re PR middle-end/51644 (va_list vs. warning: ‘noreturn’ function does return is not fixable)

	PR middle-end/51644
	PR middle-end/51647
	* tree-eh.c (decide_copy_try_finally): At -O0, return true
	even when ndests is not 1, if there are only gimple_clobber_p
	(or debug) stmts in the finally sequence.
	* tree-inline.c (estimate_num_insns): Return 0 for gimple_clobber_p
	stmts.

	* gcc.dg/pr51644.c: New test.
	* g++.dg/warn/Wreturn-4.C: New test.

From-SVN: r182589

gcc/ChangeLog

+2011-12-21  Jakub Jelinek  <jakub@redhat.com>
+
+	PR middle-end/51644
+	PR middle-end/51647
+	* tree-eh.c (decide_copy_try_finally): At -O0, return true
+	even when ndests is not 1, if there are only gimple_clobber_p
+	(or debug) stmts in the finally sequence.
+	* tree-inline.c (estimate_num_insns): Return 0 for gimple_clobber_p
+	stmts.
+
 2011-12-21  Aldy Hernandez  <aldyh@redhat.com>
 
 	PR middle-end/51472

gcc/testsuite/ChangeLog

+2011-12-21  Jakub Jelinek  <jakub@redhat.com>
+
+	PR middle-end/51644
+	PR middle-end/51647
+	* gcc.dg/pr51644.c: New test.
+	* g++.dg/warn/Wreturn-4.C: New test.
+
 2011-12-21  Michael Zolotukhin  <michael.v.zolotukhin@intel.com>
 
 	* gcc.dg/vect/no-section-anchors-vect-31.c: Adjust array size and test

gcc/testsuite/g++.dg/warn/Wreturn-4.C

+// PR middle-end/51647
+// { dg-do compile }
+// { dg-options "-Wall" }
+
+enum PropertyAttributes { NONE = 1 };
+enum PropertyType { NORMAL = 0, FIELD = 1 };
+class LookupResult;
+
+template <typename T>
+struct Handle
+{
+  inline explicit Handle (T *obj) __attribute__ ((always_inline)) {}
+  inline T *operator-> () const __attribute__ ((always_inline)) { return 0; }
+};
+
+struct JSObject
+{
+  bool IsGlobalObject () { return false; }
+};
+
+struct Isolate
+{
+  LookupResult *top_lookup_result () { return 0; }
+};
+
+struct LookupResult
+{
+  explicit LookupResult (Isolate *isolate) {}
+  JSObject *holder () { return 0; }
+  PropertyType type () { return NORMAL; }
+};
+
+int
+test (LookupResult *lookup)
+{
+  Handle <JSObject> holder (lookup->holder ());
+  switch (lookup->type ())
+    {
+    case NORMAL:
+      if (holder->IsGlobalObject ())
+	return 2;
+      else
+	return 3;
+      break;
+    default:
+      return 4;
+    }
+}	// { dg-bogus "control reaches end of non-void function" }

gcc/testsuite/gcc.dg/pr51644.c

+/* PR middle-end/51644 */
+/* { dg-do compile } */
+/* { dg-options "-Wall -fexceptions" } */
+
+#include <stdarg.h>
+
+extern void baz (int, va_list) __attribute__ ((__noreturn__));
+
+__attribute__ ((__noreturn__))
+void
+foo (int s, ...)
+{
+  va_list ap;
+  va_start (ap, s);
+  baz (s, ap);
+  va_end (ap);
+}		/* { dg-bogus "function does return" } */
+
+__attribute__ ((__noreturn__))
+void
+bar (int s, ...)
+{
+  va_list ap1;
+  va_start (ap1, s);
+  {
+    va_list ap2;
+    va_start (ap2, s);
+    baz (s, ap1);
+    baz (s, ap2);
+    va_end (ap2);
+  }
+  va_end (ap1);
+}		/* { dg-bogus "function does return" } */

gcc/tree-eh.c

@@ -1538,7 +1538,20 @@ decide_copy_try_finally (int ndests, bool may_throw, gimple_seq finally)
     }
 
   if (!optimize)
-    return ndests == 1;
+    {
+      gimple_stmt_iterator gsi;
+
+      if (ndests == 1)
+        return true;
+
+      for (gsi = gsi_start (finally); !gsi_end_p (gsi); gsi_next (&gsi))
+	{
+	  gimple stmt = gsi_stmt (gsi);
+	  if (!is_gimple_debug (stmt) && !gimple_clobber_p (stmt))
+	    return false;
+	}
+      return true;
+    }
 
   /* Finally estimate N times, plus N gotos.  */
   f_estimate = count_insns_seq (finally, &eni_size_weights);

gcc/tree-inline.c

@@ -3482,6 +3482,9 @@ estimate_num_insns (gimple stmt, eni_weights *weights)
 	 likely be a real store, so the cost of the GIMPLE_ASSIGN is the cost
 	 of moving something into "a", which we compute using the function
 	 estimate_move_cost.  */
+      if (gimple_clobber_p (stmt))
+	return 0;	/* ={v} {CLOBBER} stmt expands to nothing.  */
+
       lhs = gimple_assign_lhs (stmt);
       rhs = gimple_assign_rhs1 (stmt);