diff options
| -rw-r--r-- | lib/Transforms/Utils/SimplifyCFG.cpp | 20 |
1 files changed, 9 insertions, 11 deletions
diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp index ad3b92a714..61c44fc4b2 100644 --- a/lib/Transforms/Utils/SimplifyCFG.cpp +++ b/lib/Transforms/Utils/SimplifyCFG.cpp @@ -3741,18 +3741,20 @@ static bool SwitchToLookupTable(SwitchInst *SI, // Compute the maximum table size representable by the integer type we are // switching upon. - const unsigned CaseSize = MinCaseVal->getType()->getPrimitiveSizeInBits(); - const uint64_t MaxTableSize = CaseSize > 63? UINT64_MAX : 1ULL << CaseSize; + unsigned CaseSize = MinCaseVal->getType()->getPrimitiveSizeInBits(); + uint64_t MaxTableSize = CaseSize > 63? UINT64_MAX : 1ULL << CaseSize; assert(MaxTableSize >= TableSize && "It is impossible for a switch to have more entries than the max " "representable value of its input integer type's size."); - // If we have a covered lookup table, unconditionally branch to the lookup table - // BB. Otherwise, check if the condition value is within the case range. If it - // is so, branch to the new BB. Otherwise branch to SI's default destination. + // If we have a fully covered lookup table, unconditionally branch to the + // lookup table BB. Otherwise, check if the condition value is within the case + // range. If it is so, branch to the new BB. Otherwise branch to SI's default + // destination. const bool GeneratingCoveredLookupTable = MaxTableSize == TableSize; if (GeneratingCoveredLookupTable) { Builder.CreateBr(LookupBB); + SI->getDefaultDest()->removePredecessor(SI->getParent()); } else { Value *Cmp = Builder.CreateICmpULT(TableIndex, ConstantInt::get( MinCaseVal->getType(), TableSize)); @@ -3786,14 +3788,10 @@ static bool SwitchToLookupTable(SwitchInst *SI, Builder.CreateBr(CommonDest); // Remove the switch. - for (unsigned i = 0; i < SI->getNumSuccessors(); ++i) { + for (unsigned i = 0, e = SI->getNumSuccessors(); i < e; ++i) { BasicBlock *Succ = SI->getSuccessor(i); - // If we are not generating a covered lookup table, we will have a - // conditional branch from SI's parent BB to SI's default destination if our - // input value lies outside of our case range. Thus in that case leave the - // default destination BB as a predecessor of SI's parent BB. - if (Succ == SI->getDefaultDest() && !GeneratingCoveredLookupTable) + if (Succ == SI->getDefaultDest()) continue; Succ->removePredecessor(SI->getParent()); } |