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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/60183] [4.7/4.8/4.9 Regression] phiprop creates invalid code Date: Fri, 14 Feb 2014 09:22:00 -0000 [thread overview] Message-ID: <bug-60183-4-bnKnPxAeMK@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-60183-4@http.gcc.gnu.org/bugzilla/> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60183 --- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> --- Updated testcase that segfaults for me, no -fsanitize=address is then needed to trigger it. Works with -O0 or -O? -fno-tree-phiprop: unsigned char c[0x300001] = { 1 }; int j = 2; static void foo (unsigned long *x, unsigned char *y) { int i; unsigned long w = x[0]; for (i = 0; i < j; i++) { w += *y; y += 0x100000; w += *y; y += 0x100000; } x[1] = w; } __attribute__ ((noinline, noclone)) void bar (unsigned long *x) { foo (x, c); } int main () { unsigned long a[2] = { 0, -1UL }; asm volatile (""::"r" (c):"memory"); c[0] = 0; bar (a); if (a[1] != 0) __builtin_abort (); return 0; } Perhaps phiprop is confused by the &MEM[(void *)y_5 + 2097152B] and thinks that because of the MEM_REF in there it is safe to dereference it?
next prev parent reply other threads:[~2014-02-14 9:22 UTC|newest] Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top [not found] <bug-60183-4@http.gcc.gnu.org/bugzilla/> 2014-02-13 19:22 ` jakub at gcc dot gnu.org 2014-02-14 9:18 ` rguenth at gcc dot gnu.org 2014-02-14 9:22 ` jakub at gcc dot gnu.org [this message] 2014-02-14 9:28 ` rguenth at gcc dot gnu.org 2014-02-14 12:58 ` rguenth at gcc dot gnu.org 2014-02-15 9:55 ` rguenth at gcc dot gnu.org 2014-02-25 10:47 ` [Bug tree-optimization/60183] [4.7/4.8 " rguenth at gcc dot gnu.org 2014-02-25 10:48 ` [Bug tree-optimization/60183] [4.7 " rguenth at gcc dot gnu.org 2014-03-17 14:39 ` rguenth at gcc dot gnu.org 2014-03-17 14:40 ` rguenth at gcc dot gnu.org
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