https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106164
--- Comment #17 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:5e4a248b03f01f422b0dbc9e1464eb6c2f2bafc6 commit r14-3995-g5e4a248b03f01f422b0dbc9e1464eb6c2f2bafc6 Author: Andrew Pinski <apin...@marvell.com> Date: Wed Sep 13 16:50:33 2023 -0700 MATCH: Support `(a != (CST+1)) & (a > CST)` optimizations Even though this is done via reassocation, match can support these with a simple change to detect that the difference is just one. This allows to optimize these earlier and even during phiopt for an example. This patch adds the following cases: (a != (CST+1)) & (a > CST) -> a > (CST+1) (a != (CST-1)) & (a < CST) -> a < (CST-1) (a == (CST-1)) | (a >= CST) -> a >= (CST-1) (a == (CST+1)) | (a <= CST) -> a <= (CST+1) Canonicalizations of comparisons causes this case to show up more. OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions. PR tree-optimization/106164 gcc/ChangeLog: * match.pd (`(X CMP1 CST1) AND/IOR (X CMP2 CST2)`): Expand to support constants that are off by one. gcc/testsuite/ChangeLog: * gcc.dg/pr21643.c: Update test now that match does the combing of the comparisons. * gcc.dg/tree-ssa/cmpbit-5.c: New test. * gcc.dg/tree-ssa/phi-opt-35.c: New test.
