2 files changed, 43 insertions, 8 deletions
diff --git a/lib/Analysis/UninitializedValues.cpp b/lib/Analysis/UninitializedValues.cpp
index 858be4561c..47f2cf67c8 100644
--- a/lib/Analysis/UninitializedValues.cpp
+++ b/lib/Analysis/UninitializedValues.cpp
@@ -605,14 +605,26 @@ void TransferFunctions::VisitBlockExpr(BlockExpr *be) {
 }
 
 void TransferFunctions::VisitCallExpr(CallExpr *ce) {
-  // After a call to a function like setjmp or vfork, any variable which is
-  // initialized anywhere within this function may now be initialized. For now,
-  // just assume such a call initializes all variables.
-  // FIXME: Only mark variables as initialized if they have an initializer which
-  // is reachable from here.
-  Decl *Callee = ce->getCalleeDecl();
-  if (Callee && Callee->hasAttr<ReturnsTwiceAttr>())
-    vals.setAllScratchValues(Initialized);
+  if (Decl *Callee = ce->getCalleeDecl()) {
+    if (Callee->hasAttr<ReturnsTwiceAttr>()) {
+      // After a call to a function like setjmp or vfork, any variable which is
+      // initialized anywhere within this function may now be initialized. For
+      // now, just assume such a call initializes all variables.  FIXME: Only
+      // mark variables as initialized if they have an initializer which is
+      // reachable from here.
+      vals.setAllScratchValues(Initialized);
+    }
+    else if (Callee->hasAttr<AnalyzerNoReturnAttr>()) {
+      // Functions labeled like "analyzer_noreturn" are often used to denote
+      // "panic" functions that in special debug situations can still return,
+      // but for the most part should not be treated as returning.  This is a
+      // useful annotation borrowed from the static analyzer that is useful for
+      // suppressing branch-specific false positives when we call one of these
+      // functions but keep pretending the path continues (when in reality the
+      // user doesn't care).
+      vals.setAllScratchValues(Unknown);
+    }
+  }
 }
 
 void TransferFunctions::VisitDeclRefExpr(DeclRefExpr *dr) {
diff --git a/test/Sema/uninit-variables.c b/test/Sema/uninit-variables.c
index 634ae0dc42..9e3dd9d287 100644
--- a/test/Sema/uninit-variables.c
+++ b/test/Sema/uninit-variables.c
@@ -508,3 +508,26 @@ int self_init_in_cond(int *p) {
   int n = ((p && (0 || 1)) && (n = *p)) ? n : -1; // ok
   return n;
 }
+
+void test_analyzer_noreturn_aux() __attribute__((analyzer_noreturn));
+
+void test_analyzer_noreturn(int y) {
+  int x; // expected-note {{initialize the variable 'x' to silence this warning}}
+  if (y) {
+    test_analyzer_noreturn_aux();
+	++x; // no-warning
+  }
+  else {
+	++x; // expected-warning {{variable 'x' is uninitialized when used here}}
+  }
+}
+void test_analyzer_noreturn_2(int y) {
+  int x;
+  if (y) {
+    test_analyzer_noreturn_aux();
+  }
+  else {
+	x = 1;
+  }
+  ++x; // no-warning
+}