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[Bug c/37102] New: possible integer codegen bug
- From: "regehr at cs dot utah dot edu" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 13 Aug 2008 03:45:21 -0000
- Subject: [Bug c/37102] New: possible integer codegen bug
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
This is for svn 139046 on Ubuntu Hardy.
regehr@john-home:~/volatile/tmp0$ current-gcc -O -Wall -fwrapv small.c -o small
regehr@john-home:~/volatile/tmp0$ ./small
5
regehr@john-home:~/volatile/tmp0$ current-gcc -O3 -Wall -fwrapv small.c -o
small
regehr@john-home:~/volatile/tmp0$ ./small
0
regehr@john-home:~/volatile/tmp0$ current-gcc -v
Using built-in specs.
Target: i686-pc-linux-gnu
Configured with: ../configure --program-prefix=current-
--enable-languages=c,c++ --prefix=/home/regehr
Thread model: posix
gcc version 4.4.0 20080813 (experimental) (GCC)
regehr@john-home:~/volatile/tmp0$ cat small.c
#include <stdio.h>
unsigned int g_24;
unsigned int g_37 = 1;
unsigned char g_225;
int main (void)
{
int l_289;
for (l_289 = 1; l_289 < 5; l_289 += 1) {
if (g_225) {
g_24 = g_37;
}
}
g_24 = g_37;
unsigned short context = g_24 << 1;
do {
if (context)
context = (context << 1) ^ 1;
} while (0);
printf ("%d\n", (int)context);
return 0;
}
--
Summary: possible integer codegen bug
Product: gcc
Version: 4.4.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: regehr at cs dot utah dot edu
GCC build triplet: i686-pc-linux-gnu
GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37102