https://github.com/HerrCai0907 created
https://github.com/llvm/llvm-project/pull/95633
Fixes: #86404
>From 0022050f7b537914dff7adf937103def4c9c939a Mon Sep 17 00:00:00 2001
From: Congcong Cai <congcongcai0...@163.com>
Date: Sat, 15 Jun 2024 05:40:50 +0000
Subject: [PATCH] [clang-tidy]fix false positives of the result of std::move()
is used as rvalue for performance-move-const-arg
Fixes: #86404
---
.../clang-tidy/performance/MoveConstArgCheck.cpp | 8 +++++++-
clang-tools-extra/docs/ReleaseNotes.rst | 4 ++++
.../checkers/performance/move-const-arg.cpp | 14 +++++++++-----
3 files changed, 20 insertions(+), 6 deletions(-)
diff --git a/clang-tools-extra/clang-tidy/performance/MoveConstArgCheck.cpp
b/clang-tools-extra/clang-tidy/performance/MoveConstArgCheck.cpp
index aa54cf284f627..d29b9e91f2e35 100644
--- a/clang-tools-extra/clang-tidy/performance/MoveConstArgCheck.cpp
+++ b/clang-tools-extra/clang-tidy/performance/MoveConstArgCheck.cpp
@@ -44,7 +44,13 @@ void MoveConstArgCheck::registerMatchers(MatchFinder
*Finder) {
unless(isInTemplateInstantiation()))
.bind("call-move");
- Finder->addMatcher(MoveCallMatcher, this);
+ Finder->addMatcher(
+ expr(anyOf(
+ castExpr(hasSourceExpression(MoveCallMatcher)),
+ cxxConstructExpr(hasDeclaration(cxxConstructorDecl(anyOf(
+ isCopyConstructor(), isMoveConstructor()))),
+ hasArgument(0, MoveCallMatcher)))),
+ this);
auto ConstTypeParmMatcher =
qualType(references(isConstQualified())).bind("invocation-parm-type");
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst
b/clang-tools-extra/docs/ReleaseNotes.rst
index 5d5aecd67b2d7..aeb0d72651c34 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -387,6 +387,10 @@ Changes in existing checks
- Improved :doc:`modernize-use-using <clang-tidy/checks/modernize/use-using>`
check by adding support for detection of typedefs declared on function level.
+- Improved :doc:`performance-move-const-arg
+ <clang-tidy/checks/performance/move-const-arg>` check ignoring the result
+ of ``std::move()`` is used as rvalue.
+
- Improved :doc:`performance-unnecessary-copy-initialization
<clang-tidy/checks/performance/unnecessary-copy-initialization>` check by
detecting more cases of constant access. In particular, pointers can be
diff --git
a/clang-tools-extra/test/clang-tidy/checkers/performance/move-const-arg.cpp
b/clang-tools-extra/test/clang-tidy/checkers/performance/move-const-arg.cpp
index 4d90c124ad72c..4505eef6df24b 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/performance/move-const-arg.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/performance/move-const-arg.cpp
@@ -114,14 +114,18 @@ void f8() {
int f9() { return M2(1); }
template <typename T>
-T f10(const int x10) {
+T f_unknown_target(const int x10) {
return std::move(x10);
- // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: std::move of the const variable
'x10' of the trivially-copyable type 'const int' has no effect; remove
std::move() [performance-move-const-arg]
- // CHECK-FIXES: return x10;
}
+
void f11() {
- f10<int>(1);
- f10<double>(1);
+ f_unknown_target<int>(1);
+ f_unknown_target<double>(1);
+}
+
+A&& f_return_right_ref() {
+ static A a{};
+ return std::move(a);
}
class NoMoveSemantics {
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