[opaque pointer types] [breaking-change] [NFC] SimplifyGEPInst: take the source element type of the GEP as an argument.

[dblaikie]

Looks good - thanks!

[mjacob]

LGTM, too. I'll commit it for you.

include/llvm/Analysis/InstructionSimplify.h

Value *SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal,
                             const DataLayout &DL,
                             const TargetLibraryInfo *TLI = nullptr,
                             const DominatorTree *DT = nullptr,
                             AssumptionCache *AC = nullptr,
                             const Instruction *CxtI = nullptr);
 
   /// SimplifyGEPInst - Given operands for an GetElementPtrInst, see if we can
   /// fold the result.  If not, this returns null.
-  Value *SimplifyGEPInst(ArrayRef<Value *> Ops, const DataLayout &DL,
+  Value *SimplifyGEPInst(Type *SrcTy, ArrayRef<Value *> Ops,
+                         const DataLayout &DL,
                          const TargetLibraryInfo *TLI = nullptr,
                          const DominatorTree *DT = nullptr,
                          AssumptionCache *AC = nullptr,
                          const Instruction *CxtI = nullptr);
 
   /// SimplifyInsertValueInst - Given operands for an InsertValueInst, see if we
   /// can fold the result.  If not, this returns null.
   Value *SimplifyInsertValueInst(Value *Agg, Value *Val,

lib/Analysis/InstructionSimplify.cpp

static Value *SimplifyGEPInst(Type *SrcTy, ArrayRef<Value *> Ops,
   for (unsigned i = 0, e = Ops.size(); i != e; ++i)
     if (!isa<Constant>(Ops[i]))
       return nullptr;
 
   return ConstantExpr::getGetElementPtr(SrcTy, cast<Constant>(Ops[0]),
                                         Ops.slice(1));
 }
 
-Value *llvm::SimplifyGEPInst(ArrayRef<Value *> Ops, const DataLayout &DL,
+Value *llvm::SimplifyGEPInst(Type *SrcTy, ArrayRef<Value *> Ops,
+                             const DataLayout &DL,
                              const TargetLibraryInfo *TLI,
                              const DominatorTree *DT, AssumptionCache *AC,
                              const Instruction *CxtI) {
-  return ::SimplifyGEPInst(
-      cast<PointerType>(Ops[0]->getType()->getScalarType())->getElementType(),
-      Ops, Query(DL, TLI, DT, AC, CxtI), RecursionLimit);
+  return ::SimplifyGEPInst(SrcTy, Ops,
+                           Query(DL, TLI, DT, AC, CxtI), RecursionLimit);
 }
 
 /// Given operands for an InsertValueInst, see if we can fold the result.
 /// If not, this returns null.
 static Value *SimplifyInsertValueInst(Value *Agg, Value *Val,
                                       ArrayRef<unsigned> Idxs, const Query &Q,
                                       unsigned) {
   if (Constant *CAgg = dyn_cast<Constant>(Agg))
Result = SimplifyFCmpInst(cast<FCmpInst>(I)->getPredicate(),
                               I->getFastMathFlags(), DL, TLI, DT, AC, I);
     break;
   case Instruction::Select:
     Result = SimplifySelectInst(I->getOperand(0), I->getOperand(1),
                                 I->getOperand(2), DL, TLI, DT, AC, I);
     break;
   case Instruction::GetElementPtr: {
     SmallVector<Value*, 8> Ops(I->op_begin(), I->op_end());
-    Result = SimplifyGEPInst(Ops, DL, TLI, DT, AC, I);
+    Result = SimplifyGEPInst(cast<GetElementPtrInst>(I)->getSourceElementType(),
+                             Ops, DL, TLI, DT, AC, I);
     break;
   }
   case Instruction::InsertValue: {
     InsertValueInst *IV = cast<InsertValueInst>(I);
     Result = SimplifyInsertValueInst(IV->getAggregateOperand(),
                                      IV->getInsertedValueOperand(),
                                      IV->getIndices(), DL, TLI, DT, AC, I);
     break;

lib/Analysis/PHITransAddr.cpp

for (unsigned i = 0, e = GEP->getNumOperands(); i != e; ++i) {
       AnyChanged |= GEPOp != GEP->getOperand(i);
       GEPOps.push_back(GEPOp);
     }
 
     if (!AnyChanged)
       return GEP;
 
     // Simplify the GEP to handle 'gep x, 0' -> x etc.
-    if (Value *V = SimplifyGEPInst(GEPOps, DL, TLI, DT, AC)) {
+    if (Value *V = SimplifyGEPInst(GEP->getSourceElementType(),
+                                   GEPOps, DL, TLI, DT, AC)) {
       for (unsigned i = 0, e = GEPOps.size(); i != e; ++i)
         RemoveInstInputs(GEPOps[i], InstInputs);
 
       return AddAsInput(V);
     }
 
     // Scan to see if we have this GEP available.
     Value *APHIOp = GEPOps[0];

lib/Transforms/InstCombine/InstructionCombining.cpp

Value *InstCombiner::SimplifyVectorOp(BinaryOperator &Inst) {
   }
 
   return nullptr;
 }
 
 Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
   SmallVector<Value*, 8> Ops(GEP.op_begin(), GEP.op_end());
 
-  if (Value *V = SimplifyGEPInst(Ops, DL, TLI, DT, AC))
+  if (Value *V = SimplifyGEPInst(GEP.getSourceElementType(), Ops, DL, TLI, DT, AC))
     return ReplaceInstUsesWith(GEP, V);
 
   Value *PtrOp = GEP.getOperand(0);
 
   // Eliminate unneeded casts for indices, and replace indices which displace
   // by multiples of a zero size type with zero.
   bool MadeChange = false;
   Type *IntPtrTy =