https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96906
--- Comment #8 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by hongtao Liu <liuho...@gcc.gnu.org>: https://gcc.gnu.org/g:70310982492071f98eacdac0747521769b0f0328 commit r11-5697-g70310982492071f98eacdac0747521769b0f0328 Author: liuhongt <hongtao....@intel.com> Date: Mon Nov 30 13:27:16 2020 +0800 Optimize vpsubusw compared to 0 into vpcmpleuw or vpcmpnleuw [PR96906] For signed comparisons, it handles cases that are eq or neq to 0. For unsigned comparisons, it additionaly handles cases that are le or gt to 0(equivilent to eq or neq to 0). Transform case eq to leu, case neq to gtu. .i.e. for -mavx512bw -mavx512vl transform eq case code from vpsubusw %xmm1, %xmm0, %xmm0 vpxor %xmm1, %xmm1, %xmm1 vpcmpeqw %xmm1, %xmm0, %k0 to vpcmpleuw %xmm1, %xmm0, %k0 .i.e. for -mavx512bw -mavx512vl transform neq case code from vpsubusw %xmm1, %xmm0, %xmm0 vpxor %xmm1, %xmm1, %xmm1 vpcmpneqw %xmm1, %xmm0, %k0 to vpcmpnleuw %xmm1, %xmm0, %k0 gcc/ChangeLog PR target/96906 * config/i386/sse.md (<avx512>_ucmp<mode>3<mask_scalar_merge_name>): Add a new define_split after this insn. gcc/testsuite/ChangeLog * gcc.target/i386/avx512bw-pr96906-1.c: New test. * gcc.target/i386/pr96906-1.c: Add -mno-avx512f.
