MyDeveloperDay updated this revision to Diff 384715.
MyDeveloperDay retitled this revision from "[clang-format] Add InsertBraces 
option" to "[clang-format] Add Insert/Remove Braces option".
MyDeveloperDay edited the summary of this revision.
MyDeveloperDay added a comment.

This is very much a WIP, updating the patch (as hit a waypoint), and would like 
others to have a chance to comment on possible configuration options

- move the options to a struct.
- handle non removal in the presence of a comment
- brining in the concept of handling different control statement types 
differently (i.e. you might want braces removed only from if statements but not 
the others)
- add unit tests to codify 
(https://llvm.org/docs/CodingStandards.html#don-t-use-braces-on-simple-single-statement-bodies-of-if-else-loop-statements)

  AutomaticBraces:
      AfterIf: RemoveNoComment
      AfterElse: RemoveNoComment
      AfterFor: Remove
      AfterWhile: Remove
      AfterDo: Remove

Not completely sure  I like the `RemoveNoComment`, we could handle the non 
removal if there is a comment case globally (same with the "scope depth") e.g.

And like BreakBeforeBraces I sort of feel that we might want to have some 
predefines i.e. (LLVM/Custom/Gnu?)

At present its very much Insert or Remove, still to add tests for selective 
insertion, but I wanted to discuss the configuration options first.

  AutomaticBraces: LLVM/Custom
  AutomaticBracesOption:
      AfterIf: Remove
      AfterElse: Remove
      AfterFor: Insert
      AfterWhile: Insert
      AfterDo: Insert
      RemovalIfCommentPresent:false
      MaxScopeDepth: 2

`RemoveNoComment` is the concept of handling a comment after the if() 
differently

  if (x) {
     // comment
     return x;
  }
  `

I have also run this on some of the sections of LLVM code (Basic/Lexer/Format) 
to try and catch any potential code change issues.

Also `dogfooded it` by formatting BraceInserter.cpp.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D95168/new/

https://reviews.llvm.org/D95168

Files:
  clang/docs/ClangFormatStyleOptions.rst
  clang/docs/ReleaseNotes.rst
  clang/include/clang/Format/Format.h
  clang/lib/Format/BraceInserter.cpp
  clang/lib/Format/BraceInserter.h
  clang/lib/Format/CMakeLists.txt
  clang/lib/Format/Format.cpp
  clang/unittests/Format/BraceInserterTests.cpp
  clang/unittests/Format/CMakeLists.txt
  clang/unittests/Format/FormatTest.cpp

Index: clang/unittests/Format/FormatTest.cpp
===================================================================
--- clang/unittests/Format/FormatTest.cpp
+++ clang/unittests/Format/FormatTest.cpp
@@ -72,6 +72,8 @@
     EXPECT_EQ(Expected.str(), format(Expected, Style))
         << "Expected code is not stable";
     EXPECT_EQ(Expected.str(), format(Code, Style));
+    // clang::format::internal::reformat does not run any of the options that
+    // modify code for ObjC
     if (Style.Language == FormatStyle::LK_Cpp) {
       // Objective-C++ is a superset of C++, so everything checked for C++
       // needs to be checked for Objective-C++ as well.
@@ -22396,7 +22398,6 @@
       "}";
   EXPECT_EQ(Code, format(Code, Style));
 }
-
 } // namespace
 } // namespace format
 } // namespace clang
Index: clang/unittests/Format/CMakeLists.txt
===================================================================
--- clang/unittests/Format/CMakeLists.txt
+++ clang/unittests/Format/CMakeLists.txt
@@ -3,6 +3,7 @@
   )
 
 add_clang_unittest(FormatTests
+  BraceInserterTests.cpp
   CleanupTest.cpp
   FormatTest.cpp
   FormatTestComments.cpp
Index: clang/unittests/Format/BraceInserterTests.cpp
===================================================================
--- /dev/null
+++ clang/unittests/Format/BraceInserterTests.cpp
@@ -0,0 +1,752 @@
+//===- unittest/Format/BraceInserterTest.cpp - brace insertion unit tests -===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Format/Format.h"
+
+#include "../Tooling/ReplacementTest.h"
+#include "FormatTestUtils.h"
+
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "gtest/gtest.h"
+
+#define DEBUG_TYPE "brace-inserter-test"
+
+using clang::tooling::ReplacementTest;
+using clang::tooling::toReplacements;
+using testing::ScopedTrace;
+
+namespace clang {
+namespace format {
+namespace {
+
+class BraceInserterTest : public ::testing::Test {
+protected:
+  enum StatusCheck { SC_ExpectComplete, SC_ExpectIncomplete, SC_DoNotCheck };
+
+  std::string format(llvm::StringRef Code,
+                     const FormatStyle &Style = getLLVMStyle(),
+                     StatusCheck CheckComplete = SC_ExpectComplete) {
+    LLVM_DEBUG(llvm::errs() << "---\n");
+    LLVM_DEBUG(llvm::errs() << Code << "\n\n");
+    std::vector<tooling::Range> Ranges(1, tooling::Range(0, Code.size()));
+    FormattingAttemptStatus Status;
+    tooling::Replacements Replaces =
+        reformat(Style, Code, Ranges, "<stdin>", &Status);
+    if (CheckComplete != SC_DoNotCheck) {
+      bool ExpectedCompleteFormat = CheckComplete == SC_ExpectComplete;
+      EXPECT_EQ(ExpectedCompleteFormat, Status.FormatComplete)
+          << Code << "\n\n";
+    }
+    auto Result = applyAllReplacements(Code, Replaces);
+    EXPECT_TRUE(static_cast<bool>(Result));
+    LLVM_DEBUG(llvm::errs() << "\n" << *Result << "\n\n");
+    return *Result;
+  }
+
+  FormatStyle getStyleWithColumns(FormatStyle Style, unsigned ColumnLimit) {
+    Style.ColumnLimit = ColumnLimit;
+    return Style;
+  }
+
+  FormatStyle getLLVMStyleWithColumns(unsigned ColumnLimit) {
+    return getStyleWithColumns(getLLVMStyle(), ColumnLimit);
+  }
+
+  void _verifyFormat(const char *File, int Line, llvm::StringRef Expected,
+                     llvm::StringRef Code,
+                     const FormatStyle &Style = getLLVMStyle()) {
+    ScopedTrace t(File, Line, ::testing::Message() << Code.str());
+    EXPECT_EQ(Expected.str(), format(Expected, Style))
+        << "Expected code is not stable";
+    EXPECT_EQ(Expected.str(), format(Code, Style));
+  }
+
+  void _verifyFormat(const char *File, int Line, llvm::StringRef Code,
+                     const FormatStyle &Style = getLLVMStyle()) {
+    _verifyFormat(File, Line, Code, test::messUp(Code), Style);
+  }
+};
+
+#define verifyFormat(...) _verifyFormat(__FILE__, __LINE__, __VA_ARGS__)
+
+TEST_F(BraceInserterTest, InsertBraces) {
+  FormatStyle Style = getLLVMStyle();
+
+  StringRef IfSourceShort = "if (condition)\n"
+                            "  call_function(arg, arg);";
+  verifyFormat(IfSourceShort);
+
+  StringRef IfSourceLong = "if (condition)\n"
+                           "  call_function(arg, arg, arg, arg, arg, arg);";
+  verifyFormat(IfSourceLong);
+
+  StringRef IfElseSourceShort = "if (condition)\n"
+                                "  a_function(arg, arg);\n"
+                                "else\n"
+                                "  another_function(arg, arg);";
+  verifyFormat(IfElseSourceShort);
+
+  StringRef IfElseSourceLong =
+      "if (condition)\n"
+      "  a_function(arg, arg, arg, arg, arg, arg);\n"
+      "else\n"
+      "  another_function(arg, arg, arg, arg, arg, arg);";
+  verifyFormat(IfElseSourceLong);
+
+  StringRef ForSourceShort = "for (auto val : container)\n"
+                             "  call_function(arg, arg);";
+  verifyFormat(ForSourceShort);
+
+  StringRef ForSourceLong = "for (auto val : container)\n"
+                            "  call_function(arg, arg, arg, arg, arg, arg);";
+  verifyFormat(ForSourceLong);
+
+  StringRef WhileShort = "while (condition)\n"
+                         "  call_function(arg, arg);";
+  verifyFormat(WhileShort);
+
+  StringRef WhileLong = "while (condition)\n"
+                        "  call_function(arg, arg, arg, arg, arg, arg);";
+  verifyFormat(WhileLong);
+
+  StringRef DoShort = "do\n"
+                      "  call_function(arg, arg);\n"
+                      "while (condition);";
+  verifyFormat(DoShort);
+
+  StringRef DoLong = "do\n"
+                     "  call_function(arg, arg, arg, arg, arg, arg);\n"
+                     "while (condition);";
+  verifyFormat(DoLong);
+
+  StringRef ChainedConditionals = "if (A)\n"
+                                  "  if (B)\n"
+                                  "    callAB();\n"
+                                  "  else\n"
+                                  "    callA();\n"
+                                  "else if (B)\n"
+                                  "  callB();\n"
+                                  "else\n"
+                                  "  call();";
+  verifyFormat(ChainedConditionals);
+
+  StringRef ChainedDoWhiles = "do\n"
+                              "  while (arg++)\n"
+                              "    do\n"
+                              "      while (arg++)\n"
+                              "        call_function(arg, arg);\n"
+                              "    while (condition);\n"
+                              "while (condition);";
+  verifyFormat(ChainedDoWhiles);
+
+  StringRef IfWithMultilineComment =
+      "if /*condition*/ (condition) /*condition*/\n"
+      "  you_do_you();              /*condition*/";
+  verifyFormat(IfWithMultilineComment);
+
+  StringRef IfSinglelineCommentOnConditional = "if (condition) // my test\n"
+                                               "  you_do_you();";
+  verifyFormat(IfSinglelineCommentOnConditional);
+
+  Style.AutomaticBraces.AfterIf = FormatStyle::BIS_Always;
+  Style.AutomaticBraces.AfterFor = FormatStyle::BIS_Always;
+  Style.AutomaticBraces.AfterWhile = FormatStyle::BIS_Always;
+  Style.AutomaticBraces.AfterDo = FormatStyle::BIS_Always;
+  Style.AutomaticBraces.AfterElse = FormatStyle::BIS_Always;
+
+  verifyFormat("while (condition) {\n"
+               "  call_function(arg, arg);\n"
+               "}",
+               WhileShort, Style);
+
+  verifyFormat("while (condition) {\n"
+               "  call_function(arg, arg, arg, arg, arg, arg);\n"
+               "}",
+               WhileLong, Style);
+
+  verifyFormat("do {\n"
+               "  call_function(arg, arg);\n"
+               "} while (condition);",
+               DoShort, Style);
+
+  verifyFormat("do {\n"
+               "  call_function(arg, arg, arg, arg, arg, arg);\n"
+               "} while (condition);",
+               DoLong, Style);
+
+  verifyFormat("if (condition) {\n"
+               "  call_function(arg, arg);\n"
+               "}",
+               IfSourceShort, Style);
+
+  verifyFormat("if (condition) {\n"
+               "  call_function(arg, arg);\n"
+               "}",
+               IfSourceShort, Style);
+
+  verifyFormat("if (condition) {\n"
+               "  call_function(arg, arg, arg, arg, arg, arg);\n"
+               "}",
+               IfSourceLong, Style);
+
+  verifyFormat("if (condition) {\n"
+               "  a_function(arg, arg);\n"
+               "} else {\n"
+               "  another_function(arg, arg);\n"
+               "}",
+               IfElseSourceShort, Style);
+
+  verifyFormat("if (condition) {\n"
+               "  a_function(arg, arg, arg, arg, arg, arg);\n"
+               "} else {\n"
+               "  another_function(arg, arg, arg, arg, arg, arg);\n"
+               "}",
+               IfElseSourceLong, Style);
+
+  verifyFormat("for (auto val : container) {\n"
+               "  call_function(arg, arg);\n"
+               "}",
+               ForSourceShort, Style);
+
+  verifyFormat("for (auto val : container) {\n"
+               "  call_function(arg, arg, arg, arg, arg, arg);\n"
+               "}",
+               ForSourceLong, Style);
+
+  verifyFormat("if (A)\n"
+               "  if (B) {\n"
+               "    callAB();\n"
+               "  } else {\n"
+               "    callA();\n"
+               "  }\n"
+               "else if (B) {\n"
+               "  callB();\n"
+               "} else {\n"
+               "  call();\n"
+               "}",
+               ChainedConditionals, Style);
+
+  verifyFormat("do\n"
+               "  while (arg++)\n"
+               "    do\n"
+               "      while (arg++) {\n"
+               "        call_function(arg, arg);\n"
+               "      }\n"
+               "    while (condition);\n"
+               "while (condition);",
+               ChainedDoWhiles, Style);
+
+  verifyFormat("if /*condition*/ (condition) /*condition*/\n"
+               "{\n"
+               "  you_do_you(); /*condition*/\n"
+               "}",
+               IfWithMultilineComment, Style);
+
+  verifyFormat("if (condition) // my test\n"
+               "{\n"
+               "  you_do_you();\n"
+               "}",
+               IfSinglelineCommentOnConditional, Style);
+
+  Style.AutomaticBraces.AfterIf = FormatStyle::BIS_WrapLikely;
+  Style.AutomaticBraces.AfterFor = FormatStyle::BIS_WrapLikely;
+  Style.AutomaticBraces.AfterWhile = FormatStyle::BIS_WrapLikely;
+  Style.AutomaticBraces.AfterDo = FormatStyle::BIS_WrapLikely;
+  Style.AutomaticBraces.AfterElse = FormatStyle::BIS_WrapLikely;
+  Style.ColumnLimit = 35;
+
+  verifyFormat(IfSourceShort, IfSourceShort, Style);
+
+  verifyFormat("if (condition) {\n"
+               "  call_function(arg, arg, arg, arg,\n"
+               "                arg, arg);\n"
+               "}",
+               IfSourceLong, Style);
+
+  verifyFormat(IfElseSourceShort, IfElseSourceShort, Style);
+
+  verifyFormat("if (condition) {\n"
+               "  a_function(arg, arg, arg, arg,\n"
+               "             arg, arg);\n"
+               "} else {\n"
+               "  another_function(arg, arg, arg,\n"
+               "                   arg, arg, arg);\n"
+               "}",
+               IfElseSourceLong, Style);
+
+  verifyFormat(ForSourceShort, ForSourceShort, Style);
+
+  verifyFormat("for (auto val : container) {\n"
+               "  call_function(arg, arg, arg, arg,\n"
+               "                arg, arg);\n"
+               "}",
+               ForSourceLong, Style);
+
+  format("while (foo) ", Style);
+}
+
+TEST_F(BraceInserterTest, InsertBracesMacro) {
+  auto Style = getLLVMStyleWithColumns(20);
+
+  verifyFormat("#define FOO1(x)    \\\n"
+               "  if (x)           \\\n"
+               "    return true;   \\\n"
+               "  else             \\\n"
+               "    return false;",
+               Style);
+
+  Style.AutomaticBraces.AfterIf = FormatStyle::BIS_Always;
+  Style.AutomaticBraces.AfterFor = FormatStyle::BIS_Always;
+  Style.AutomaticBraces.AfterWhile = FormatStyle::BIS_Always;
+  Style.AutomaticBraces.AfterDo = FormatStyle::BIS_Always;
+  Style.AutomaticBraces.AfterElse = FormatStyle::BIS_Always;
+
+  verifyFormat("#define FOO2(x)    \\\n"
+               "  if (x) {         \\\n"
+               "    return true;   \\\n"
+               "  } else {         \\\n"
+               "    return false;  \\\n"
+               "  }",
+               "#define FOO2(x)    \\\n"
+               "  if (x)           \\\n"
+               "    return true;   \\\n"
+               "  else             \\\n"
+               "    return false;",
+               Style);
+
+  verifyFormat("#define FOO3(x)    \\\n"
+               "  if (x) {         \\\n"
+               "    return true;   \\\n"
+               "  } else {         \\\n"
+               "    return false;  \\\n"
+               "  }",
+               Style);
+}
+
+TEST_F(BraceInserterTest, InsertBracesComments) {
+  auto Style = getLLVMStyle();
+
+  verifyFormat("if (x)\n"
+               "  return true;\n"
+               "else\n"
+               "  return false;",
+               Style);
+
+  Style.AutomaticBraces.AfterIf = FormatStyle::BIS_Always;
+  Style.AutomaticBraces.AfterFor = FormatStyle::BIS_Always;
+  Style.AutomaticBraces.AfterWhile = FormatStyle::BIS_Always;
+  Style.AutomaticBraces.AfterDo = FormatStyle::BIS_Always;
+  Style.AutomaticBraces.AfterElse = FormatStyle::BIS_Always;
+
+  verifyFormat("if (x) {\n"
+               "  return true; // Comment\n"
+               "} else {\n"
+               "  return false; // Comment\n"
+               "}",
+               "if (x)\n"
+               "  return true; // Comment\n"
+               "else\n"
+               "  return false; // Comment",
+               Style);
+}
+
+TEST_F(BraceInserterTest, RemoveBraces) {
+  auto Style = getLLVMStyle();
+
+  Style.AutomaticBraces.AfterIf = FormatStyle::BIS_Remove;
+  Style.AutomaticBraces.AfterFor = FormatStyle::BIS_Remove;
+  Style.AutomaticBraces.AfterWhile = FormatStyle::BIS_Remove;
+  Style.AutomaticBraces.AfterDo = FormatStyle::BIS_Remove;
+  Style.AutomaticBraces.AfterElse = FormatStyle::BIS_Remove;
+
+  verifyFormat("if (x)\n"
+               "  return true;\n",
+               "if (x) {\n"
+               "  return true;\n"
+               "}",
+               Style);
+
+  verifyFormat("while (x)\n"
+               "  foo();\n",
+               "while (x) {\n"
+               "  foo();\n"
+               "}",
+               Style);
+
+  verifyFormat("if (x)\n"
+               "  return true;\n"
+               "else\n"
+               "  return false;\n",
+               "if (x) {\n"
+               "  return true;\n"
+               "} else {\n"
+               "  return false;\n"
+               "}\n",
+               Style);
+
+  verifyFormat("if (x)\n"
+               "  return true;\n"
+               "else if (x == 1)\n"
+               "  return false;\n",
+               "if (x) {\n"
+               "  return true;\n"
+               "} else if (x == 1) {\n"
+               "  return false;\n"
+               "}\n",
+               Style);
+
+  verifyFormat("if (x) {\n"
+               "  foo();\n"
+               "  bar();\n"
+               "} else if (x == 1)\n"
+               "  return false;\n",
+               "if (x) {\n"
+               "  foo();\n"
+               "  bar();\n"
+               "} else if (x == 1) {\n"
+               "  return false;\n"
+               "}\n",
+               Style);
+
+  verifyFormat("if (x)\n"
+               "  foo();\n"
+               "else if (x == 1) {\n"
+               "  baz();\n"
+               "  bar();\n"
+               "}\n",
+               "if (x) {\n"
+               "  foo();\n"
+               "} else if (x == 1) {\n"
+               "  baz();\n"
+               "  bar();\n"
+               "}\n",
+               Style);
+
+  verifyFormat("if (x) {\n"
+               "  if (y)\n"
+               "    foo();\n"
+               "} else {\n"
+               "  baz();\n"
+               "  bar();\n"
+               "}\n",
+               Style);
+
+  verifyFormat("if (a)\n"
+               "  b;\n"
+               "else if (c)\n"
+               "  d;\n"
+               "else\n"
+               "  e;\n",
+               "if (a) {\n"
+               "  b;\n"
+               "} else if (c) {\n"
+               "  d;\n"
+               "} else {\n"
+               "  e;\n"
+               "}\n",
+               Style);
+
+  verifyFormat("if (a) {\n"
+               "  if (b)\n"
+               "    c;\n"
+               "} else if (d)\n"
+               "  e;\n",
+               "if (a) {\n"
+               "  if (b) {\n"
+               "    c;\n"
+               "  }\n"
+               "} else if (d) {\n"
+               "  e;\n"
+               "}",
+               Style);
+}
+
+TEST_F(BraceInserterTest, RemoveLLVMBraces) {
+  auto Style = getLLVMStyle();
+
+  Style.AutomaticBraces.AfterIf = FormatStyle::BIS_RemoveNoComment;
+  Style.AutomaticBraces.AfterElse = FormatStyle::BIS_RemoveNoComment;
+  Style.AutomaticBraces.AfterFor = FormatStyle::BIS_RemoveNoComment;
+  Style.AutomaticBraces.AfterDo = FormatStyle::BIS_RemoveNoComment;
+  Style.AutomaticBraces.AfterWhile = FormatStyle::BIS_RemoveNoComment;
+
+  // Omit the braces, since the body is simple and clearly associated with the
+  // if.
+  verifyFormat("if (isa<FunctionDecl>(D))\n"
+               "  handleFunctionDecl(D);\n"
+               "else if (isa<VarDecl>(D))\n"
+               "  handleVarDecl(D);\n",
+               Style);
+
+  verifyFormat("if (isa<FunctionDecl>(D))\n"
+               "  handleFunctionDecl(D);\n"
+               "else if (isa<VarDecl>(D))\n"
+               "  handleVarDecl(D);\n",
+               "if (isa<FunctionDecl>(D)) {\n"
+               "  handleFunctionDecl(D);\n"
+               "} else if (isa<VarDecl>(D)) {\n"
+               "  handleVarDecl(D);\n"
+               "}",
+               Style);
+
+  verifyFormat("while (isa<FunctionDecl>(D))\n"
+               "  handleFunctionDecl(D);\n",
+               Style);
+  
+  verifyFormat("while (isa<FunctionDecl>(D))\n"
+               "  handleFunctionDecl(D);\n",
+               "while (isa<FunctionDecl>(D)) {\n"
+               "  handleFunctionDecl(D);\n"
+               "}",
+               Style);
+  
+  verifyFormat("while (isa<FunctionDecl>(D)) {\n"
+               "  // Long comment\n"
+               "  handleFunctionDecl(D);\n"
+               "}",
+               Style);
+
+  verifyFormat("do\n"
+               "  handleFunctionDecl(D);\n"
+               "while (true);",
+               Style);
+  
+  verifyFormat("do\n"
+               "  handleFunctionDecl(D);\n"
+               "while (true);",
+               "do {\n"
+               "  handleFunctionDecl(D);\n"
+               "} while (true);",
+               Style);
+
+  verifyFormat("do {\n"
+               "  // A very long comment\n"
+               "  handleFunctionDecl(D);\n"
+               "} while (true);",
+               Style);
+
+  verifyFormat("for (auto i : list)\n"
+               "  handleFunctionDecl(D);\n",
+               Style);
+  
+  verifyFormat("for (auto i : list)\n"
+               "  handleFunctionDecl(D);\n",
+               "for(auto i : list) {\n"
+               "  handleFunctionDecl(D);\n"
+               "}",
+               Style);
+  
+  verifyFormat("for (auto i : list) {\n"
+               "  // Long comment\n"
+               "  handleFunctionDecl(D);\n"
+               "}",
+               Style);
+
+  
+
+  // Here we document the condition itself and not the body.
+  verifyFormat(
+      "if (isa<VarDecl>(D)) {\n"
+      "  // It is necessary that we explain the situation with this "
+      "surprisingly long\n"
+      "  // comment, so it would be unclear without the braces whether the "
+      "following\n"
+      "  // statement is in the scope of the `if`.\n"
+      "  // Because the condition is documented, we can't really hoist this\n"
+      "  // comment that applies to the body above the if.\n"
+      "  handleOtherDecl(D);\n"
+      "}",
+      Style);
+
+  // Use braces on the outer `if` to avoid a potential dangling else situation.
+  verifyFormat("if (isa<VarDecl>(D)) {\n"
+               "  for (auto *A : D.attrs())\n"
+               "    if (shouldProcessAttr(A))\n"
+               "      handleAttr(A);\n"
+               "}\n",
+               Style);
+  verifyFormat("if (isa<VarDecl>(D)) {\n"
+               "  for (auto *A : D.attrs()) {\n"
+               "    if (shouldProcessAttr(A))\n"
+               "      handleAttr(A);\n"
+               "  }\n"
+               "}\n",
+               "if (isa<VarDecl>(D)) {\n"
+               "  for (auto *A : D.attrs()) {\n"
+               "    if (shouldProcessAttr(A)) {\n"
+               "      handleAttr(A);\n"
+               "    }\n"
+               "  }\n"
+               "}\n",
+               Style);
+
+  // if the for or if have {} here should they be removed?
+  verifyFormat("if (isa<VarDecl>(D)) {\n"
+               "  for (auto *A : D.attrs())\n"
+               "    if (shouldProcessAttr(A))\n"
+               "      handleAttr(A);\n"
+               "}\n",
+               "if (isa<VarDecl>(D)) {\n"
+               "  for (auto *A : D.attrs())\n"
+               "    if (shouldProcessAttr(A))\n"
+               "      handleAttr(A);\n"
+               "}\n",
+               Style);
+
+  // Use braces for the `if` block to keep it uniform with the else block.
+  verifyFormat(
+      "if (isa<FunctionDecl>(D)) {\n"
+      "  handleFunctionDecl(D);\n"
+      "} else {\n"
+      "  // In this else case, it is necessary that we explain the situation "
+      "with\n"
+      "  // this surprisingly long comment, so it would be unclear without the "
+      "braces\n"
+      "  // whether the following statement is in the scope of the `if`.\n"
+      "  handleOtherDecl(D);\n"
+      "}\n",
+      Style);
+
+  // This should also omit braces.  The `for` loop contains only a single
+  // statement, so it shouldn't have braces.  The `if` also only contains a
+  // single simple statement (the for loop), so it also should omit braces.
+  verifyFormat("if (isa<FunctionDecl>(D))\n"
+               "  for (auto *A : D.attrs())\n"
+               "    handleAttr(A);\n",
+               Style);
+
+  verifyFormat("if (isa<FunctionDecl>(D))\n"
+               "  for (auto *A : D.attrs())\n"
+               "    handleAttr(A);\n",
+               "if (isa<FunctionDecl>(D)) {\n"
+               "  for (auto *A : D.attrs()) {\n"
+               "    handleAttr(A);\n"
+               "  }\n"
+               "}",
+               Style);
+
+  // Use braces for the outer `if` since the nested `for` is braced.
+  verifyFormat("if (isa<FunctionDecl>(D)) {\n"
+               "  for (auto *A : D.attrs()) {\n"
+               "    // In this for loop body, it is necessary that we explain "
+               "the situation\n"
+               "    // with this surprisingly long comment, forcing braces on "
+               "the `for` block.\n"
+               "    handleAttr(A);\n"
+               "  }\n"
+               "}",
+               Style);
+
+  // Use braces on the outer block because there are more than two levels of
+  // nesting.
+  verifyFormat("if (isa<FunctionDecl>(D)) {\n"
+               "  for (auto *A : D.attrs())\n"
+               "    for (ssize_t i : llvm::seq<ssize_t>(count))\n"
+               "      handleAttrOnDecl(D, A, i);\n"
+               "}\n",
+               Style);
+
+  verifyFormat("if (isa<FunctionDecl>(D)) {\n"
+               "  for (auto *A : D.attrs())\n"
+               "    for (ssize_t i : llvm::seq<ssize_t>(count))\n"
+               "      handleAttrOnDecl(D, A, i);\n"
+               "}\n",
+               "if (isa<FunctionDecl>(D)) {\n"
+               "  for (auto *A : D.attrs()) {\n"
+               "    for (ssize_t i : llvm::seq<ssize_t>(count)) {\n"
+               "      handleAttrOnDecl(D, A, i);\n"
+               "    }\n"
+               "  }\n"
+               "}\n",
+               Style);
+
+  // Use braces on the outer block because of a nested `if`, otherwise the
+  // compiler would warn: `add explicit braces to avoid dangling else`
+  verifyFormat("if (auto *D = dyn_cast<FunctionDecl>(D)) {\n"
+               "  if (shouldProcess(D))\n"
+               "    handleVarDecl(D);\n"
+               "  else\n"
+               "    markAsIgnored(D);\n"
+               "}\n",
+               Style);
+
+  verifyFormat("if (auto *D = dyn_cast<FunctionDecl>(D)) {\n"
+               "  if (shouldProcess(D))\n"
+               "    handleVarDecl(D);\n"
+               "  else\n"
+               "    markAsIgnored(D);\n"
+               "}\n",
+               "if (auto *D = dyn_cast<FunctionDecl>(D)) {\n"
+               "  if (shouldProcess(D)) {\n"
+               "    handleVarDecl(D);\n"
+               "  } else {\n"
+               "    markAsIgnored(D);\n"
+               "  }\n"
+               "}\n",
+               Style);
+
+    // Removing as {} evem though we have a comment comment
+    Style.AutomaticBraces.AfterIf = FormatStyle::BIS_Remove;
+    verifyFormat(
+      "if (isa<VarDecl>(D))\n"
+      "  // It is necessary that we explain the situation with this "
+      "surprisingly long\n"
+      "  // comment, so it would be unclear without the braces whether the "
+      "following\n"
+      "  // statement is in the scope of the `if`.\n"
+      "  // Because the condition is documented, we can't really hoist this\n"
+      "  // comment that applies to the body above the if.\n"
+      "  handleOtherDecl(D);\n",
+      "if (isa<VarDecl>(D)) {\n"
+      "  // It is necessary that we explain the situation with this "
+      "surprisingly long\n"
+      "  // comment, so it would be unclear without the braces whether the "
+      "following\n"
+      "  // statement is in the scope of the `if`.\n"
+      "  // Because the condition is documented, we can't really hoist this\n"
+      "  // comment that applies to the body above the if.\n"
+      "  handleOtherDecl(D);\n"
+      "}"
+      ,Style);
+
+    Style.AutomaticBraces.AfterDo = FormatStyle::BIS_Remove;
+    verifyFormat("do\n"
+                 "  // A very long comment\n"
+                 "  handleFunctionDecl(D);\n"
+                 "while (true);",
+                "do {\n"
+                "  // A very long comment\n"
+                "  handleFunctionDecl(D);\n"
+                "} while (true);",
+               Style);
+
+    Style.AutomaticBraces.AfterWhile = FormatStyle::BIS_Remove;
+    verifyFormat("while (isa<FunctionDecl>(D))\n"
+                 "  // Long comment\n"
+                 "  handleFunctionDecl(D);\n",
+                 "while (isa<FunctionDecl>(D)) {\n"
+                 "  // Long comment\n"
+                 "  handleFunctionDecl(D);\n"
+                 "}",
+               Style);
+
+    Style.AutomaticBraces.AfterFor = FormatStyle::BIS_Remove;
+    verifyFormat("for (auto i : list)\n"
+                 "  // Long comment\n"
+                 "  handleFunctionDecl(D);\n",
+                 "for (auto i : list) {\n"
+                 "  // Long comment\n"
+                 "  handleFunctionDecl(D);\n"
+                 "}",
+               Style);
+}
+
+} // namespace
+} // namespace format
+} // namespace clang
Index: clang/lib/Format/Format.cpp
===================================================================
--- clang/lib/Format/Format.cpp
+++ clang/lib/Format/Format.cpp
@@ -14,6 +14,7 @@
 
 #include "clang/Format/Format.h"
 #include "AffectedRangeManager.h"
+#include "BraceInserter.h"
 #include "BreakableToken.h"
 #include "ContinuationIndenter.h"
 #include "FormatInternal.h"
@@ -214,6 +215,18 @@
   }
 };
 
+template <>
+struct ScalarEnumerationTraits<FormatStyle::BraceInsertionRemovalStyle> {
+  static void enumeration(IO &IO,
+                          FormatStyle::BraceInsertionRemovalStyle &Value) {
+    IO.enumCase(Value, "Leave", FormatStyle::BIS_Leave);
+    IO.enumCase(Value, "Always", FormatStyle::BIS_Always);
+    IO.enumCase(Value, "WrapLikely", FormatStyle::BIS_WrapLikely);
+    IO.enumCase(Value, "Remove", FormatStyle::BIS_Remove);
+    IO.enumCase(Value, "RemoveNoComment", FormatStyle::BIS_RemoveNoComment);
+  }
+};
+
 template <> struct ScalarEnumerationTraits<FormatStyle::BinaryOperatorStyle> {
   static void enumeration(IO &IO, FormatStyle::BinaryOperatorStyle &Value) {
     IO.enumCase(Value, "All", FormatStyle::BOS_All);
@@ -613,6 +626,7 @@
     IO.mapOptional("AlwaysBreakTemplateDeclarations",
                    Style.AlwaysBreakTemplateDeclarations);
     IO.mapOptional("AttributeMacros", Style.AttributeMacros);
+    IO.mapOptional("AutomaticBraces", Style.AutomaticBraces);
     IO.mapOptional("BinPackArguments", Style.BinPackArguments);
     IO.mapOptional("BinPackParameters", Style.BinPackParameters);
     IO.mapOptional("BraceWrapping", Style.BraceWrapping);
@@ -822,6 +836,16 @@
   }
 };
 
+template <> struct MappingTraits<FormatStyle::AutomaticBracesStyle> {
+  static void mapping(IO &IO, FormatStyle::AutomaticBracesStyle &BracesStyle) {
+    IO.mapOptional("AfterIf", BracesStyle.AfterIf);
+    IO.mapOptional("AfterFor", BracesStyle.AfterFor);
+    IO.mapOptional("AfterWhile", BracesStyle.AfterWhile);
+    IO.mapOptional("AfterDo", BracesStyle.AfterDo);
+    IO.mapOptional("AfterElse", BracesStyle.AfterElse);
+  }
+};
+
 template <> struct MappingTraits<FormatStyle::BraceWrappingFlags> {
   static void mapping(IO &IO, FormatStyle::BraceWrappingFlags &Wrapping) {
     IO.mapOptional("AfterCaseLabel", Wrapping.AfterCaseLabel);
@@ -1137,6 +1161,12 @@
   LLVMStyle.IndentRequires = false;
   LLVMStyle.IndentWrappedFunctionNames = false;
   LLVMStyle.IndentWidth = 2;
+  LLVMStyle.AutomaticBraces = {/*AfterIf=*/FormatStyle::BIS_Leave,
+                               /*AfterFor=*/FormatStyle::BIS_Leave,
+                               /*AfterWhile=*/FormatStyle::BIS_Leave,
+                               /*AfterDo=*/FormatStyle::BIS_Leave,
+                               /*AfterElse=*/FormatStyle::BIS_Leave};
+
   LLVMStyle.PPIndentWidth = -1;
   LLVMStyle.InsertTrailingCommas = FormatStyle::TCS_None;
   LLVMStyle.JavaScriptQuotes = FormatStyle::JSQS_Leave;
@@ -2982,6 +3012,10 @@
       });
   }
 
+  Passes.emplace_back([&](const Environment &Env) {
+    return BracesInserter(Env, Expanded).process();
+  });
+
   if (Style.Language == FormatStyle::LK_JavaScript &&
       Style.JavaScriptQuotes != FormatStyle::JSQS_Leave)
     Passes.emplace_back([&](const Environment &Env) {
Index: clang/lib/Format/CMakeLists.txt
===================================================================
--- clang/lib/Format/CMakeLists.txt
+++ clang/lib/Format/CMakeLists.txt
@@ -3,6 +3,7 @@
 add_clang_library(clangFormat
   AffectedRangeManager.cpp
   BreakableToken.cpp
+  BraceInserter.cpp
   ContinuationIndenter.cpp
   Format.cpp
   FormatToken.cpp
Index: clang/lib/Format/BraceInserter.h
===================================================================
--- /dev/null
+++ clang/lib/Format/BraceInserter.h
@@ -0,0 +1,45 @@
+//===--- BraceInserter.h - Format C++ code --------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file defines the class for inserting braces
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_LIB_FORMAT_BRACEINSERTER_H
+#define LLVM_CLANG_LIB_FORMAT_BRACEINSERTER_H
+
+#include "TokenAnalyzer.h"
+
+namespace clang {
+namespace format {
+
+class BracesInserter : public TokenAnalyzer {
+public:
+  BracesInserter(const Environment &Env, const FormatStyle &Style)
+      : TokenAnalyzer(Env, Style) {}
+
+  std::pair<tooling::Replacements, unsigned>
+  analyze(TokenAnnotator &Annotator,
+          SmallVectorImpl<AnnotatedLine *> &AnnotatedLines,
+          FormatTokenLexer &Tokens) override;
+
+private:
+  void insertBraces(SmallVectorImpl<AnnotatedLine *> &Lines,
+                    tooling::Replacements &Result);
+
+  void removeBraces(SmallVectorImpl<AnnotatedLine *> &Lines,
+                    tooling::Replacements &Result);
+
+  std::set<SourceLocation> Done;
+};
+
+} // namespace format
+} // namespace clang
+
+#endif
Index: clang/lib/Format/BraceInserter.cpp
===================================================================
--- /dev/null
+++ clang/lib/Format/BraceInserter.cpp
@@ -0,0 +1,389 @@
+//===--- BraceInserter.cpp - Format C++ code ------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file implements functions declared in Format.h. This will be
+/// split into separate files as we go.
+///
+//===----------------------------------------------------------------------===//
+
+#include "BraceInserter.h"
+#include "clang/Format/Format.h"
+
+namespace clang {
+namespace format {
+
+bool SupportsAnyAutomaticBraces(FormatStyle &Style, bool insertion) {
+  if (insertion) {
+    if (Style.AutomaticBraces.AfterIf == FormatStyle::BIS_Always)
+      return true;
+    if (Style.AutomaticBraces.AfterIf == FormatStyle::BIS_WrapLikely)
+      return true;
+    if (Style.AutomaticBraces.AfterFor == FormatStyle::BIS_Always)
+      return true;
+    if (Style.AutomaticBraces.AfterFor == FormatStyle::BIS_WrapLikely)
+      return true;
+    if (Style.AutomaticBraces.AfterWhile == FormatStyle::BIS_Always)
+      return true;
+    if (Style.AutomaticBraces.AfterWhile == FormatStyle::BIS_WrapLikely)
+      return true;
+    if (Style.AutomaticBraces.AfterDo == FormatStyle::BIS_Always)
+      return true;
+    if (Style.AutomaticBraces.AfterDo == FormatStyle::BIS_WrapLikely)
+      return true;
+    if (Style.AutomaticBraces.AfterElse == FormatStyle::BIS_Always)
+      return true;
+    if (Style.AutomaticBraces.AfterElse == FormatStyle::BIS_WrapLikely)
+      return true;
+  } else {
+    if (Style.AutomaticBraces.AfterIf >= FormatStyle::BIS_Remove)
+      return true;
+    if (Style.AutomaticBraces.AfterFor >= FormatStyle::BIS_Remove)
+      return true;
+    if (Style.AutomaticBraces.AfterWhile >= FormatStyle::BIS_Remove)
+      return true;
+    if (Style.AutomaticBraces.AfterDo >= FormatStyle::BIS_Remove)
+      return true;
+    if (Style.AutomaticBraces.AfterElse >= FormatStyle::BIS_Remove)
+      return true;
+  }
+  return false;
+}
+
+std::pair<tooling::Replacements, unsigned>
+BracesInserter::analyze(TokenAnnotator &Annotator,
+                        SmallVectorImpl<AnnotatedLine *> &AnnotatedLines,
+                        FormatTokenLexer &Tokens) {
+  tooling::Replacements Result;
+  if (AffectedRangeMgr.computeAffectedLines(AnnotatedLines)) {
+    if (SupportsAnyAutomaticBraces(Style, /*insertion=*/true))
+      insertBraces(AnnotatedLines, Result);
+
+    if (SupportsAnyAutomaticBraces(Style, /*insertion=*/false))
+      removeBraces(AnnotatedLines, Result);
+  }
+  return {Result, 0};
+}
+
+void BracesInserter::insertBraces(SmallVectorImpl<AnnotatedLine *> &Lines,
+                                  tooling::Replacements &Result) {
+  bool InsideCtrlFlowStmt = false;
+
+  tok::TokenKind ControlFlowType = tok::unknown;
+  for (AnnotatedLine *Line : Lines) {
+    insertBraces(Line->Children, Result);
+
+    // Get first token that is not a comment.
+    const FormatToken *FirstTok = Line->First;
+    if (FirstTok->is(tok::comment))
+      FirstTok = FirstTok->getNextNonComment();
+    // The line is a comment.
+    if (!FirstTok)
+      continue;
+    // Get last token that is not a comment.
+    const FormatToken *LastTok = Line->Last;
+    if (LastTok->is(tok::comment))
+      LastTok = LastTok->getPreviousNonComment();
+
+    // If this token starts a control flow stmt, mark it.
+    if (FirstTok->isOneOf(tok::kw_if, tok::kw_else, tok::kw_for, tok::kw_do,
+                          tok::kw_while)) {
+      ControlFlowType = FirstTok->Tok.getKind();
+      InsideCtrlFlowStmt = !LastTok->isOneOf(tok::l_brace, tok::semi);
+      continue;
+    }
+
+    // If the previous line started a ctrl flow block and this line does not
+    // start with curly.
+    if (Line->Affected && !FirstTok->Finalized && InsideCtrlFlowStmt &&
+        FirstTok->isNot(tok::l_brace)) {
+      const SourceLocation startBraceLoc = Line->First->Tok.getLocation();
+      // In some cases clang-format will run the same transform twice which
+      // could lead to adding the curlies twice, skip if we already added one
+      // at this location.
+      if (Done.count(startBraceLoc))
+        break;
+
+      bool ShouldInsert = false;
+
+      switch (ControlFlowType) {
+      case tok::kw_if:
+        ShouldInsert = (Style.AutomaticBraces.AfterIf ==
+                        FormatStyle::BraceInsertionRemovalStyle::BIS_Always);
+        break;
+      case tok::kw_for:
+        ShouldInsert = (Style.AutomaticBraces.AfterFor ==
+                        FormatStyle::BraceInsertionRemovalStyle::BIS_Always);
+        break;
+      case tok::kw_while:
+        ShouldInsert = (Style.AutomaticBraces.AfterWhile ==
+                        FormatStyle::BraceInsertionRemovalStyle::BIS_Always);
+        break;
+      case tok::kw_do:
+        ShouldInsert = (Style.AutomaticBraces.AfterDo ==
+                        FormatStyle::BraceInsertionRemovalStyle::BIS_Always);
+        break;
+      case tok::kw_else:
+        ShouldInsert = (Style.AutomaticBraces.AfterElse ==
+                        FormatStyle::BraceInsertionRemovalStyle::BIS_Always);
+        break;
+      default:
+        ShouldInsert = false;
+        break;
+      }
+
+      if (ShouldInsert || Line->Last->OriginalColumn > Style.ColumnLimit) {
+        Done.insert(startBraceLoc);
+        cantFail(Result.add(tooling::Replacement(Env.getSourceManager(),
+                                                 startBraceLoc, 0, "{")));
+
+        // Mostly we can ignore putting a \n before the } and let the
+        // Formatter handle it, unless the last token is a // comment, Doing
+        // so avoids issues with macro continuation. And a line comment
+        // cannot be part of a continuation.
+        std::string ending = "}";
+        if (Line->Last->is(tok::comment))
+          ending = "\n}";
+        cantFail(Result.add(
+            tooling::Replacement(Env.getSourceManager(),
+                                 Line->Last->Tok.getLocation().getLocWithOffset(
+                                     Line->Last->TokenText.size()),
+                                 0, ending)));
+      }
+    }
+    InsideCtrlFlowStmt = false;
+  }
+}
+
+// Class that allows getting Next over multiple annotated lines
+class NextTokenFetcher {
+  SmallVectorImpl<AnnotatedLine *> &Lines;
+
+public:
+  NextTokenFetcher(SmallVectorImpl<AnnotatedLine *> &Lines) : Lines(Lines) {}
+
+  const FormatToken *getNext(int &Line, const FormatToken *current) {
+    if (current == nullptr)
+      return Lines[0]->First;
+
+    if (current && current->Next)
+      return current->Next;
+
+    // I'm at the end so I can't take the next
+    if (current && !current->Next) {
+      // I'm at the end of all the lines
+      if (current && Lines[Lines.size() - 1]->Last == current)
+        return nullptr;
+
+      for (int NLine = 0; NLine < Lines.size(); NLine++) {
+        FormatToken *tok = Lines[NLine]->Last;
+        if (current == tok) {
+          // if I'm at the end of a line then the next is the
+          // First of the next line
+          return Lines[NLine + 1]->First;
+        }
+      }
+      return nullptr;
+    }
+
+    if (current && !current->Next && Line < (Lines.size() - 1)) {
+      Line++;
+      return Lines[Line]->First;
+    }
+    return current->Next;
+  }
+
+  bool startsSequence(int LineNumber, const FormatToken *RBrace,
+                      tok::TokenKind tok1, tok::TokenKind tok2,
+                      tok::TokenKind tok3, tok::TokenKind tok4) {
+
+    if (!RBrace)
+      return false;
+
+    if (!RBrace->is(tok1))
+      return false;
+    const FormatToken *Next = getNext(LineNumber, RBrace);
+    if (!Next->is(tok2))
+      return false;
+    Next = getNext(LineNumber, Next);
+    if (!Next->is(tok3))
+      return false;
+    Next = getNext(LineNumber, Next);
+    if (!Next->is(tok4))
+      return false;
+    return true;
+  }
+};
+
+// Scan thorough tokens looking for if/for/while etc...
+// find matching ()  e.g. if(), for(), while()
+// if { follows then find matching }
+// count number of ; between { ...  }
+// if number of ; > 1 leave braces
+// if number of ; <= 1 remove braces
+// if {} contain "if" or { before seeing } then don't attempt to
+// remove (This could leads to some false negatives)
+void BracesInserter::removeBraces(SmallVectorImpl<AnnotatedLine *> &Lines,
+                                  tooling::Replacements &Result) {
+
+  NextTokenFetcher fetcher(Lines);
+  int LineNumber = 0;
+
+  const FormatToken *NextToken = fetcher.getNext(LineNumber, nullptr);
+  while (NextToken) {
+    const FormatToken *StartingToken = NextToken;
+    NextToken = fetcher.getNext(LineNumber, NextToken);
+
+    // Does the line start with one of the tokens we are expecting to
+    // remove a brace from
+    if (!StartingToken->isOneOf(tok::kw_if, tok::kw_for, tok::kw_else,
+                                tok::kw_while, tok::kw_do))
+      continue;
+
+    const FormatToken *Next = fetcher.getNext(LineNumber, StartingToken);
+    if (!Next) {
+      // We are are the end of the annotated lines.
+      continue;
+    }
+
+    // if/for and while are handled a little differently
+    if (StartingToken->isOneOf(tok::kw_if, tok::kw_for, tok::kw_while)) {
+      if (!Next->is(tok::l_paren) || !Next->MatchingParen)
+        continue;
+      FormatToken *RParen = Next->MatchingParen;
+      if (!RParen->Next)
+        continue;
+      Next = RParen;
+    } else if (StartingToken->isOneOf(tok::kw_else, tok::kw_do)) {
+      // If we are an 'else' then simple move onto removing the braces.
+      Next = StartingToken;
+    }
+
+    const FormatToken *LBrace = fetcher.getNext(LineNumber, Next);
+    if (!LBrace)
+      continue;
+
+    // We could be `while(x);` or `else if` just continue from
+    // this point if we are.
+    if (LBrace && LBrace->isOneOf(tok::semi, tok::kw_if)) {
+      NextToken = LBrace;
+      continue;
+    }
+
+    if (LBrace && !LBrace->is(tok::l_brace)) {
+      LBrace = nullptr;
+      continue;
+    }
+
+    if (LBrace->startsSequence(tok::l_brace, tok::comment)) {
+      if ((StartingToken->is(tok::kw_if) &&
+           Style.AutomaticBraces.AfterIf == FormatStyle::BIS_RemoveNoComment) ||
+          (StartingToken->is(tok::kw_else) &&
+           Style.AutomaticBraces.AfterElse ==
+               FormatStyle::BIS_RemoveNoComment) ||
+          (StartingToken->is(tok::kw_do) &&
+           Style.AutomaticBraces.AfterDo == FormatStyle::BIS_RemoveNoComment) ||
+          (StartingToken->is(tok::kw_while) &&
+           Style.AutomaticBraces.AfterWhile ==
+               FormatStyle::BIS_RemoveNoComment) ||
+          (StartingToken->is(tok::kw_while) &&
+           Style.AutomaticBraces.AfterFor ==
+               FormatStyle::BIS_RemoveNoComment)) {
+        NextToken = LBrace;
+        continue;
+      }
+    }
+
+    // Shoot along until we get to the end brace, but count
+    // the number of functional lines by counting semi's
+    const FormatToken *InnerScopeToken = LBrace;
+
+    int CountSemi = 0;
+    int ScopeInducingTokens = 0;
+    int Scope = 0;
+    while (InnerScopeToken) {
+      InnerScopeToken = fetcher.getNext(LineNumber, InnerScopeToken);
+      if (InnerScopeToken->is(tok::l_brace))
+        Scope++;
+      if (InnerScopeToken->is(tok::r_brace)) {
+        if (Scope == 0)
+          break;
+        Scope--;
+      }
+      if (InnerScopeToken->is(tok::semi))
+        CountSemi++;
+      if (InnerScopeToken->is(tok::comment) &&
+          Style.AutomaticBraces.AfterIf == FormatStyle::BIS_RemoveNoComment) {
+        LBrace = nullptr;
+        break;
+      }
+      // This can cause a dangling if
+      if (InnerScopeToken->is(tok::kw_if)) {
+        NextToken = InnerScopeToken;
+        ScopeInducingTokens++;
+        break;
+      }
+      if (InnerScopeToken->is(tok::kw_for)) {
+        ScopeInducingTokens++;
+        continue;
+      }
+    }
+
+    // We should now be at the end of at an }.
+    const FormatToken *RBrace = InnerScopeToken;
+    if (!RBrace || !RBrace->is(tok::r_brace))
+      continue;
+
+    // Too many lines.
+    if (CountSemi != 1) {
+      NextToken = RBrace;
+      continue;
+    }
+
+    // Too many levels of scope
+    if (ScopeInducingTokens >= 2) {
+      // Move back to the inner scope.
+      NextToken = LBrace;
+      continue;
+    }
+
+    // Don't remove the braces from if(){} if the else already has braces.
+    if (fetcher.startsSequence(LineNumber, RBrace, tok::r_brace, tok::kw_else,
+                               tok::l_brace, tok::comment)) {
+      RBrace = nullptr;
+      LBrace = nullptr;
+      continue;
+    }
+
+    if (LBrace && RBrace) {
+      // We are finally at the point where we know the positions of {}
+      // And we think this is for just a single line of scope.
+      const SourceLocation startBraceLoc = LBrace->Tok.getLocation();
+      const SourceLocation endBraceLoc = RBrace->Tok.getLocation();
+
+      const char *text = Env.getSourceManager().getCharacterData(
+          endBraceLoc.getLocWithOffset(1));
+
+      // Determine if we need to remove the "}\n" or just "}".
+      int endSize = 1;
+      if (text && text[0] == '\n')
+        endSize++;
+
+      // Remove the { and } (or }\n).
+      cantFail(Result.add(
+          tooling::Replacement(Env.getSourceManager(), startBraceLoc, 1, "")));
+      cantFail(Result.add(tooling::Replacement(Env.getSourceManager(),
+                                               endBraceLoc, endSize, "")));
+      // Move on from where we got to.
+    }
+    NextToken = LBrace;
+  }
+}
+
+} // namespace format
+} // namespace clang
Index: clang/include/clang/Format/Format.h
===================================================================
--- clang/include/clang/Format/Format.h
+++ clang/include/clang/Format/Format.h
@@ -933,6 +933,52 @@
   /// \version 12
   std::vector<std::string> AttributeMacros;
 
+  enum BraceInsertionRemovalStyle {
+    /// Do not insert or remove braces.
+    BIS_Leave,
+    /// Always insert braces.
+    BIS_Always,
+    /// Insert braces if the line is likely to wrap.
+    BIS_WrapLikely,
+    /// Always remove braces.
+    BIS_Remove,
+    /// Remove if there is no comment
+    BIS_RemoveNoComment
+  };
+
+  /// The style of inserting braces in control flow statements.
+  struct AutomaticBracesStyle {
+    // Insert/Remove after if()
+    BraceInsertionRemovalStyle AfterIf;
+
+    // Insert/Remove after for()
+    BraceInsertionRemovalStyle AfterFor;
+
+    // Insert/Remove after while()
+    BraceInsertionRemovalStyle AfterWhile;
+
+    // Insert/Remove after do
+    BraceInsertionRemovalStyle AfterDo;
+
+    // Insert/Remove after else
+    BraceInsertionRemovalStyle AfterElse;
+  };
+
+  /// If set to ``WrapLikely`` will insert braces if the line after the
+  /// control flow statement is likely to wrap.
+  /// If set to ``Always`` will always insert braces.
+  /// If set to ``Remove`` will remove braces where possible.
+  /// The default is the disabled value of ``BIS_Leave``.
+  /// \warning
+  ///  Setting ``AutomaticBraces``  to something other than `Leave`, COULD
+  ///  lead to incorrect code formatting due to incorrect decisions made due to
+  ///  clang-formats lack of complete semantic information.
+  ///  As such extra care should be taken to review code changes made by the use
+  ///  of this option.
+  /// \endwarning
+  /// \version 14
+  AutomaticBracesStyle AutomaticBraces;
+
   /// If ``false``, a function call's arguments will either be all on the
   /// same line or will have one line each.
   /// \code
Index: clang/docs/ReleaseNotes.rst
===================================================================
--- clang/docs/ReleaseNotes.rst
+++ clang/docs/ReleaseNotes.rst
@@ -228,6 +228,9 @@
   `const` `volatile` `static` `inline` `constexpr` `restrict`
   to be controlled relative to the `type`.
 
+- Option ``AutomaticBraces`` has been added to allow the insertion
+  and removal of {} from if/for/while scope
+
 libclang
 --------
 
Index: clang/docs/ClangFormatStyleOptions.rst
===================================================================
--- clang/docs/ClangFormatStyleOptions.rst
+++ clang/docs/ClangFormatStyleOptions.rst
@@ -1101,6 +1101,37 @@
 
     AttributeMacros: ['__capability', '__output', '__ununsed']
 
+**AutomaticBraces** (``BraceInsertionStyle``) :versionbadge:`clang-format 14`
+  If set to ``WrapLikely`` will insert braces if the line after the
+  control flow statement is likely to wrap.
+  If set to ``Always`` will always insert braces.
+  If set to ``Remove`` will remove braces where possible.
+  The default is the disabled value of ``BIS_Leave``.
+
+  .. warning:: 
+
+   Setting ``AutomaticBraces``  to something other than `Leave`, COULD
+   lead to incorrect code formatting due to incorrect decisions made due to
+   clang-formats lack of complete semantic information.
+   As such extra care should be taken to review code changes made by the use
+   of this option.
+
+  Possible values:
+
+  * ``BIS_Leave`` (in configuration: ``Leave``)
+    Do not insert or remove braces.
+
+  * ``BIS_Always`` (in configuration: ``Always``)
+    Always insert braces.
+
+  * ``BIS_WrapLikely`` (in configuration: ``WrapLikely``)
+    Insert braces if the line is likely to wrap.
+
+  * ``BIS_Remove`` (in configuration: ``Remove``)
+    Always remove braces.
+
+
+
 **BinPackArguments** (``Boolean``) :versionbadge:`clang-format 3.7`
   If ``false``, a function call's arguments will either be all on the
   same line or will have one line each.
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