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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug rtl-optimization/66444] New: [5/6 Regression] Miscompilation of Xen since r211078 Date: Sat, 06 Jun 2015 19:39:00 -0000 [thread overview] Message-ID: <bug-66444-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66444 Bug ID: 66444 Summary: [5/6 Regression] Miscompilation of Xen since r211078 Product: gcc Version: 5.1.1 Status: UNCONFIRMED Keywords: wrong-code Severity: normal Priority: P3 Component: rtl-optimization Assignee: unassigned at gcc dot gnu.org Reporter: jakub at gcc dot gnu.org CC: vmakarov at gcc dot gnu.org, vries at gcc dot gnu.org Target Milestone: --- void foo (unsigned long); int bar (unsigned long); unsigned long a, c, d, f, g; volatile void *b; int e; struct S { unsigned long p, q, r; void *v; }; void fn2 (struct S *x); __attribute__((noinline, noclone)) void * fn1 (struct S *x) { unsigned long y = x->q; unsigned long z = a; do { if ((x->q + 2 & 1UL << 63 - 10) <= 2) return (void *) 0; } while (y = z != x->q); return x->v ? x->v : (void *) 0; } int baz (void) { foo (f); struct S *x = (struct S *) 0xe000000000UL; x += bar (f); fn1 (x); fn2 (x); return 0; } reduced from Xen is miscompiled at -O2 starting with r211078 on x86_64-linux. Still in *.optimized dump we have: _6 = bar (f.0_4); _7 = (long unsigned int) _6; _8 = _7 * 32; x_9 = 962072674304B + _8; fn1 (x_9); fn2 (x_9); (note the same value, constant + 32 * result of bar) is passed to both fn1 and fn2. But starting with *.reload we get: movabsq $962072674304, %r8 salq $5, %rax leaq (%r8,%rax), %rdi call fn1 movq %r8, %rdi call fn2 which is wrong, it passes just the constant, without the added 32 * bar (), to the second function.
next reply other threads:[~2015-06-06 19:39 UTC|newest] Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-06-06 19:39 jakub at gcc dot gnu.org [this message] 2015-06-06 19:40 ` [Bug rtl-optimization/66444] " jakub at gcc dot gnu.org 2015-06-07 22:03 ` vries at gcc dot gnu.org 2015-06-07 22:09 ` vries at gcc dot gnu.org 2015-06-08 6:42 ` jakub at gcc dot gnu.org 2015-06-08 8:31 ` vries at gcc dot gnu.org 2015-06-08 8:34 ` vries at gcc dot gnu.org 2015-06-08 8:36 ` jakub at gcc dot gnu.org 2015-06-08 9:41 ` vries at gcc dot gnu.org 2015-06-08 9:44 ` jakub at gcc dot gnu.org 2015-06-08 12:05 ` vries at gcc dot gnu.org 2015-06-08 17:00 ` vries at gcc dot gnu.org 2015-06-08 17:09 ` vries at gcc dot gnu.org 2015-06-08 17:11 ` vries at gcc dot gnu.org 2015-06-08 17:25 ` vries at gcc dot gnu.org
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