add a GEP helper function

llvm-svn: 36515

llvm/include/llvm/Instructions.h

@@ -441,6 +441,12 @@ public:
   /// zeros.  If so, the result pointer and the first operand have the same
   /// value, just potentially different types.
   bool hasAllZeroIndices() const;
+  
+  /// hasAllConstantIndices - Return true if all of the indices of this GEP are
+  /// constant integers.  If so, the result pointer and the first operand have
+  /// a constant offset between them.
+  bool hasAllConstantIndices() const;
+  
 
   // Methods for support type inquiry through isa, cast, and dyn_cast:
   static inline bool classof(const GetElementPtrInst *) { return true; }

llvm/lib/VMCore/Instructions.cpp

@@ -1043,6 +1043,17 @@ bool GetElementPtrInst::hasAllZeroIndices() const {
   return true;
 }
 
+/// hasAllConstantIndices - Return true if all of the indices of this GEP are
+/// constant integers.  If so, the result pointer and the first operand have
+/// a constant offset between them.
+bool GetElementPtrInst::hasAllConstantIndices() const {
+  for (unsigned i = 1, e = getNumOperands(); i != e; ++i) {
+    if (!isa<ConstantInt>(getOperand(i)))
+      return false;
+  }
+  return true;
+}
+
 
 //===----------------------------------------------------------------------===//
 //                           ExtractElementInst Implementation