https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91994
--- Comment #7 from rsandifo at gcc dot gnu.org <rsandifo at gcc dot gnu.org> --- Author: rsandifo Date: Mon Oct 7 08:36:06 2019 New Revision: 276648 URL: https://gcc.gnu.org/viewcvs?rev=276648&root=gcc&view=rev Log: [i386] Make the vzeroupper pattern describe its effects (PR91994) The problem in this PR was that vzeroupper has an effect on register contents, but those effects weren't modelled in the rtl pattern, which was just an unspec_volatile. This patch fixes that by running a subpass after vzeroupper insertion to add SETs and CLOBBERs as appropriate. See the comments in the patch for more details. 2019-10-07 Richard Sandiford <richard.sandif...@arm.com> gcc/ PR target/91994 * config/i386/sse.md (avx_vzeroupper): Turn into a define_expand and wrap the unspec_volatile in a parallel. (*avx_vzeroupper): New define_insn. Use a match_parallel around the unspec_volatile. * config/i386/predicates.md (vzeroupper_pattern): Expect the unspec_volatile to be wrapped in a parallel. * config/i386/i386-features.c (ix86_add_reg_usage_to_vzeroupper) (ix86_add_reg_usage_to_vzerouppers): New functions. (rest_of_handle_insert_vzeroupper): Use them to add register usage information to the vzeroupper instructions. gcc/testsuite/ PR target/91994 * gcc.target/i386/pr91994.c: New test. Added: trunk/gcc/testsuite/gcc.target/i386/pr91994.c Modified: trunk/gcc/ChangeLog trunk/gcc/config/i386/i386-features.c trunk/gcc/config/i386/predicates.md trunk/gcc/config/i386/sse.md trunk/gcc/testsuite/ChangeLog
