Index: clang-tidy/performance/UnnecessaryValueParamCheck.cpp =================================================================== --- clang-tidy/performance/UnnecessaryValueParamCheck.cpp +++ clang-tidy/performance/UnnecessaryValueParamCheck.cpp @@ -104,6 +104,8 @@ if (!IsConstQualified) { auto CanonicalType = Param->getType().getCanonicalType(); if (AllDeclRefExprs.size() == 1 && + !utils::decl_ref_expr::hasLoopStmtAncestor( + **AllDeclRefExprs.begin(), *Function->getBody(), *Result.Context) && ((utils::type_traits::hasNonTrivialMoveConstructor(CanonicalType) && utils::decl_ref_expr::isCopyConstructorArgument( **AllDeclRefExprs.begin(), *Function->getBody(), Index: clang-tidy/utils/DeclRefExprUtils.h =================================================================== --- clang-tidy/utils/DeclRefExprUtils.h +++ clang-tidy/utils/DeclRefExprUtils.h @@ -47,6 +47,11 @@ bool isCopyAssignmentArgument(const DeclRefExpr &DeclRef, const Stmt &Stmt, ASTContext &Context); +// Returns true if DeclRefExpr has a loop statement (ForStmt, CXXForRangeStmt, +// WhileStmt, DoStmt) as ancestor. +bool hasLoopStmtAncestor(const DeclRefExpr &DeclRef, const Stmt &Stmt, + ASTContext &Context); + } // namespace decl_ref_expr } // namespace utils } // namespace tidy Index: clang-tidy/utils/DeclRefExprUtils.cpp =================================================================== --- clang-tidy/utils/DeclRefExprUtils.cpp +++ clang-tidy/utils/DeclRefExprUtils.cpp @@ -120,6 +120,17 @@ return !Matches.empty(); } +bool hasLoopStmtAncestor(const DeclRefExpr &DeclRef, const Stmt &Stmt, + ASTContext &Context) { + auto Matches = + match(findAll(declRefExpr(equalsNode(&DeclRef), + unless(hasAncestor(stmt(anyOf( + forStmt(), cxxForRangeStmt(), whileStmt(), + doStmt()))))).bind("declRef")), + Stmt, Context); + return Matches.empty(); +} + } // namespace decl_ref_expr } // namespace utils } // namespace tidy Index: test/clang-tidy/performance-unnecessary-value-param.cpp =================================================================== --- test/clang-tidy/performance-unnecessary-value-param.cpp +++ test/clang-tidy/performance-unnecessary-value-param.cpp @@ -225,6 +225,15 @@ // CHECK-FIXES: F = std::move(E); } +// The argument could be moved but is not since copy statement is inside a loop. +void PositiveNoMoveInsideLoop(ExpensiveMovableType E) { + // CHECK-MESSAGES: [[@LINE-1]]:52: warning: the parameter 'E' is copied + // CHECK-FIXES: void PositiveNoMoveInsideLoop(const ExpensiveMovableType& E) { + for (;;) { + auto F = E; + } +} + void PositiveConstRefNotMoveConstructible(ExpensiveToCopyType T) { // CHECK-MESSAGES: [[@LINE-1]]:63: warning: the parameter 'T' is copied // CHECK-FIXES: void PositiveConstRefNotMoveConstructible(const ExpensiveToCopyType& T) {