Index: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
+++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
@@ -598,6 +598,10 @@
 def note_include_header_or_declare : Note<
   "include the header <%0> or explicitly provide a declaration for '%1'">;
 def note_previous_builtin_declaration : Note<"%0 is a builtin with type %1">;
+def warn_implicit_decl_no_jmp_buf
+    : Warning<"declaration of built-in function '%0' requires the declaration"
+    " of the 'jmp_buf' type, commonly provided in the header <setjmp.h>.">,
+      InGroup<DiagGroup<"incomplete-setjmp-declaration">>;
 def warn_implicit_decl_requires_sysheader : Warning<
   "declaration of built-in function '%1' requires inclusion of the header <%0>">,
   InGroup<BuiltinRequiresHeader>;
Index: cfe/trunk/lib/Sema/SemaDecl.cpp
===================================================================
--- cfe/trunk/lib/Sema/SemaDecl.cpp
+++ cfe/trunk/lib/Sema/SemaDecl.cpp
@@ -1983,10 +1983,27 @@
   ASTContext::GetBuiltinTypeError Error;
   QualType R = Context.GetBuiltinType(ID, Error);
   if (Error) {
-    if (ForRedeclaration)
-      Diag(Loc, diag::warn_implicit_decl_requires_sysheader)
-          << getHeaderName(Context.BuiltinInfo, ID, Error)
+    if (!ForRedeclaration)
+      return nullptr;
+
+    // If we have a builtin without an associated type we should not emit a
+    // warning when we were not able to find a type for it.
+    if (Error == ASTContext::GE_Missing_type)
+      return nullptr;
+
+    // If we could not find a type for setjmp it is because the jmp_buf type was
+    // not defined prior to the setjmp declaration.
+    if (Error == ASTContext::GE_Missing_setjmp) {
+      Diag(Loc, diag::warn_implicit_decl_no_jmp_buf)
           << Context.BuiltinInfo.getName(ID);
+      return nullptr;
+    }
+
+    // Generally, we emit a warning that the declaration requires the
+    // appropriate header.
+    Diag(Loc, diag::warn_implicit_decl_requires_sysheader)
+        << getHeaderName(Context.BuiltinInfo, ID, Error)
+        << Context.BuiltinInfo.getName(ID);
     return nullptr;
   }
 
Index: cfe/trunk/test/Analysis/retain-release.m
===================================================================
--- cfe/trunk/test/Analysis/retain-release.m
+++ cfe/trunk/test/Analysis/retain-release.m
@@ -2,7 +2,7 @@
 // RUN: %clang_analyze_cc1 -triple x86_64-apple-darwin10\
 // RUN:     -analyzer-checker=core,osx.coreFoundation.CFRetainRelease\
 // RUN:     -analyzer-checker=osx.cocoa.ClassRelease,osx.cocoa.RetainCount\
-// RUN:     -analyzer-checker=debug.ExprInspection -fblocks -verify=expected,C %s\
+// RUN:     -analyzer-checker=debug.ExprInspection -fblocks -verify %s\
 // RUN:     -Wno-objc-root-class -analyzer-output=plist -o %t.objc.plist
 // RUN: %clang_analyze_cc1 -triple x86_64-apple-darwin10\
 // RUN:     -analyzer-checker=core,osx.coreFoundation.CFRetainRelease\
@@ -1231,7 +1231,7 @@
 typedef unsigned long __darwin_pthread_key_t;
 typedef __darwin_pthread_key_t pthread_key_t;
 
-int pthread_create(pthread_t *, const pthread_attr_t *,  // C-warning{{declaration of built-in function 'pthread_create' requires inclusion of the header <pthread.h>}}
+int pthread_create(pthread_t *, const pthread_attr_t *,
                    void *(*)(void *), void *);
 
 int pthread_setspecific(pthread_key_t key, const void *value);
Index: cfe/trunk/test/Sema/builtin-setjmp.c
===================================================================
--- cfe/trunk/test/Sema/builtin-setjmp.c
+++ cfe/trunk/test/Sema/builtin-setjmp.c
@@ -0,0 +1,10 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -fsyntax-only -verify -DNO_JMP_BUF %s
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -fsyntax-only -verify %s
+
+#ifdef NO_JMP_BUF
+extern long setjmp(long *);   // expected-warning {{declaration of built-in function 'setjmp' requires the declaration of the 'jmp_buf' type, commonly provided in the header <setjmp.h>.}}
+#else
+typedef long jmp_buf;
+extern int setjmp(char);      // expected-warning@8 {{incompatible redeclaration of library function 'setjmp'}}
+                              // expected-note@8    {{'setjmp' is a builtin with type 'int (jmp_buf)' (aka 'int (long)')}}
+#endif
Index: cfe/trunk/test/Sema/implicit-builtin-decl.c
===================================================================
--- cfe/trunk/test/Sema/implicit-builtin-decl.c
+++ cfe/trunk/test/Sema/implicit-builtin-decl.c
@@ -55,14 +55,17 @@
 
 void snprintf() { }
 
-// PR8316
-void longjmp(); // expected-warning{{declaration of built-in function 'longjmp' requires inclusion of the header <setjmp.h>}}
+// PR8316 & PR40692
+void longjmp(); // expected-warning{{declaration of built-in function 'longjmp' requires the declaration of the 'jmp_buf' type, commonly provided in the header <setjmp.h>.}}
 
 extern float fmaxf(float, float);
 
 struct __jmp_buf_tag {};
-void sigsetjmp(struct __jmp_buf_tag[1], int); // expected-warning{{declaration of built-in function 'sigsetjmp' requires inclusion of the header <setjmp.h>}}
+void sigsetjmp(struct __jmp_buf_tag[1], int); // expected-warning{{declaration of built-in function 'sigsetjmp' requires the declaration of the 'jmp_buf' type, commonly provided in the header <setjmp.h>.}}
 
 // CHECK:     FunctionDecl {{.*}} <line:[[@LINE-2]]:1, col:44> col:6 sigsetjmp '
 // CHECK-NOT: FunctionDecl
 // CHECK:     ReturnsTwiceAttr {{.*}} <{{.*}}> Implicit
+
+// PR40692
+void pthread_create(); // no warning expected