diff --git a/llvm/lib/CodeGen/TypePromotion.cpp b/llvm/lib/CodeGen/TypePromotion.cpp
--- a/llvm/lib/CodeGen/TypePromotion.cpp
+++ b/llvm/lib/CodeGen/TypePromotion.cpp
@@ -539,8 +539,8 @@
         I->setOperand(i, UndefValue::get(ExtTy));
     }
 
-    // Mutate the result type, unless this is an icmp.
-    if (!isa<ICmpInst>(I)) {
+    // Mutate the result type, unless this is an icmp or switch.
+    if (!isa<ICmpInst>(I) && !isa<SwitchInst>(I)) {
       I->mutateType(ExtTy);
       Promoted.insert(I);
     }
diff --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp
--- a/llvm/lib/IR/Verifier.cpp
+++ b/llvm/lib/IR/Verifier.cpp
@@ -2691,6 +2691,7 @@
 }
 
 void Verifier::visitSwitchInst(SwitchInst &SI) {
+  Assert(SI.getType()->isVoidTy(), "Switch must have void result type!", &SI);
   // Check to make sure that all of the constants in the switch instruction
   // have the same type as the switched-on value.
   Type *SwitchTy = SI.getCondition()->getType();