Only copy small types in modernize-loop-convert.

Summary: If the size of the type is above a certain bound, we'll take a const reference. This bound can be set as an option. For now, the default value is 16 bytes.

Reviewers: klimek

Subscribers: alexfh, cfe-commits

Differential Revision: http://reviews.llvm.org/D14176

llvm-svn: 251694

1 files changed, 8 insertions, 0 deletions

diff --git a/clang-tools-extra/test/clang-tidy/modernize-loop-convert-basic.cpp b/clang-tools-extra/test/clang-tidy/modernize-loop-convert-basic.cpp
index f98795f82f9..13a8226d18f 100644
--- a/clang-tools-extra/test/clang-tidy/modernize-loop-convert-basic.cpp
+++ b/clang-tools-extra/test/clang-tidy/modernize-loop-convert-basic.cpp
@@ -113,6 +113,14 @@ const int *constArray() {
   // CHECK-FIXES: for (const auto & Elem : NonCopy)
   // CHECK-FIXES-NEXT: printf("2 * %d = %d\n", Elem.X, Elem.X + Elem.X);
 
+  const TriviallyCopyableButBig Big[N]{};
+  for (int I = 0; I < N; ++I) {
+    printf("2 * %d = %d\n", Big[I].X, Big[I].X + Big[I].X);
+  }
+  // CHECK-MESSAGES: :[[@LINE-3]]:3: warning: use range-based for loop instead
+  // CHECK-FIXES: for (const auto & Elem : Big)
+  // CHECK-FIXES-NEXT: printf("2 * %d = %d\n", Elem.X, Elem.X + Elem.X);
+
   bool Something = false;
   for (int I = 0; I < N; ++I) {
     if (Something)