gimple.c (gimple_call_builtin_p): New function.

	* gimple.c (gimple_call_builtin_p): New function.
	* gimple.h (gimple_call_builtin_p): Declare.
	* tree-cfg.c (make_edges): Produce edge from BUILT_IN_RETURN
	to exit.
	(execute_warn_function_return): BUILT_IN_RETURN is return.
	(split_critical_edges): Return edges are not critical.
	(is_ctrl_altering_stmt): Builtin_in_return is altering.
	(gimple_verify_flow_info): Handle built_in_return.
	(execute_warn_function_return): Handle built_in_return.
	* ipa-pure-const.c (check_call): Ignore builtin_return.

	* gcc.dg/builtin-apply4.c: Compile with -Wmissing-return.

From-SVN: r160079

gcc/gimple.c

@@ -4732,4 +4732,16 @@ gimple_decl_printable_name (tree decl, int verbosity)
   return IDENTIFIER_POINTER (DECL_NAME (decl));
 }
 
+/* Return true when STMT is builtins call to CODE.  */
+
+bool
+gimple_call_builtin_p (gimple stmt, enum built_in_function code)
+{
+  tree fndecl;
+  return (is_gimple_call (stmt)
+	  && (fndecl = gimple_call_fndecl (stmt)) != NULL
+	  && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL
+	  && DECL_FUNCTION_CODE (fndecl) == code);
+}
+
 #include "gt-gimple.h"

gcc/gimple.h

@@ -961,6 +961,7 @@ extern bool walk_stmt_load_store_ops (gimple, void *,
 				      bool (*)(gimple, tree, void *),
 				      bool (*)(gimple, tree, void *));
 extern bool gimple_ior_addresses_taken (bitmap, gimple);
+extern bool gimple_call_builtin_p (gimple, enum built_in_function);
 
 /* In gimplify.c  */
 extern tree create_tmp_var_raw (tree, const char *);

gcc/ipa-pure-const.c

@@ -369,6 +369,9 @@ check_call (funct_state local, gimple call, bool ipa)
      graph.  */
   if (callee_t)
     {
+      /* built_in_return is really just an return statemnt.  */
+      if (gimple_call_builtin_p (call, BUILT_IN_RETURN))
+	return;
       /* When bad things happen to bad functions, they cannot be const
 	 or pure.  */
       if (setjmp_call_p (callee_t))

gcc/tree-cfg.c

@@ -568,8 +568,12 @@ make_edges (void)
 		 create abnormal edges to them.  */
 	      make_eh_edges (last);
 
+	      /* BUILTIN_RETURN is really a return statement.  */
+	      if (gimple_call_builtin_p (last, BUILT_IN_RETURN))
+		make_edge (bb, EXIT_BLOCK_PTR, 0), fallthru = false;
 	      /* Some calls are known not to return.  */
-	      fallthru = !(gimple_call_flags (last) & ECF_NORETURN);
+	      else
+	        fallthru = !(gimple_call_flags (last) & ECF_NORETURN);
 	      break;
 
 	    case GIMPLE_ASSIGN:
@@ -2248,6 +2252,10 @@ is_ctrl_altering_stmt (gimple t)
 	/* A call also alters control flow if it does not return.  */
 	if (flags & ECF_NORETURN)
 	  return true;
+
+	/* BUILT_IN_RETURN call is same as return statement.  */
+	if (gimple_call_builtin_p (t, BUILT_IN_RETURN))
+	  return true;
       }
       break;
 
@@ -4436,6 +4444,10 @@ gimple_verify_flow_info (void)
 	    }
 	  break;
 
+	case GIMPLE_CALL:
+	  if (!gimple_call_builtin_p (stmt, BUILT_IN_RETURN))
+	    break;
+	  /* ... fallthru ... */
 	case GIMPLE_RETURN:
 	  if (!single_succ_p (bb)
 	      || (single_succ_edge (bb)->flags
@@ -7050,7 +7062,9 @@ split_critical_edges (void)
 	      gsi = gsi_last_bb (e->src);
 	      if (!gsi_end_p (gsi)
 		  && stmt_ends_bb_p (gsi_stmt (gsi))
-		  && gimple_code (gsi_stmt (gsi)) != GIMPLE_RETURN)
+		  && (gimple_code (gsi_stmt (gsi)) != GIMPLE_RETURN
+		      && !gimple_call_builtin_p (gsi_stmt (gsi),
+						 BUILT_IN_RETURN)))
 		split_edge (e);
 	    }
 	}
@@ -7148,7 +7162,8 @@ execute_warn_function_return (void)
       FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
 	{
 	  last = last_stmt (e->src);
-	  if (gimple_code (last) == GIMPLE_RETURN
+	  if ((gimple_code (last) == GIMPLE_RETURN
+	       || gimple_call_builtin_p (last, BUILT_IN_RETURN))
 	      && (location = gimple_location (last)) != UNKNOWN_LOCATION)
 	    break;
 	}