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Fix disable-checking bootstrap problem on ppc-darwin
- From: gkeating at apple dot com (Geoffrey Keating)
- To: gcc-patches at gcc dot gnu dot org
- Cc: Daniel Berlin <dan at dberlin dot org>, Diego Novillo <dnovillo at redhat dot com>
- Date: Tue, 10 Aug 2004 10:56:57 -0700 (PDT)
- Subject: Fix disable-checking bootstrap problem on ppc-darwin
Under just the right circumstances, usually involving
--disable-checking, and dependent on environment size and ulimit
settings, you can get a hash collision in value_table which causes two
things with different vuses to compare the same, which is (I think)
not what is wanted.
I see that the whole vuses thing is a work-in-progress, so I won't
worry too much about some of the things I saw. I would point out,
though, that it seems somewhat strange that in
x = a + b;
y = *x;
the two 'x's get numbered differently; there might be an opportunity
there.
Bootstrapped & tested on powerpc-darwin.
--
- Geoffrey Keating <geoffk@apple.com>
===File ~/patches/gcc-treevn-hasheq.patch===================
2004-08-10 Geoffrey Keating <geoffk@apple.com>
* tree-vn.c (val_expr_pair_expr_eq): Compare vuses, to match the
hash function.
Index: tree-vn.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/tree-vn.c,v
retrieving revision 2.3.12.1
diff -u -p -u -p -r2.3.12.1 tree-vn.c
--- tree-vn.c 6 Aug 2004 05:16:47 -0000 2.3.12.1
+++ tree-vn.c 10 Aug 2004 09:13:04 -0000
@@ -151,11 +151,20 @@ val_expr_pair_expr_eq (const void *p1, c
{
const val_expr_pair_t ve1 = (val_expr_pair_t) p1;
const val_expr_pair_t ve2 = (val_expr_pair_t) p2;
+ size_t i;
- if (expressions_equal_p (ve1->e, ve2->e))
- return true;
+ if (! expressions_equal_p (ve1->e, ve2->e))
+ return false;
+
+ if (NUM_VUSES (ve1->vuses) != NUM_VUSES (ve2->vuses))
+ return false;
+
+ for (i = 0; i < NUM_VUSES (ve1->vuses); i++)
+ if (! expressions_equal_p (VUSE_OP (ve1->vuses, i),
+ VUSE_OP (ve2->vuses, i)))
+ return false;
- return false;
+ return true;
}
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