Fix debug field names for vectors > 4 elements

Author: simoll

tools/clang/lib/CodeGen/CGDebugInfo.cpp

@@ -1047,8 +1047,15 @@ bool CGDebugInfo::TryCollectHLSLRecordElements(const RecordType *Ty,
     unsigned VecSize = hlsl::GetHLSLVecSize(QualTy);
     unsigned ElemSizeInBits = CGM.getContext().getTypeSize(ElemQualTy);
     unsigned CurrentAlignedOffset = 0;
+    std::string FieldNameBuf;
     for (unsigned ElemIdx = 0; ElemIdx < VecSize; ++ElemIdx) {
-      StringRef FieldName = StringRef(&"xyzw"[ElemIdx], 1);
+      StringRef FieldName;
+      if (VecSize <= 4) {
+        FieldName = StringRef(&"xyzw"[ElemIdx], 1);
+      } else {
+        FieldNameBuf = "c" + std::to_string(ElemIdx);
+        FieldName = FieldNameBuf;
+      }
       CurrentAlignedOffset =
           llvm::RoundUpToAlignment(CurrentAlignedOffset, AlignBits);
       llvm::DIType *FieldType =