------- Comment #13 from rguenth at gcc dot gnu dot org 2006-10-10 11:58
-------
On mainline we now have
f:
xorl %eax, %eax
movl a, %edx
cmpl $0, 4(%esp)
movl b, %ecx
jne .L4
movl %edx, %eax
sarl $31, %edx
idivl %ecx
.L4:
rep ; ret
which still loads a and b unconditionally, but it looks less "messy". 4.1.1
is the mess as in comment #1.
We end up with
f (bool1)
{
int c1;
int c;
int b.1;
int a.0;
<bb 2>:
# VUSE <a_2>;
a.0_3 = a;
# VUSE <b_4>;
b.1_5 = b;
if (bool1_7 != 0) goto <L2>; else goto <L1>;
<L1>:;
c1_6 = a.0_3 / b.1_5;
# c_1 = PHI <0(2), c1_6(3)>;
<L2>:;
return c_1;
}
where the best thing would be to sink the loads to the single-use a.0_3 and
b.1_5 into the conditional BB. It looks like TER has code to deal with this
case and could replace a.0_3 and b.1_5 with a and b, but this doesn't happen.
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |amacleod at redhat dot com
Last reconfirmed|2006-07-05 09:35:27 |2006-10-10 11:58:07
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23346
