Index: lib/Target/AMDGPU/SIISelLowering.cpp
===================================================================
--- lib/Target/AMDGPU/SIISelLowering.cpp
+++ lib/Target/AMDGPU/SIISelLowering.cpp
@@ -1123,8 +1123,7 @@
 static bool isFlatGlobalAddrSpace(unsigned AS) {
   return AS == AMDGPUAS::GLOBAL_ADDRESS ||
          AS == AMDGPUAS::FLAT_ADDRESS ||
-         AS == AMDGPUAS::CONSTANT_ADDRESS ||
-         AS == AMDGPUAS::CONSTANT_ADDRESS_32BIT;
+         AS == AMDGPUAS::CONSTANT_ADDRESS;
 }
 
 bool SITargetLowering::isNoopAddrSpaceCast(unsigned SrcAS,
Index: test/CodeGen/AMDGPU/invalid-addrspacecast.ll
===================================================================
--- test/CodeGen/AMDGPU/invalid-addrspacecast.ll
+++ test/CodeGen/AMDGPU/invalid-addrspacecast.ll
@@ -6,3 +6,10 @@
   store volatile i32 0, i32 addrspace(1)* %stof
   ret void
 }
+
+; ERROR: error: <unknown>:0:0: in function use_constant32bit_to_flat_addrspacecast void (i32 addrspace(6)*): invalid addrspacecast
+define amdgpu_kernel void @use_constant32bit_to_flat_addrspacecast(i32 addrspace(6)* %ptr) #0 {
+  %stof = addrspacecast i32 addrspace(6)* %ptr to i32*
+  store volatile i32 7, i32* %stof
+  ret void
+}