[PATCH] D51145: make copyFMF consistent with AnyDefined for detection of any FMF flag set to true

[Sanjay Patel via Phabricator via llvm-commits]

spatel added inline comments.


================
Comment at: include/llvm/IR/Operator.h:394-395
   static bool classof(const Value *V) {
     return (isa<Instruction>(V) && classof(cast<Instruction>(V))) ||
            (isa<ConstantExpr>(V) && classof(cast<ConstantExpr>(V)));
   }
----------------
I don't see the benefit of treating Instruction/ConstantExpr separately when the logic is identical for both and likely to keep growing.

Ie, can we do this:

```
  static bool classof(const Value *V) {
    unsigned Opcode;
    if (auto *I = dyn_cast<Instruction>(V))
      Opcode = I->getOpcode();
    else if (auto *CE = dyn_cast<ConstantExpr>(V))
      Opcode = CE->getOpcode();
    else
      return false;

    switch (Opcode) {
    case Instruction::FCmp:
      return true;
    // Vector operators may have FP type, but they don't do math.
    case Instruction::ExtractElement:
    case Instruction::ShuffleVector:
    case Instruction::InsertElement:
      return false;
    default:
      return V->getType()->isFPOrFPVectorTy();
    }
  }

```


https://reviews.llvm.org/D51145