From: Chris Lattner <sabre@nondot.org>
Date: Wed, 16 Jan 2008 05:56:59 +0000 (+0000)
Subject: My previous commit had an incomplete message, it should have been:
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=7ff79c2d9d5e0c014ca8283cd38f5fbf3dd67790;p=oota-llvm.git

My previous commit had an incomplete message, it should have been:

make the 'fp return in ST(0)' optimization smart enough to
look through token factor nodes.  THis allows us to compile
testcases like CodeGen/X86/fp-stack-retcopy.ll into:

_carg:
	subl	$12, %esp
	call	L_foo$stub
	fstpl	(%esp)
	fldl	(%esp)
	addl	$12, %esp
	ret

instead of:

_carg:
	subl	$28, %esp
	call	L_foo$stub
	fstpl	16(%esp)
	movsd	16(%esp), %xmm0
	movsd	%xmm0, 8(%esp)
	fldl	8(%esp)
	addl	$28, %esp
	ret

Still not optimal, but much better and this is a trivial patch.  Fixing
the rest requires invasive surgery that is is not llvm 2.2 material.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46054 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index eb8e5e38320..de55a7c6f4b 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -767,7 +767,7 @@ SDOperand X86TargetLowering::LowerRET(SDOperand Op, SelectionDAG &DAG) {
       // If this is a load into a scalarsse value, don't store the loaded value
       // back to the stack, only to reload it: just replace the scalar-sse load.
       if (ISD::isNON_EXTLoad(Value.Val) &&
-          Chain.reachesChainWithoutSideEffects(Value.getOperand(0))) {
+           Chain.reachesChainWithoutSideEffects(Value.getOperand(0))) {
         Chain  = Value.getOperand(0);
         MemLoc = Value.getOperand(1);
       } else {
diff --git a/test/CodeGen/X86/fp-stack-retcopy.ll b/test/CodeGen/X86/fp-stack-retcopy.ll
new file mode 100644
index 00000000000..997f8df20fe
--- /dev/null
+++ b/test/CodeGen/X86/fp-stack-retcopy.ll
@@ -0,0 +1,12 @@
+; This should not copy the result of foo into an xmm register.
+; RUN: llvm-as < %s | llc -march=x86 -mcpu=yonah -mtriple=i686-apple-darwin9 | not grep xmm
+; rdar://5689903
+
+declare double @foo()
+
+define double @carg({ double, double }* byval  %z) nounwind  {
+entry:
+	%tmp5 = tail call double @foo() nounwind 		; <double> [#uses=1]
+	ret double %tmp5
+}
+