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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/113703] ivopts miscompiles loop Date: Thu, 01 Feb 2024 14:12:49 +0000 [thread overview] Message-ID: <bug-113703-4-c48TZgoUaY@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-113703-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113703 Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Keywords| |wrong-code CC| |rguenth at gcc dot gnu.org --- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> --- I think the point is we fail to represent Analyzing # of iterations of loop 1 exit condition [i_5(D) + 1, + , 1] < n_11(D) bounds on difference of bases: -18446744073709551615 ... 18446744073709551615 result: zero if i_5(D) + 1 > n_11(D) # of iterations (n_11(D) - i_5(D)) + 18446744073709551615, bounded by 18446744073709551615 number of iterations (n_11(D) - i_5(D)) + 18446744073709551615; zero if i_5(D) + 1 > n_11(D) specifically the 'zero if i_5(D) + 1 > n_11(D)' I think may_eliminate_iv is wrong here, maybe not considering overflow of the niter expression? I wonder if it is possible to write a runtime testcase that FAILs with reasonable memory requirement/layout.
next prev parent reply other threads:[~2024-02-01 14:12 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2024-02-01 11:17 [Bug tree-optimization/113703] New: " kristerw at gcc dot gnu.org 2024-02-01 14:12 ` rguenth at gcc dot gnu.org [this message] 2024-02-01 15:01 ` [Bug tree-optimization/113703] " kristerw at gcc dot gnu.org 2024-02-01 15:30 ` kristerw at gcc dot gnu.org 2024-02-05 10:04 ` rguenth at gcc dot gnu.org 2024-02-06 11:33 ` rguenth at gcc dot gnu.org
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