Commit Graph

2 Commits

Author SHA1 Message Date
Chris Lattner
cee56e7d33 generalize the previous code to use the full generality of LEA
for i32/i64 expressions (we could also do i16 on cpus where
i16 lea is fast, but I didn't add this).  On the example, we now
generate:

_test:
	movl	4(%esp), %eax
	cmpl	$42, (%eax)
	setl	%al
	movzbl	%al, %eax
	leal	4(%eax,%eax,8), %eax
	ret

instead of:

_test:
	movl	4(%esp), %eax
	cmpl	$41, (%eax)
	movl	$4, %ecx
	movl	$13, %eax
	cmovg	%ecx, %eax
	ret



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66869 91177308-0d34-0410-b5e6-96231b3b80d8
2009-03-13 05:53:31 +00:00
Chris Lattner
97a29a5fee optimize the case of cond ? 42 : 41 and friends. This compiles the
example to:

_test:
	movl	4(%esp), %eax
	cmpl	$41, (%eax)
	setg	%al
	movzbl	%al, %eax
	orl	$4294967294, %eax
	ret

instead of:

        movl    4(%esp), %eax
        cmpl    $41, (%eax)
	movl	$4294967294, %ecx
	movl	$4294967295, %eax
	cmova	%ecx, %eax
	ret

which is smaller in code size and faster. rdar://6668608



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66868 91177308-0d34-0410-b5e6-96231b3b80d8
2009-03-13 05:22:11 +00:00