Make sure DAGCombiner doesn't introduce multiple loads from the same memory location. PR10747, part 2.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147283 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 80cf0a8..8166185 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -6905,6 +6905,10 @@
EVT LVT = ExtVT;
if (InVec.getOpcode() == ISD::BITCAST) {
+ // Don't duplicate a load with other uses.
+ if (!InVec.hasOneUse())
+ return SDValue();
+
EVT BCVT = InVec.getOperand(0).getValueType();
if (!BCVT.isVector() || ExtVT.bitsGT(BCVT.getVectorElementType()))
return SDValue();
@@ -6922,12 +6926,20 @@
} else if (InVec.getOpcode() == ISD::SCALAR_TO_VECTOR &&
InVec.getOperand(0).getValueType() == ExtVT &&
ISD::isNormalLoad(InVec.getOperand(0).getNode())) {
+ // Don't duplicate a load with other uses.
+ if (!InVec.hasOneUse())
+ return SDValue();
+
LN0 = cast<LoadSDNode>(InVec.getOperand(0));
} else if ((SVN = dyn_cast<ShuffleVectorSDNode>(InVec))) {
// (vextract (vector_shuffle (load $addr), v2, <1, u, u, u>), 1)
// =>
// (load $addr+1*size)
+ // Don't duplicate a load with other uses.
+ if (!InVec.hasOneUse())
+ return SDValue();
+
// If the bit convert changed the number of elements, it is unsafe
// to examine the mask.
if (BCNumEltsChanged)
@@ -6938,14 +6950,21 @@
int Idx = (Elt > (int)NumElems) ? -1 : SVN->getMaskElt(Elt);
InVec = (Idx < (int)NumElems) ? InVec.getOperand(0) : InVec.getOperand(1);
- if (InVec.getOpcode() == ISD::BITCAST)
+ if (InVec.getOpcode() == ISD::BITCAST) {
+ // Don't duplicate a load with other uses.
+ if (!InVec.hasOneUse())
+ return SDValue();
+
InVec = InVec.getOperand(0);
+ }
if (ISD::isNormalLoad(InVec.getNode())) {
LN0 = cast<LoadSDNode>(InVec);
Elt = (Idx < (int)NumElems) ? Idx : Idx - (int)NumElems;
}
}
+ // Make sure we found a non-volatile load and the extractelement is
+ // the only use.
if (!LN0 || !LN0->hasNUsesOfValue(1,0) || LN0->isVolatile())
return SDValue();
@@ -6982,6 +7001,9 @@
// The replacement we need to do here is a little tricky: we need to
// replace an extractelement of a load with a load.
// Use ReplaceAllUsesOfValuesWith to do the replacement.
+ // Note that this replacement assumes that the extractvalue is the only
+ // use of the load; that's okay because we don't want to perform this
+ // transformation in other cases anyway.
SDValue Load = DAG.getLoad(LVT, N->getDebugLoc(), LN0->getChain(), NewPtr,
LN0->getPointerInfo().getWithOffset(PtrOff),
LN0->isVolatile(), LN0->isNonTemporal(),