Hello, Everyone.
Please find updated LowerSwitch patch (synced with latest APInt-related
changes).
--
With best regards, Anton Korobeynikov.
Faculty of Mathematics & Mechanics, Saint Petersburg State University.
diff -r 1f58690658d2 lib/Transforms/Utils/LowerSwitch.cpp
--- a/lib/Transforms/Utils/LowerSwitch.cpp Sat Mar 03 07:36:44 2007 +0000
+++ b/lib/Transforms/Utils/LowerSwitch.cpp Sat Mar 03 11:32:18 2007 +0300
@@ -22,6 +22,7 @@
#include "llvm/Support/Debug.h"
#include "llvm/Support/Compiler.h"
#include <algorithm>
+#include <list>
using namespace llvm;
namespace {
@@ -40,9 +41,19 @@ namespace {
AU.addPreservedID(LowerInvokePassID);
AU.addPreservedID(LowerAllocationsID);
}
-
- typedef std::pair<Constant*, BasicBlock*> Case;
- typedef std::vector<Case>::iterator CaseItr;
+
+ struct Case {
+ Constant* Low;
+ Constant* High;
+ BasicBlock* BB;
+
+ Case(Constant* _Low = NULL, Constant* _High = NULL,
+ BasicBlock* _BB = NULL):
+ Low(_Low), High(_High), BB(_BB) { }
+ };
+
+ typedef std::vector<Case> CaseVector;
+ typedef std::vector<Case>::iterator CaseItr;
private:
void processSwitchInst(SwitchInst *SI);
@@ -50,16 +61,18 @@ namespace {
BasicBlock* OrigBlock, BasicBlock* Default);
BasicBlock* newLeafBlock(Case& Leaf, Value* Val,
BasicBlock* OrigBlock, BasicBlock* Default);
+ unsigned Clusterify(CaseVector& Cases, SwitchInst *SI);
};
/// The comparison function for sorting the switch case values in the vector.
+ /// WARNING: Case ranges should be disjoint!
struct CaseCmp {
bool operator () (const LowerSwitch::Case& C1,
const LowerSwitch::Case& C2) {
- const ConstantInt* CI1 = cast<const ConstantInt>(C1.first);
- const ConstantInt* CI2 = cast<const ConstantInt>(C2.first);
- return CI1->getValue().ult(CI2->getValue());
+ const ConstantInt* CI1 = cast<const ConstantInt>(C1.Low);
+ const ConstantInt* CI2 = cast<const ConstantInt>(C2.High);
+ return CI1->getValue().slt(CI2->getValue());
}
};
@@ -91,19 +104,20 @@ bool LowerSwitch::runOnFunction(Function
// operator<< - Used for debugging purposes.
//
-std::ostream& operator<<(std::ostream &O,
- const std::vector<LowerSwitch::Case> &C) {
+static std::ostream& operator<<(std::ostream &O,
+ const LowerSwitch::CaseVector &C) {
O << "[";
- for (std::vector<LowerSwitch::Case>::const_iterator B = C.begin(),
+ for (LowerSwitch::CaseVector::const_iterator B = C.begin(),
E = C.end(); B != E; ) {
- O << *B->first;
+ O << *B->Low << " -" << *B->High;
if (++B != E) O << ", ";
}
return O << "]";
}
-OStream& operator<<(OStream &O, const std::vector<LowerSwitch::Case> &C) {
+
+static OStream& operator<<(OStream &O, const LowerSwitch::CaseVector &C) {
if (O.stream()) *O.stream() << C;
return O;
}
@@ -128,7 +142,9 @@ BasicBlock* LowerSwitch::switchConvert(C
Case& Pivot = *(Begin + Mid);
DEBUG( DOUT << "Pivot ==> "
- << cast<ConstantInt>(Pivot.first)->getValue().toStringSigned(10)
+ << cast<ConstantInt>(Pivot.Low)->getValue().toStringSigned(10)
+ << " -"
+ << cast<ConstantInt>(Pivot.High)->getValue().toStringSigned(10)
<< "\n");
BasicBlock* LBranch = switchConvert(LHS.begin(), LHS.end(), Val,
@@ -142,7 +158,7 @@ BasicBlock* LowerSwitch::switchConvert(C
BasicBlock* NewNode = new BasicBlock("NodeBlock");
F->getBasicBlockList().insert(OrigBlock->getNext(), NewNode);
- ICmpInst* Comp = new ICmpInst(ICmpInst::ICMP_ULT, Val, Pivot.first, "Pivot");
+ ICmpInst* Comp = new ICmpInst(ICmpInst::ICMP_ULT, Val, Pivot.Low, "Pivot");
NewNode->getInstList().push_back(Comp);
new BranchInst(LBranch, RBranch, Comp, NewNode);
return NewNode;
@@ -162,25 +178,93 @@ BasicBlock* LowerSwitch::newLeafBlock(Ca
BasicBlock* NewLeaf = new BasicBlock("LeafBlock");
F->getBasicBlockList().insert(OrigBlock->getNext(), NewLeaf);
- // Make the seteq instruction...
- ICmpInst* Comp = new ICmpInst(ICmpInst::ICMP_EQ, Val,
- Leaf.first, "SwitchLeaf");
- NewLeaf->getInstList().push_back(Comp);
+ // Emit comparison
+ ICmpInst* Comp = NULL;
+ if (Leaf.Low == Leaf.High) {
+ // Make the seteq instruction...
+ Comp = new ICmpInst(ICmpInst::ICMP_EQ, Val, Leaf.Low,
+ "SwitchLeaf", NewLeaf);
+ } else {
+ // Make range comparison
+ if (cast<ConstantInt>(Leaf.Low)->isMinValue(true /*isSigned*/)) {
+ // Val >= Min && Val <= Hi --> Val <= Hi
+ Comp = new ICmpInst(ICmpInst::ICMP_SLE, Val, Leaf.High,
+ "SwitchLeaf", NewLeaf);
+ } else {
+ // Emit V-Lo <=u Hi-Lo
+ Constant* NegLo = ConstantExpr::getNeg(Leaf.Low);
+ Instruction* Add = BinaryOperator::createAdd(Val, NegLo,
+ Val->getName()+".off",
+ NewLeaf);
+ Constant *UpperBound = ConstantExpr::getAdd(NegLo, Leaf.High);
+ Comp = new ICmpInst(ICmpInst::ICMP_ULE, Add, UpperBound,
+ "SwitchLeaf", NewLeaf);
+ }
+ }
// Make the conditional branch...
- BasicBlock* Succ = Leaf.second;
+ BasicBlock* Succ = Leaf.BB;
new BranchInst(Succ, Default, Comp, NewLeaf);
// If there were any PHI nodes in this successor, rewrite one entry
// from OrigBlock to come from NewLeaf.
for (BasicBlock::iterator I = Succ->begin(); isa<PHINode>(I); ++I) {
PHINode* PN = cast<PHINode>(I);
+ // Remove all but one incoming entries from the cluster
+ uint64_t Range = cast<ConstantInt>(Leaf.High)->getSExtValue() -
+ cast<ConstantInt>(Leaf.Low)->getSExtValue();
+ for (uint64_t j = 0; j < Range; ++j) {
+ PN->removeIncomingValue(OrigBlock);
+ }
+
int BlockIdx = PN->getBasicBlockIndex(OrigBlock);
assert(BlockIdx != -1 && "Switch didn't go to this successor??");
PN->setIncomingBlock((unsigned)BlockIdx, NewLeaf);
}
return NewLeaf;
+}
+
+unsigned LowerSwitch::Clusterify(CaseVector& Cases, SwitchInst *SI)
+{
+ std::list<Case> tmpCases;
+ unsigned numCmps = 0;
+
+ // Start with "simple" cases
+ for (unsigned i = 1; i < SI->getNumSuccessors(); ++i)
+ tmpCases.push_back(Case(SI->getSuccessorValue(i),
+ SI->getSuccessorValue(i),
+ SI->getSuccessor(i)));
+ tmpCases.sort(CaseCmp());
+
+ // Merge case into clusters
+ if (tmpCases.size()>=2)
+ for (std::list<Case>::iterator I=tmpCases.begin(), J=++(tmpCases.begin()),
+ E=tmpCases.end(); J!=E; ) {
+ int64_t nextValue = cast<ConstantInt>(J->Low)->getSExtValue();
+ int64_t currentValue = cast<ConstantInt>(I->High)->getSExtValue();
+ BasicBlock* nextBB = J->BB;
+ BasicBlock* currentBB = I->BB;
+
+ if ((nextValue-currentValue==1) && (currentBB == nextBB)) {
+ I->High = J->High;
+ tmpCases.erase(J++);
+ } else {
+ I = J++;
+ }
+ }
+
+ Cases.clear();
+ for (std::list<Case>::iterator I=tmpCases.begin(), E=tmpCases.end();
+ I!=E; ++I, ++numCmps) {
+ if (I->Low != I->High)
+ // A range counts double, since it requires two compares.
+ ++numCmps;
+
+ Cases.push_back(*I);
+ }
+
+ return numCmps;
}
// processSwitchInst - Replace the specified switch instruction with a sequence
@@ -216,14 +300,14 @@ void LowerSwitch::processSwitchInst(Swit
PN->setIncomingBlock((unsigned)BlockIdx, NewDefault);
}
- std::vector<Case> Cases;
-
- // Expand comparisons for all of the non-default cases...
- for (unsigned i = 1; i < SI->getNumSuccessors(); ++i)
- Cases.push_back(Case(SI->getSuccessorValue(i), SI->getSuccessor(i)));
-
- std::sort(Cases.begin(), Cases.end(), CaseCmp());
+ // Prepare cases vector.
+ CaseVector Cases;
+ unsigned numCmps = Clusterify(Cases, SI);
+
+ DOUT << "Clusterify finished. Total clusters: " << Cases.size()
+ << ". Total compares: " << numCmps << "\n";
DOUT << "Cases: " << Cases << "\n";
+
BasicBlock* SwitchBlock = switchConvert(Cases.begin(), Cases.end(), Val,
OrigBlock, NewDefault);
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