As discussed in
http://gcc.gnu.org/ml/gcc-help/2010-06/msg00191.html
I am filing a PR for the following piece of C:
int abssat2 (int x)
{
unsigned int y = x;
if (x < 0)
y = -y;
if (y >= 0x80000000)
y--;
return y;
}
Code looks fine until pass CE1 which introduces ABS rtx for the first
comparison (ifcvt.c:noce_try_abs).
Pass insn combine then calls combine.c:combine_simplify_rtx() which calls
simplify_rtx.c:simplify_relational_operation (code=LT, mode=SImode,
cmp_mode=SImode, op0=(abs:SI (reg:SI)), op1=(const_int 0))
and the latter removes the second comparison against 0x80000000.
As this problem occurs on a non-standard target, let me know if I con you
provide with any additional information.
--
Summary: unspecified signed overflow applied to unsigned int
Product: gcc
Version: 4.4.3
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: middle-end
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: avr at gjlay dot de
GCC build triplet: pc-linux
GCC host triplet: pc-linux
GCC target triplet: private
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44608
