Commit Graph

2 Commits

Author SHA1 Message Date
Evan Cheng
a06ec9efe1 Now not UINT_TO_FP is legal (it's marked custom), dag combiner won't
optimize it to a SINT_TO_FP when the sign bit is known zero. X86 isel should perform the optimization itself.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@62504 91177308-0d34-0410-b5e6-96231b3b80d8
2009-01-19 08:08:22 +00:00
Chris Lattner
cda8875433 when we know the signbit of an input to uint_to_fp is zero,
change it to sint_to_fp on targets where that is cheaper (and
visaversa of course).  This allows us to compile uint_to_fp to:

_test:
	movl	4(%esp), %eax
	shrl	$23, %eax
	cvtsi2ss	%eax, %xmm0
	movl	8(%esp), %eax
	movss	%xmm0, (%eax)
	ret

instead of:

	.align	3
LCPI1_0:					##  double
	.long	0	## double least significant word 4.5036e+15
	.long	1127219200	## double most significant word 4.5036e+15
	.text
	.align	4,0x90
	.globl	_test
_test:
	subl	$12, %esp
	movl	16(%esp), %eax
	shrl	$23, %eax
	movl	%eax, (%esp)
	movl	$1127219200, 4(%esp)
	movsd	(%esp), %xmm0
	subsd	LCPI1_0, %xmm0
	cvtsd2ss	%xmm0, %xmm0
	movl	20(%esp), %eax
	movss	%xmm0, (%eax)
	addl	$12, %esp
	ret




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52747 91177308-0d34-0410-b5e6-96231b3b80d8
2008-06-26 00:16:49 +00:00