Index: lib/Format/UnwrappedLineParser.cpp
===================================================================
--- lib/Format/UnwrappedLineParser.cpp
+++ lib/Format/UnwrappedLineParser.cpp
@@ -102,7 +102,8 @@
   bool eof() {
     return Token && Token->HasUnescapedNewline &&
            !(PreviousToken && isLineComment(*PreviousToken) &&
-             isLineComment(*Token) && Token->NewlinesBefore == 1);
+             isLineComment(*Token) && Token->NewlinesBefore == 1 &&
+             Token->OriginalColumn == PreviousToken->OriginalColumn);
   }
 
   FormatToken *getFakeEOF() {
Index: unittests/Format/FormatTestComments.cpp
===================================================================
--- unittests/Format/FormatTestComments.cpp
+++ unittests/Format/FormatTestComments.cpp
@@ -1020,6 +1020,24 @@
                    getLLVMStyleWithColumns(20)));
 }
 
+TEST_F(FormatTestComments, KeepsTrailingPPCommentsAndSectionCommentsSeparate) {
+  verifyFormat("#ifdef A // line about A\n"
+               "// section comment\n"
+               "#endif",
+               getLLVMStyleWithColumns(80));
+  verifyFormat("int f() {\n"
+               "  int i;\n"
+               "#ifdef A // comment about A\n"
+               "  // section comment 1\n"
+               "  // section comment 2\n"
+               "  i = 2;\n"
+               "#else // comment about #else\n"
+               "  // section comment 3\n"
+               "  i = 4;\n"
+               "#endif\n"
+               "}", getLLVMStyleWithColumns(80));
+}
+
 TEST_F(FormatTestComments, CommentsInStaticInitializers) {
   EXPECT_EQ(
       "static SomeType type = {aaaaaaaaaaaaaaaaaaaa, /* comment */\n"