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This ugly patch works around a GCC bug where it is compiling SelectCode to
use too much stack space, overflowing the stack for large functions. Instead of emitting new SDOperands in each match block, we emit some common ones at the top of SelectCode then reuse them when possible. This reduces the stack size of SelectCode from 28K to 21K. Note that GCC compiles it to 512 bytes :-/ I've filed GCC PR 25505 to track this. llvm-svn: 24882
This commit is contained in:
Chris Lattner
parent
338c0b2011
commit
28cf136707
@ -1772,6 +1772,21 @@ public:
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ISE(ise), Predicates(preds), Pattern(pattern), Instruction(instr),
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PatternNo(PatNum), OS(os), FoundChain(false), TmpNo(0) {};
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/// DeclareSDOperand - Emit "SDOperand <opname>" or "<opname>". This works
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/// around an ugly GCC bug where SelectCode is using too much stack space
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void DeclareSDOperand(const std::string &OpName) const {
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// If it's one of the common cases declared at the top of SelectCode, just
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// use the existing declaration.
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if (OpName == "N0" || OpName == "N1" || OpName == "N2" ||
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OpName == "N00" || OpName == "N01" ||
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OpName == "N10" || OpName == "N11" ||
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OpName == "Tmp0" || OpName == "Tmp1" ||
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OpName == "Tmp2" || OpName == "Tmp3")
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OS << OpName;
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else
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OS << "SDOperand " << OpName;
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}
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/// EmitMatchCode - Emit a matcher for N, going to the label for PatternNo
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/// if the match fails. At this point, we already know that the opcode for N
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/// matches, and the SDNode for the result has the RootName specified name.
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@ -1845,8 +1860,9 @@ public:
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}
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for (unsigned i = 0, e = N->getNumChildren(); i != e; ++i, ++OpNo) {
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OS << " SDOperand " << RootName << OpNo <<" = " << RootName
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<< ".getOperand(" << OpNo << ");\n";
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OS << " ";
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DeclareSDOperand(RootName+utostr(OpNo));
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OS << " = " << RootName << ".getOperand(" << OpNo << ");\n";
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TreePatternNode *Child = N->getChild(i);
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if (!Child->isLeaf()) {
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@ -1915,7 +1931,7 @@ public:
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if (HasChain) {
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if (!FoundChain) {
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OS << " SDOperand Chain = " << RootName << ".getOperand(0);\n";
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OS << " Chain = " << RootName << ".getOperand(0);\n";
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FoundChain = true;
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}
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}
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@ -1954,28 +1970,35 @@ public:
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case MVT::i64: OS << " uint64_t Tmp"; break;
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}
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OS << ResNo << "C = cast<ConstantSDNode>(" << Val << ")->getValue();\n";
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OS << " SDOperand Tmp" << ResNo << " = CurDAG->getTargetConstant(Tmp"
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OS << " ";
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DeclareSDOperand("Tmp"+utostr(ResNo));
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OS << " = CurDAG->getTargetConstant(Tmp"
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<< ResNo << "C, MVT::" << getEnumName(N->getType()) << ");\n";
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} else if (!N->isLeaf() && N->getOperator()->getName() == "tglobaladdr") {
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OS << " SDOperand Tmp" << ResNo << " = " << Val << ";\n";
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OS << " ";
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DeclareSDOperand("Tmp"+utostr(ResNo));
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OS << " = " << Val << ";\n";
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} else if (!N->isLeaf() && N->getOperator()->getName() == "tconstpool") {
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OS << " SDOperand Tmp" << ResNo << " = " << Val << ";\n";
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OS << " ";
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DeclareSDOperand("Tmp"+utostr(ResNo));
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OS << " = " << Val << ";\n";
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} else if (N->isLeaf() && (CP = NodeGetComplexPattern(N, ISE))) {
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std::string Fn = CP->getSelectFunc();
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NumRes = CP->getNumOperands();
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OS << " SDOperand ";
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for (unsigned i = 0; i < NumRes; i++) {
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if (i != 0) OS << ", ";
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OS << "Tmp" << i + ResNo;
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for (unsigned i = 0; i != NumRes; ++i) {
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OS << " ";
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DeclareSDOperand("Tmp" + utostr(i+ResNo));
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OS << ";\n";
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}
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OS << ";\n";
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OS << " if (!" << Fn << "(" << Val;
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for (unsigned i = 0; i < NumRes; i++)
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OS << ", Tmp" << i + ResNo;
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OS << ")) goto P" << PatternNo << "Fail;\n";
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TmpNo = ResNo + NumRes;
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} else {
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OS << " SDOperand Tmp" << ResNo << " = Select(" << Val << ");\n";
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OS << " ";
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DeclareSDOperand("Tmp"+utostr(ResNo));
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OS << " = Select(" << Val << ");\n";
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}
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// Add Tmp<ResNo> to VariableMap, so that we don't multiply select this
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// value if used multiple times by this pattern result.
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@ -1988,7 +2011,9 @@ public:
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if (DefInit *DI = dynamic_cast<DefInit*>(N->getLeafValue())) {
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unsigned ResNo = TmpNo++;
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if (DI->getDef()->isSubClassOf("Register")) {
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OS << " SDOperand Tmp" << ResNo << " = CurDAG->getRegister("
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OS << " ";
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DeclareSDOperand("Tmp"+utostr(ResNo));
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OS << " = CurDAG->getRegister("
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<< ISE.getQualifiedName(DI->getDef()) << ", MVT::"
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<< getEnumName(N->getType())
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<< ");\n";
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@ -1996,7 +2021,9 @@ public:
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}
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} else if (IntInit *II = dynamic_cast<IntInit*>(N->getLeafValue())) {
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unsigned ResNo = TmpNo++;
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OS << " SDOperand Tmp" << ResNo << " = CurDAG->getTargetConstant("
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OS << " ";
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DeclareSDOperand("Tmp"+utostr(ResNo));
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OS << " = CurDAG->getTargetConstant("
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<< II->getValue() << ", MVT::"
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<< getEnumName(N->getType())
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<< ");\n";
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@ -2018,7 +2045,7 @@ public:
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bool IsCopyFromReg = false;
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if (InFlag || OutFlag)
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OS << " SDOperand InFlag = SDOperand(0,0);\n";
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OS << " InFlag = SDOperand(0, 0);\n";
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// Determine operand emission order. Complex pattern first.
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std::vector<std::pair<unsigned, TreePatternNode*> > EmitOrder;
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@ -2063,7 +2090,9 @@ public:
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unsigned NumResults = Inst.getNumResults();
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unsigned ResNo = TmpNo++;
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if (!isRoot) {
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OS << " SDOperand Tmp" << ResNo << " = CurDAG->getTargetNode("
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OS << " ";
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DeclareSDOperand("Tmp"+utostr(ResNo));
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OS << " = CurDAG->getTargetNode("
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<< II.Namespace << "::" << II.TheDef->getName();
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if (N->getType() != MVT::isVoid)
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OS << ", MVT::" << getEnumName(N->getType());
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@ -2082,7 +2111,7 @@ public:
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<< NumResults << ");\n";
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}
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} else if (II.hasCtrlDep || OutFlag) {
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OS << " SDOperand Result = CurDAG->getTargetNode("
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OS << " Result = CurDAG->getTargetNode("
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<< II.Namespace << "::" << II.TheDef->getName();
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// Output order: results, chain, flags
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@ -2184,7 +2213,9 @@ public:
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assert(N->getNumChildren() == 1 && "node xform should have one child!");
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unsigned OpVal = EmitResultCode(N->getChild(0)).second;
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unsigned ResNo = TmpNo++;
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OS << " SDOperand Tmp" << ResNo << " = Transform_" << Op->getName()
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OS << " ";
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DeclareSDOperand("Tmp"+utostr(ResNo));
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OS << " = Transform_" << Op->getName()
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<< "(Tmp" << OpVal << ".Val);\n";
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if (isRoot) {
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OS << " CodeGenMap[N] = Tmp" << ResNo << ";\n";
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@ -2285,7 +2316,7 @@ private:
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OS << " Chain = Result.getValue(1);\n";
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OS << " InFlag = Result.getValue(2);\n";
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} else {
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OS << " SDOperand Chain;\n";
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OS << " Chain;\n";
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OS << " Result = CurDAG->getCopyFromReg("
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<< "CurDAG->getEntryNode(), ISE.getQualifiedName(RR)"
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<< ", MVT::" << getEnumName(RVT) << ", InFlag);\n";
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@ -2394,6 +2425,9 @@ void DAGISelEmitter::EmitInstructionSelector(std::ostream &OS) {
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<< " return N; // Already selected.\n\n"
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<< " std::map<SDOperand, SDOperand>::iterator CGMI = CodeGenMap.find(N);\n"
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<< " if (CGMI != CodeGenMap.end()) return CGMI->second;\n"
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<< " // Work arounds for GCC stack overflow bugs.\n"
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<< " SDOperand N0, N1, N2, N00, N01, N10, N11, Tmp0, Tmp1, Tmp2, Tmp3;\n"
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<< " SDOperand Chain, InFlag, Result;\n"
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<< " switch (N.getOpcode()) {\n"
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<< " default: break;\n"
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<< " case ISD::EntryToken: // These leaves remain the same.\n"
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@ -2419,7 +2453,7 @@ void DAGISelEmitter::EmitInstructionSelector(std::ostream &OS) {
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<< " CurDAG->getNode(ISD::TokenFactor, MVT::Other, Ops);\n"
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<< " }\n"
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<< " case ISD::CopyFromReg: {\n"
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<< " SDOperand Chain = Select(N.getOperand(0));\n"
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<< " Chain = Select(N.getOperand(0));\n"
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<< " unsigned Reg = cast<RegisterSDNode>(N.getOperand(1))->getReg();\n"
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<< " MVT::ValueType VT = N.Val->getValueType(0);\n"
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<< " if (N.Val->getNumValues() == 2) {\n"
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@ -2442,10 +2476,10 @@ void DAGISelEmitter::EmitInstructionSelector(std::ostream &OS) {
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<< " }\n"
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<< " }\n"
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<< " case ISD::CopyToReg: {\n"
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<< " SDOperand Chain = Select(N.getOperand(0));\n"
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<< " Chain = Select(N.getOperand(0));\n"
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<< " unsigned Reg = cast<RegisterSDNode>(N.getOperand(1))->getReg();\n"
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<< " SDOperand Val = Select(N.getOperand(2));\n"
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<< " SDOperand Result = N;\n"
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<< " Result = N;\n"
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<< " if (N.Val->getNumValues() == 1) {\n"
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<< " if (Chain != N.getOperand(0) || Val != N.getOperand(2))\n"
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<< " Result = CurDAG->getCopyToReg(Chain, Reg, Val);\n"
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