[llvm-commits] [llvm] r71717 - /llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp

[Duncan Sands]

Hi Dale,

> +/// findGlobalVariableBase - Recurse into a ConstantExpr to find the underlying
> +/// GlobalVariable, if there is one.
> +static GlobalVariable* findGlobalVariableBase(ConstantExpr* CE) {
> +  if (isa<GlobalVariable>(CE))
> +    return dyn_cast<GlobalVariable>(CE);
> +  if (CE->getOpcode()==Instruction::GetElementPtr ||
> +      CE->getOpcode()==Instruction::BitCast) {
> +    if (isa<GlobalVariable>(CE->getOperand(0)))
> +      return dyn_cast<GlobalVariable>(CE->getOperand(0));
> +    if (ConstantExpr *CE2 = dyn_cast<ConstantExpr>(CE->getOperand(0)))
> +      return findGlobalVariableBase(CE2);
> +  }
> +  return NULL;
> +}

this looks very similar to what CE->stripPointerCasts() does.

> +        GlobalVariable* GV = dyn_cast<GlobalVariable>(I->getOperand(0));
> +        if (GV && GV->hasExternalWeakLinkage())
> +          return false;

How about adding an "address of this global value may be null" method to
GlobalValue (which would currently just check the linkage type) and use
that instead?

Ciao,

Duncan.