Link to the compiler explorer: https://godbolt.org/z/WYoT4hW9v Reproducer: #include <stdio.h> unsigned long long a; void b(unsigned long long *c, int g) { *c = g; } int d, e = -38921963; long f; int main() { d = (-1807546494482798067UL - f < (6033086967267 > 0)) & e | !(-1807546494482798067UL - f < (6033086967267 > 0)); b(&a, d); printf("%llu\n", a); if (a != 1) __builtin_abort(); } Error: >$ g++ -O0 test.cpp && ./a.out 18446744073670629653 Aborted (core dumped) >$ /usr/bin/g++-11 -O0 test.cpp && ./a.out 1 gcc version 14.0.0 20230808 (20659be04c2749f9f47b085f1789eee0d145fb36)
I think this is mine.
Generic has different type constraints than gimple and that is what is confusing here. bitwise_inverted_equal_p cannot check comparisons to see if they are inverse of each other unless the type is a boolean type ...
Cleaned and simplified up testcase: ``` #define comparison (f < 0) int main() { int f = 0; int d = comparison | !comparison; if (d != 1) __builtin_abort(); } ```
Patch posted: https://gcc.gnu.org/pipermail/gcc-patches/2023-August/626896.html
Created attachment 55718 [details] new patch which I am testing The only thing is it is sometimes overly conserative with the check of `!wascmp || element_precision (type) == 1` for vector types but that is ok those were not handled before either anyways. We do handle `a & ~a` and `a |^ ~a` for all cases (correctly) like we did previously and before r14-2925-g2bae476b511dc441bf61da8a4 .
The trunk branch has been updated by Andrew Pinski <pinskia@gcc.gnu.org>: https://gcc.gnu.org/g:f956c232649e4bb7482786cd54e5d5b4085cd00a commit r14-3140-gf956c232649e4bb7482786cd54e5d5b4085cd00a Author: Andrew Pinski <apinski@marvell.com> Date: Wed Aug 9 13:49:24 2023 -0700 Fix PR 110954: wrong code with cmp | !cmp This was an oversight on my part forgetting that cmp will might have a different true value than all ones but will have a value of 1 in most cases. This means if we have `(f < 0) | !(f < 0)` we would optimize this to -1 rather than just 1. This is version 2 of the patch. Decided to go down a different route than just checking if the precission was 1 inside bitwise_inverted_equal_p. So instead bitwise_inverted_equal_p gets passed an argument that will be set if there was a comparison that was being compared and the user of bitwise_inverted_equal_p decides what needs to be done. In most uses of bitwise_inverted_equal_p, the check will be `!wascmp || element_precision (type) == 1` . But in the case of `a & ~a` and `a ^| ~a` we can handle the case of wascmp by using constant_boolean_node isntead. OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions. PR tree-optimization/110954 gcc/ChangeLog: * generic-match-head.cc (bitwise_inverted_equal_p): Add wascmp argument and set it accordingly. * gimple-match-head.cc (bitwise_inverted_equal_p): Add wascmp argument to the macro. (gimple_bitwise_inverted_equal_p): Add wascmp argument and set it accordingly. * match.pd (`a & ~a`, `a ^| ~a`): Update call to bitwise_inverted_equal_p and handle wascmp case. (`(~x | y) & x`, `(~x | y) & x`, `a?~t:t`): Update call to bitwise_inverted_equal_p and check to see if was !wascmp or if precision was 1. gcc/testsuite/ChangeLog: * gcc.c-torture/execute/pr110954-1.c: New test.
*** Bug 111007 has been marked as a duplicate of this bug. ***
Fixed.