Upgrade the ugly darwin 64-bit bswap idiom (bswap %eax / bswap %edx /
xchgl %eax, %edx) to llvm.bswap.i64. This compiles:
long long test2(long long A) {
return _OSSwapInt64(A);
}
to:
_test2:
movl 8(%esp), %eax
movl 4(%esp), %edx
bswapl %eax
bswapl %edx
ret
instead of:
_test2:
movl 8(%esp), %edx
movl 4(%esp), %eax
bswap %eax
bswap %edx
xchgl %eax, %edx
ret
GCC manages (with -fomit-frame-pointer) the uglier:
_test2:
subl $4, %esp
movl 8(%esp), %eax
movl 12(%esp), %edx
bswap %eax
bswap %edx
xchgl %eax, %edx
addl $4, %esp
ret
llvm-svn: 32001
38084725a2