Author: lattner
Date: Tue Jan 15 23:56:59 2008
New Revision: 46054
URL: http://llvm.org/viewvc/llvm-project?rev=46054&view=rev
Log:
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.
Added:
llvm/trunk/test/CodeGen/X86/fp-stack-retcopy.ll
Modified:
llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
URL:
http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=46054&r1=46053&r2=46054&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Tue Jan 15 23:56:59 2008
@@ -767,7 +767,7 @@
// 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 {
Added: llvm/trunk/test/CodeGen/X86/fp-stack-retcopy.ll
URL:
http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/fp-stack-retcopy.ll?rev=46054&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/X86/fp-stack-retcopy.ll (added)
+++ llvm/trunk/test/CodeGen/X86/fp-stack-retcopy.ll Tue Jan 15 23:56:59 2008
@@ -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
+}
+
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