https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116120
--- Comment #4 from GCC 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:c5ccdfdcab0b24afba2a661af861bec1d63f0595 commit r15-2637-gc5ccdfdcab0b24afba2a661af861bec1d63f0595 Author: Andrew Pinski <quic_apin...@quicinc.com> Date: Mon Jul 29 14:00:13 2024 -0700 match: Fix wrong code due to `(a ? e : f) !=/== (b ? e : f)` patterns [PR116120] When this pattern was converted from being only dealing with 0/-1, we missed that if `e == f` is true then the optimization is wrong and needs an extra check for that. This changes the patterns to be: /* (a ? x : y) != (b ? x : y) --> (a^b & (x != y)) ? TRUE : FALSE */ /* (a ? x : y) == (b ? x : y) --> (a^b & (x != y)) ? FALSE : TRUE */ /* (a ? x : y) != (b ? y : x) --> (a^b | (x == y)) ? FALSE : TRUE */ /* (a ? x : y) == (b ? y : x) --> (a^b | (x == y)) ? TRUE : FALSE */ Also this can't be done if the X can be a NaNs either. Since that changes the value there too. This still produces better code than the original case and in many cases (x != y) will still reduce to either false or true. With this change we also need to make sure `a`, `b` and the resulting types are all the same for the same reason as the previous patch. I updated (well added) to the testcases to make sure there are the right amount of comparisons left. Changes since v1: * v2: Fixed the testcase names and fixed dg-run to be `dg-do run`. Added a check for HONORS_NANS too. Bootstrapped and tested on x86_64-linux-gnu with no regressions. PR tree-optimization/116120 gcc/ChangeLog: * match.pd (`(a ? x : y) eq/ne (b ? x : y)`): Add test for `x != y` in result. (`(a ? x : y) eq/ne (b ? y : x)`): Add test for `x == y` in result. gcc/testsuite/ChangeLog: * g++.dg/tree-ssa/pr111150.C: Add extra checks on the test. * gcc.dg/tree-ssa/pr111150-1.c: Likewise. * gcc.dg/tree-ssa/pr111150.c: Likewise. * g++.dg/torture/pr116120-1.C: New test. * g++.dg/torture/pr116120-2.C: New test. Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com>
