[DAGCombiner] Add support for TRUNCATE + FP_EXTEND vector constant folding
This patch adds supports for the vector constant folding of TRUNCATE and FP_EXTEND instructions and tidies up the SINT_TO_FP and UINT_TO_FP instructions to match.
It also moves the vector constant folding for the FNEG and FABS instructions to use the DAG.getNode() functionality like the other unary instructions.
Differential Revision: http://reviews.llvm.org/D8593
llvm-svn: 233224
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index dbdde4e..8b3d057 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -251,7 +251,6 @@
SDValue visitORLike(SDValue N0, SDValue N1, SDNode *LocReference);
SDValue visitXOR(SDNode *N);
SDValue SimplifyVBinOp(SDNode *N);
- SDValue SimplifyVUnaryOp(SDNode *N);
SDValue visitSHL(SDNode *N);
SDValue visitSRA(SDNode *N);
SDValue visitSRL(SDNode *N);
@@ -716,6 +715,22 @@
return nullptr;
}
+static SDNode *isConstantIntBuildVectorOrConstantInt(SDValue N) {
+ if (isa<ConstantSDNode>(N))
+ return N.getNode();
+ if (ISD::isBuildVectorOfConstantSDNodes(N.getNode()))
+ return N.getNode();
+ return nullptr;
+}
+
+static SDNode *isConstantFPBuildVectorOrConstantFP(SDValue N) {
+ if (isa<ConstantFPSDNode>(N))
+ return N.getNode();
+ if (ISD::isBuildVectorOfConstantFPSDNodes(N.getNode()))
+ return N.getNode();
+ return nullptr;
+}
+
// \brief Returns the SDNode if it is a constant splat BuildVector or constant
// int.
static ConstantSDNode *isConstOrConstSplat(SDValue N) {
@@ -6557,7 +6572,7 @@
if (N0.getValueType() == N->getValueType(0))
return N0;
// fold (truncate c1) -> c1
- if (isa<ConstantSDNode>(N0))
+ if (isConstantIntBuildVectorOrConstantInt(N0))
return DAG.getNode(ISD::TRUNCATE, SDLoc(N), VT, N0);
// fold (truncate (truncate x)) -> (truncate x)
if (N0.getOpcode() == ISD::TRUNCATE)
@@ -7947,8 +7962,7 @@
EVT OpVT = N0.getValueType();
// fold (sint_to_fp c1) -> c1fp
- ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
- if (N0C &&
+ if (isConstantIntBuildVectorOrConstantInt(N0) &&
// ...but only if the target supports immediate floating-point values
(!LegalOperations ||
TLI.isOperationLegalOrCustom(llvm::ISD::ConstantFP, VT)))
@@ -8000,8 +8014,7 @@
EVT OpVT = N0.getValueType();
// fold (uint_to_fp c1) -> c1fp
- ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
- if (N0C &&
+ if (isConstantIntBuildVectorOrConstantInt(N0) &&
// ...but only if the target supports immediate floating-point values
(!LegalOperations ||
TLI.isOperationLegalOrCustom(llvm::ISD::ConstantFP, VT)))
@@ -8159,7 +8172,6 @@
SDValue DAGCombiner::visitFP_EXTEND(SDNode *N) {
SDValue N0 = N->getOperand(0);
- ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
EVT VT = N->getValueType(0);
// If this is fp_round(fpextend), don't fold it, allow ourselves to be folded.
@@ -8168,7 +8180,7 @@
return SDValue();
// fold (fp_extend c1fp) -> c1fp
- if (N0CFP)
+ if (isConstantFPBuildVectorOrConstantFP(N0))
return DAG.getNode(ISD::FP_EXTEND, SDLoc(N), VT, N0);
// Turn fp_extend(fp_round(X, 1)) -> x since the fp_round doesn't affect the
@@ -8243,14 +8255,9 @@
SDValue N0 = N->getOperand(0);
EVT VT = N->getValueType(0);
- if (VT.isVector()) {
- SDValue FoldedVOp = SimplifyVUnaryOp(N);
- if (FoldedVOp.getNode()) return FoldedVOp;
- }
-
// Constant fold FNEG.
- if (isa<ConstantFPSDNode>(N0))
- return DAG.getNode(ISD::FNEG, SDLoc(N), VT, N->getOperand(0));
+ if (isConstantFPBuildVectorOrConstantFP(N0))
+ return DAG.getNode(ISD::FNEG, SDLoc(N), VT, N0);
if (isNegatibleForFree(N0, LegalOperations, DAG.getTargetLoweringInfo(),
&DAG.getTarget().Options))
@@ -8345,13 +8352,8 @@
SDValue N0 = N->getOperand(0);
EVT VT = N->getValueType(0);
- if (VT.isVector()) {
- SDValue FoldedVOp = SimplifyVUnaryOp(N);
- if (FoldedVOp.getNode()) return FoldedVOp;
- }
-
// fold (fabs c1) -> fabs(c1)
- if (isa<ConstantFPSDNode>(N0))
+ if (isConstantFPBuildVectorOrConstantFP(N0))
return DAG.getNode(ISD::FABS, SDLoc(N), VT, N0);
// fold (fabs (fabs x)) -> (fabs x)
@@ -12401,38 +12403,6 @@
return SDValue();
}
-/// Visit a binary vector operation, like FABS/FNEG.
-SDValue DAGCombiner::SimplifyVUnaryOp(SDNode *N) {
- assert(N->getValueType(0).isVector() &&
- "SimplifyVUnaryOp only works on vectors!");
-
- SDValue N0 = N->getOperand(0);
-
- if (N0.getOpcode() != ISD::BUILD_VECTOR)
- return SDValue();
-
- // Operand is a BUILD_VECTOR node, see if we can constant fold it.
- SmallVector<SDValue, 8> Ops;
- for (unsigned i = 0, e = N0.getNumOperands(); i != e; ++i) {
- SDValue Op = N0.getOperand(i);
- if (Op.getOpcode() != ISD::UNDEF &&
- Op.getOpcode() != ISD::ConstantFP)
- break;
- EVT EltVT = Op.getValueType();
- SDValue FoldOp = DAG.getNode(N->getOpcode(), SDLoc(N0), EltVT, Op);
- if (FoldOp.getOpcode() != ISD::UNDEF &&
- FoldOp.getOpcode() != ISD::ConstantFP)
- break;
- Ops.push_back(FoldOp);
- AddToWorklist(FoldOp.getNode());
- }
-
- if (Ops.size() != N0.getNumOperands())
- return SDValue();
-
- return DAG.getNode(ISD::BUILD_VECTOR, SDLoc(N), N0.getValueType(), Ops);
-}
-
SDValue DAGCombiner::SimplifySelect(SDLoc DL, SDValue N0,
SDValue N1, SDValue N2){
assert(N0.getOpcode() ==ISD::SETCC && "First argument must be a SetCC node!");
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index eef07d9..b52f648 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -196,6 +196,22 @@
return true;
}
+/// \brief Return true if the specified node is a BUILD_VECTOR node of
+/// all ConstantFPSDNode or undef.
+bool ISD::isBuildVectorOfConstantFPSDNodes(const SDNode *N) {
+ if (N->getOpcode() != ISD::BUILD_VECTOR)
+ return false;
+
+ for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
+ SDValue Op = N->getOperand(i);
+ if (Op.getOpcode() == ISD::UNDEF)
+ continue;
+ if (!isa<ConstantFPSDNode>(Op))
+ return false;
+ }
+ return true;
+}
+
/// isScalarToVector - Return true if the specified node is a
/// ISD::SCALAR_TO_VECTOR node or a BUILD_VECTOR node where only the low
/// element is not an undef.
@@ -2827,7 +2843,7 @@
}
}
- // Constant fold unary operations with a vector integer operand.
+ // Constant fold unary operations with a vector integer or float operand.
if (BuildVectorSDNode *BV = dyn_cast<BuildVectorSDNode>(Operand.getNode())) {
if (BV->isConstant()) {
switch (Opcode) {
@@ -2835,6 +2851,10 @@
// FIXME: Entirely reasonable to perform folding of other unary
// operations here as the need arises.
break;
+ case ISD::FNEG:
+ case ISD::FABS:
+ case ISD::FP_EXTEND:
+ case ISD::TRUNCATE:
case ISD::UINT_TO_FP:
case ISD::SINT_TO_FP: {
// Let the above scalar folding handle the folding of each element.
@@ -2842,9 +2862,14 @@
for (int i = 0, e = VT.getVectorNumElements(); i != e; ++i) {
SDValue OpN = BV->getOperand(i);
OpN = getNode(Opcode, DL, VT.getVectorElementType(), OpN);
+ if (OpN.getOpcode() != ISD::UNDEF &&
+ OpN.getOpcode() != ISD::Constant &&
+ OpN.getOpcode() != ISD::ConstantFP)
+ break;
Ops.push_back(OpN);
}
- return getNode(ISD::BUILD_VECTOR, DL, VT, Ops);
+ if (Ops.size() == VT.getVectorNumElements())
+ return getNode(ISD::BUILD_VECTOR, DL, VT, Ops);
}
}
}