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From: "kristerw at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/106884] ifcombine may move shift so it shifts more than bitwidth Date: Thu, 08 Sep 2022 10:53:16 +0000 [thread overview] Message-ID: <bug-106884-4-oRlXI0inrD@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-106884-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106884 --- Comment #2 from Krister Walfridsson <kristerw at gcc dot gnu.org> --- This optimization is invalid if (int)1 << 33 is _not_ undefined behavior in GIMPLE! Consider an architecture where (int)1 << 33 evaluates to 0. foo(2, 1, 33) evaluates to 0 for the original GIMPLE, but it evaluates to 2 in the optimized IR.
next prev parent reply other threads:[~2022-09-08 10:53 UTC|newest] Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-09-08 0:20 [Bug tree-optimization/106884] New: " kristerw at gcc dot gnu.org 2022-09-08 9:52 ` [Bug tree-optimization/106884] " rguenth at gcc dot gnu.org 2022-09-08 10:53 ` kristerw at gcc dot gnu.org [this message] 2022-09-30 11:34 ` kristerw at gcc dot gnu.org 2023-07-11 9:45 ` rguenth at gcc dot gnu.org 2023-07-11 15:36 ` pinskia at gcc dot gnu.org 2023-08-06 0:07 ` kristerw at gcc dot gnu.org 2023-11-01 15:57 ` pinskia at gcc dot gnu.org
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