[Bug target/30665] New: peephole2 misapplied on postinc mem
hp at gcc dot gnu dot org
gcc-bugzilla@gcc.gnu.org
Thu Feb 1 11:34:00 GMT 2007
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
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