Codegen:
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
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 598536d..08bf340 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -839,6 +839,7 @@
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 @@
// 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 @@
// 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);
}