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From: "cvs-commit at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/94899] Failure to optimize out add before compare with INT_MIN Date: Tue, 21 Jun 2022 10:22:15 +0000 [thread overview] Message-ID: <bug-94899-4-fU05DJoBBw@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-94899-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94899 --- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>: https://gcc.gnu.org/g:ab981aab92cbc71918fbaadcf6fa64bdb2b69be7 commit r13-1187-gab981aab92cbc71918fbaadcf6fa64bdb2b69be7 Author: Arjun Shankar <arjun@redhat.com> Date: Tue Jun 21 12:12:11 2022 +0200 match.pd: Remove "+ 0x80000000" in int comparisons [PR94899] Expressions of the form "X + CST < Y + CST" where: * CST is an unsigned integer constant with only the MSB set, and * X and Y's types have integer conversion ranks <= CST's can be simplified to "(signed) X < (signed) Y". This is because, assuming a 32-bit signed numbers, (unsigned) INT_MIN + 0x80000000 is 0, and (unsigned) INT_MAX + 0x80000000 is UINT_MAX. i.e. the result increases monotonically with signed input. This means: ((signed) X < (signed) Y) iff (X + 0x80000000 < Y + 0x80000000) gcc/ PR tree-optimization/94899 * match.pd (X + C < Y + C -> (signed) X < (signed) Y, if C is 0x80000000): New simplification. gcc/testsuite/ * gcc.dg/pr94899.c: New test.
next prev parent reply other threads:[~2022-06-21 10:22 UTC|newest] Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-05-01 0:17 [Bug tree-optimization/94899] New: Failure to optimize out add before compare gabravier at gmail dot com 2020-05-01 1:30 ` [Bug tree-optimization/94899] Failure to optimize out add before compare with INT_MIN pinskia at gcc dot gnu.org 2020-05-01 1:37 ` pinskia at gcc dot gnu.org 2020-05-01 1:38 ` pinskia at gcc dot gnu.org 2020-05-01 8:47 ` rsandifo at gcc dot gnu.org 2022-06-21 10:22 ` cvs-commit at gcc dot gnu.org [this message] 2022-06-22 22:37 ` gabravier at gmail dot com 2023-02-17 20:46 ` gabravier at gmail dot com 2023-02-17 20:50 ` pinskia at gcc dot gnu.org 2023-05-17 21:31 ` pinskia at gcc dot gnu.org
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