x86 isel peeps.

llvm-svn: 92509

llvm-svn: 81290

llvm-svn: 47711

llvm-svn: 47355

This compiles test-nofold.ll into:

_test:
	movl	$15, %ecx
	andl	4(%esp), %ecx
	testl	%ecx, %ecx
	movl	$42, %eax
	cmove	%ecx, %eax
	ret

instead of:
_test:
	movl	4(%esp), %eax
	movl	%eax, %ecx
	andl	$15, %ecx
	testl	$15, %eax
	movl	$42, %eax
	cmove	%ecx, %eax
	ret

llvm-svn: 47330