diff options
Diffstat (limited to 'llvm/lib/Transforms/Utils')
| -rw-r--r-- | llvm/lib/Transforms/Utils/LowerSwitch.cpp | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/llvm/lib/Transforms/Utils/LowerSwitch.cpp b/llvm/lib/Transforms/Utils/LowerSwitch.cpp index 76ad35832dc..e99ecfef19c 100644 --- a/llvm/lib/Transforms/Utils/LowerSwitch.cpp +++ b/llvm/lib/Transforms/Utils/LowerSwitch.cpp @@ -74,7 +74,7 @@ namespace { LowerSwitch() : FunctionPass(ID) { initializeLowerSwitchPass(*PassRegistry::getPassRegistry()); - } + } bool runOnFunction(Function &F) override; @@ -327,7 +327,7 @@ BasicBlock* LowerSwitch::newLeafBlock(CaseRange& Leaf, Value* Val, } else if (Leaf.Low->isZero()) { // Val >= 0 && Val <= Hi --> Val <=u Hi Comp = new ICmpInst(*NewLeaf, ICmpInst::ICMP_ULE, Val, Leaf.High, - "SwitchLeaf"); + "SwitchLeaf"); } else { // Emit V-Lo <=u Hi-Lo Constant* NegLo = ConstantExpr::getNeg(Leaf.Low); @@ -354,7 +354,7 @@ BasicBlock* LowerSwitch::newLeafBlock(CaseRange& Leaf, Value* Val, 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); @@ -495,6 +495,10 @@ void LowerSwitch::processSwitchInst(SwitchInst *SI, } #endif + // As the default block in the switch is unreachable, update the PHI nodes + // (remove the entry to the default block) to reflect this. + Default->removePredecessor(OrigBlock); + // Use the most popular block as the new default, reducing the number of // cases. assert(MaxPop > 0 && PopSucc); @@ -508,6 +512,10 @@ void LowerSwitch::processSwitchInst(SwitchInst *SI, if (Cases.empty()) { BranchInst::Create(Default, CurBlock); SI->eraseFromParent(); + // As all the cases have been replaced with a single branch, only keep + // one entry in the PHI nodes. + for (unsigned I = 0 ; I < (MaxPop - 1) ; ++I) + PopSucc->removePredecessor(OrigBlock); return; } } |
