Index: lib/Analysis/ConstantFolding.cpp
===================================================================
--- lib/Analysis/ConstantFolding.cpp
+++ lib/Analysis/ConstantFolding.cpp
@@ -1137,6 +1137,15 @@
           return ConstantFoldCompareInstOperands(Predicate, C, Null, DL, TLI);
         }
       }
+
+      // ConstantFold a compare instruction with addrspacecast as the
+      // first operand.
+      // fold: icmp (addrspacecast x), y     -> icmp x, y
+      if (CE0->getOpcode() == Instruction::AddrSpaceCast) {
+        Constant *C = CE0->getOperand(0);
+        Constant *Null = Constant::getNullValue(C->getType());
+        return ConstantFoldCompareInstOperands(Predicate, C, Null, DL, TLI);
+      }
     }
 
     if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(Ops1)) {
Index: test/Transforms/InstCombine/OptimizeAddrspaceCast.ll
===================================================================
--- test/Transforms/InstCombine/OptimizeAddrspaceCast.ll
+++ test/Transforms/InstCombine/OptimizeAddrspaceCast.ll
@@ -0,0 +1,28 @@
+; Test to make sure that the addrspacecast is constantfolded correctly
+; during InstCombine pass.
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+target datalayout = "e-i64:64-f80:128-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024-n8:16:32:64"
+
+@testKernel.some_value = internal addrspace(3) global i32 undef, align 4
+
+; Function Attrs: nounwind
+define void @testKernel(i32 addrspace(1)* %results) nounwind {
+  %1 = alloca i32 addrspace(1)*, align 8
+  %ptr = alloca i32 addrspace(4)*, align 8
+  %lptr = alloca i32 addrspace(3)*, align 8
+  store i32 addrspace(1)* %results, i32 addrspace(1)** %1, align 8
+  store i32 7, i32 addrspace(3)* @testKernel.some_value, align 4
+  store i32 addrspace(4)* null, i32 addrspace(4)** %ptr, align 8
+  store i32 addrspace(3)* @testKernel.some_value, i32 addrspace(3)** %lptr, align 8
+  %2 = load i32 addrspace(4)*, i32 addrspace(4)** %ptr, align 8
+  %3 = load i32 addrspace(3)*, i32 addrspace(3)** %lptr, align 8
+  %4 = addrspacecast i32 addrspace(3)* %3 to i32 addrspace(4)*
+  %5 = icmp ne i32 addrspace(4)* %2, %4
+  %6 = zext i1 %5 to i32
+  %7 = load i32 addrspace(1)*, i32 addrspace(1)** %1, align 8
+  %8 = getelementptr inbounds i32, i32 addrspace(1)* %7, i64 0
+  store i32 %6, i32 addrspace(1)* %8, align 4
+; CHECK: store i32 1, i32 addrspace(1)* %results
+  ret void
+}