), the expansion uses the + generic permutation to merge the data back into the right place. This + permutation results in VPERMQ, which is slow, so better fall back to + ix86_expand_vecop_qihi. */ + if (!TARGET_AVX512BW) + return false; + if ((qimode == V16QImode && !TARGET_AVX2) || (qimode == V32QImode && (!TARGET_AVX512BW || !TARGET_EVEX512)) /* There are no V64HImode instructions. */ diff --git a/gcc/testsuite/gcc.target/i386/pr115069.c b/gcc/testsuite/gcc.target/i386/pr115069.c new file mode 100644 index 0000000..50a3e03 --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr115069.c @@ -0,0 +1,9 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -mavx2" } */ +/* { dg-final { scan-assembler-not "vpermq" } } */ + +typedef char v16qi __attribute__((vector_size(16))); + +v16qi foo (v16qi a, v16qi b) { + return a * b; +} -- cgit v1.1