[clang-tools-extra] [clang-tidy] Add performance-expensive-value-or check (PR #200166)

[Endre Fülöp via cfe-commits]

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@@ -0,0 +1,70 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "ExpensiveValueOrCheck.h"
+#include "../utils/OptionsUtils.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang::tidy::performance {
+
+ExpensiveValueOrCheck::ExpensiveValueOrCheck(StringRef Name,
+                                             ClangTidyContext *Context)
+    : ClangTidyCheck(Name, Context),
+      SizeThreshold(Options.get("SizeThreshold", 8U)),
+      WarnOnRvalueOptional(Options.get("WarnOnRvalueOptional", false)),
+      OptionalTypes(utils::options::parseStringList(
+          Options.get("OptionalTypes", "::std::optional"))) {}
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gamesh411 wrote:

I also think this would not lead to false positives.
The 'value_or' naming suggests clear adherence to how optionals work.

https://github.com/llvm/llvm-project/pull/200166