[clang-tidy] Do not move parameter if only DeclRefExpr occurs inside of a loop

Summary: This fixes a bug where the performance-unnecessary-value-param check suggests a fix to move the parameter inside of a loop which could be invoked multiple times.

Reviewers: sbenza, aaron.ballman, alexfh

Subscribers: JDevlieghere, cfe-commits

Differential Revision: https://reviews.llvm.org/D27187

llvm-svn: 289912

1 files changed, 9 insertions, 0 deletions

diff --git a/clang-tools-extra/test/clang-tidy/performance-unnecessary-value-param.cpp b/clang-tools-extra/test/clang-tidy/performance-unnecessary-value-param.cpp
index 5f7a4dd91d4..18fcf0ffca2 100644
--- a/clang-tools-extra/test/clang-tidy/performance-unnecessary-value-param.cpp
+++ b/clang-tools-extra/test/clang-tidy/performance-unnecessary-value-param.cpp
@@ -225,6 +225,15 @@ void PositiveMoveOnCopyAssignment(ExpensiveMovableType E) {
   // 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) {