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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/112736] New: vectorizer is introducing out of bounds memory access Date: Mon, 27 Nov 2023 22:30:36 +0000 [thread overview] Message-ID: <bug-112736-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112736 Bug ID: 112736 Summary: vectorizer is introducing out of bounds memory access Product: gcc Version: 14.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization Assignee: unassigned at gcc dot gnu.org Reporter: kristerw at gcc dot gnu.org Target Milestone: --- The following function (from gcc.dg/torture/pr68379.c) int a, b[3], c[3][5]; void fn1 () { int e; for (a = 2; a >= 0; a--) for (e = 0; e < 4; e++) c[a][e] = b[a]; } generates out of bound memory access (where the three movdqu instructions read 1, 2, and 3 elements before b) when compiled as -O3 for x86_64: fn1: movdqu b-4(%rip), %xmm1 movdqu b-8(%rip), %xmm2 movl $-1, a(%rip) movdqu b-12(%rip), %xmm3 pshufd $255, %xmm1, %xmm0 movups %xmm0, c+40(%rip) pshufd $255, %xmm2, %xmm0 movups %xmm0, c+20(%rip) pshufd $255, %xmm3, %xmm0 movaps %xmm0, c(%rip) ret The vector operations were introduced by the "vect" pass.
next reply other threads:[~2023-11-27 22:30 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-11-27 22:30 kristerw at gcc dot gnu.org [this message] 2023-11-27 22:44 ` [Bug tree-optimization/112736] [14 Regression] " pinskia at gcc dot gnu.org 2023-11-28 12:10 ` rguenth at gcc dot gnu.org 2023-12-11 13:43 ` rguenth at gcc dot gnu.org 2023-12-12 14:26 ` cvs-commit at gcc dot gnu.org 2023-12-12 14:27 ` rguenth at gcc dot gnu.org
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