Index: clang/lib/Format/UnwrappedLineParser.cpp
===================================================================
--- clang/lib/Format/UnwrappedLineParser.cpp
+++ clang/lib/Format/UnwrappedLineParser.cpp
@@ -815,6 +815,10 @@
   auto Length = LastToken->TotalLength;
   if (OpeningBrace) {
     assert(OpeningBrace != Tokens.front().Tok);
+    if (auto Prev = OpeningBrace->Previous;
+        Prev && Prev->TotalLength + ColumnLimit == OpeningBrace->TotalLength) {
+      Length -= ColumnLimit;
+    }
     Length -= OpeningBrace->TokenText.size() + 1;
   }
 
Index: clang/unittests/Format/FormatTest.cpp
===================================================================
--- clang/unittests/Format/FormatTest.cpp
+++ clang/unittests/Format/FormatTest.cpp
@@ -25815,6 +25815,14 @@
                "}",
                Style);
 
+  verifyFormat("if (a) // comment\n"
+               "  b = 1;",
+               "if (a) // comment\n"
+               "{\n"
+               "  b = 1;\n"
+               "}",
+               Style);
+
   verifyFormat("if (a) {\n"
                "Label:\n"
                "}",