Commit 9915ebaa authored by Nikita Popov's avatar Nikita Popov
Browse files

[ConstantFold] Remove redundant constantFoldCompareGlobalToNull() fold (NFCI) 

This is already handled in evaluateICmpRelation().
parent 17970df6

llvm/lib/IR/ConstantFold.cpp

+0 −27
Original line number Diff line number Diff line
@@ -1252,25 +1252,6 @@ static ICmpInst::Predicate evaluateICmpRelation(Constant *V1, Constant *V2) { 
  return ICmpInst::BAD_ICMP_PREDICATE;

}



static Constant *constantFoldCompareGlobalToNull(CmpInst::Predicate Predicate,

                                                 Constant *C1, Constant *C2) {

  const GlobalValue *GV = dyn_cast<GlobalValue>(C2);

  if (!GV || !C1->isNullValue())

    return nullptr;



  // Don't try to evaluate aliases.  External weak GV can be null.

  if (!isa<GlobalAlias>(GV) && !GV->hasExternalWeakLinkage() &&

      !NullPointerIsDefined(nullptr /* F */,

                            GV->getType()->getAddressSpace())) {

    if (Predicate == ICmpInst::ICMP_EQ)

      return ConstantInt::getFalse(C1->getContext());

    else if (Predicate == ICmpInst::ICMP_NE)

      return ConstantInt::getTrue(C1->getContext());

  }



  return nullptr;

}



Constant *llvm::ConstantFoldCompareInstruction(CmpInst::Predicate Predicate,

                                               Constant *C1, Constant *C2) {

  Type *ResultTy;
@@ -1309,14 +1290,6 @@ Constant *llvm::ConstantFoldCompareInstruction(CmpInst::Predicate Predicate, 
    return ConstantInt::get(ResultTy, CmpInst::isUnordered(Predicate));

  }



  // icmp eq/ne(null,GV) -> false/true

  if (Constant *Folded = constantFoldCompareGlobalToNull(Predicate, C1, C2))

    return Folded;



  // icmp eq/ne(GV,null) -> false/true

  if (Constant *Folded = constantFoldCompareGlobalToNull(Predicate, C2, C1))

    return Folded;



  if (C2->isNullValue()) {

    // The caller is expected to commute the operands if the constant expression

    // is C2.