Hello, Everyone.
This is updated LowerSwitch patch. I've also attached examples - before
& after. I'll add testcase soon after commit.
--
With best regards, Anton Korobeynikov.
Faculty of Mathematics & Mechanics, Saint Petersburg State University.
diff -r d294d12d3530 lib/Transforms/Utils/LowerSwitch.cpp
--- a/lib/Transforms/Utils/LowerSwitch.cpp Sun Mar 04 06:36:24 2007 +0000
+++ b/lib/Transforms/Utils/LowerSwitch.cpp Sun Mar 04 23:24:14 2007 +0300
@@ -40,26 +40,38 @@ namespace {
AU.addPreservedID(LowerInvokePassID);
AU.addPreservedID(LowerAllocationsID);
}
-
- typedef std::pair<Constant*, BasicBlock*> Case;
- typedef std::vector<Case>::iterator CaseItr;
+
+ struct CaseRange {
+ Constant* Low;
+ Constant* High;
+ BasicBlock* BB;
+
+ CaseRange(Constant* _Low = NULL, Constant* _High = NULL,
+ BasicBlock* _BB = NULL):
+ Low(_Low), High(_High), BB(_BB) { }
+ };
+
+ typedef std::vector<CaseRange> CaseVector;
+ typedef std::vector<CaseRange>::iterator CaseItr;
private:
void processSwitchInst(SwitchInst *SI);
BasicBlock* switchConvert(CaseItr Begin, CaseItr End, Value* Val,
BasicBlock* OrigBlock, BasicBlock* Default);
- BasicBlock* newLeafBlock(Case& Leaf, Value* Val,
+ BasicBlock* newLeafBlock(CaseRange& 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());
+ bool operator () (const LowerSwitch::CaseRange& C1,
+ const LowerSwitch::CaseRange& C2) {
+
+ const ConstantInt* CI1 = cast<const ConstantInt>(C1.Low);
+ const ConstantInt* CI2 = cast<const ConstantInt>(C2.High);
+ return CI1->getValue().slt(CI2->getValue());
}
};
@@ -91,19 +103,20 @@ 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;
}
@@ -121,14 +134,16 @@ BasicBlock* LowerSwitch::switchConvert(C
return newLeafBlock(*Begin, Val, OrigBlock, Default);
unsigned Mid = Size / 2;
- std::vector<Case> LHS(Begin, Begin + Mid);
+ std::vector<CaseRange> LHS(Begin, Begin + Mid);
DOUT << "LHS: " << LHS << "\n";
- std::vector<Case> RHS(Begin + Mid, End);
+ std::vector<CaseRange> RHS(Begin + Mid, End);
DOUT << "RHS: " << RHS << "\n";
- Case& Pivot = *(Begin + Mid);
+ CaseRange& 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 +157,7 @@ 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_SLT, Val, Pivot.Low, "Pivot");
NewNode->getInstList().push_back(Comp);
new BranchInst(LBranch, RBranch, Comp, NewNode);
return NewNode;
@@ -154,7 +169,7 @@ BasicBlock* LowerSwitch::switchConvert(C
// can't be another valid case value, so the jump to the "default" branch
// is warranted.
//
-BasicBlock* LowerSwitch::newLeafBlock(Case& Leaf, Value* Val,
+BasicBlock* LowerSwitch::newLeafBlock(CaseRange& Leaf, Value* Val,
BasicBlock* OrigBlock,
BasicBlock* Default)
{
@@ -162,25 +177,92 @@ 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 if (cast<ConstantInt>(Leaf.Low)->isZero()) {
+ // Val >= 0 && Val <= Hi --> Val <=u Hi
+ Comp = new ICmpInst(ICmpInst::ICMP_ULE, 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) {
+ unsigned numCmps;
+
+ // Start with "simple" cases
+ for (unsigned i = 1; i < SI->getNumSuccessors(); ++i)
+ Cases.push_back(CaseRange(SI->getSuccessorValue(i),
+ SI->getSuccessorValue(i),
+ SI->getSuccessor(i)));
+ sort(Cases.begin(), Cases.end(), CaseCmp());
+
+ // Merge case into clusters
+ if (Cases.size()>=2)
+ for (CaseItr I=Cases.begin(), J=++(Cases.begin()), E=Cases.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 the two neighboring cases go to the same destination, merge them
+ // into a single case.
+ if ((nextValue-currentValue==1) && (currentBB == nextBB)) {
+ I->High = J->High;
+ J = Cases.erase(J);
+ } else {
+ I = J++;
+ }
+ }
+
+ for (CaseItr I=Cases.begin(), E=Cases.end(); I!=E; ++I, ++numCmps) {
+ if (I->Low != I->High)
+ // A range counts double, since it requires two compares.
+ ++numCmps;
+ }
+
+ return numCmps;
}
// processSwitchInst - Replace the specified switch instruction with a sequence
@@ -216,14 +298,14 @@ 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);
; ModuleID = '2.bc'
implementation ; Functions:
define i32 @main(i32 %tmp158) {
entry:
br label %NodeBlock19
NodeBlock19: ; preds = %entry
icmp slt i32 %tmp158, 10 ; <i1>:0 [#uses=1]
br i1 %0, label %NodeBlock7, label %NodeBlock18
NodeBlock18: ; preds = %NodeBlock19
icmp slt i32 %tmp158, 13 ; <i1>:1 [#uses=1]
br i1 %1, label %NodeBlock12, label %NodeBlock17
NodeBlock17: ; preds = %NodeBlock18
icmp slt i32 %tmp158, 14 ; <i1>:2 [#uses=1]
br i1 %2, label %LeafBlock13, label %NodeBlock16
NodeBlock16: ; preds = %NodeBlock17
icmp slt i32 %tmp158, 15 ; <i1>:3 [#uses=1]
br i1 %3, label %LeafBlock14, label %LeafBlock15
LeafBlock15: ; preds = %NodeBlock16
icmp eq i32 %tmp158, 15 ; <i1>:4 [#uses=1]
br i1 %4, label %bb334, label %NewDefault
LeafBlock14: ; preds = %NodeBlock16
icmp eq i32 %tmp158, 14 ; <i1>:5 [#uses=1]
br i1 %5, label %bb332, label %NewDefault
LeafBlock13: ; preds = %NodeBlock17
icmp eq i32 %tmp158, 13 ; <i1>:6 [#uses=1]
br i1 %6, label %bb330, label %NewDefault
NodeBlock12: ; preds = %NodeBlock18
icmp slt i32 %tmp158, 11 ; <i1>:7 [#uses=1]
br i1 %7, label %LeafBlock8, label %NodeBlock11
NodeBlock11: ; preds = %NodeBlock12
icmp slt i32 %tmp158, 12 ; <i1>:8 [#uses=1]
br i1 %8, label %LeafBlock9, label %LeafBlock10
LeafBlock10: ; preds = %NodeBlock11
icmp eq i32 %tmp158, 12 ; <i1>:9 [#uses=1]
br i1 %9, label %bb328, label %NewDefault
LeafBlock9: ; preds = %NodeBlock11
icmp eq i32 %tmp158, 11 ; <i1>:10 [#uses=1]
br i1 %10, label %bb326, label %NewDefault
LeafBlock8: ; preds = %NodeBlock12
icmp eq i32 %tmp158, 10 ; <i1>:11 [#uses=1]
br i1 %11, label %bb324, label %NewDefault
NodeBlock7: ; preds = %NodeBlock19
icmp slt i32 %tmp158, 7 ; <i1>:12 [#uses=1]
br i1 %12, label %NodeBlock, label %NodeBlock6
NodeBlock6: ; preds = %NodeBlock7
icmp slt i32 %tmp158, 8 ; <i1>:13 [#uses=1]
br i1 %13, label %LeafBlock2, label %NodeBlock5
NodeBlock5: ; preds = %NodeBlock6
icmp slt i32 %tmp158, 9 ; <i1>:14 [#uses=1]
br i1 %14, label %LeafBlock3, label %LeafBlock4
LeafBlock4: ; preds = %NodeBlock5
icmp eq i32 %tmp158, 9 ; <i1>:15 [#uses=1]
br i1 %15, label %bb322, label %NewDefault
LeafBlock3: ; preds = %NodeBlock5
icmp eq i32 %tmp158, 8 ; <i1>:16 [#uses=1]
br i1 %16, label %bb338, label %NewDefault
LeafBlock2: ; preds = %NodeBlock6
icmp eq i32 %tmp158, 7 ; <i1>:17 [#uses=1]
br i1 %17, label %bb, label %NewDefault
NodeBlock: ; preds = %NodeBlock7
icmp slt i32 %tmp158, 0 ; <i1>:18 [#uses=1]
br i1 %18, label %LeafBlock, label %LeafBlock1
LeafBlock1: ; preds = %NodeBlock
icmp ule i32 %tmp158, 6 ; <i1>:19 [#uses=1]
br i1 %19, label %bb338, label %NewDefault
LeafBlock: ; preds = %NodeBlock
%tmp158.off = add i32 %tmp158, 6 ; <i32> [#uses=1]
icmp ule i32 %tmp158.off, 4 ; <i1>:20 [#uses=1]
br i1 %20, label %bb338, label %NewDefault
bb: ; preds = %LeafBlock2
ret i32 2
bb322: ; preds = %LeafBlock4
ret i32 3
bb324: ; preds = %LeafBlock8
ret i32 4
bb326: ; preds = %LeafBlock9
ret i32 5
bb328: ; preds = %LeafBlock10
ret i32 6
bb330: ; preds = %LeafBlock13
ret i32 7
bb332: ; preds = %LeafBlock14
ret i32 8
bb334: ; preds = %LeafBlock15
ret i32 9
NewDefault: ; preds = %LeafBlock, %LeafBlock1, %LeafBlock2,
%LeafBlock3, %LeafBlock4, %LeafBlock8, %LeafBlock9, %LeafBlock10, %LeafBlock13,
%LeafBlock14, %LeafBlock15
br label %bb336
bb336: ; preds = %NewDefault
ret i32 10
bb338: ; preds = %LeafBlock, %LeafBlock1, %LeafBlock3
ret i32 11
}
define i32 @main(i32 %tmp158) {
entry:
switch i32 %tmp158, label %bb336 [
i32 -2, label %bb338
i32 -3, label %bb338
i32 -4, label %bb338
i32 -5, label %bb338
i32 -6, label %bb338
i32 0, label %bb338
i32 1, label %bb338
i32 2, label %bb338
i32 3, label %bb338
i32 4, label %bb338
i32 5, label %bb338
i32 6, label %bb338
i32 7, label %bb
i32 8, label %bb338
i32 9, label %bb322
i32 10, label %bb324
i32 11, label %bb326
i32 12, label %bb328
i32 13, label %bb330
i32 14, label %bb332
i32 15, label %bb334
]
bb:
ret i32 2
bb322:
ret i32 3
bb324:
ret i32 4
bb326:
ret i32 5
bb328:
ret i32 6
bb330:
ret i32 7
bb332:
ret i32 8
bb334:
ret i32 9
bb336:
ret i32 10
bb338:
ret i32 11
}
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