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[Bug tree-optimization/57877] New: wrong code at -Os on x86_64-linux-gnu in 32-bit mode
- From: "su at cs dot ucdavis.edu" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Wed, 10 Jul 2013 18:01:33 +0000
- Subject: [Bug tree-optimization/57877] New: wrong code at -Os on x86_64-linux-gnu in 32-bit mode
- Auto-submitted: auto-generated
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57877
Bug ID: 57877
Summary: wrong code at -Os on x86_64-linux-gnu in 32-bit mode
Product: gcc
Version: 4.9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: su at cs dot ucdavis.edu
The current gcc trunk mis-compiles the following code on x86_64-linux at -Os in
32-bit mode. This is a regression from 4.8.x.
$ gcc-trunk -v
gcc version 4.9.0 20130710 (experimental) [trunk revision 200864] (GCC)
$
$ gcc-trunk -m32 -Os small.c
$ a.out
0
$ gcc-trunk -m32 -O3 small.c
$ a.out
1
$ gcc-4.8 -m32 -Os small.c
$ a.out
1
$
-----------------------------------------------------
int printf (const char *, ...);
int a, b, *c = &b, e, f = 6, g, h;
short d;
static unsigned char
foo (unsigned long long p1, int *p2)
{
for (; g <= 0; g++)
{
short *i = &d;
int *j = &e;
h = *c;
*i = h;
*j = (*i == *p2) < p1;
}
return 0;
}
int
main ()
{
foo (f, &a);
printf ("%d\n", e);
return 0;
}