https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109791
--- Comment #13 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Richard Biener <rgue...@gcc.gnu.org>: https://gcc.gnu.org/g:560a3e35fe01c499bd5b1e95ddc4c3e958cf5abd commit r14-785-g560a3e35fe01c499bd5b1e95ddc4c3e958cf5abd Author: Richard Biener <rguent...@suse.de> Date: Thu May 11 14:28:11 2023 +0200 tree-optimization/109791 - simplify (unsigned)&foo - (unsigned)(&foo + o) The following adds another variant of address difference simplification. The utility ptr_difference_const only handles constant differences (we also cannot code generate anything else), so exposing a possible POINTER_PLUS_EXPR in the match and computing the difference on the base only makes it possible to handle one case of a variable offset. This simplifies (unsigned long) &MEM <char[3]> [(void *)&str + 2B] - (unsigned long) (&str + (_69 + 1)) down to (1 - (unsigned long) _69) during niter analysis, allowing ranger to eliminate a condition later and avoiding a bogus -Wstringop-overflow diagnostic for the testcase in the PR. PR tree-optimization/109791 * match.pd (minus (convert ADDR_EXPR@0) (convert (pointer_plus @1 @2))): New pattern. (minus (convert (pointer_plus @1 @2)) (convert ADDR_EXPR@0)): Likewise.
