https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94884
--- Comment #7 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The trunk branch has been updated by Andrew Pinski <pins...@gcc.gnu.org>: https://gcc.gnu.org/g:a5e69e94591ae282857d59e868ff6cea7306c802 commit r14-4965-ga5e69e94591ae282857d59e868ff6cea7306c802 Author: Andrew Pinski <apin...@marvell.com> Date: Tue Sep 12 18:24:22 2023 -0700 MATCH: Simplify `(X &| B) CMP X` if possible [PR 101590] I noticed we were missing these simplifications so let's add them. This adds the following simplifications: U & N <= U -> true U & N > U -> false When U is known to be as non-negative. When N is also known to be non-negative, this is also true: U | N < U -> false U | N >= U -> true When N is a negative integer, the result flips and we get: U | N < U -> true U | N >= U -> false We could extend this later on to be the case where we know N is nonconstant but is known to be negative. Bootstrapped and tested on x86_64-linux-gnu with no regressions. PR tree-optimization/101590 PR tree-optimization/94884 gcc/ChangeLog: * match.pd (`(X BIT_OP Y) CMP X`): New pattern. gcc/testsuite/ChangeLog: * gcc.dg/tree-ssa/bitcmp-1.c: New test. * gcc.dg/tree-ssa/bitcmp-2.c: New test. * gcc.dg/tree-ssa/bitcmp-3.c: New test. * gcc.dg/tree-ssa/bitcmp-4.c: New test. * gcc.dg/tree-ssa/bitcmp-5.c: New test. * gcc.dg/tree-ssa/bitcmp-6.c: New test.
