On Tue, Jul 7, 2020 at 8:56 AM Kirill Yukhin <kirill.yuk...@gmail.com> wrote: > > Hello HJ, > > On 28 июн 07:19, H.J. Lu via Gcc-patches wrote: > > Enable FMA in rsqrt<mode>2 expander and fold rsqrtv16sf2 expander into > > rsqrt<mode>2 expander which expands to UNSPEC_RSQRT28 for TARGET_AVX512ER. > > Although it doesn't show performance change in our workloads, FMA can > > improve other workloads. > > > > gcc/ > > > > PR target/88713 > > * config/i386/i386-expand.c (ix86_emit_swsqrtsf): Enable FMA. > > * config/i386/sse.md (VF_AVX512VL_VF1_128_256): New. > > (rsqrt<mode>2): Replace VF1_128_256 with VF_AVX512VL_VF1_128_256. > > (rsqrtv16sf2): Removed. > > > > gcc/testsuite/ > > > > PR target/88713 > > * gcc.target/i386/pr88713-1.c: New test. > > * gcc.target/i386/pr88713-2.c: Likewise. > > So, you've introduced new rsqrt expanders for DF vectors and relaxed > condition for V16SF. What I didn't get is why did you change unspec > type from RSQRT to RSQRT28 for V16SF expander? >
UNSPEC in define_expand is meaningless when the pattern is fully expanded by ix86_emit_swsqrtsf. I believe that UNSPEC in rsqrt<mode>2 expander can be removed. -- H.J.
