https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96681
--- Comment #2 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:5c046034e3ea61dd68965154a398f8f813daf8f2 commit r11-6738-g5c046034e3ea61dd68965154a398f8f813daf8f2 Author: Jakub Jelinek <ja...@redhat.com> Date: Fri Jan 15 21:10:44 2021 +0100 match.pd: Optimize (x < 0) ^ (y < 0) to (x ^ y) < 0 etc. [PR96681] This patch simplifies comparisons that test the sign bit xored together. If the comparisons are both < 0 or both >= 0, then we should xor the operands together and compare the result to < 0, if the comparisons are different, we should compare to >= 0. 2021-01-15 Jakub Jelinek <ja...@redhat.com> PR tree-optimization/96681 * match.pd ((x < 0) ^ (y < 0) to (x ^ y) < 0): New simplification. ((x >= 0) ^ (y >= 0) to (x ^ y) < 0): Likewise. ((x < 0) ^ (y >= 0) to (x ^ y) >= 0): Likewise. ((x >= 0) ^ (y < 0) to (x ^ y) >= 0): Likewise. * gcc.dg/tree-ssa/pr96681.c: New test.
