[llvm] r237651 - SelectionDAG: Cleanup and simplify FoldConstantArithmetic
Matthias Braun
matze at braunis.de
Mon May 18 18:40:21 PDT 2015
Author: matze
Date: Mon May 18 20:40:21 2015
New Revision: 237651
URL: http://llvm.org/viewvc/llvm-project?rev=237651&view=rev
Log:
SelectionDAG: Cleanup and simplify FoldConstantArithmetic
This cleans up the FoldConstantArithmetic code by factoring out the case
of two ConstantSDNodes into an own function. This avoids unnecessary
complexity for many callers who already have ConstantSDNode arguments.
This also avoids an intermeidate SmallVector datastructure and a loop
over that datastructure.
Modified:
llvm/trunk/include/llvm/CodeGen/SelectionDAG.h
llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
Modified: llvm/trunk/include/llvm/CodeGen/SelectionDAG.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/SelectionDAG.h?rev=237651&r1=237650&r2=237651&view=diff
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/SelectionDAG.h (original)
+++ llvm/trunk/include/llvm/CodeGen/SelectionDAG.h Mon May 18 20:40:21 2015
@@ -1128,6 +1128,10 @@ public:
SDValue FoldConstantArithmetic(unsigned Opcode, SDLoc DL, EVT VT,
SDNode *Cst1, SDNode *Cst2);
+ SDValue FoldConstantArithmetic(unsigned Opcode, SDLoc DL, EVT VT,
+ const ConstantSDNode *Cst1,
+ const ConstantSDNode *Cst2);
+
/// Constant fold a setcc to true or false.
SDValue FoldSetCC(EVT VT, SDValue N1,
SDValue N2, ISD::CondCode Cond, SDLoc dl);
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp?rev=237651&r1=237650&r2=237651&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp Mon May 18 20:40:21 2015
@@ -49,6 +49,7 @@
#include "llvm/Target/TargetSubtargetInfo.h"
#include <algorithm>
#include <cmath>
+#include <utility>
using namespace llvm;
@@ -3109,6 +3110,53 @@ SDValue SelectionDAG::getNode(unsigned O
return SDValue(N, 0);
}
+static std::pair<APInt, bool> FoldValue(unsigned Opcode, const APInt &C1,
+ const APInt &C2) {
+ switch (Opcode) {
+ case ISD::ADD: return std::make_pair(C1 + C2, true);
+ case ISD::SUB: return std::make_pair(C1 - C2, true);
+ case ISD::MUL: return std::make_pair(C1 * C2, true);
+ case ISD::AND: return std::make_pair(C1 & C2, true);
+ case ISD::OR: return std::make_pair(C1 | C2, true);
+ case ISD::XOR: return std::make_pair(C1 ^ C2, true);
+ case ISD::SHL: return std::make_pair(C1 << C2, true);
+ case ISD::SRL: return std::make_pair(C1.lshr(C2), true);
+ case ISD::SRA: return std::make_pair(C1.ashr(C2), true);
+ case ISD::ROTL: return std::make_pair(C1.rotl(C2), true);
+ case ISD::ROTR: return std::make_pair(C1.rotr(C2), true);
+ case ISD::UDIV:
+ if (!C2.getBoolValue())
+ break;
+ return std::make_pair(C1.udiv(C2), true);
+ case ISD::UREM:
+ if (!C2.getBoolValue())
+ break;
+ return std::make_pair(C1.urem(C2), true);
+ case ISD::SDIV:
+ if (!C2.getBoolValue())
+ break;
+ return std::make_pair(C1.sdiv(C2), true);
+ case ISD::SREM:
+ if (!C2.getBoolValue())
+ break;
+ return std::make_pair(C1.srem(C2), true);
+ }
+ return std::make_pair(APInt(1, 0), false);
+}
+
+SDValue SelectionDAG::FoldConstantArithmetic(unsigned Opcode, SDLoc DL, EVT VT,
+ const ConstantSDNode *Cst1,
+ const ConstantSDNode *Cst2) {
+ if (Cst1->isOpaque() || Cst2->isOpaque())
+ return SDValue();
+
+ std::pair<APInt, bool> Folded = FoldValue(Opcode, Cst1->getAPIntValue(),
+ Cst2->getAPIntValue());
+ if (!Folded.second)
+ return SDValue();
+ return getConstant(Folded.first, DL, VT);
+}
+
SDValue SelectionDAG::FoldConstantArithmetic(unsigned Opcode, SDLoc DL, EVT VT,
SDNode *Cst1, SDNode *Cst2) {
// If the opcode is a target-specific ISD node, there's nothing we can
@@ -3117,116 +3165,59 @@ SDValue SelectionDAG::FoldConstantArithm
if (Opcode >= ISD::BUILTIN_OP_END)
return SDValue();
- SmallVector<std::pair<ConstantSDNode *, ConstantSDNode *>, 4> Inputs;
- SmallVector<SDValue, 4> Outputs;
- EVT SVT = VT.getScalarType();
+ // Handle the case of two scalars.
+ if (const ConstantSDNode *Scalar1 = dyn_cast<ConstantSDNode>(Cst1)) {
+ if (const ConstantSDNode *Scalar2 = dyn_cast<ConstantSDNode>(Cst2)) {
+ if (SDValue Folded =
+ FoldConstantArithmetic(Opcode, DL, VT, Scalar1, Scalar2)) {
+ if (!VT.isVector())
+ return Folded;
+ SmallVector<SDValue, 4> Outputs;
+ // We may have a vector type but a scalar result. Create a splat.
+ Outputs.resize(VT.getVectorNumElements(), Outputs.back());
+ // Build a big vector out of the scalar elements we generated.
+ return getNode(ISD::BUILD_VECTOR, SDLoc(), VT, Outputs);
+ } else {
+ return SDValue();
+ }
+ }
+ }
- ConstantSDNode *Scalar1 = dyn_cast<ConstantSDNode>(Cst1);
- ConstantSDNode *Scalar2 = dyn_cast<ConstantSDNode>(Cst2);
- if (Scalar1 && Scalar2 && (Scalar1->isOpaque() || Scalar2->isOpaque()))
+ // For vectors extract each constant element into Inputs so we can constant
+ // fold them individually.
+ BuildVectorSDNode *BV1 = dyn_cast<BuildVectorSDNode>(Cst1);
+ BuildVectorSDNode *BV2 = dyn_cast<BuildVectorSDNode>(Cst2);
+ if (!BV1 || !BV2)
return SDValue();
- if (Scalar1 && Scalar2)
- // Scalar instruction.
- Inputs.push_back(std::make_pair(Scalar1, Scalar2));
- else {
- // For vectors extract each constant element into Inputs so we can constant
- // fold them individually.
- BuildVectorSDNode *BV1 = dyn_cast<BuildVectorSDNode>(Cst1);
- BuildVectorSDNode *BV2 = dyn_cast<BuildVectorSDNode>(Cst2);
- if (!BV1 || !BV2)
- return SDValue();
-
- assert(BV1->getNumOperands() == BV2->getNumOperands() && "Out of sync!");
-
- for (unsigned I = 0, E = BV1->getNumOperands(); I != E; ++I) {
- ConstantSDNode *V1 = dyn_cast<ConstantSDNode>(BV1->getOperand(I));
- ConstantSDNode *V2 = dyn_cast<ConstantSDNode>(BV2->getOperand(I));
- if (!V1 || !V2) // Not a constant, bail.
- return SDValue();
+ assert(BV1->getNumOperands() == BV2->getNumOperands() && "Out of sync!");
- if (V1->isOpaque() || V2->isOpaque())
- return SDValue();
-
- // Avoid BUILD_VECTOR nodes that perform implicit truncation.
- // FIXME: This is valid and could be handled by truncating the APInts.
- if (V1->getValueType(0) != SVT || V2->getValueType(0) != SVT)
- return SDValue();
+ EVT SVT = VT.getScalarType();
+ SmallVector<SDValue, 4> Outputs;
+ for (unsigned I = 0, E = BV1->getNumOperands(); I != E; ++I) {
+ ConstantSDNode *V1 = dyn_cast<ConstantSDNode>(BV1->getOperand(I));
+ ConstantSDNode *V2 = dyn_cast<ConstantSDNode>(BV2->getOperand(I));
+ if (!V1 || !V2) // Not a constant, bail.
+ return SDValue();
- Inputs.push_back(std::make_pair(V1, V2));
- }
- }
+ if (V1->isOpaque() || V2->isOpaque())
+ return SDValue();
- // We have a number of constant values, constant fold them element by element.
- for (unsigned I = 0, E = Inputs.size(); I != E; ++I) {
- const APInt &C1 = Inputs[I].first->getAPIntValue();
- const APInt &C2 = Inputs[I].second->getAPIntValue();
+ // Avoid BUILD_VECTOR nodes that perform implicit truncation.
+ // FIXME: This is valid and could be handled by truncating the APInts.
+ if (V1->getValueType(0) != SVT || V2->getValueType(0) != SVT)
+ return SDValue();
- switch (Opcode) {
- case ISD::ADD:
- Outputs.push_back(getConstant(C1 + C2, DL, SVT));
- break;
- case ISD::SUB:
- Outputs.push_back(getConstant(C1 - C2, DL, SVT));
- break;
- case ISD::MUL:
- Outputs.push_back(getConstant(C1 * C2, DL, SVT));
- break;
- case ISD::UDIV:
- if (!C2.getBoolValue())
- return SDValue();
- Outputs.push_back(getConstant(C1.udiv(C2), DL, SVT));
- break;
- case ISD::UREM:
- if (!C2.getBoolValue())
- return SDValue();
- Outputs.push_back(getConstant(C1.urem(C2), DL, SVT));
- break;
- case ISD::SDIV:
- if (!C2.getBoolValue())
- return SDValue();
- Outputs.push_back(getConstant(C1.sdiv(C2), DL, SVT));
- break;
- case ISD::SREM:
- if (!C2.getBoolValue())
- return SDValue();
- Outputs.push_back(getConstant(C1.srem(C2), DL, SVT));
- break;
- case ISD::AND:
- Outputs.push_back(getConstant(C1 & C2, DL, SVT));
- break;
- case ISD::OR:
- Outputs.push_back(getConstant(C1 | C2, DL, SVT));
- break;
- case ISD::XOR:
- Outputs.push_back(getConstant(C1 ^ C2, DL, SVT));
- break;
- case ISD::SHL:
- Outputs.push_back(getConstant(C1 << C2, DL, SVT));
- break;
- case ISD::SRL:
- Outputs.push_back(getConstant(C1.lshr(C2), DL, SVT));
- break;
- case ISD::SRA:
- Outputs.push_back(getConstant(C1.ashr(C2), DL, SVT));
- break;
- case ISD::ROTL:
- Outputs.push_back(getConstant(C1.rotl(C2), DL, SVT));
- break;
- case ISD::ROTR:
- Outputs.push_back(getConstant(C1.rotr(C2), DL, SVT));
- break;
- default:
+ // Fold one vector element.
+ std::pair<APInt, bool> Folded = FoldValue(Opcode, V1->getAPIntValue(),
+ V2->getAPIntValue());
+ if (!Folded.second)
return SDValue();
- }
+ Outputs.push_back(getConstant(Folded.first, DL, SVT));
}
- assert((Scalar1 && Scalar2) || (VT.getVectorNumElements() == Outputs.size() &&
- "Expected a scalar or vector!"));
-
- // Handle the scalar case first.
- if (!VT.isVector())
- return Outputs.back();
+ assert(VT.getVectorNumElements() == Outputs.size() &&
+ "Vector size mismatch!");
// We may have a vector type but a scalar result. Create a splat.
Outputs.resize(VT.getVectorNumElements(), Outputs.back());
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