[NFC] Replace several manual GEP loops with gep_type_iterator.

[dblaikie]

Looks good - thanks!

lib/CodeGen/SelectionDAG/FastISel.cpp

 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/CodeGen/MachineModuleInfo.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/CodeGen/StackMaps.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/DebugInfo.h"
 #include "llvm/IR/Function.h"
+#include "llvm/IR/GetElementPtrTypeIterator.h"
 #include "llvm/IR/GlobalVariable.h"
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/Mangler.h"
 #include "llvm/IR/Operator.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/raw_ostream.h"
if (!N) // Unhandled operand. Halt "fast" selection and bail.
     return false;
   bool NIsKill = hasTrivialKill(I->getOperand(0));
 
   // Keep a running tab of the total offset to coalesce multiple N = N + Offset
   // into a single N = N + TotalOffset.
   uint64_t TotalOffs = 0;
   // FIXME: What's a good SWAG number for MaxOffs?
   uint64_t MaxOffs = 2048;
-  Type *Ty = I->getOperand(0)->getType();
   MVT VT = TLI.getPointerTy(DL);
-  for (GetElementPtrInst::const_op_iterator OI = I->op_begin() + 1,
-                                            E = I->op_end();
-       OI != E; ++OI) {
-    const Value *Idx = *OI;
-    if (auto *StTy = dyn_cast<StructType>(Ty)) {
+  for (gep_type_iterator GTI = gep_type_begin(I), E = gep_type_end(I);
+       GTI != E; ++GTI) {
+    const Value *Idx = GTI.getOperand();
+    if (auto *StTy = dyn_cast<StructType>(*GTI)) {
       uint64_t Field = cast<ConstantInt>(Idx)->getZExtValue();
       if (Field) {
         // N = N + Offset
         TotalOffs += DL.getStructLayout(StTy)->getElementOffset(Field);
         if (TotalOffs >= MaxOffs) {
           N = fastEmit_ri_(VT, ISD::ADD, N, NIsKill, TotalOffs, VT);
           if (!N) // Unhandled operand. Halt "fast" selection and bail.
             return false;
           NIsKill = true;
           TotalOffs = 0;
         }
       }
-      Ty = StTy->getElementType(Field);
     } else {
-      if (Ty->isPointerTy()) {
-        // The only pointer type is for the very first index,
-        // therefore the next type is the source element type.
-        Ty = cast<GEPOperator>(I)->getSourceElementType();
-      } else {
-        Ty = cast<SequentialType>(Ty)->getElementType();
-      }
+      Type *Ty = GTI.getIndexedType();
 
       // If this is a constant subscript, handle it quickly.
       if (const auto *CI = dyn_cast<ConstantInt>(Idx)) {
         if (CI->isZero())
           continue;
         // N = N + Offset
         uint64_t IdxN = CI->getValue().sextOrTrunc(64).getSExtValue();
         TotalOffs += DL.getTypeAllocSize(Ty) * IdxN;

lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

 #include "llvm/CodeGen/StackMaps.h"
 #include "llvm/CodeGen/WinEHFuncInfo.h"
 #include "llvm/IR/CallingConv.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/DebugInfo.h"
 #include "llvm/IR/DerivedTypes.h"
 #include "llvm/IR/Function.h"
+#include "llvm/IR/GetElementPtrTypeIterator.h"
 #include "llvm/IR/GlobalVariable.h"
 #include "llvm/IR/InlineAsm.h"
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/Intrinsics.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Module.h"
 #include "llvm/IR/Statepoint.h"
void SelectionDAGBuilder::visitExtractValue(const ExtractValueInst &I) {
   setValue(&I, DAG.getNode(ISD::MERGE_VALUES, getCurSDLoc(),
                            DAG.getVTList(ValValueVTs), Values));
 }
 
 void SelectionDAGBuilder::visitGetElementPtr(const User &I) {
   Value *Op0 = I.getOperand(0);
   // Note that the pointer operand may be a vector of pointers. Take the scalar
   // element which holds a pointer.
-  Type *Ty = Op0->getType()->getScalarType();
-  unsigned AS = Ty->getPointerAddressSpace();
+  unsigned AS = Op0->getType()->getScalarType()->getPointerAddressSpace();
   SDValue N = getValue(Op0);
   SDLoc dl = getCurSDLoc();
 
   // Normalize Vector GEP - all scalar operands should be converted to the
   // splat vector.
   unsigned VectorWidth = I.getType()->isVectorTy() ?
     cast<VectorType>(I.getType())->getVectorNumElements() : 0;
 
   if (VectorWidth && !N.getValueType().isVector()) {
     MVT VT = MVT::getVectorVT(N.getValueType().getSimpleVT(), VectorWidth);
     SmallVector<SDValue, 16> Ops(VectorWidth, N);
     N = DAG.getNode(ISD::BUILD_VECTOR, dl, VT, Ops);
   }
-  for (GetElementPtrInst::const_op_iterator OI = I.op_begin()+1, E = I.op_end();
-       OI != E; ++OI) {
-    const Value *Idx = *OI;
-    if (StructType *StTy = dyn_cast<StructType>(Ty)) {
+  for (gep_type_iterator GTI = gep_type_begin(&I), E = gep_type_end(&I);
+       GTI != E; ++GTI) {
+    const Value *Idx = GTI.getOperand();
+    if (StructType *StTy = dyn_cast<StructType>(*GTI)) {
       unsigned Field = cast<Constant>(Idx)->getUniqueInteger().getZExtValue();
       if (Field) {
         // N = N + Offset
         uint64_t Offset = DL->getStructLayout(StTy)->getElementOffset(Field);
 
         // In an inbouds GEP with an offset that is nonnegative even when
         // interpreted as signed, assume there is no unsigned overflow.
         SDNodeFlags Flags;
         if (int64_t(Offset) >= 0 && cast<GEPOperator>(I).isInBounds())
           Flags.setNoUnsignedWrap(true);
 
         N = DAG.getNode(ISD::ADD, dl, N.getValueType(), N,
                         DAG.getConstant(Offset, dl, N.getValueType()), &Flags);
       }
-
-      Ty = StTy->getElementType(Field);
-    } else {
-      if (Ty->isPointerTy()) {
-        // The only pointer type is for the very first index,
-        // therefore the next type is the source element type.
-        Ty = cast<GEPOperator>(&I)->getSourceElementType();
-      } else {
-        Ty = cast<SequentialType>(Ty)->getElementType();
-      }
-
       MVT PtrTy =
           DAG.getTargetLoweringInfo().getPointerTy(DAG.getDataLayout(), AS);
       unsigned PtrSize = PtrTy.getSizeInBits();
-      APInt ElementSize(PtrSize, DL->getTypeAllocSize(Ty));
+      APInt ElementSize(PtrSize, DL->getTypeAllocSize(GTI.getIndexedType()));
 
       // If this is a scalar constant or a splat vector of constants,
       // handle it quickly.
       const auto *CI = dyn_cast<ConstantInt>(Idx);
       if (!CI && isa<ConstantDataVector>(Idx) &&
           cast<ConstantDataVector>(Idx)->getSplatValue())
         CI = cast<ConstantInt>(cast<ConstantDataVector>(Idx)->getSplatValue());
 

lib/Target/AArch64/AArch64FastISel.cpp

case Instruction::PtrToInt: {
     break;
   }
   case Instruction::GetElementPtr: {
     Address SavedAddr = Addr;
     uint64_t TmpOffset = Addr.getOffset();
 
     // Iterate through the GEP folding the constants into offsets where
     // we can.
-    gep_type_iterator GTI = gep_type_begin(U);
-    for (User::const_op_iterator i = U->op_begin() + 1, e = U->op_end(); i != e;
-         ++i, ++GTI) {
-      const Value *Op = *i;
+    for (gep_type_iterator GTI = gep_type_begin(U), E = gep_type_end(U);
+         GTI != E; ++GTI) {
+      const Value *Op = GTI.getOperand();
       if (StructType *STy = dyn_cast<StructType>(*GTI)) {
         const StructLayout *SL = DL.getStructLayout(STy);
         unsigned Idx = cast<ConstantInt>(Op)->getZExtValue();
         TmpOffset += SL->getElementOffset(Idx);
       } else {
         uint64_t S = DL.getTypeAllocSize(GTI.getIndexedType());
         for (;;) {
           if (const ConstantInt *CI = dyn_cast<ConstantInt>(Op)) {
bool AArch64FastISel::selectGetElementPtr(const Instruction *I) {
   unsigned N = getRegForValue(I->getOperand(0));
   if (!N)
     return false;
   bool NIsKill = hasTrivialKill(I->getOperand(0));
 
   // Keep a running tab of the total offset to coalesce multiple N = N + Offset
   // into a single N = N + TotalOffset.
   uint64_t TotalOffs = 0;
-  Type *Ty = I->getOperand(0)->getType();
   MVT VT = TLI.getPointerTy(DL);
-  for (auto OI = std::next(I->op_begin()), E = I->op_end(); OI != E; ++OI) {
-    const Value *Idx = *OI;
-    if (auto *StTy = dyn_cast<StructType>(Ty)) {
+  for (gep_type_iterator GTI = gep_type_begin(I), E = gep_type_end(I);
+       GTI != E; ++GTI) {
+    const Value *Idx = GTI.getOperand();
+    if (auto *StTy = dyn_cast<StructType>(*GTI)) {
       unsigned Field = cast<ConstantInt>(Idx)->getZExtValue();
       // N = N + Offset
       if (Field)
         TotalOffs += DL.getStructLayout(StTy)->getElementOffset(Field);
-      Ty = StTy->getElementType(Field);
     } else {
-      if (Ty->isPointerTy()) {
-        // The only pointer type is for the very first index,
-        // therefore the next type is the source element type.
-        Ty = cast<GEPOperator>(I)->getSourceElementType();
-      } else {
-        Ty = cast<SequentialType>(Ty)->getElementType();
-      }
+      Type *Ty = GTI.getIndexedType();
+
       // If this is a constant subscript, handle it quickly.
       if (const auto *CI = dyn_cast<ConstantInt>(Idx)) {
         if (CI->isZero())
           continue;
         // N = N + Offset
         TotalOffs +=
             DL.getTypeAllocSize(Ty) * cast<ConstantInt>(CI)->getSExtValue();
         continue;