diff options
Diffstat (limited to 'llvm/lib/Analysis/InstructionSimplify.cpp')
| -rw-r--r-- | llvm/lib/Analysis/InstructionSimplify.cpp | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp index cb898772170..11a12ab84e9 100644 --- a/llvm/lib/Analysis/InstructionSimplify.cpp +++ b/llvm/lib/Analysis/InstructionSimplify.cpp @@ -543,10 +543,16 @@ static Value *ThreadCmpOverPHI(CmpInst::Predicate Pred, Value *LHS, Value *RHS, // Evaluate the BinOp on the incoming phi values. Value *CommonValue = nullptr; - for (Value *Incoming : PI->incoming_values()) { + for (unsigned u = 0, e = PI->getNumIncomingValues(); u < e; ++u) { + Value *Incoming = PI->getIncomingValue(u); + Instruction *InTI = PI->getIncomingBlock(u)->getTerminator(); // If the incoming value is the phi node itself, it can safely be skipped. if (Incoming == PI) continue; - Value *V = SimplifyCmpInst(Pred, Incoming, RHS, Q, MaxRecurse); + // Change the context instruction to the "edge" that flows into the phi. + // This is important because that is where incoming is actually "evaluated" + // even though it is used later somewhere else. + Value *V = SimplifyCmpInst(Pred, Incoming, RHS, Q.getWithInstruction(InTI), + MaxRecurse); // If the operation failed to simplify, or simplified to a different value // to previously, then give up. if (!V || (CommonValue && V != CommonValue)) |
