[DAGCombiner] Call SimplifyDemandedVectorElts from EXTRACT_VECTOR_ELT
If we are only extracting vector elements via EXTRACT_VECTOR_ELT(s) we may be able to use SimplifyDemandedVectorElts to avoid unnecessary vector ops.
Differential Revision: https://reviews.llvm.org/D49262
llvm-svn: 337258
diff --git a/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp b/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
index e69afd8..302c788 100644
--- a/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
+++ b/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
@@ -3893,20 +3893,34 @@
return nullptr;
}
-// Convert the mask of the given VECTOR_SHUFFLE into a byte-level mask,
+// Convert the mask of the given shuffle op into a byte-level mask,
// as if it had type vNi8.
-static void getVPermMask(ShuffleVectorSDNode *VSN,
+static bool getVPermMask(SDValue ShuffleOp,
SmallVectorImpl<int> &Bytes) {
- EVT VT = VSN->getValueType(0);
+ EVT VT = ShuffleOp.getValueType();
unsigned NumElements = VT.getVectorNumElements();
unsigned BytesPerElement = VT.getVectorElementType().getStoreSize();
- Bytes.resize(NumElements * BytesPerElement, -1);
- for (unsigned I = 0; I < NumElements; ++I) {
- int Index = VSN->getMaskElt(I);
- if (Index >= 0)
+
+ if (auto *VSN = dyn_cast<ShuffleVectorSDNode>(ShuffleOp)) {
+ Bytes.resize(NumElements * BytesPerElement, -1);
+ for (unsigned I = 0; I < NumElements; ++I) {
+ int Index = VSN->getMaskElt(I);
+ if (Index >= 0)
+ for (unsigned J = 0; J < BytesPerElement; ++J)
+ Bytes[I * BytesPerElement + J] = Index * BytesPerElement + J;
+ }
+ return true;
+ }
+ if (SystemZISD::SPLAT == ShuffleOp.getOpcode() &&
+ isa<ConstantSDNode>(ShuffleOp.getOperand(1))) {
+ unsigned Index = ShuffleOp.getConstantOperandVal(1);
+ Bytes.resize(NumElements * BytesPerElement, -1);
+ for (unsigned I = 0; I < NumElements; ++I)
for (unsigned J = 0; J < BytesPerElement; ++J)
Bytes[I * BytesPerElement + J] = Index * BytesPerElement + J;
+ return true;
}
+ return false;
}
// Bytes is a VPERM-like permute vector, except that -1 is used for
@@ -4075,7 +4089,8 @@
// See whether the bytes we need come from a contiguous part of one
// operand.
SmallVector<int, SystemZ::VectorBytes> OpBytes;
- getVPermMask(cast<ShuffleVectorSDNode>(Op), OpBytes);
+ if (!getVPermMask(Op, OpBytes))
+ break;
int NewByte;
if (!getShuffleInput(OpBytes, Byte, BytesPerElement, NewByte))
break;
@@ -5109,13 +5124,14 @@
if (Opcode == ISD::BITCAST)
// Look through bitcasts.
Op = Op.getOperand(0);
- else if (Opcode == ISD::VECTOR_SHUFFLE &&
+ else if ((Opcode == ISD::VECTOR_SHUFFLE || Opcode == SystemZISD::SPLAT) &&
canTreatAsByteVector(Op.getValueType())) {
// Get a VPERM-like permute mask and see whether the bytes covered
// by the extracted element are a contiguous sequence from one
// source operand.
SmallVector<int, SystemZ::VectorBytes> Bytes;
- getVPermMask(cast<ShuffleVectorSDNode>(Op), Bytes);
+ if (!getVPermMask(Op, Bytes))
+ break;
int First;
if (!getShuffleInput(Bytes, Index * BytesPerElement,
BytesPerElement, First))