https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95535
--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jakub Jelinek <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:892b51cb73f24157391cd18c2215e8d703af97e7 commit r11-965-g892b51cb73f24157391cd18c2215e8d703af97e7 Author: Jakub Jelinek <ja...@redhat.com> Date: Fri Jun 5 10:44:23 2020 +0200 ix86: Improve __builtin_c[lt]z followed by extension [PR95535] In January I've added patterns to optimize SImode -> DImode sign or zero extension of __builtin_popcount, this patch does the same for __builtin_c[lt]z. Like most other instructions, the [tl]zcntl instructions clear the upper 32 bits of the destination register and as the instructions only result in values 0 to 32 inclusive, both sign and zero extensions behave the same. 2020-06-05 Jakub Jelinek <ja...@redhat.com> PR target/95535 * config/i386/i386.md (*ctzsi2_zext, *clzsi2_lzcnt_zext): New define_insn_and_split patterns. (*ctzsi2_zext_falsedep, *clzsi2_lzcnt_zext_falsedep): New define_insn patterns. * gcc.target/i386/pr95535-1.c: New test. * gcc.target/i386/pr95535-2.c: New test.
