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* [Bug middle-end/113164] New: [missed optimization] struct fields should not alias @ 2023-12-28 14:55 powerboat9.gamer at gmail dot com 2023-12-28 18:22 ` [Bug middle-end/113164] " pinskia at gcc dot gnu.org ` (2 more replies) 0 siblings, 3 replies; 4+ messages in thread From: powerboat9.gamer at gmail dot com @ 2023-12-28 14:55 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113164 Bug ID: 113164 Summary: [missed optimization] struct fields should not alias Product: gcc Version: 13.2.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: middle-end Assignee: unassigned at gcc dot gnu.org Reporter: powerboat9.gamer at gmail dot com Target Milestone: --- I have the following code > struct sss { > int a; > int b; > }; > > int foo(struct sss *a, struct sss *b) { > return &a->a == &b->b; > } When I compile it with > gcc -c -O3 -Wall -Wextra test.c I get > 0000000000000000 <foo>: > 0: 48 83 c6 04 add $0x4,%rsi > 4: 31 c0 xor %eax,%eax > 6: 48 39 fe cmp %rdi,%rsi > 9: 0f 94 c0 sete %al > c: c3 ret , but GCC should be able to infer that the two pointers being compared can not alias. ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug middle-end/113164] [missed optimization] struct fields should not alias 2023-12-28 14:55 [Bug middle-end/113164] New: [missed optimization] struct fields should not alias powerboat9.gamer at gmail dot com @ 2023-12-28 18:22 ` pinskia at gcc dot gnu.org 2024-01-08 14:16 ` rguenth at gcc dot gnu.org 2024-05-16 12:47 ` rguenth at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: pinskia at gcc dot gnu.org @ 2023-12-28 18:22 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113164 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Severity|normal |enhancement Keywords| |alias, missed-optimization ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug middle-end/113164] [missed optimization] struct fields should not alias 2023-12-28 14:55 [Bug middle-end/113164] New: [missed optimization] struct fields should not alias powerboat9.gamer at gmail dot com 2023-12-28 18:22 ` [Bug middle-end/113164] " pinskia at gcc dot gnu.org @ 2024-01-08 14:16 ` rguenth at gcc dot gnu.org 2024-05-16 12:47 ` rguenth at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: rguenth at gcc dot gnu.org @ 2024-01-08 14:16 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113164 Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Last reconfirmed| |2024-01-08 Ever confirmed|0 |1 CC| |hubicka at gcc dot gnu.org, | |rguenth at gcc dot gnu.org Status|UNCONFIRMED |NEW --- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> --- This would rely on TBAA btw, with -fno-strict-aliasing we allow *a and *b to overlap, aka a = &b->b; confirmed. I think we have all the bits in aliasing_component_refs_p and friends, it just would need to be factored/wired up for addresses. ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug middle-end/113164] [missed optimization] struct fields should not alias 2023-12-28 14:55 [Bug middle-end/113164] New: [missed optimization] struct fields should not alias powerboat9.gamer at gmail dot com 2023-12-28 18:22 ` [Bug middle-end/113164] " pinskia at gcc dot gnu.org 2024-01-08 14:16 ` rguenth at gcc dot gnu.org @ 2024-05-16 12:47 ` rguenth at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: rguenth at gcc dot gnu.org @ 2024-05-16 12:47 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113164 Bug 113164 depends on bug 13962, which changed state. Bug 13962 Summary: [tree-ssa] make "fold" use alias information to optimize pointer comparisons https://gcc.gnu.org/bugzilla/show_bug.cgi?id=13962 What |Removed |Added ---------------------------------------------------------------------------- Status|ASSIGNED |RESOLVED Resolution|--- |FIXED ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2024-05-16 12:47 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2023-12-28 14:55 [Bug middle-end/113164] New: [missed optimization] struct fields should not alias powerboat9.gamer at gmail dot com 2023-12-28 18:22 ` [Bug middle-end/113164] " pinskia at gcc dot gnu.org 2024-01-08 14:16 ` rguenth at gcc dot gnu.org 2024-05-16 12:47 ` rguenth at gcc dot gnu.org
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