http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55147
Bug #: 55147
Summary: x86: wrong code for 64-bit load
Classification: Unclassified
Product: gcc
Version: 4.8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
AssignedTo: [email protected]
ReportedBy: [email protected]
> cat foo.c
unsigned foo(unsigned long long *p, int i)
{
return __builtin_bswap64(p[i]);
}
> gcc-4.8.0 -m32 -O1 -S foo.c
foo:
movl 8(%esp), %edx
movl 4(%esp), %eax
movl (%eax,%edx,8), %edx
movl 4(%eax,%edx,8), %eax
bswap %eax
ret
Note the first movl overwriting the index register %edx.
