move DecomposeGEPExpression out into ValueTracking.cpp

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89956 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 15 insertions, 0 deletions

diff --git a/include/llvm/Analysis/ValueTracking.h b/include/llvm/Analysis/ValueTracking.h
index 121da79..0596891 100644
--- a/include/llvm/Analysis/ValueTracking.h
+++ b/include/llvm/Analysis/ValueTracking.h
@@ -19,6 +19,7 @@
 #include <string>
 
 namespace llvm {
+  template <typename T> class SmallVectorImpl;
   class Value;
   class Instruction;
   class APInt;
@@ -77,6 +78,20 @@ namespace llvm {
   ///
   bool CannotBeNegativeZero(const Value *V, unsigned Depth = 0);
 
+  /// DecomposeGEPExpression - If V is a symbolic pointer expression, decompose
+  /// it into a base pointer with a constant offset and a number of scaled
+  /// symbolic offsets.
+  ///
+  /// When TargetData is around, this function is capable of analyzing
+  /// everything that Value::getUnderlyingObject() can look through.  When not,
+  /// it just looks through pointer casts.
+  ///
+  const Value *DecomposeGEPExpression(const Value *V, int64_t &BaseOffs,
+                 SmallVectorImpl<std::pair<const Value*, int64_t> > &VarIndices,
+                                      const TargetData *TD);
+    
+  
+  
   /// FindScalarValue - Given an aggregrate and an sequence of indices, see if
   /// the scalar value indexed is already around as a register, for example if
   /// it were inserted directly into the aggregrate.