Hoist the GEP constant address offset computation to a common home on

the GEP instruction class.

This is part of the continued refactoring and cleaning of the
infrastructure used by SROA. This particular operation is also done in
a few other places which I'll try to refactor to share this
implementation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169852 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 12 insertions, 2 deletions

diff --git a/include/llvm/Analysis/PtrUseVisitor.h b/include/llvm/Analysis/PtrUseVisitor.h
index e15f2b45a8..f5daf2c63e 100644
--- a/include/llvm/Analysis/PtrUseVisitor.h
+++ b/include/llvm/Analysis/PtrUseVisitor.h
@@ -29,7 +29,6 @@
 #include "llvm/InstVisitor.h"
 #include "llvm/IntrinsicInst.h"
 #include "llvm/Support/Compiler.h"
-#include "llvm/Support/GetElementPtrTypeIterator.h"
 
 namespace llvm {
 
diff --git a/include/llvm/Instructions.h b/include/llvm/Instructions.h
index 9c5a2db2fe..b5c75e3782 100644
--- a/include/llvm/Instructions.h
+++ b/include/llvm/Instructions.h
@@ -29,9 +29,10 @@
 
 namespace llvm {
 
+class APInt;
 class ConstantInt;
 class ConstantRange;
-class APInt;
+class DataLayout;
 class LLVMContext;
 
 enum AtomicOrdering {
@@ -850,6 +851,16 @@ public:
   /// isInBounds - Determine whether the GEP has the inbounds flag.
   bool isInBounds() const;
 
+  /// \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;
+
   // Methods for support type inquiry through isa, cast, and dyn_cast:
   static inline bool classof(const Instruction *I) {
     return (I->getOpcode() == Instruction::GetElementPtr);