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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/106131] [10/11/12/13 Regression] -fstrict-aliasing breaks normal program that does not use any pointer or reference Date: Thu, 30 Jun 2022 08:31:00 +0000 [thread overview] Message-ID: <bug-106131-4-wbcjjqg8op@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-106131-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106131 --- Comment #9 from Richard Biener <rguenth at gcc dot gnu.org> --- So the issue is in processing x = MEM[(const struct Pair &)_11]; _47 = MEM[(const int &)&x + 4]; where we when visiting the def for 'x' continue the lookup with an effective MEM[(const struct Pair &)_11 + 4]; but that looks for a store of TBAA 'Pair' where we then correctly determine that _7->b = _46; doesn't possibly alias. A conservative fix restoring behavior before the relevant change is to force alias set zero (no TBAA) for the offsetted lookup.
next prev parent reply other threads:[~2022-06-30 8:31 UTC|newest] Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-06-29 2:05 [Bug c++/106131] New: " 18307130172 at fudan dot edu.cn 2022-06-29 2:09 ` [Bug c++/106131] " 18307130172 at fudan dot edu.cn 2022-06-29 2:36 ` pinskia at gcc dot gnu.org 2022-06-29 9:26 ` redi at gcc dot gnu.org 2022-06-29 19:20 ` [Bug c++/106131] [10/11/12/13 Regression] " pinskia at gcc dot gnu.org 2022-06-29 19:21 ` pinskia at gcc dot gnu.org 2022-06-29 19:38 ` mpolacek at gcc dot gnu.org 2022-06-29 19:39 ` [Bug tree-optimization/106131] " mpolacek at gcc dot gnu.org 2022-06-29 19:39 ` mpolacek at gcc dot gnu.org 2022-06-30 0:50 ` 18307130172 at fudan dot edu.cn 2022-06-30 6:47 ` rguenther at suse dot de 2022-06-30 7:57 ` rguenth at gcc dot gnu.org 2022-06-30 8:31 ` rguenth at gcc dot gnu.org [this message] 2022-07-01 6:53 ` cvs-commit at gcc dot gnu.org 2022-07-01 6:54 ` [Bug tree-optimization/106131] [10/11/12 " rguenth at gcc dot gnu.org 2022-07-19 11:38 ` cvs-commit at gcc dot gnu.org 2022-10-11 13:04 ` [Bug tree-optimization/106131] [10/11 " cvs-commit at gcc dot gnu.org 2022-10-14 10:47 ` [Bug tree-optimization/106131] [10 " cvs-commit at gcc dot gnu.org 2022-10-14 10:48 ` rguenth at gcc dot gnu.org
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