f1 in the following could be optimized to generate the same code as f2.
(Taken from rs6000.c:rs6000_legitimate_offset_address_p.)
int
f1 (unsigned long offset, int x)
{
unsigned long extra = 0;
if (x)
extra = 4;
return offset < 0x100 && offset + extra < 0x100;
}
int
f2 (unsigned long offset, int x)
{
unsigned long extra = 0;
if (x)
extra = 4;
return offset < 0x100 - extra;
}
--
Summary: missed vrp optimization with unsigned comparison
Product: gcc
Version: 4.2.0
Status: UNCONFIRMED
Severity: enhancement
Priority: P3
Component: tree-optimization
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: amodra at bigpond dot net dot au
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26270
