Index: lib/IR/AutoUpgrade.cpp
===================================================================
--- lib/IR/AutoUpgrade.cpp
+++ lib/IR/AutoUpgrade.cpp
@@ -1912,19 +1912,14 @@
   }
 
   std::string Name = CI->getName();
-  if (!Name.empty())
-    CI->setName(Name + ".old");
-
+  CallInst *NewCall = nullptr;
   switch (NewFn->getIntrinsicID()) {
   default: {
     // Handle generic mangling change, but nothing else
     assert(
         (CI->getCalledFunction()->getName() != NewFn->getName()) &&
         "Unknown function for CallInst upgrade and isn't just a name change");
-    SmallVector<Value *, 4> Args(CI->arg_operands().begin(),
-                                 CI->arg_operands().end());
-    CI->replaceAllUsesWith(Builder.CreateCall(NewFn, Args));
-    CI->eraseFromParent();
+    CI->setCalledFunction(NewFn);
     return;
   }
 
@@ -1944,47 +1939,39 @@
   case Intrinsic::arm_neon_vst4lane: {
     SmallVector<Value *, 4> Args(CI->arg_operands().begin(),
                                  CI->arg_operands().end());
-    CI->replaceAllUsesWith(Builder.CreateCall(NewFn, Args));
-    CI->eraseFromParent();
-    return;
+    NewCall = Builder.CreateCall(NewFn, Args);
+    break;
   }
 
   case Intrinsic::bitreverse:
-    CI->replaceAllUsesWith(Builder.CreateCall(NewFn, {CI->getArgOperand(0)}));
-    CI->eraseFromParent();
-    return;
+    NewCall = Builder.CreateCall(NewFn, {CI->getArgOperand(0)});
+    break;
 
   case Intrinsic::ctlz:
   case Intrinsic::cttz:
     assert(CI->getNumArgOperands() == 1 &&
            "Mismatch between function args and call args");
-    CI->replaceAllUsesWith(Builder.CreateCall(
-        NewFn, {CI->getArgOperand(0), Builder.getFalse()}, Name));
-    CI->eraseFromParent();
-    return;
+    NewCall = Builder.CreateCall(
+        NewFn, {CI->getArgOperand(0), Builder.getFalse()}, Name);
+    break;
 
   case Intrinsic::objectsize:
-    CI->replaceAllUsesWith(Builder.CreateCall(
-        NewFn, {CI->getArgOperand(0), CI->getArgOperand(1)}, Name));
-    CI->eraseFromParent();
-    return;
+    NewCall = Builder.CreateCall(
+        NewFn, {CI->getArgOperand(0), CI->getArgOperand(1)}, Name);
+    break;
 
   case Intrinsic::ctpop:
-    CI->replaceAllUsesWith(Builder.CreateCall(NewFn, {CI->getArgOperand(0)}));
-    CI->eraseFromParent();
-    return;
+    NewCall = Builder.CreateCall(NewFn, {CI->getArgOperand(0)});
+    break;
 
   case Intrinsic::convert_from_fp16:
-    CI->replaceAllUsesWith(Builder.CreateCall(NewFn, {CI->getArgOperand(0)}));
-    CI->eraseFromParent();
-    return;
+    NewCall = Builder.CreateCall(NewFn, {CI->getArgOperand(0)});
+    break;
 
   case Intrinsic::x86_xop_vfrcz_ss:
   case Intrinsic::x86_xop_vfrcz_sd:
-    CI->replaceAllUsesWith(
-        Builder.CreateCall(NewFn, {CI->getArgOperand(1)}, Name));
-    CI->eraseFromParent();
-    return;
+    NewCall = Builder.CreateCall(NewFn, {CI->getArgOperand(1)}, Name);
+    break;
 
   case Intrinsic::x86_xop_vpermil2pd:
   case Intrinsic::x86_xop_vpermil2ps:
@@ -1995,9 +1982,8 @@
     VectorType *FltIdxTy = cast<VectorType>(Args[2]->getType());
     VectorType *IntIdxTy = VectorType::getInteger(FltIdxTy);
     Args[2] = Builder.CreateBitCast(Args[2], IntIdxTy);
-    CI->replaceAllUsesWith(Builder.CreateCall(NewFn, Args, Name));
-    CI->eraseFromParent();
-    return;
+    NewCall = Builder.CreateCall(NewFn, Args, Name);
+    break;
   }
 
   case Intrinsic::x86_sse41_ptestc:
@@ -2019,10 +2005,8 @@
     Value *BC0 = Builder.CreateBitCast(Arg0, NewVecTy, "cast");
     Value *BC1 = Builder.CreateBitCast(Arg1, NewVecTy, "cast");
 
-    CallInst *NewCall = Builder.CreateCall(NewFn, {BC0, BC1}, Name);
-    CI->replaceAllUsesWith(NewCall);
-    CI->eraseFromParent();
-    return;
+    NewCall = Builder.CreateCall(NewFn, {BC0, BC1}, Name);
+    break;
   }
 
   case Intrinsic::x86_sse41_insertps:
@@ -2038,17 +2022,13 @@
 
     // Replace the last argument with a trunc.
     Args.back() = Builder.CreateTrunc(Args.back(), Type::getInt8Ty(C), "trunc");
-
-    CallInst *NewCall = Builder.CreateCall(NewFn, Args);
-    CI->replaceAllUsesWith(NewCall);
-    CI->eraseFromParent();
-    return;
+    NewCall = Builder.CreateCall(NewFn, Args);
+    break;
   }
 
   case Intrinsic::thread_pointer: {
-    CI->replaceAllUsesWith(Builder.CreateCall(NewFn, {}));
-    CI->eraseFromParent();
-    return;
+    NewCall = Builder.CreateCall(NewFn, {});
+    break;
   }
 
   case Intrinsic::invariant_start:
@@ -2057,11 +2037,18 @@
   case Intrinsic::masked_store: {
     SmallVector<Value *, 4> Args(CI->arg_operands().begin(),
                                  CI->arg_operands().end());
-    CI->replaceAllUsesWith(Builder.CreateCall(NewFn, Args));
-    CI->eraseFromParent();
-    return;
+    NewCall = Builder.CreateCall(NewFn, Args);
+    break;
   }
   }
+  assert(NewCall && "Should have either set this variable or returned through "
+                    "the default case");
+  if (!Name.empty()) {
+    CI->setName(Name + ".old");
+    NewCall->setName(Name);
+  }
+  CI->replaceAllUsesWith(NewCall);
+  CI->eraseFromParent();
 }
 
 void llvm::UpgradeCallsToIntrinsic(Function *F) {
Index: test/CodeGen/Generic/overloaded-intrinsic-name.ll
===================================================================
--- test/CodeGen/Generic/overloaded-intrinsic-name.ll
+++ test/CodeGen/Generic/overloaded-intrinsic-name.ll
@@ -1,4 +1,5 @@
 ; RUN: opt -verify -S < %s
+; RUN: opt -S < %s | FileCheck %s
 
 ; Tests the name mangling performed by the codepath following
 ; getMangledTypeStr(). Only tests that code with the various manglings
@@ -67,7 +68,9 @@
 
 define %i32* @test_broken_names(%i32* %v) gc "statepoint-example" {
 entry:
-      %tok = call token (i64, i32, i1 ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.deadbeef(i64 0, i32 0, i1 ()* @return_i1, i32 0, i32 0, i32 0, i32 0, %i32* %v)
+      %tok = call fastcc token (i64, i32, i1 ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.deadbeef(i64 0, i32 0, i1 ()* @return_i1, i32 0, i32 0, i32 0, i32 0, %i32* %v)
+; Make sure we do not destroy the calling convention when remangling
+; CHECK: fastcc
       %v-new = call %i32* @llvm.experimental.gc.relocate.beefdead(token %tok,  i32 7, i32 7)
       ret %i32* %v-new
 }