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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/110896] [12/13/14 Regression] gcc.dg/ubsan/pr81981.c is xfailed Date: Fri, 04 Aug 2023 07:07:13 +0000 [thread overview] Message-ID: <bug-110896-4-ilBLrtgLFS@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-110896-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110896 Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Ever confirmed|0 |1 Status|UNCONFIRMED |NEW Last reconfirmed| |2023-08-04 --- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> --- We simplify this to t[0] * 2 (by luck, so it could also be u[0] * 2) which means we lose track of the use of the other variable. Value numbering stmt = t$0_4 = PHI <t$0_13(D)(2), t$0_15(3)> Setting value number of t$0_4 to t$0_4 (changed) Making available beyond BB4 t$0_4 for value t$0_4 Value numbering stmt = u$0_12 = PHI <u$0_14(D)(2), u$0_16(3)> Marking CSEd to PHI node t$0_4 = PHI <t$0_13(D)(2), t$0_15(3)> Setting value number of u$0_12 to t$0_4 (changed) ... Replaced redundant PHI node defining u$0_12 with t$0_4 gimple_simplified to _9 = t$0_4 * 2; early uninit sees conditional init of the memory and so refrains from diagnosing this. I suppose this is kind-of a duplicate of the many missed uninit diagnostics because of CCP optimistic propagation (and only because we don't do optimistic copyprop we do not have even more such cases).
next prev parent reply other threads:[~2023-08-04 7:07 UTC|newest] Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-08-03 22:46 [Bug tree-optimization/110896] New: " pinskia at gcc dot gnu.org 2023-08-03 22:47 ` [Bug tree-optimization/110896] " pinskia at gcc dot gnu.org 2023-08-04 7:07 ` rguenth at gcc dot gnu.org [this message] 2024-03-07 23:26 ` law at gcc dot gnu.org
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