diff --git a/lib/Transforms/InstCombine/InstructionCombining.cpp b/lib/Transforms/InstCombine/InstructionCombining.cpp index 1737be8f2e3..b63044820a9 100644 --- a/lib/Transforms/InstCombine/InstructionCombining.cpp +++ b/lib/Transforms/InstCombine/InstructionCombining.cpp @@ -520,12 +520,13 @@ Instruction *InstCombiner::FoldOpIntoPhi(Instruction &I, AllowAggressive = false; PHINode *PN = cast(I.getOperand(0)); unsigned NumPHIValues = PN->getNumIncomingValues(); - if (NumPHIValues == 0 || - // We normally only transform phis with a single use, unless we're trying - // hard to make jump threading happen. - (!PN->hasOneUse() && !AllowAggressive)) + if (NumPHIValues == 0) return 0; + // We normally only transform phis with a single use, unless we're trying + // hard to make jump threading happen. + if (!PN->hasOneUse() && !AllowAggressive) + return 0; // Check to see if all of the operands of the PHI are simple constants // (constantint/constantfp/undef). If there is one non-constant value, @@ -533,18 +534,21 @@ Instruction *InstCombiner::FoldOpIntoPhi(Instruction &I, // bail out. We don't do arbitrary constant expressions here because moving // their computation can be expensive without a cost model. BasicBlock *NonConstBB = 0; - for (unsigned i = 0; i != NumPHIValues; ++i) - if (!isa(PN->getIncomingValue(i)) || - isa(PN->getIncomingValue(i))) { - if (NonConstBB) return 0; // More than one non-const value. - if (isa(PN->getIncomingValue(i))) return 0; // Itself a phi. - NonConstBB = PN->getIncomingBlock(i); - - // If the incoming non-constant value is in I's block, we have an infinite - // loop. - if (NonConstBB == I.getParent()) - return 0; - } + for (unsigned i = 0; i != NumPHIValues; ++i) { + Value *InVal = PN->getIncomingValue(i); + if (isa(InVal) && !isa(InVal)) + continue; + + if (isa(InVal)) return 0; // Itself a phi. + if (NonConstBB) return 0; // More than one non-const value. + + NonConstBB = PN->getIncomingBlock(i); + + // If the incoming non-constant value is in I's block, we have an infinite + // loop. + if (NonConstBB == I.getParent()) + return 0; + } // If there is exactly one non-constant value, we can insert a copy of the // operation in that block. However, if this is a critical edge, we would be