Revert this patch:

	2000-03-04  Mark Mitchell  <mark@codesourcery.com>

From-SVN: r32343

gcc/ChangeLog

+2000-03-05  Mark Mitchell  <mark@codesourcery.com>
+
+	Revert this patch:
+	2000-03-04  Mark Mitchell  <mark@codesourcery.com>
+
 2000-03-04  Thomas Schuster <Thomas.Schuster@gmx.net>
 
 	* regmove.c (copy_src_to_dest)  Do not create src->dest move

gcc/emit-rtl.c

@@ -3376,6 +3376,7 @@ start_sequence ()
   tem->next = seq_stack;
   tem->first = first_insn;
   tem->last = last_insn;
+  tem->sequence_rtl_expr = seq_rtl_expr;
 
   seq_stack = tem;
 
@@ -3383,6 +3384,19 @@ start_sequence ()
   last_insn = 0;
 }
 
+/* Similarly, but indicate that this sequence will be placed in T, an
+   RTL_EXPR.  See the documentation for start_sequence for more
+   information about how to use this function.  */
+
+void
+start_sequence_for_rtl_expr (t)
+     tree t;
+{
+  start_sequence ();
+
+  seq_rtl_expr = t;
+}
+
 /* Set up the insn chain starting with FIRST as the current sequence,
    saving the previously current one.  See the documentation for
    start_sequence for more information about how to use this function.  */
@@ -3416,6 +3430,7 @@ push_topmost_sequence ()
 
   first_insn = top->first;
   last_insn = top->last;
+  seq_rtl_expr = top->sequence_rtl_expr;
 }
 
 /* After emitting to the outer-level insn chain, update the outer-level
@@ -3431,6 +3446,7 @@ pop_topmost_sequence ()
 
   top->first = first_insn;
   top->last = last_insn;
+  /* ??? Why don't we save seq_rtl_expr here?  */
 
   end_sequence ();
 }
@@ -3455,6 +3471,7 @@ end_sequence ()
 
   first_insn = tem->first;
   last_insn = tem->last;
+  seq_rtl_expr = tem->sequence_rtl_expr;
   seq_stack = tem->next;
 
   free (tem);
@@ -3743,6 +3760,7 @@ init_emit ()
   f->emit = (struct emit_status *) xmalloc (sizeof (struct emit_status));
   first_insn = NULL;
   last_insn = NULL;
+  seq_rtl_expr = NULL;
   cur_insn_uid = 1;
   reg_rtx_no = LAST_VIRTUAL_REGISTER + 1;
   last_linenum = 0;
@@ -3816,6 +3834,7 @@ mark_sequence_stack (ss)
   while (ss)
     {
       ggc_mark_rtx (ss->first);
+      ggc_mark_tree (ss->sequence_rtl_expr);
       ss = ss->next;
     }
 }
@@ -3837,6 +3856,7 @@ mark_emit_status (es)
     ggc_mark_rtx (*r);
 
   mark_sequence_stack (es->sequence_stack);
+  ggc_mark_tree (es->sequence_rtl_expr);
   ggc_mark_rtx (es->x_first_insn);
 }
 

gcc/except.c

@@ -2095,7 +2095,7 @@ protect_with_terminate (e)
       TREE_TYPE (handler) = void_type_node;
       RTL_EXPR_RTL (handler) = const0_rtx;
       TREE_SIDE_EFFECTS (handler) = 1;
-      start_sequence ();
+      start_sequence_for_rtl_expr (handler);
 
       emit_library_call (terminate_libfunc, 0, VOIDmode, 0);
       emit_barrier ();

gcc/expr.c

@@ -6306,6 +6306,8 @@ expand_expr (exp, target, tmode, modifier)
 	  emit_insns (RTL_EXPR_SEQUENCE (exp));
 	  RTL_EXPR_SEQUENCE (exp) = const0_rtx;
 	}
+      preserve_rtl_expr_result (RTL_EXPR_RTL (exp));
+      free_temps_for_rtl_expr (exp);
       return RTL_EXPR_RTL (exp);
 
     case CONSTRUCTOR:

gcc/function.c

@@ -708,6 +708,7 @@ assign_stack_temp_for_type (mode, size, keep, type)
 						    rounded_size));
 	      p->align = best_p->align;
 	      p->address = 0;
+	      p->rtl_expr = 0;
 	      p->next = temp_slots;
 	      temp_slots = p;
 
@@ -775,6 +776,7 @@ assign_stack_temp_for_type (mode, size, keep, type)
 
   p->in_use = 1;
   p->addr_taken = 0;
+  p->rtl_expr = seq_rtl_expr;
 
   if (keep == 2)
     {
@@ -1127,6 +1129,34 @@ preserve_temp_slots (x)
       p->level--;
 }
 
+/* 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
+   RTL_EXPR.  */
+
+void
+preserve_rtl_expr_result (x)
+     rtx x;
+{
+  struct temp_slot *p;
+
+  /* If X is not in memory or is at a constant address, it cannot be in
+     a temporary slot.  */
+  if (x == 0 || GET_CODE (x) != MEM || CONSTANT_P (XEXP (x, 0)))
+    return;
+
+  /* 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 != 0)
+    {
+      p->level = MIN (p->level, temp_slot_level);
+      p->rtl_expr = 0;
+    }
+
+  return;
+}
+
 /* Free all temporaries used so far.  This is normally called at the end
    of generating code for a statement.  Don't free any temporaries
    currently in use for an RTL_EXPR that hasn't yet been emitted.
@@ -1140,7 +1170,23 @@ free_temp_slots ()
   struct temp_slot *p;
 
   for (p = temp_slots; p; p = p->next)
-    if (p->in_use && p->level == temp_slot_level && ! p->keep)
+    if (p->in_use && p->level == temp_slot_level && ! p->keep
+	&& p->rtl_expr == 0)
+      p->in_use = 0;
+
+  combine_temp_slots ();
+}
+
+/* Free all temporary slots used in T, an RTL_EXPR node.  */
+
+void
+free_temps_for_rtl_expr (t)
+     tree t;
+{
+  struct temp_slot *p;
+
+  for (p = temp_slots; p; p = p->next)
+    if (p->rtl_expr == t)
       p->in_use = 0;
 
   combine_temp_slots ();
@@ -1218,7 +1264,7 @@ pop_temp_slots ()
   struct temp_slot *p;
 
   for (p = temp_slots; p; p = p->next)
-    if (p->in_use && p->level == temp_slot_level)
+    if (p->in_use && p->level == temp_slot_level && p->rtl_expr == 0)
       p->in_use = 0;
 
   combine_temp_slots ();
@@ -6934,6 +6980,8 @@ mark_temp_slot (t)
     {
       ggc_mark_rtx (t->slot);
       ggc_mark_rtx (t->address);
+      ggc_mark_tree (t->rtl_expr);
+
       t = t->next;
     }
 }

gcc/function.h

@@ -46,6 +46,7 @@ struct sequence_stack
 {
   /* First and last insns in the chain of the saved sequence.  */
   rtx first, last;
+  tree sequence_rtl_expr;
   struct sequence_stack *next;
 };
 
@@ -76,6 +77,11 @@ struct emit_status
   rtx x_first_insn;
   rtx x_last_insn;
 
+  /* RTL_EXPR within which the current sequence will be placed.  Use to
+     prevent reuse of any temporaries within the sequence until after the
+     RTL_EXPR is emitted.  */
+  tree sequence_rtl_expr;
+
   /* Stack of pending (incomplete) sequences saved by `start_sequence'.
      Each element describes one pending sequence.
      The main insn-chain is saved in the last element of the chain,
@@ -111,6 +117,7 @@ struct emit_status
 
 /* For backward compatibility... eventually these should all go away.  */
 #define reg_rtx_no (cfun->emit->x_reg_rtx_no)
+#define seq_rtl_expr (cfun->emit->sequence_rtl_expr)
 #define regno_reg_rtx (cfun->emit->x_regno_reg_rtx)
 #define seq_stack (cfun->emit->sequence_stack)
 

gcc/rtl.h

@@ -1508,6 +1508,7 @@ extern void reposition_prologue_and_epilogue_notes	PARAMS ((rtx));
 extern void thread_prologue_and_epilogue_insns		PARAMS ((rtx));
 extern int prologue_epilogue_contains			PARAMS ((rtx));
 extern HOST_WIDE_INT get_frame_size			PARAMS ((void));
+extern void preserve_rtl_expr_result			PARAMS ((rtx));
 extern void mark_temp_addr_taken			PARAMS ((rtx));
 extern void update_temp_slot_address			PARAMS ((rtx, rtx));
 extern void purge_addressof				PARAMS ((rtx));

gcc/stmt.c

@@ -2025,7 +2025,7 @@ expand_start_stmt_expr ()
   t = make_node (RTL_EXPR);
   resume_momentary (momentary);
   do_pending_stack_adjust ();
-  start_sequence ();
+  start_sequence_for_rtl_expr (t);
   NO_DEFER_POP;
   expr_stmts_for_value++;
   return t;

gcc/tree.h

@@ -2452,6 +2452,7 @@ extern void preserve_temp_slots		PARAMS ((struct rtx_def *));
 extern int aggregate_value_p		PARAMS ((tree));
 extern tree reorder_blocks		PARAMS ((tree,
 						struct rtx_def *));
+extern void free_temps_for_rtl_expr	PARAMS ((tree));
 extern void instantiate_virtual_regs	PARAMS ((tree, struct rtx_def *));
 extern void unshare_all_rtl		PARAMS ((tree, struct rtx_def *));
 extern int max_parm_reg_num		PARAMS ((void));
@@ -2485,6 +2486,7 @@ extern struct rtx_def *store_expr		PARAMS ((tree, struct rtx_def *,
 extern void check_max_integer_computation_mode	PARAMS ((tree));
 
 /* In emit-rtl.c */
+extern void start_sequence_for_rtl_expr		PARAMS ((tree));
 extern struct rtx_def *emit_line_note_after	PARAMS ((char *, int,
 							struct rtx_def *));
 extern struct rtx_def *emit_line_note		PARAMS ((char *, int));