diff --git a/clang/lib/Format/TokenAnnotator.cpp b/clang/lib/Format/TokenAnnotator.cpp
--- a/clang/lib/Format/TokenAnnotator.cpp
+++ b/clang/lib/Format/TokenAnnotator.cpp
@@ -3663,8 +3663,11 @@
   }
 
   if (isAllmanBrace(Left) || isAllmanBrace(Right)) {
+    // The tokens that could force an enum to not be on a single line are a
+    // trailing comment and a trailing comma on the last case. This checks for
+    // those.
     bool lineContainsBreakingTokens = false;
-    FormatToken *breakingSearchToken = Right.Previous;
+    const FormatToken *breakingSearchToken = &Right;
     while ((breakingSearchToken = breakingSearchToken->Next)) {
       bool hasBreakingComma = breakingSearchToken->is(tok::comma) &&
                               breakingSearchToken->Next->is(tok::r_brace);
@@ -3674,15 +3677,16 @@
       }
     }
     bool isAllowedByAfterEnum =
-        (Line.startsWith(tok::kw_enum) && Style.BraceWrapping.AfterEnum) ||
-        (Line.startsWith(tok::kw_typedef, tok::kw_enum) &&
-         Style.BraceWrapping.AfterEnum);
+        (Line.startsWith(tok::kw_enum) ||
+         Line.startsWith(tok::kw_typedef, tok::kw_enum)) &&
+        Style.BraceWrapping.AfterEnum;
     bool isLineTooBig = (strlen(Right.TokenText.data()) +
                          Right.OriginalColumn) > Style.ColumnLimit;
-    bool isAllowedByShortEnums = !Style.AllowShortEnumsOnASingleLine ||
-                                 isLineTooBig || lineContainsBreakingTokens;
-    return (isAllowedByAfterEnum &&
-            (isAllowedByShortEnums || lineContainsBreakingTokens)) ||
+    // AllowShortEnumsOnASingleLine is ignored if the line is too long or
+    // contains breaking tokens.
+    bool isAllowedByShortEnums = isLineTooBig || lineContainsBreakingTokens ||
+                                 !Style.AllowShortEnumsOnASingleLine;
+    return (isAllowedByAfterEnum && isAllowedByShortEnums) ||
            (Line.startsWith(tok::kw_class) && Style.BraceWrapping.AfterClass) ||
            (Line.startsWith(tok::kw_struct) && Style.BraceWrapping.AfterStruct);
   }