[clang-format] Handle attributes for for/while loops

Fixes #55853.

Differential Revision: https://reviews.llvm.org/D127054

Author: owenca

clang/lib/Format/UnwrappedLineParser.cpp

@@ -2889,6 +2889,7 @@ void UnwrappedLineParser::parseForOrWhileLoop() {
   if (FormatTok->is(tok::l_paren))
     parseParens();
 
+  handleAttributes();
   parseLoopBody(KeepBraces, /*WrapRightBrace=*/true);
 }
 

clang/unittests/Format/FormatTest.cpp

@@ -23846,6 +23846,22 @@ TEST_F(FormatTest, LikelyUnlikely) {
                "  return 29;\n",
                Style);
 
+  verifyFormat("while (limit > 0) [[unlikely]] {\n"
+               "  --limit;\n"
+               "}",
+               Style);
+  verifyFormat("for (auto &limit : limits) [[likely]] {\n"
+               "  --limit;\n"
+               "}",
+               Style);
+
+  verifyFormat("for (auto &limit : limits) [[unlikely]]\n"
+               "  --limit;",
+               Style);
+  verifyFormat("while (limit > 0) [[likely]]\n"
+               "  --limit;",
+               Style);
+
   Style.AttributeMacros.push_back("UNLIKELY");
   Style.AttributeMacros.push_back("LIKELY");
   verifyFormat("if (argc > 5) UNLIKELY\n"
@@ -23874,6 +23890,22 @@ TEST_F(FormatTest, LikelyUnlikely) {
                "  return 42;\n"
                "}\n",
                Style);
+
+  verifyFormat("for (auto &limit : limits) UNLIKELY {\n"
+               "  --limit;\n"
+               "}",
+               Style);
+  verifyFormat("while (limit > 0) LIKELY {\n"
+               "  --limit;\n"
+               "}",
+               Style);
+
+  verifyFormat("while (limit > 0) UNLIKELY\n"
+               "  --limit;",
+               Style);
+  verifyFormat("for (auto &limit : limits) LIKELY\n"
+               "  --limit;",
+               Style);
 }
 
 TEST_F(FormatTest, PenaltyIndentedWhitespace) {