function.c (free_temps_for_rtl_expr): Don't free slots that have been pushed into a higher level.

	* function.c (free_temps_for_rtl_expr): Don't free slots
	that have been pushed into a higher level.

	* expr.c (cplus_expand_expr, case STMT_EXPR): Don't set
	RTL_EXPR_HAS_NO_SCOPE after all.

From-SVN: r32355

gcc/ChangeLog

+2000-03-06  Mark Mitchell  <mark@codesourcery.com>
+
+	* function.c (free_temps_for_rtl_expr): Don't free slots
+	that have been pushed into a higher level.
+	
+	Revert this patch:
+	2000-03-05  Mark Mitchell  <mark@codesourcery.com>
+
 2000-03-05  Mark Mitchell  <mark@codesourcery.com>
 
 	* basic-block.h (ALLOCA_REG_SET): Remove.

gcc/cp/ChangeLog

+2000-03-06  Mark Mitchell  <mark@codesourcery.com>
+
+	* expr.c (cplus_expand_expr, case STMT_EXPR): Don't set
+	RTL_EXPR_HAS_NO_SCOPE after all.
+
 2000-03-05  Mark Mitchell  <mark@codesourcery.com>
 
 	* expr.c (cplus_expand_expr, case STMT_EXPR): Use

gcc/cp/expr.c

@@ -148,7 +148,6 @@ cplus_expand_expr (exp, target, tmode, modifier)
 	tree rtl_expr = expand_start_stmt_expr ();
 	expand_stmt (STMT_EXPR_STMT (exp));
 	expand_end_stmt_expr (rtl_expr);
-	RTL_EXPR_HAS_NO_SCOPE (rtl_expr) = 1;
 	return expand_expr (rtl_expr, target, tmode, modifier);
       }
       break;

gcc/expr.c

@@ -6306,13 +6306,8 @@ expand_expr (exp, target, tmode, modifier)
 	  emit_insns (RTL_EXPR_SEQUENCE (exp));
 	  RTL_EXPR_SEQUENCE (exp) = const0_rtx;
 	}
-      if (RTL_EXPR_HAS_NO_SCOPE (exp))
-	preserve_rtl_expr_temps (exp);
-      else
-	{
-	  preserve_rtl_expr_result (RTL_EXPR_RTL (exp));
-	  free_temps_for_rtl_expr (exp);
-	}
+      preserve_rtl_expr_result (RTL_EXPR_RTL (exp));
+      free_temps_for_rtl_expr (exp);
       return RTL_EXPR_RTL (exp);
 
     case CONSTRUCTOR:

gcc/function.c

@@ -293,7 +293,6 @@ static void mark_function_chain PARAMS ((void *));
 static void prepare_function_start PARAMS ((void));
 static void do_clobber_return_reg PARAMS ((rtx, void *));
 static void do_use_return_reg PARAMS ((rtx, void *));
-static void preserve_rtl_expr_temp PARAMS ((struct temp_slot *));
 
 /* Pointer to chain of `struct function' for containing functions.  */
 struct function *outer_function_chain;
@@ -1130,36 +1129,6 @@ preserve_temp_slots (x)
       p->level--;
 }
 
-/* Preserve the temporary slot given by P (originally created during
-   the building of an RTL_EXPR) at least as long as things in our
-   current scope.  */
-
-static void
-preserve_rtl_expr_temp (p)
-     struct temp_slot *p;
-{
-  /* Set the slot level to that of the currently prevailing scope.  */
-  p->level = MIN (p->level, temp_slot_level);
-  /* This slot is no longer associated with the RTL_EXPR from which it
-     originated.  */
-  p->rtl_expr = NULL_TREE;
-}
-
-/* Preserve the temporary slots created during the building of the
-   RTL_EXPR given by T at least as long as things in our current
-   scope.  */
-
-void
-preserve_rtl_expr_temps (t)
-     tree t;
-{
-  struct temp_slot *p;
-
-  for (p = temp_slots; p; p = p->next)
-    if (p->in_use && p->rtl_expr == t)
-      preserve_rtl_expr_temp (p);
-}
-
 /* X is the result of an RTL_EXPR.  If it is a temporary slot associated
    with that RTL_EXPR, promote it into a temporary slot at the present
    level so it will not be freed when we free slots made in the
@@ -1179,8 +1148,11 @@ preserve_rtl_expr_result (x)
   /* If we can find a match, move it to our level unless it is already at
      an upper level.  */
   p = find_temp_slot_from_address (XEXP (x, 0));
-  if (p)
-    preserve_rtl_expr_temp (p);
+  if (p != 0)
+    {
+      p->level = MIN (p->level, temp_slot_level);
+      p->rtl_expr = 0;
+    }
 
   return;
 }
@@ -1215,7 +1187,16 @@ free_temps_for_rtl_expr (t)
 
   for (p = temp_slots; p; p = p->next)
     if (p->rtl_expr == t)
-      p->in_use = 0;
+      {
+	/* If this slot is below the current TEMP_SLOT_LEVEL, then it
+	   needs to be preserved.  This can happen if a temporary in
+	   the RTL_EXPR was addressed; preserve_temp_slots will move
+	   the temporary into a higher level.   */
+	if (temp_slot_level <= p->level)
+	  p->in_use = 0;
+	else
+	  p->rtl_expr = NULL_TREE;
+      }
 
   combine_temp_slots ();
 }

gcc/tree.def

@@ -689,11 +689,10 @@ DEFTREECODE (UNSAVE_EXPR, "unsave_expr", 'e', 1)
 /* Represents something whose RTL has already been expanded as a
    sequence which should be emitted when this expression is expanded.
    The first operand is the RTL to emit.  It is the first of a chain
-   of insns.  The second is the RTL expression for the result.  If
-   RTL_EXPR_HAS_NO_SCOPE does not hold for this expression, then all
-   temporaries created within this RTL_EXPR (except for the
-   RTL_EXPR_RTL) are out-of-scope after the RTL_EXPR is expanded.  (In
-   other words, their stack slots may be reused.)  */
+   of insns.  The second is the RTL expression for the result.  Any
+   temporaries created during the building of the RTL_EXPR can be
+   reused once the RTL_EXPR has been expanded, with the exception of
+   the RTL_EXPR_RTL.  */
 DEFTREECODE (RTL_EXPR, "rtl_expr", 'e', 2)
 
 /* & in C.  Value is the address at which the operand's value resides.

gcc/tree.h

@@ -749,10 +749,6 @@ struct tree_vec
 /* In a RTL_EXPR node.  */
 #define RTL_EXPR_SEQUENCE(NODE) (*(struct rtx_def **) &EXPR_CHECK (NODE)->exp.operands[0])
 #define RTL_EXPR_RTL(NODE) (*(struct rtx_def **) &EXPR_CHECK (NODE)->exp.operands[1])
-/* Nonzero if the RTL_EXPR does not define a scope, i.e., if
-   temporaries defined during its scope should persist even after the
-   RTL_EXPR has been expanded.  */
-#define RTL_EXPR_HAS_NO_SCOPE(NODE) TREE_ASM_WRITTEN (NODE)
 
 /* In a CALL_EXPR node.  */
 #define CALL_EXPR_RTL(NODE) (*(struct rtx_def **) &EXPR_CHECK (NODE)->exp.operands[2])