MemCpyOpt: When forming a memset from stores also take GEP constexprs into account.

This is common when storing to global variables.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163809 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/MemCpyOptimizer.cpp b/lib/Transforms/Scalar/MemCpyOptimizer.cpp
index 2a5ee33..35acc79 100644
--- a/lib/Transforms/Scalar/MemCpyOptimizer.cpp
+++ b/lib/Transforms/Scalar/MemCpyOptimizer.cpp
@@ -38,7 +38,7 @@
 STATISTIC(NumMoveToCpy,   "Number of memmoves converted to memcpy");
 STATISTIC(NumCpyToSet,    "Number of memcpys converted to memset");
 
-static int64_t GetOffsetFromIndex(const GetElementPtrInst *GEP, unsigned Idx,
+static int64_t GetOffsetFromIndex(const GEPOperator *GEP, unsigned Idx,
                                   bool &VariableIdxFound, const TargetData &TD){
   // Skip over the first indices.
   gep_type_iterator GTI = gep_type_begin(GEP);
@@ -75,8 +75,8 @@
                             const TargetData &TD) {
   Ptr1 = Ptr1->stripPointerCasts();
   Ptr2 = Ptr2->stripPointerCasts();
-  GetElementPtrInst *GEP1 = dyn_cast<GetElementPtrInst>(Ptr1);
-  GetElementPtrInst *GEP2 = dyn_cast<GetElementPtrInst>(Ptr2);
+  GEPOperator *GEP1 = dyn_cast<GEPOperator>(Ptr1);
+  GEPOperator *GEP2 = dyn_cast<GEPOperator>(Ptr2);
 
   bool VariableIdxFound = false;