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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/106883] New: SLSR may generate signed wrap Date: Thu, 08 Sep 2022 00:05:37 +0000 [thread overview] Message-ID: <bug-106883-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106883 Bug ID: 106883 Summary: SLSR may generate signed wrap Product: gcc Version: 13.0 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: --- SLSR may generate new signed wrap for cases where the original did not wrap. This can be seen in the function f from gcc.dg/tree-ssa/slsr-19.c: int f (int c, int s) { int x1, x2, y1, y2; y1 = c + 2; x1 = s * y1; y2 = y1 + 2; x2 = s * y2; return x1 + x2; } SLSR optimizes this to int f (int c, int s) { int y1; int x2; int x1; int _7; int slsr_9; <bb 2>: y1_2 = c_1(D) + 2; x1_4 = y1_2 * s_3(D); slsr_9 = s_3(D) * 2; x2_6 = x1_4 + slsr_9; _7 = x1_4 + x2_6; return _7; Calling f(-3, 0x75181005) does not make any operation wrap in the original function, but slsr_9 overflow in the optimized code.
next reply other threads:[~2022-09-08 0:05 UTC|newest] Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-09-08 0:05 kristerw at gcc dot gnu.org [this message] 2022-09-08 9:44 ` [Bug tree-optimization/106883] " rguenth at gcc dot gnu.org
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