3 files changed, 44 insertions, 62 deletions

diff --git a/include/llvm/Operator.h b/include/llvm/Operator.h
index d31e09e2b4..b2bb2e6b31 100644
--- a/include/llvm/Operator.h
+++ b/include/llvm/Operator.h
@@ -16,9 +16,11 @@
 #define LLVM_OPERATOR_H
 
 #include "llvm/Constants.h"
+#include "llvm/DataLayout.h"
 #include "llvm/DerivedTypes.h"
 #include "llvm/Instruction.h"
 #include "llvm/Type.h"
+#include "llvm/Support/GetElementPtrTypeIterator.h"
 
 namespace llvm {
 
@@ -430,6 +432,45 @@ public:
     }
     return true;
   }
+
+  /// \brief Accumulate the constant address offset of this GEP if possible.
+  ///
+  /// This routine accepts an APInt into which it will accumulate the constant
+  /// offset of this GEP if the GEP is in fact constant. If the GEP is not
+  /// all-constant, it returns false and the value of the offset APInt is
+  /// undefined (it is *not* preserved!). The APInt passed into this routine
+  /// must be at least as wide as the IntPtr type for the address space of
+  /// the base GEP pointer.
+  bool accumulateConstantOffset(const DataLayout &DL, APInt &Offset) const {
+    assert(Offset.getBitWidth() ==
+           DL.getPointerSizeInBits(getPointerAddressSpace()) &&
+           "The offset must have exactly as many bits as our pointer.");
+
+    for (gep_type_iterator GTI = gep_type_begin(this), GTE = gep_type_end(this);
+         GTI != GTE; ++GTI) {
+      ConstantInt *OpC = dyn_cast<ConstantInt>(GTI.getOperand());
+      if (!OpC)
+        return false;
+      if (OpC->isZero())
+        continue;
+
+      // Handle a struct index, which adds its field offset to the pointer.
+      if (StructType *STy = dyn_cast<StructType>(*GTI)) {
+        unsigned ElementIdx = OpC->getZExtValue();
+        const StructLayout *SL = DL.getStructLayout(STy);
+        Offset += APInt(Offset.getBitWidth(),
+                        SL->getElementOffset(ElementIdx));
+        continue;
+      }
+
+      // For array or vector indices, scale the index by the size of the type.
+      APInt Index = OpC->getValue().sextOrTrunc(Offset.getBitWidth());
+      Offset += Index * APInt(Offset.getBitWidth(),
+                              DL.getTypeAllocSize(GTI.getIndexedType()));
+    }
+    return true;
+  }
+
 };
 
 } // End llvm namespace
diff --git a/lib/Analysis/InstructionSimplify.cpp b/lib/Analysis/InstructionSimplify.cpp
index 00689475a4..dd109bde3a 100644
--- a/lib/Analysis/InstructionSimplify.cpp
+++ b/lib/Analysis/InstructionSimplify.cpp
@@ -657,39 +657,6 @@ Value *llvm::SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
                            RecursionLimit);
 }
 
-/// \brief Accumulate the constant integer offset a GEP represents.
-///
-/// Given a getelementptr instruction/constantexpr, accumulate the constant
-/// offset from the base pointer into the provided APInt 'Offset'. Returns true
-/// if the GEP has all-constant indices. Returns false if any non-constant
-/// index is encountered leaving the 'Offset' in an undefined state. The
-/// 'Offset' APInt must be the bitwidth of the target's pointer size.
-static bool accumulateGEPOffset(const DataLayout &TD, GEPOperator *GEP,
-                                APInt &Offset) {
-  unsigned IntPtrWidth = TD.getPointerSizeInBits();
-  assert(IntPtrWidth == Offset.getBitWidth());
-
-  gep_type_iterator GTI = gep_type_begin(GEP);
-  for (User::op_iterator I = GEP->op_begin() + 1, E = GEP->op_end(); I != E;
-       ++I, ++GTI) {
-    ConstantInt *OpC = dyn_cast<ConstantInt>(*I);
-    if (!OpC) return false;
-    if (OpC->isZero()) continue;
-
-    // Handle a struct index, which adds its field offset to the pointer.
-    if (StructType *STy = dyn_cast<StructType>(*GTI)) {
-      unsigned ElementIdx = OpC->getZExtValue();
-      const StructLayout *SL = TD.getStructLayout(STy);
-      Offset += APInt(IntPtrWidth, SL->getElementOffset(ElementIdx));
-      continue;
-    }
-
-    APInt TypeSize(IntPtrWidth, TD.getTypeAllocSize(GTI.getIndexedType()));
-    Offset += OpC->getValue().sextOrTrunc(IntPtrWidth) * TypeSize;
-  }
-  return true;
-}
-
 /// \brief Compute the base pointer and cumulative constant offsets for V.
 ///
 /// This strips all constant offsets off of V, leaving it the base pointer, and
@@ -710,7 +677,7 @@ static Constant *stripAndComputeConstantOffsets(const DataLayout &TD,
   Visited.insert(V);
   do {
     if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
-      if (!GEP->isInBounds() || !accumulateGEPOffset(TD, GEP, Offset))
+      if (!GEP->isInBounds() || !GEP->accumulateConstantOffset(TD, Offset))
         break;
       V = GEP->getPointerOperand();
     } else if (Operator::getOpcode(V) == Instruction::BitCast) {
diff --git a/lib/VMCore/Instructions.cpp b/lib/VMCore/Instructions.cpp
index 3bc4bfe2de..17ab34f4f8 100644
--- a/lib/VMCore/Instructions.cpp
+++ b/lib/VMCore/Instructions.cpp
@@ -23,7 +23,6 @@
 #include "llvm/Support/CallSite.h"
 #include "llvm/Support/ConstantRange.h"
 #include "llvm/Support/ErrorHandling.h"
-#include "llvm/Support/GetElementPtrTypeIterator.h"
 #include "llvm/Support/MathExtras.h"
 using namespace llvm;
 
@@ -1427,33 +1426,8 @@ bool GetElementPtrInst::isInBounds() const {
 
 bool GetElementPtrInst::accumulateConstantOffset(const DataLayout &DL,
                                                  APInt &Offset) const {
-  assert(Offset.getBitWidth() ==
-         DL.getPointerSizeInBits(getPointerAddressSpace()) &&
-         "The offset must have exactly as many bits as our pointer.");
-
-  for (gep_type_iterator GTI = gep_type_begin(this), GTE = gep_type_end(this);
-       GTI != GTE; ++GTI) {
-    ConstantInt *OpC = dyn_cast<ConstantInt>(GTI.getOperand());
-    if (!OpC)
-      return false;
-    if (OpC->isZero())
-      continue;
-
-    // Handle a struct index, which adds its field offset to the pointer.
-    if (StructType *STy = dyn_cast<StructType>(*GTI)) {
-      unsigned ElementIdx = OpC->getZExtValue();
-      const StructLayout *SL = DL.getStructLayout(STy);
-      Offset += APInt(Offset.getBitWidth(),
-                      SL->getElementOffset(ElementIdx));
-      continue;
-    }
-
-    // For array or vector indices, scale the index by the size of the type.
-    APInt Index = OpC->getValue().sextOrTrunc(Offset.getBitWidth());
-    Offset += Index * APInt(Offset.getBitWidth(),
-                            DL.getTypeAllocSize(GTI.getIndexedType()));
-  }
-  return true;
+  // Delegate to the generic GEPOperator implementation.
+  return cast<GEPOperator>(this)->accumulateConstantOffset(DL, Offset);
 }
 
 //===----------------------------------------------------------------------===//