diff --git a/lib/CodeGen/CodeGenPrepare.cpp b/lib/CodeGen/CodeGenPrepare.cpp
index e81a9098ef5..0c765b64313 100644
--- a/lib/CodeGen/CodeGenPrepare.cpp
+++ b/lib/CodeGen/CodeGenPrepare.cpp
@@ -1756,7 +1756,12 @@ AddressingModeMatcher::IsPromotionProfitable(unsigned MatchedSize,
   Instruction *PromotedInst = dyn_cast<Instruction>(PromotedOperand);
   if (!PromotedInst)
     return false;
-  return TLI.isOperationLegalOrCustom(PromotedInst->getOpcode(),
+  int ISDOpcode = TLI.InstructionOpcodeToISD(PromotedInst->getOpcode());
+  // If the ISDOpcode is undefined, it was undefined before the promotion.
+  if (!ISDOpcode)
+    return true;
+  // Otherwise, check if the promoted instruction is legal or not.
+  return TLI.isOperationLegalOrCustom(ISDOpcode,
                                       EVT::getEVT(PromotedInst->getType()));
 }
 
diff --git a/test/CodeGen/R600/codegen-prepare-addrmode-sext.ll b/test/CodeGen/R600/codegen-prepare-addrmode-sext.ll
index 6c8b26a3ae9..f8b4a61a7db 100644
--- a/test/CodeGen/R600/codegen-prepare-addrmode-sext.ll
+++ b/test/CodeGen/R600/codegen-prepare-addrmode-sext.ll
@@ -1,11 +1,14 @@
-; RUN: opt -codegenprepare -S -o - %s | FileCheck %s
+; RUN: opt -codegenprepare -S -o - %s | FileCheck --check-prefix=OPT --check-prefix=FUNC %s
+; RUN: llc < %s -march=r600 -mcpu=verde -verify-machineinstrs | FileCheck --check-prefix=SI-LLC --check-prefix=FUNC %s
 
 target datalayout = "e-p:32:32-p1:64:64-p2:64:64-p3:32:32-p4:32:32-p5:64:64-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 = "r600--"
 
-; CHECK-LABEL: @test
-; CHECK: mul
-; CHECK-NEXT: sext
+; FUNC-LABEL: @test
+; OPT: mul nsw i32
+; OPT-NEXT: sext
+; SI-LLC: V_MUL_LO_I32
+; SI-LLC-NOT: V_MUL_HI
 define void @test(i8 addrspace(1)* nocapture readonly %in, i32 %a, i8 %b) {
 entry:
   %0 = mul nsw i32 %a, 3