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From: "wangjiefeng at huawei dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c/65784] New: after reload, the memrefs_conflict_p is unreliable? Date: Thu, 16 Apr 2015 06:00:00 -0000 [thread overview] Message-ID: <bug-65784-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65784 Bug ID: 65784 Summary: after reload, the memrefs_conflict_p is unreliable? Product: gcc Version: unknown Status: UNCONFIRMED Severity: normal Priority: P3 Component: c Assignee: unassigned at gcc dot gnu.org Reporter: wangjiefeng at huawei dot com int f = -1; int foo(int * pa) { int a = 1; *(pa) = a; pa = pa + f; a = *(pa + 1); return a; } With -O2, the ARM's assembler is as follows: foo: @ args = 0, pretend = 0, frame = 0 @ frame_needed = 0, uses_anonymous_args = 0 @ link register save eliminated. movw r3, #:lower16:.LANCHOR0 @ 20 *arm_movsi_insn/4 [length = 4] mov r2, #1 @ 6 *arm_movsi_insn/2 [length = 4] movt r3, #:upper16:.LANCHOR0 @ 21 *arm_movt [length = 4] str r2, [r0] @ 7 *arm_movsi_insn/6 [length = 4] ldr r3, [r3] @ 9 *arm_movsi_insn/5 [length = 4] add r0, r0, r3, asl #2 @ 11 *arith_shiftsi/1 [length = 4] ldr r0, [r0, #4] @ 17 *arm_movsi_insn/5 [length = 4] bx lr @ 26 *arm_return [length = 12] .size foo, .-foo .global f .data .align 2 In sched1, insn 7 and insn 17 has true dependence, but in sched2, the true dependence between insn 7 and insn 17 is omitted. It seems after reload, in function true_dependence_1, the memrefs_conflict_p is unreliable?
next reply other threads:[~2015-04-16 6:00 UTC|newest] Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-04-16 6:00 wangjiefeng at huawei dot com [this message] 2015-04-16 6:46 ` [Bug c/65784] " pinskia at gcc dot gnu.org
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