[InlineCost] Move the code in isGEPOffsetConstant to a lambda. NFC.

[eraman]

I'm now thinking that this might be better off as part of the main patch and not as a standalone refactoring patch. I'll revert this if you concur.

[chandlerc]

I'm fine if you want this in the main patch, but I actually think this makes sense as a stand-alone refactoring, so LGTM.

[eraman]

Thanks. Since this looks good to you, I'll go ahead and commit this.

llvm/trunk/lib/Analysis/InlineCost.cpp

class CallAnalyzer : public InstVisitor<CallAnalyzer, bool> {
   // Custom simplification helper routines.
   bool isAllocaDerivedArg(Value *V);
   bool lookupSROAArgAndCost(Value *V, Value *&Arg,
                             DenseMap<Value *, int>::iterator &CostIt);
   void disableSROA(DenseMap<Value *, int>::iterator CostIt);
   void disableSROA(Value *V);
   void accumulateSROACost(DenseMap<Value *, int>::iterator CostIt,
                           int InstructionCost);
-  bool isGEPOffsetConstant(GetElementPtrInst &GEP);
   bool isGEPFree(GetElementPtrInst &GEP);
   bool accumulateGEPOffset(GEPOperator &GEP, APInt &Offset);
   bool simplifyCallSite(Function *F, CallSite CS);
   template <typename Callable>
   bool simplifyInstruction(Instruction &I, Callable Evaluate);
   ConstantInt *stripAndComputeInBoundsConstantOffsets(Value *&V);
 
   /// Return true if the given argument to the function being considered for

 
 /// \brief Accumulate the given cost for a particular SROA candidate.
 void CallAnalyzer::accumulateSROACost(DenseMap<Value *, int>::iterator CostIt,
                                       int InstructionCost) {
   CostIt->second += InstructionCost;
   SROACostSavings += InstructionCost;
 }
 
-/// \brief Check whether a GEP's indices are all constant.
-///
-/// Respects any simplified values known during the analysis of this callsite.
-bool CallAnalyzer::isGEPOffsetConstant(GetElementPtrInst &GEP) {
-  for (User::op_iterator I = GEP.idx_begin(), E = GEP.idx_end(); I != E; ++I)
-    if (!isa<Constant>(*I) && !SimplifiedValues.lookup(*I))
-      return false;
-
-  return true;
-}
-
 /// \brief Accumulate a constant GEP offset into an APInt if possible.
 ///
 /// Returns false if unable to compute the offset for any reason. Respects any
 /// simplified values known during the analysis of this callsite.
 bool CallAnalyzer::accumulateGEPOffset(GEPOperator &GEP, APInt &Offset) {
   const DataLayout &DL = F.getParent()->getDataLayout();
   unsigned IntPtrWidth = DL.getPointerSizeInBits();
   assert(IntPtrWidth == Offset.getBitWidth());
if (BaseAndOffset.first) {
       // all-constant indexed.
       if (SROACandidate)
         SROAArgValues[&I] = SROAArg;
 
       return true;
     }
   }
 
-  if (isGEPOffsetConstant(I)) {
+  // Lambda to check whether a GEP's indices are all constant.
+  auto IsGEPOffsetConstant = [&](GetElementPtrInst &GEP) {
+    for (User::op_iterator I = GEP.idx_begin(), E = GEP.idx_end(); I != E; ++I)
+      if (!isa<Constant>(*I) && !SimplifiedValues.lookup(*I))
+        return false;
+    return true;
+  };
+
+  if (IsGEPOffsetConstant(I)) {
     if (SROACandidate)
       SROAArgValues[&I] = SROAArg;
 
     // Constant GEPs are modeled as free.
     return true;
   }
 
   // Variable GEPs will require math and will disable SROA.