Index: llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp
===================================================================
--- llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -2559,7 +2559,12 @@
 static bool isCompatibleIVType(Value *LVal, Value *RVal) {
   Type *LType = LVal->getType();
   Type *RType = RVal->getType();
-  return (LType == RType) || (LType->isPointerTy() && RType->isPointerTy());
+  return (LType == RType) || (LType->isPointerTy() && RType->isPointerTy() &&
+                              // Different address spaces means (possibly)
+                              // different types of the pointer implementation,
+                              // e.g. i16 vs i32 so disallow that.
+                              (LType->getPointerAddressSpace() ==
+                               RType->getPointerAddressSpace()));
 }
 
 /// Return an approximation of this SCEV expression's "base", or NULL for any
Index: llvm/trunk/test/Transforms/LoopStrengthReduce/AMDGPU/different-addrspace-crash.ll
===================================================================
--- llvm/trunk/test/Transforms/LoopStrengthReduce/AMDGPU/different-addrspace-crash.ll
+++ llvm/trunk/test/Transforms/LoopStrengthReduce/AMDGPU/different-addrspace-crash.ll
@@ -0,0 +1,31 @@
+; RUN: llc < %s | FileCheck %s
+
+target datalayout = "e-p:32:32-p1:64:64-p2:64:64-p3:32:32-p4:64:64-p5:32:32-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024-v2048:2048-n32:64"
+target triple = "amdgcn--"
+
+; We need to compile this for a target where we have different address spaces,
+; and where pointers in those address spaces have different size.
+; E.g. for amdgcn-- pointers in address space 0 are 32 bits and pointers in
+; address space 1 are 64 bits.
+
+; We shouldn't crash. Check that we get a loop with the two stores.
+;CHECK-LABEL: foo:
+;CHECK: [[LOOP_LABEL:BB[0-9]+_[0-9]+]]:
+;CHECK: buffer_store_dword
+;CHECK: buffer_store_dword
+;CHECK: s_branch [[LOOP_LABEL]]
+
+define void @foo() {
+entry:
+  br label %loop
+
+loop:
+  %idx0 = phi i32 [ %next_idx0, %loop ], [ 0, %entry ]
+  %0 = getelementptr inbounds i32, i32* null, i32 %idx0
+  %1 = getelementptr inbounds i32, i32 addrspace(1)* null, i32 %idx0
+  store i32 1, i32* %0
+  store i32 7, i32 addrspace(1)* %1
+  %next_idx0 = add nuw nsw i32 %idx0, 1
+  br label %loop
+}
+