http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47521
Summary: Unnecessary usage of edx register
Product: gcc
Version: 4.6.0
Status: UNCONFIRMED
Severity: minor
Priority: P3
Component: rtl-optimization
AssignedTo: [email protected]
ReportedBy: [email protected]
In testing PR46235 I noticed some minor inefficiency in the usage of an extra
register.
The C code is:
int foo(int a, int x, int y)
{
if (a & (16))
return a;
return 1;
}
Which produces the asm:
movl %edi, %eax
movl $1, %edx
testb $16, %al
cmove %edx, %eax
ret
The above code could have been further optimized to remove the usage of edx:
movl $1, %eax
test $16, %edi
cmove %edi, %eax
ret
