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Codegen:

Browse Source 
as:

_bar:
	pushl	%esi
	subl	$8, %esp
	movl	16(%esp), %esi
	call	L_foo$stub
	fstps	(%esi)
	addl	$8, %esp
	popl	%esi
	#FP_REG_KILL
	ret

instead of:

_bar:
	pushl	%esi
	subl	$8, %esp
	movl	16(%esp), %esi
	call	L_foo$stub
	fstpl	(%esi)
	cvtsd2ss	(%esi), %xmm0
	movss	%xmm0, (%esi)
	addl	$8, %esp
	popl	%esi
	#FP_REG_KILL
	ret



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45401 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2007-12-29 06:57:38 +00:00
parent 5938bef2d2
commit d60eedca01
2 changed files with 40 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

33
lib/Target/X86/X86ISelLowering.cpp
View File

@ -839,6 +839,7 @@ LowerCallResult(SDOperand Chain, SDOperand InFlag, SDNode *TheCall,
SDOperand StoreLoc;
const Value *SrcVal = 0;
int SrcValOffset = 0;
MVT::ValueType RetStoreVT = RVLocs[0].getValVT();
// Determine where to store the value. If the call result is directly
// used by a store, see if we can store directly into the location. In
@ -848,15 +849,34 @@ LowerCallResult(SDOperand Chain, SDOperand InFlag, SDNode *TheCall,
// intermediate stack slot.
if (SDOperand(TheCall, 0).hasOneUse() &&
SDOperand(TheCall, 1).hasOneUse()) {
// In addition to direct uses, we also support a FP_ROUND that uses the
// value, if it is directly stored somewhere.
SDNode *User = *TheCall->use_begin();
if (User->getOpcode() == ISD::FP_ROUND && User->hasOneUse())
User = *User->use_begin();
// Ok, we have one use of the value and one use of the chain. See if
// they are the same node: a store.
if (StoreSDNode *N = dyn_cast<StoreSDNode>(*TheCall->use_begin())) {
if (N->getChain().Val == TheCall && N->getValue().Val == TheCall &&
if (StoreSDNode *N = dyn_cast<StoreSDNode>(User)) {
// Verify that the value being stored is either the call or a
// truncation of the call.
SDNode *StoreVal = N->getValue().Val;
if (StoreVal == TheCall)
; // ok.
else if (StoreVal->getOpcode() == ISD::FP_ROUND &&
StoreVal->hasOneUse() &&
StoreVal->getOperand(0).Val == TheCall)
; // ok.
else
N = 0; // not ok.
if (N && N->getChain().Val == TheCall &&
!N->isVolatile() && !N->isTruncatingStore() &&
N->getAddressingMode() == ISD::UNINDEXED) {
StoreLoc = N->getBasePtr();
SrcVal = N->getSrcValue();
SrcValOffset = N->getSrcValueOffset();
RetStoreVT = N->getValue().getValueType();
}
}
}
@ -875,12 +895,17 @@ LowerCallResult(SDOperand Chain, SDOperand InFlag, SDNode *TheCall,
// multiple blocks and scheduled in between them). When stackifier is
// fixed, they can be uncoupled.
SDOperand Ops[] = {
Chain, RetVal, StoreLoc, DAG.getValueType(RVLocs[0].getValVT()), InFlag
Chain, RetVal, StoreLoc, DAG.getValueType(RetStoreVT), InFlag
};
Chain = DAG.getNode(X86ISD::FST, MVT::Other, Ops, 5);
RetVal = DAG.getLoad(RVLocs[0].getValVT(), Chain,
RetVal = DAG.getLoad(RetStoreVT, Chain,
StoreLoc, SrcVal, SrcValOffset);
Chain = RetVal.getValue(1);
// If we optimized a truncate, then extend the result back to its desired
// type.
if (RVLocs[0].getValVT() != RetStoreVT)
RetVal = DAG.getNode(ISD::FP_EXTEND, RVLocs[0].getValVT(), RetVal);
}
ResultVals.push_back(RetVal);
}

11
test/CodeGen/X86/fp-stack-ret-store.ll
View File

@ -13,3 +13,14 @@ entry:
}
declare double @foo(...)
define void @bar2(float* %P) {
entry:
%tmp = tail call double (...)* @foo2( ) ; <double> [#uses=1]
%tmp1 = fptrunc double %tmp to float ; <float> [#uses=1]
store float %tmp1, float* %P, align 4
ret void
}
declare double @foo2(...)