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Re: c++/7754: ICE SIGSEGV on union with template parameter
- From: Pop Sébastian <pop at gauvain dot u-strasbg dot fr>
- To: nathan at gcc dot gnu dot org, dv at vollmann dot ch, gcc-bugs at gcc dot gnu dot org,gcc-prs at gcc dot gnu dot org, nobody at gcc dot gnu dot org, gcc-gnats at gcc dot gnu dot org
- Cc: aoliva at redhat dot com
- Date: Sun, 29 Sep 2002 10:29:05 +0200
- Subject: Re: c++/7754: ICE SIGSEGV on union with template parameter
- References: <20020913210423.30313.qmail@sources.redhat.com>
On Fri, Sep 13, 2002 at 09:04:23PM -0000, nathan@gcc.gnu.org wrote:
> Synopsis: ICE SIGSEGV on union with template parameter
>
> State-Changed-From-To: open->analyzed
> State-Changed-By: nathan
> State-Changed-When: Fri Sep 13 14:04:22 2002
> State-Changed-Why:
> confirmed as a regression
>
> http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=7754
SIGSEGV happens in tree.c:
/* Nonzero if integer constants T1 and T2 represent values that satisfy <.
The precise way of comparison depends on their data type. */
int
tree_int_cst_lt (t1, t2)
tree t1, t2;
{
if (t1 == t2)
return 0;
=>if (TREE_UNSIGNED (TREE_TYPE (t1)) != TREE_UNSIGNED (TREE_TYPE (t2)))
{
int t1_sgn = tree_int_cst_sgn (t1);
int t2_sgn = tree_int_cst_sgn (t2);
if (t1_sgn < t2_sgn)
return 1;
else if (t1_sgn > t2_sgn)
return 0;
/* Otherwise, both are non-negative, so we compare them as
unsigned just in case one of them would overflow a signed
type. */
}
else if (! TREE_UNSIGNED (TREE_TYPE (t1)))
return INT_CST_LT (t1, t2);
return INT_CST_LT_UNSIGNED (t1, t2);
}
At this point t2 is equal to 0, and that crashes the compiler.
The following patch introduced this code without checking of non-NULL for t2:
2002-04-26 Alexandre Oliva <aoliva@redhat.com>
http://gcc.gnu.org/ml/gcc-patches/2002-04/msg01549.html
Alexandre, could you review this patch and the associated bug-report please?
Thanks,
Sebastian