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[Bug tree-optimization/64365] [4.9/5 Regression] Predictive commoning after loop vectorization produces incorrect code.
- From: "rguenth at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Wed, 14 Jan 2015 12:44:27 +0000
- Subject: [Bug tree-optimization/64365] [4.9/5 Regression] Predictive commoning after loop vectorization produces incorrect code.
- Auto-submitted: auto-generated
- References: <bug-64365-4 at http dot gcc dot gnu dot org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64365
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Known to work|4.9.2 |4.8.3
Summary|[5 Regression] Predictive |[4.9/5 Regression]
|commoning after loop |Predictive commoning after
|vectorization produces |loop vectorization produces
|incorrect code. |incorrect code.
Known to fail| |4.9.2
--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
Testcase that also fails on the 4.9 branch:
extern void abort (void);
extern int memcmp (const void * , const void *, __SIZE_TYPE__);
void __attribute__((noinline,noclone))
foo(int *in)
{
int i;
for (i = 62; i >= 10; i--)
{
in[i - 8] -= in[i];
in[i - 5] += in[i] * 2;
in[i - 4] += in[i];
}
}
int main()
{
int x[64];
int y[64] = { 0, 1, -2380134, -1065336, -1026376, 3264240, 3113534, 2328130,
3632054, 3839634, 2380136, 1065339, 1026380, 1496037, 1397286, 789976, 386408,
450984, 597112, 497464, 262008, 149184, 194768, 231519, 173984, 87753, 60712,
82042, 87502, 60014, 30050, 25550, 33570, 32386, 20464, 10675, 10868, 13329,
11794, 6892, 3988, 4564, 5148, 4228, 2284, 1568, 1848, 1943, 1472, 741, 628,
702, 714, 474, 230, 234, 238, 242, 120, 59, 60, 61, 62, 63 };
int i;
for (i = 0; i < 64; ++i)
{
x[i] = i;
__asm__ volatile ("");
}
foo (x);
if (memcmp (x, y, sizeof (x)) != 0)
abort ();
return 0;
}