diff --git a/llvm/lib/Analysis/ConstantFolding.cpp b/llvm/lib/Analysis/ConstantFolding.cpp
index 22f36e56bcf2..e093631d8f19 100644
--- a/llvm/lib/Analysis/ConstantFolding.cpp
+++ b/llvm/lib/Analysis/ConstantFolding.cpp
@@ -224,7 +224,8 @@ static bool IsConstantOffsetFromGlobal(Constant *C, GlobalValue *&GV,
                                        APInt &Offset, const DataLayout &TD) {
   // Trivial case, constant is the global.
   if ((GV = dyn_cast<GlobalValue>(C))) {
-    Offset.clearAllBits();
+    unsigned BitWidth = TD.getPointerTypeSizeInBits(GV->getType());
+    Offset = APInt(BitWidth, 0);
     return true;
   }
 
@@ -238,16 +239,23 @@ static bool IsConstantOffsetFromGlobal(Constant *C, GlobalValue *&GV,
     return IsConstantOffsetFromGlobal(CE->getOperand(0), GV, Offset, TD);
 
   // i32* getelementptr ([5 x i32]* @a, i32 0, i32 5)
-  if (GEPOperator *GEP = dyn_cast<GEPOperator>(CE)) {
-    // If the base isn't a global+constant, we aren't either.
-    if (!IsConstantOffsetFromGlobal(CE->getOperand(0), GV, Offset, TD))
-      return false;
+  GEPOperator *GEP = dyn_cast<GEPOperator>(CE);
+  if (!GEP)
+    return false;
 
-    // Otherwise, add any offset that our operands provide.
-    return GEP->accumulateConstantOffset(TD, Offset);
-  }
+  unsigned BitWidth = TD.getPointerTypeSizeInBits(GEP->getType());
+  APInt TmpOffset(BitWidth, 0);
 
-  return false;
+  // If the base isn't a global+constant, we aren't either.
+  if (!IsConstantOffsetFromGlobal(CE->getOperand(0), GV, TmpOffset, TD))
+    return false;
+
+  // Otherwise, add any offset that our operands provide.
+  if (!GEP->accumulateConstantOffset(TD, TmpOffset))
+    return false;
+
+  Offset = TmpOffset;
+  return true;
 }
 
 /// ReadDataFromGlobal - Recursive helper to read bits out of global.  C is the
@@ -416,7 +424,7 @@ static Constant *FoldReinterpretLoadFromConstPtr(Constant *C,
     return 0;
 
   GlobalValue *GVal;
-  APInt Offset(TD.getPointerTypeSizeInBits(PTy), 0);
+  APInt Offset;
   if (!IsConstantOffsetFromGlobal(C, GVal, Offset, TD))
     return 0;
 
@@ -585,8 +593,7 @@ static Constant *SymbolicallyEvaluateBinop(unsigned Opc, Constant *Op0,
   // constant.  This happens frequently when iterating over a global array.
   if (Opc == Instruction::Sub && DL) {
     GlobalValue *GV1, *GV2;
-    unsigned PtrSize = DL->getPointerSizeInBits();
-    APInt Offs1(PtrSize, 0), Offs2(PtrSize, 0);
+    APInt Offs1, Offs2;
 
     if (IsConstantOffsetFromGlobal(Op0, GV1, Offs1, *DL))
       if (IsConstantOffsetFromGlobal(Op1, GV2, Offs2, *DL) &&
diff --git a/llvm/test/Transforms/InstCombine/constant-fold-gep.ll b/llvm/test/Transforms/InstCombine/constant-fold-gep.ll
index 9f82e66b3830..5fb56023a4f6 100644
--- a/llvm/test/Transforms/InstCombine/constant-fold-gep.ll
+++ b/llvm/test/Transforms/InstCombine/constant-fold-gep.ll
@@ -1,5 +1,5 @@
 ; RUN: opt < %s -instcombine -S | FileCheck %s
-target datalayout = "E-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64"
+target datalayout = "E-p:64:64:64-p1:16:16:16-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64"
 
 ; Constant folding should fix notionally out-of-bounds indices
 ; and add inbounds keywords.
@@ -72,3 +72,21 @@ entry:
   ret i64 %E
   ; CHECK: ret i64 1000
 }
+
+@X_as1 = addrspace(1) global [1000 x i8] zeroinitializer, align 16
+
+define i16 @test2_as1() {
+; CHECK-LABEL: @test2_as1(
+  ; CHECK: ret i16 1000
+
+entry:
+  %A = bitcast i8 addrspace(1)* getelementptr inbounds ([1000 x i8] addrspace(1)* @X_as1, i64 1, i64 0) to i8 addrspace(1)*
+  %B = bitcast i8 addrspace(1)* getelementptr inbounds ([1000 x i8] addrspace(1)* @X_as1, i64 0, i64 0) to i8 addrspace(1)*
+
+  %B2 = ptrtoint i8 addrspace(1)* %B to i16
+  %C = sub i16 0, %B2
+  %D = getelementptr i8 addrspace(1)* %A, i16 %C
+  %E = ptrtoint i8 addrspace(1)* %D to i16
+
+  ret i16 %E
+}