Index: lib/Basic/TargetInfo.cpp
===================================================================
--- lib/Basic/TargetInfo.cpp
+++ lib/Basic/TargetInfo.cpp
@@ -75,7 +75,8 @@
   Int64Type = SignedLongLong;
   SigAtomicType = SignedInt;
   ProcessIDType = SignedInt;
-  UseSignedCharForObjCBool = true;
+  // New Darwin platforms use the true bool type.
+  UseSignedCharForObjCBool = !Triple.isOSDarwin();
   UseBitFieldTypeAlignment = true;
   UseZeroLengthBitfieldAlignment = false;
   UseExplicitBitFieldAlignment = true;
Index: lib/Basic/Targets/AArch64.cpp
===================================================================
--- lib/Basic/Targets/AArch64.cpp
+++ lib/Basic/Targets/AArch64.cpp
@@ -538,7 +538,6 @@
                                                  const TargetOptions &Opts)
     : DarwinTargetInfo<AArch64leTargetInfo>(Triple, Opts) {
   Int64Type = SignedLongLong;
-  UseSignedCharForObjCBool = false;
 
   LongDoubleWidth = LongDoubleAlign = SuitableAlign = 64;
   LongDoubleFormat = &llvm::APFloat::IEEEdouble();
Index: lib/Basic/Targets/ARM.cpp
===================================================================
--- lib/Basic/Targets/ARM.cpp
+++ lib/Basic/Targets/ARM.cpp
@@ -1051,11 +1051,11 @@
   if (Triple.isWatchABI()) {
     // Darwin on iOS uses a variant of the ARM C++ ABI.
     TheCXXABI.set(TargetCXXABI::WatchOS);
-
-    // BOOL should be a real boolean on the new ABI
-    UseSignedCharForObjCBool = false;
-  } else
+  } else {
     TheCXXABI.set(TargetCXXABI::iOS);
+    // BOOL should be a character on the iOS ABI.
+    UseSignedCharForObjCBool = true;
+  }
 }
 
 void DarwinARMTargetInfo::getOSDefines(const LangOptions &Opts,
Index: lib/Basic/Targets/PPC.h
===================================================================
--- lib/Basic/Targets/PPC.h
+++ lib/Basic/Targets/PPC.h
@@ -346,6 +346,7 @@
     BoolWidth = BoolAlign = 32; // XXX support -mone-byte-bool?
     PtrDiffType = SignedInt; // for http://llvm.org/bugs/show_bug.cgi?id=15726
     LongLongAlign = 32;
+    UseSignedCharForObjCBool = true;
     resetDataLayout("E-m:o-p:32:32-f64:32:64-n32");
   }
 
@@ -360,6 +361,7 @@
   DarwinPPC64TargetInfo(const llvm::Triple &Triple, const TargetOptions &Opts)
       : DarwinTargetInfo<PPC64TargetInfo>(Triple, Opts) {
     HasAlignMac68kSupport = true;
+    UseSignedCharForObjCBool = true;
     resetDataLayout("E-m:o-i64:64-n32:64");
   }
 };
Index: lib/Basic/Targets/X86.h
===================================================================
--- lib/Basic/Targets/X86.h
+++ lib/Basic/Targets/X86.h
@@ -412,8 +412,7 @@
     MaxVectorAlign = 256;
     // The watchOS simulator uses the builtin bool type for Objective-C.
     llvm::Triple T = llvm::Triple(Triple);
-    if (T.isWatchOS())
-      UseSignedCharForObjCBool = false;
+    UseSignedCharForObjCBool = !T.isWatchOS();
     SizeType = UnsignedLong;
     IntPtrType = SignedLong;
     resetDataLayout("e-m:o-p:32:32-f64:32:64-f80:128-n8:16:32-S128");
@@ -780,8 +779,7 @@
     Int64Type = SignedLongLong;
     // The 64-bit iOS simulator uses the builtin bool type for Objective-C.
     llvm::Triple T = llvm::Triple(Triple);
-    if (T.isiOS())
-      UseSignedCharForObjCBool = false;
+    UseSignedCharForObjCBool = !T.isiOS();
     resetDataLayout("e-m:o-i64:64-f80:128-n8:16:32:64-S128");
   }
 
Index: test/Frontend/objc-bool-is-bool.m
===================================================================
--- test/Frontend/objc-bool-is-bool.m
+++ test/Frontend/objc-bool-is-bool.m
@@ -1,5 +1,22 @@
 // RUN: %clang_cc1 -fsyntax-only -E -dM -triple=armv7k-apple-watchos %s | FileCheck --check-prefix=BOOL %s
+// RUN: %clang_cc1 -fsyntax-only -E -dM -triple=armv7-apple-watchos %s | FileCheck --check-prefix=CHAR %s
+// RUN: %clang_cc1 -fsyntax-only -E -dM -triple=armv7-apple-ios %s | FileCheck --check-prefix=CHAR %s
+
+// RUN: %clang_cc1 -fsyntax-only -E -dM -triple=arm64-apple-ios %s | FileCheck --check-prefix=BOOL %s
+
+// RUN: %clang_cc1 -fsyntax-only -E -dM -triple=i686-apple-darwin16 %s | FileCheck --check-prefix=CHAR %s
+// RUN: %clang_cc1 -fsyntax-only -E -dM -triple=i686-apple-ios %s | FileCheck --check-prefix=CHAR %s
+// RUN: %clang_cc1 -fsyntax-only -E -dM -triple=i686-apple-tvos %s | FileCheck --check-prefix=CHAR %s
+// RUN: %clang_cc1 -fsyntax-only -E -dM -triple=i686-apple-watchos %s | FileCheck --check-prefix=BOOL %s
+
 // RUN: %clang_cc1 -fsyntax-only -E -dM -triple=x86_64-apple-darwin16 %s | FileCheck --check-prefix=CHAR %s
+// RUN: %clang_cc1 -fsyntax-only -E -dM -triple=x86_64-apple-ios %s | FileCheck --check-prefix=BOOL %s
+// RUN: %clang_cc1 -fsyntax-only -E -dM -triple=x86_64-apple-tvos %s | FileCheck --check-prefix=BOOL %s
+// RUN: %clang_cc1 -fsyntax-only -E -dM -triple=x86_64-apple-watchos %s | FileCheck --check-prefix=CHAR %s
+
+// RUN: %clang_cc1 -fsyntax-only -E -dM -triple=ppc32-apple-darwin16 %s | FileCheck --check-prefix=CHAR %s
+// RUN: %clang_cc1 -fsyntax-only -E -dM -triple=ppc64-apple-darwin16 %s | FileCheck --check-prefix=CHAR %s
+
 // RUN: %clang_cc1 -x c -fsyntax-only -E -dM -triple=x86_64-apple-darwin16 %s | FileCheck --check-prefix=CHAR %s
 // RUN: %clang_cc1 -x objective-c++ -fsyntax-only -E -dM -triple=x86_64-apple-darwin16 %s | FileCheck --check-prefix=CHAR %s
 // RUN: %clang_cc1 -x c++ -fsyntax-only -E -dM -triple=x86_64-apple-darwin16 %s | FileCheck --check-prefix=CHAR %s