This is the mail archive of the
gcc-bugs@gcc.gnu.org
mailing list for the GCC project.
[Bug target/30665] New: peephole2 misapplied on postinc mem
- From: "hp at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 1 Feb 2007 11:34:06 -0000
- Subject: [Bug target/30665] New: peephole2 misapplied on postinc mem
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
This testcase is miscompiled on all versions of GCC (visible on r111226):
int __attribute__ ((__noinline__)) f (unsigned *p, int *x)
{
int y = *p++ & 0xfff;
*x++ = y;
*x = *p;
return y;
}
int main (void)
{
unsigned u[2] = { 0xbaad, 0xdad1 };
int x[2] = {17689, 23456};
if (f (u, x) != 0xaad || x[0] != 0xaad || x[1] != 0xdad1)
abort ();
exit (0);
}
It's caused by the cris.md peephole2 marked "andu (casesi+45)" allowing
post-inc memory in operand 1, effectively "shrinking" the post-inc.
The fix is to replace all "(GET_CODE (operands[1]) != MEM || ! MEM_VOLATILE_P
(operands[1]))" with "!side_effects_p (operands[1])" everywhere.
--
Summary: peephole2 misapplied on postinc mem
Product: gcc
Version: 3.2.1
Status: UNCONFIRMED
Keywords: wrong-code
Severity: normal
Priority: P3
Component: target
AssignedTo: hp at gcc dot gnu dot org
ReportedBy: hp at gcc dot gnu dot org
GCC target triplet: cris-*
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30665