On Tue, May 21, 2024 at 11:01 AM Haochen Jiang <haochen.ji...@intel.com> wrote: > > Hi all, > > This is the v3 patch to fix PR115069. The new testcase has passed. > > Changes in v3: > - Simplify the testcase. > > Changes in v2: > - Add a testcase. > - Change the comment for the early exit. > > Thx, > Haochen > > 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.
LGTM, with a nit below. Thanks, Uros. > --- > gcc/config/i386/i386-expand.cc | 7 +++++++ > gcc/testsuite/gcc.target/i386/pr115069.c | 10 ++++++++++ > 2 files changed, 17 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 a6132911e6a..f7939761879 100644 > --- a/gcc/config/i386/i386-expand.cc > +++ b/gcc/config/i386/i386-expand.cc > @@ -24323,6 +24323,13 @@ 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 00000000000..7f1ff209f26 > --- /dev/null > +++ b/gcc/testsuite/gcc.target/i386/pr115069.c > @@ -0,0 +1,10 @@ > +/* { 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; > +} > + Please remove the trailing line. > -- > 2.31.1 >