gimple-low.c (lower_stmt): If the call is noreturn, remove a subsequent GOTO or RETURN statement.

* gimple-low.c (lower_stmt) <GIMPLE_CALL>: If the call is noreturn,
	remove a subsequent GOTO or RETURN statement.

From-SVN: r152959

gcc/ChangeLog

@@ -1,10 +1,15 @@
+2009-10-17  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* gimple-low.c (lower_stmt) <GIMPLE_CALL>: If the call is noreturn,
+	remove a subsequent GOTO or RETURN statement.
+
 2009-10-17  Andy Hutchinson  <hutchinsonandy@aim.com>
 
 	* config/avr.md (*movqi): Add zero as equally preferable constraint
 	as general register.
-	(*movhi): Ditto. 
+	(*movhi): Ditto.
 
-	2009-10-17  Eric Botcazou  <ebotcazou@adacore.com>
+2009-10-17  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* print-tree.c (print_node): Fix string for DECL_STRUCT_FUNCTION.
 

gcc/gimple-low.c

@@ -387,6 +387,19 @@ lower_stmt (gimple_stmt_iterator *gsi, struct lower_data *data)
 	    lower_builtin_setjmp (gsi);
 	    return;
 	  }
+
+	/* After a noreturn call, remove a subsequent GOTO or RETURN that might
+	   have been mechanically added; this will prevent the EH lowering pass
+	   from adding useless edges and thus complicating the initial CFG.  */
+	if (decl && (flags_from_decl_or_type (decl) & ECF_NORETURN))
+	  {
+	    gsi_next (gsi);
+	    if (!gsi_end_p (*gsi)
+		&& (gimple_code (gsi_stmt (*gsi)) == GIMPLE_GOTO
+		    || gimple_code (gsi_stmt (*gsi)) == GIMPLE_RETURN))
+	      gsi_remove (gsi, false);
+	    return;
+	  }
       }
       break;
 

gcc/testsuite/ChangeLog

@@ -1,3 +1,7 @@
+2009-10-17  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* gnat.dg/noreturn1.ad[sb]: New test.
+
 2009-10-17  Janus Weil  <janus@gcc.gnu.org>
 	    Paul Thomas  <pault@gcc.gnu.org>
 

gcc/testsuite/gnat.dg/noreturn1.adb

@@ -0,0 +1,15 @@
+-- { dg-compile }
+
+package body Noreturn1 is
+
+   procedure Error (E : in Exception_Occurrence) is
+      Occurrence_Message : constant String := Exception_Message (E);
+   begin
+      if Occurrence_Message = "$" then
+         raise Program_Error;
+      else
+         raise Constraint_Error;
+      end if;
+   end;
+
+end Noreturn1;

gcc/testsuite/gnat.dg/noreturn1.ads

@@ -0,0 +1,8 @@
+with Ada.Exceptions; use Ada.Exceptions;
+
+package Noreturn1 is
+
+   procedure Error (E : in Exception_Occurrence);
+   pragma No_Return (Error);
+
+end Noreturn1;