address pr feedback

Author: farzonl

clang/test/CodeGenDirectX/unsupported_intrinsic.hlsl

@@ -1,4 +1,5 @@
-// RUN: %if clang-dxc %{not %clang_dxc -T lib_6_3 %s 2>&1 | FileCheck %s %}
+// REQUIRES: directx-registered-target
+// RUN: not %clang_dxc -T lib_6_3 %s 2>&1 | FileCheck %s
 
 // CHECK: error: Unsupported intrinsic llvm.vector.reduce.and.v4i32 for DXIL lowering
 

llvm/include/llvm/IR/DiagnosticInfo.h

@@ -139,7 +139,7 @@ class DiagnosticInfo {
 using DiagnosticHandlerFunction = std::function<void(const DiagnosticInfo &)>;
 
 class DiagnosticInfoGeneric : public DiagnosticInfo {
-  const Twine MsgStr;
+  const Twine &MsgStr;
   const Instruction *Inst = nullptr;
 
 public:

llvm/lib/Target/DirectX/DXILOpLowering.cpp

@@ -756,9 +756,8 @@ class OpLowerer {
       case Intrinsic::not_intrinsic:
         continue;
       default: {
-        std::string Msg =
-            formatv("Unsupported intrinsic {0} for DXIL lowering", F.getName())
-                .str();
+        SmallString<128> Msg =
+            formatv("Unsupported intrinsic {0} for DXIL lowering", F.getName());
         M.getContext().emitError(Msg);
         HasErrors |= true;
         break;