[clang-tools-extra] [clang-tidy] add check to suggest replacement of nested std::min or std::max with initializer lists (PR #85572)

[Piotr Zegar via cfe-commits]

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@@ -0,0 +1,58 @@
+//===--- MinMaxUseInitializerListCheck.h - clang-tidy -----------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MODERNIZE_MINMAXUSEINITIALIZERLISTCHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MODERNIZE_MINMAXUSEINITIALIZERLISTCHECK_H
+
+#include "../ClangTidyCheck.h"
+#include "../utils/IncludeInserter.h"
+
+namespace clang::tidy::modernize {
+
+/// Transforms the repeated calls to `std::min` and `std::max` into a single
+/// call using initializer lists.
+///
+/// It identifies cases where `std::min` or `std::max` is used to find the
+/// minimum or maximum value among more than two items through repeated calls.
+/// The check replaces these calls with a single call to `std::min` or
+/// `std::max` that uses an initializer list. This makes the code slightly more
+/// efficient.
+/// \n\n
+/// For example:
+///
+/// \code
+///   int a = std::max(std::max(i, j), k);
+/// \endcode
+///
+/// This code is transformed to:
+///
+/// \code
+///   int a = std::max({i, j, k});
+/// \endcode
+class MinMaxUseInitializerListCheck : public ClangTidyCheck {
+public:
+  MinMaxUseInitializerListCheck(StringRef Name, ClangTidyContext *Context);
+
+  bool isLanguageVersionSupported(const LangOptions &LangOpts) const override {
+    return LangOpts.CPlusPlus11;
+  }
+  void storeOptions(ClangTidyOptions::OptionMap &Opts) override;
+  void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+  void registerPPCallbacks(const SourceManager &SM, Preprocessor *PP,
+                           Preprocessor *ModuleExpanderPP) override;
+  void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+
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PiotrZSL wrote:

consider using TK_IgnoreUnlessSpelledInSource to exclude implicit code.

https://github.com/llvm/llvm-project/pull/85572