https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110235
--- Comment #6 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:58e61a3ab1c13b6d5b07d86a30cf48a46e0345c8 commit r14-1916-g58e61a3ab1c13b6d5b07d86a30cf48a46e0345c8 Author: liuhongt <hongtao....@intel.com> Date: Wed Jun 14 10:34:32 2023 +0800 Reimplement packuswb/packusdw with UNSPEC_US_TRUNCATE instead of original us_truncate. packuswb/packusdw does unsigned saturation for signed source, but rtl us_truncate means does unsigned saturation for unsigned source. So for value -1, packuswb will produce 0, but us_truncate produces 255. The patch reimplement those related patterns and functions with UNSPEC_US_TRUNCATE instead of us_truncate. gcc/ChangeLog: PR target/110235 * config/i386/i386-expand.cc (ix86_split_mmx_pack): Use UNSPEC_US_TRUNCATE instead of original us_truncate for packusdw/packuswb. * config/i386/mmx.md (mmx_pack<s_trunsuffix>swb): Substitute with .. (mmx_packsswb): .. this and .. (mmx_packuswb): .. this. (mmx_packusdw): Use UNSPEC_US_TRUNCATE instead of original us_truncate. (s_trunsuffix): Removed code iterator. (any_s_truncate): Ditto. * config/i386/sse.md (<sse2_avx2>_packuswb<mask_name>): Use UNSPEC_US_TRUNCATE instead of original us_truncate. (<sse4_1_avx2>_packusdw<mask_name>): Ditto. * config/i386/i386.md (UNSPEC_US_TRUNCATE): New unspec_c_enum.
