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This ugly patch works around a GCC bug where it is compiling SelectCode to

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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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@24882 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2005-12-20 19:41:03 +00:00
parent aca0901dd3
commit 2f0f9a6973
1 changed files with 56 additions and 22 deletions
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78
utils/TableGen/DAGISelEmitter.cpp
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@ -1772,6 +1772,21 @@ public:
ISE(ise), Predicates(preds), Pattern(pattern), Instruction(instr), ISE(ise), Predicates(preds), Pattern(pattern), Instruction(instr),
PatternNo(PatNum), OS(os), FoundChain(false), TmpNo(0) {}; PatternNo(PatNum), OS(os), FoundChain(false), TmpNo(0) {};
/// DeclareSDOperand - Emit "SDOperand <opname>" or "<opname>". This works
/// around an ugly GCC bug where SelectCode is using too much stack space
void DeclareSDOperand(const std::string &OpName) const {
// If it's one of the common cases declared at the top of SelectCode, just
// use the existing declaration.
if (OpName == "N0" || OpName == "N1" || OpName == "N2" ||
OpName == "N00" || OpName == "N01" ||
OpName == "N10" || OpName == "N11" ||
OpName == "Tmp0" || OpName == "Tmp1" ||
OpName == "Tmp2" || OpName == "Tmp3")
OS << OpName;
else
OS << "SDOperand " << OpName;
}
/// EmitMatchCode - Emit a matcher for N, going to the label for PatternNo /// EmitMatchCode - Emit a matcher for N, going to the label for PatternNo
/// if the match fails. At this point, we already know that the opcode for N /// if the match fails. At this point, we already know that the opcode for N
/// matches, and the SDNode for the result has the RootName specified name. /// matches, and the SDNode for the result has the RootName specified name.
@ -1845,8 +1860,9 @@ public:
} }
for (unsigned i = 0, e = N->getNumChildren(); i != e; ++i, ++OpNo) { for (unsigned i = 0, e = N->getNumChildren(); i != e; ++i, ++OpNo) {
OS << " SDOperand " << RootName << OpNo <<" = " << RootName OS << " ";
<< ".getOperand(" << OpNo << ");\n"; DeclareSDOperand(RootName+utostr(OpNo));
OS << " = " << RootName << ".getOperand(" << OpNo << ");\n";
TreePatternNode *Child = N->getChild(i); TreePatternNode *Child = N->getChild(i);
if (!Child->isLeaf()) { if (!Child->isLeaf()) {
@ -1915,7 +1931,7 @@ public:
if (HasChain) { if (HasChain) {
if (!FoundChain) { if (!FoundChain) {
OS << " SDOperand Chain = " << RootName << ".getOperand(0);\n"; OS << " Chain = " << RootName << ".getOperand(0);\n";
FoundChain = true; FoundChain = true;
} }
} }
@ -1954,28 +1970,35 @@ public:
case MVT::i64: OS << " uint64_t Tmp"; break; case MVT::i64: OS << " uint64_t Tmp"; break;
} }
OS << ResNo << "C = cast<ConstantSDNode>(" << Val << ")->getValue();\n"; OS << ResNo << "C = cast<ConstantSDNode>(" << Val << ")->getValue();\n";
OS << " SDOperand Tmp" << ResNo << " = CurDAG->getTargetConstant(Tmp" OS << " ";
DeclareSDOperand("Tmp"+utostr(ResNo));
OS << " = CurDAG->getTargetConstant(Tmp"
<< ResNo << "C, MVT::" << getEnumName(N->getType()) << ");\n"; << ResNo << "C, MVT::" << getEnumName(N->getType()) << ");\n";
} else if (!N->isLeaf() && N->getOperator()->getName() == "tglobaladdr") { } else if (!N->isLeaf() && N->getOperator()->getName() == "tglobaladdr") {
OS << " SDOperand Tmp" << ResNo << " = " << Val << ";\n"; OS << " ";
DeclareSDOperand("Tmp"+utostr(ResNo));
OS << " = " << Val << ";\n";
} else if (!N->isLeaf() && N->getOperator()->getName() == "tconstpool") { } else if (!N->isLeaf() && N->getOperator()->getName() == "tconstpool") {
OS << " SDOperand Tmp" << ResNo << " = " << Val << ";\n"; OS << " ";
DeclareSDOperand("Tmp"+utostr(ResNo));
OS << " = " << Val << ";\n";
} else if (N->isLeaf() && (CP = NodeGetComplexPattern(N, ISE))) { } else if (N->isLeaf() && (CP = NodeGetComplexPattern(N, ISE))) {
std::string Fn = CP->getSelectFunc(); std::string Fn = CP->getSelectFunc();
NumRes = CP->getNumOperands(); NumRes = CP->getNumOperands();
OS << " SDOperand "; for (unsigned i = 0; i != NumRes; ++i) {
for (unsigned i = 0; i < NumRes; i++) { OS << " ";
if (i != 0) OS << ", "; DeclareSDOperand("Tmp" + utostr(i+ResNo));
OS << "Tmp" << i + ResNo;
}
OS << ";\n"; OS << ";\n";
}
OS << " if (!" << Fn << "(" << Val; OS << " if (!" << Fn << "(" << Val;
for (unsigned i = 0; i < NumRes; i++) for (unsigned i = 0; i < NumRes; i++)
OS << ", Tmp" << i + ResNo; OS << ", Tmp" << i + ResNo;
OS << ")) goto P" << PatternNo << "Fail;\n"; OS << ")) goto P" << PatternNo << "Fail;\n";
TmpNo = ResNo + NumRes; TmpNo = ResNo + NumRes;
} else { } else {
OS << " SDOperand Tmp" << ResNo << " = Select(" << Val << ");\n"; OS << " ";
DeclareSDOperand("Tmp"+utostr(ResNo));
OS << " = Select(" << Val << ");\n";
} }
// Add Tmp<ResNo> to VariableMap, so that we don't multiply select this // Add Tmp<ResNo> to VariableMap, so that we don't multiply select this
// value if used multiple times by this pattern result. // value if used multiple times by this pattern result.
@ -1988,7 +2011,9 @@ public:
if (DefInit *DI = dynamic_cast<DefInit*>(N->getLeafValue())) { if (DefInit *DI = dynamic_cast<DefInit*>(N->getLeafValue())) {
unsigned ResNo = TmpNo++; unsigned ResNo = TmpNo++;
if (DI->getDef()->isSubClassOf("Register")) { if (DI->getDef()->isSubClassOf("Register")) {
OS << " SDOperand Tmp" << ResNo << " = CurDAG->getRegister(" OS << " ";
DeclareSDOperand("Tmp"+utostr(ResNo));
OS << " = CurDAG->getRegister("
<< ISE.getQualifiedName(DI->getDef()) << ", MVT::" << ISE.getQualifiedName(DI->getDef()) << ", MVT::"
<< getEnumName(N->getType()) << getEnumName(N->getType())
<< ");\n"; << ");\n";
@ -1996,7 +2021,9 @@ public:
} }
} else if (IntInit *II = dynamic_cast<IntInit*>(N->getLeafValue())) { } else if (IntInit *II = dynamic_cast<IntInit*>(N->getLeafValue())) {
unsigned ResNo = TmpNo++; unsigned ResNo = TmpNo++;
OS << " SDOperand Tmp" << ResNo << " = CurDAG->getTargetConstant(" OS << " ";
DeclareSDOperand("Tmp"+utostr(ResNo));
OS << " = CurDAG->getTargetConstant("
<< II->getValue() << ", MVT::" << II->getValue() << ", MVT::"
<< getEnumName(N->getType()) << getEnumName(N->getType())
<< ");\n"; << ");\n";
@ -2018,7 +2045,7 @@ public:
bool IsCopyFromReg = false; bool IsCopyFromReg = false;
if (InFlag || OutFlag) if (InFlag || OutFlag)
OS << " SDOperand InFlag = SDOperand(0,0);\n"; OS << " InFlag = SDOperand(0, 0);\n";
// Determine operand emission order. Complex pattern first. // Determine operand emission order. Complex pattern first.
std::vector<std::pair<unsigned, TreePatternNode*> > EmitOrder; std::vector<std::pair<unsigned, TreePatternNode*> > EmitOrder;
@ -2063,7 +2090,9 @@ public:
unsigned NumResults = Inst.getNumResults(); unsigned NumResults = Inst.getNumResults();
unsigned ResNo = TmpNo++; unsigned ResNo = TmpNo++;
if (!isRoot) { if (!isRoot) {
OS << " SDOperand Tmp" << ResNo << " = CurDAG->getTargetNode(" OS << " ";
DeclareSDOperand("Tmp"+utostr(ResNo));
OS << " = CurDAG->getTargetNode("
<< II.Namespace << "::" << II.TheDef->getName(); << II.Namespace << "::" << II.TheDef->getName();
if (N->getType() != MVT::isVoid) if (N->getType() != MVT::isVoid)
OS << ", MVT::" << getEnumName(N->getType()); OS << ", MVT::" << getEnumName(N->getType());
@ -2082,7 +2111,7 @@ public:
<< NumResults << ");\n"; << NumResults << ");\n";
} }
} else if (II.hasCtrlDep || OutFlag) { } else if (II.hasCtrlDep || OutFlag) {
OS << " SDOperand Result = CurDAG->getTargetNode(" OS << " Result = CurDAG->getTargetNode("
<< II.Namespace << "::" << II.TheDef->getName(); << II.Namespace << "::" << II.TheDef->getName();
// Output order: results, chain, flags // Output order: results, chain, flags
@ -2184,7 +2213,9 @@ public:
assert(N->getNumChildren() == 1 && "node xform should have one child!"); assert(N->getNumChildren() == 1 && "node xform should have one child!");
unsigned OpVal = EmitResultCode(N->getChild(0)).second; unsigned OpVal = EmitResultCode(N->getChild(0)).second;
unsigned ResNo = TmpNo++; unsigned ResNo = TmpNo++;
OS << " SDOperand Tmp" << ResNo << " = Transform_" << Op->getName() OS << " ";
DeclareSDOperand("Tmp"+utostr(ResNo));
OS << " = Transform_" << Op->getName()
<< "(Tmp" << OpVal << ".Val);\n"; << "(Tmp" << OpVal << ".Val);\n";
if (isRoot) { if (isRoot) {
OS << " CodeGenMap[N] = Tmp" << ResNo << ";\n"; OS << " CodeGenMap[N] = Tmp" << ResNo << ";\n";
@ -2285,7 +2316,7 @@ private:
OS << " Chain = Result.getValue(1);\n"; OS << " Chain = Result.getValue(1);\n";
OS << " InFlag = Result.getValue(2);\n"; OS << " InFlag = Result.getValue(2);\n";
} else { } else {
OS << " SDOperand Chain;\n"; OS << " Chain;\n";
OS << " Result = CurDAG->getCopyFromReg(" OS << " Result = CurDAG->getCopyFromReg("
<< "CurDAG->getEntryNode(), ISE.getQualifiedName(RR)" << "CurDAG->getEntryNode(), ISE.getQualifiedName(RR)"
<< ", MVT::" << getEnumName(RVT) << ", InFlag);\n"; << ", MVT::" << getEnumName(RVT) << ", InFlag);\n";
@ -2394,6 +2425,9 @@ void DAGISelEmitter::EmitInstructionSelector(std::ostream &OS) {
<< " return N; // Already selected.\n\n" << " return N; // Already selected.\n\n"
<< " std::map<SDOperand, SDOperand>::iterator CGMI = CodeGenMap.find(N);\n" << " std::map<SDOperand, SDOperand>::iterator CGMI = CodeGenMap.find(N);\n"
<< " if (CGMI != CodeGenMap.end()) return CGMI->second;\n" << " if (CGMI != CodeGenMap.end()) return CGMI->second;\n"
<< " // Work arounds for GCC stack overflow bugs.\n"
<< " SDOperand N0, N1, N2, N00, N01, N10, N11, Tmp0, Tmp1, Tmp2, Tmp3;\n"
<< " SDOperand Chain, InFlag, Result;\n"
<< " switch (N.getOpcode()) {\n" << " switch (N.getOpcode()) {\n"
<< " default: break;\n" << " default: break;\n"
<< " case ISD::EntryToken: // These leaves remain the same.\n" << " case ISD::EntryToken: // These leaves remain the same.\n"
@ -2419,7 +2453,7 @@ void DAGISelEmitter::EmitInstructionSelector(std::ostream &OS) {
<< " CurDAG->getNode(ISD::TokenFactor, MVT::Other, Ops);\n" << " CurDAG->getNode(ISD::TokenFactor, MVT::Other, Ops);\n"
<< " }\n" << " }\n"
<< " case ISD::CopyFromReg: {\n" << " case ISD::CopyFromReg: {\n"
<< " SDOperand Chain = Select(N.getOperand(0));\n" << " Chain = Select(N.getOperand(0));\n"
<< " unsigned Reg = cast<RegisterSDNode>(N.getOperand(1))->getReg();\n" << " unsigned Reg = cast<RegisterSDNode>(N.getOperand(1))->getReg();\n"
<< " MVT::ValueType VT = N.Val->getValueType(0);\n" << " MVT::ValueType VT = N.Val->getValueType(0);\n"
<< " if (N.Val->getNumValues() == 2) {\n" << " if (N.Val->getNumValues() == 2) {\n"
@ -2442,10 +2476,10 @@ void DAGISelEmitter::EmitInstructionSelector(std::ostream &OS) {
<< " }\n" << " }\n"
<< " }\n" << " }\n"
<< " case ISD::CopyToReg: {\n" << " case ISD::CopyToReg: {\n"
<< " SDOperand Chain = Select(N.getOperand(0));\n" << " Chain = Select(N.getOperand(0));\n"
<< " unsigned Reg = cast<RegisterSDNode>(N.getOperand(1))->getReg();\n" << " unsigned Reg = cast<RegisterSDNode>(N.getOperand(1))->getReg();\n"
<< " SDOperand Val = Select(N.getOperand(2));\n" << " SDOperand Val = Select(N.getOperand(2));\n"
<< " SDOperand Result = N;\n" << " Result = N;\n"
<< " if (N.Val->getNumValues() == 1) {\n" << " if (N.Val->getNumValues() == 1) {\n"
<< " if (Chain != N.getOperand(0) || Val != N.getOperand(2))\n" << " if (Chain != N.getOperand(0) || Val != N.getOperand(2))\n"
<< " Result = CurDAG->getCopyToReg(Chain, Reg, Val);\n" << " Result = CurDAG->getCopyToReg(Chain, Reg, Val);\n"