diff options
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/Transforms/Scalar/GVN.cpp | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/llvm/lib/Transforms/Scalar/GVN.cpp b/llvm/lib/Transforms/Scalar/GVN.cpp index 1cb7198e9ee..1f9630ed511 100644 --- a/llvm/lib/Transforms/Scalar/GVN.cpp +++ b/llvm/lib/Transforms/Scalar/GVN.cpp @@ -129,6 +129,7 @@ namespace { uint32_t lookup(Value *V) const; uint32_t lookup_or_add_cmp(unsigned Opcode, CmpInst::Predicate Pred, Value *LHS, Value *RHS); + bool exists(Value *V) const; void add(Value *V, uint32_t num); void clear(); void erase(Value *v); @@ -389,6 +390,9 @@ uint32_t ValueTable::lookup_or_add_call(CallInst *C) { } } +/// Returns true if a value number exists for the specified value. +bool ValueTable::exists(Value *V) const { return valueNumbering.count(V) != 0; } + /// lookup_or_add - Returns the value number for the specified value, assigning /// it a new number if it did not have one before. uint32_t ValueTable::lookup_or_add(Value *V) { @@ -2534,7 +2538,14 @@ bool GVN::performScalarPREInsertion(Instruction *Instr, BasicBlock *Pred, Value *Op = Instr->getOperand(i); if (isa<Argument>(Op) || isa<Constant>(Op) || isa<GlobalValue>(Op)) continue; - + // This could be a newly inserted instruction, in which case, we won't + // find a value number, and should give up before we hurt ourselves. + // FIXME: Rewrite the infrastructure to let it easier to value number + // and process newly inserted instructions. + if (!VN.exists(Op)) { + success = false; + break; + } if (Value *V = findLeader(Pred, VN.lookup(Op))) { Instr->setOperand(i, V); } else { |
