https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97786
--- Comment #4 from Surya Kumari Jangala <jskumari at gcc dot gnu.org> ---
For the following test:
int test1 (double x)
{
return __builtin_isinf_sign (x);
}
The assembly generated by trunk is:
xststdcdp 0,1,48
mfcr 3,128
rlwinm 3,3,3,1
bne 0,.L2
mfvsrd 10,1
li 3,1
li 9,-1
cmpdi 0,10,0
isel 3,9,3,0
.L2:
extsw 3,3
blr
However, the sign of 'x' is stored in the CR register at bit 32. So the code
for the builtin can be optimized as follows:
xststdcdp 0,1,48
mfcr 4,128
rlwinm 3,4,3,1
bne 0,.L2
li 9,-1
isel 3,9,3,0 //r3 already contains 1 due to 'rlwinm'
.L2:
extsw 3,3
blr
