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[Bug tree-optimization/49632] ICE in compute_affine_dependence (tree-data-ref.c:4038) with -O3
- From: "spop at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Fri, 8 Jul 2011 04:56:17 +0000
- Subject: [Bug tree-optimization/49632] ICE in compute_affine_dependence (tree-data-ref.c:4038) with -O3
- Auto-submitted: auto-generated
- References: <bug-49632-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49632
Sebastian Pop <spop at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Priority|P3 |P5
Status|UNCONFIRMED |NEW
Last reconfirmed| |2011.07.08 04:55:59
Ever Confirmed|0 |1
Severity|normal |minor
--- Comment #2 from Sebastian Pop <spop at gcc dot gnu.org> 2011-07-08 04:55:59 UTC ---
Further reduced the testcase to:
extern int k, A[7][7];
void f (void)
{
for (int i = 0; i < 5; ++i)
for (int j = 0; j < 5; ++j)
for (k = 4; k >= 0; --k)
A[i][j] = A[i][j+1];
}
And with this testcase, I have the following error:
| (Number of distance vectors differ: Banerjee has 1, Omega has 2.
| Banerjee dist vectors:
| 0 1 0
| Omega dist vectors:
| 0 1 0
| 0 -1 0
And here again, Omega is wrong: a distance vector has to be
lexicographically positive: i.e., the first non zero component in a
distance vector (lexicographically = from left to right) should be
positive, and so the distance vector "0 -1 0" is wrong.
As in PR46851, I will just lower the priority of this bug: Omega is
not used elsewhere than in the implementation of -fcheck-data-deps.