diff --git a/clang/lib/CodeGen/CGObjCMac.cpp b/clang/lib/CodeGen/CGObjCMac.cpp
--- a/clang/lib/CodeGen/CGObjCMac.cpp
+++ b/clang/lib/CodeGen/CGObjCMac.cpp
@@ -3329,7 +3329,7 @@
   struct _objc_method_list *instance_methods;
   struct _objc_method_list *class_methods;
   struct _objc_protocol_list *protocols;
-  uint32_t size; // <rdar://4585769>
+  uint32_t size; // sizeof(struct _objc_category)
   struct _objc_property_list *instance_properties;
   struct _objc_property_list *class_properties;
   };
@@ -4486,14 +4486,10 @@
   want to implement correct ObjC/C++ exception interactions for the
   fragile ABI.
 
-  Note that for this use of setjmp/longjmp to be correct, we may need
-  to mark some local variables volatile: if a non-volatile local
-  variable is modified between the setjmp and the longjmp, it has
-  indeterminate value.  For the purposes of LLVM IR, it may be
-  sufficient to make loads and stores within the @try (to variables
-  declared outside the @try) volatile.  This is necessary for
-  optimized correctness, but is not currently being done; this is
-  being tracked as rdar://problem/8160285
+  Note that for this use of setjmp/longjmp to be correct in the presence of
+  optimization, we use inline assembly on the set of local variables to force
+  flushing locals to memory immediately before any protected calls and to
+  inhibit optimizing locals across the setjmp->catch edge.
 
   The basic framework for a @try-catch-finally is as follows:
   {
@@ -5092,7 +5088,8 @@
   eImageInfo_OptimizedByDyld     = (1 << 3), // This flag is set by the dyld shared cache.
 
   // A flag indicating that the module has no instances of a @synthesize of a
-  // superclass variable. <rdar://problem/6803242>
+  // superclass variable. This flag used to be consumed by the runtime to work
+  // around miscompile by gcc.
   eImageInfo_CorrectedSynthesize = (1 << 4), // This flag is no longer set by clang.
   eImageInfo_ImageIsSimulated    = (1 << 5),
   eImageInfo_ClassProperties     = (1 << 6)
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -5983,7 +5983,7 @@
   }
 
   // Note: -fwritable-strings doesn't make the backing store strings of
-  // CFStrings writable. (See <rdar://problem/10657500>)
+  // CFStrings writable.
   auto *GV =
       new llvm::GlobalVariable(getModule(), C->getType(), /*isConstant=*/true,
                                llvm::GlobalValue::PrivateLinkage, C, ".str");
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -5578,8 +5578,8 @@
   }
 
   // Enable -mconstructor-aliases except on darwin, where we have to work around
-  // a linker bug (see <rdar://problem/7651567>), and CUDA device code, where
-  // aliases aren't supported.
+  // a linker bug (see https://openradar.appspot.com/7198997), and CUDA device
+  // code, where aliases aren't supported.
   if (!RawTriple.isOSDarwin() && !RawTriple.isNVPTX())
     CmdArgs.push_back("-mconstructor-aliases");
 
diff --git a/clang/lib/Sema/SemaObjCProperty.cpp b/clang/lib/Sema/SemaObjCProperty.cpp
--- a/clang/lib/Sema/SemaObjCProperty.cpp
+++ b/clang/lib/Sema/SemaObjCProperty.cpp
@@ -2795,9 +2795,7 @@
     }
 
     // FIXME: Implement warning dependent on NSCopying being
-    // implemented. See also:
-    // <rdar://5168496&4855821&5607453&5096644&4947311&5698469&4947014&5168496>
-    // (please trim this list while you are at it).
+    // implemented.
   }
 
   if (!(Attributes & ObjCPropertyAttribute::kind_copy) &&