[PATCH] Fix middle-end/15054 (take 2)

[Ulrich Weigand]

Mike Stump wrote:

> I see the problem.  I don't like your patch, it gets the lifetime 
> wrong.  Please just do this:
[snip]

Ah, I see.  I've implemented your suggestion in the patch below,
and it does indeed also fix the test case. 

Bootstrapped/regtested on s390-ibm-linux and s390x-ibm-linux.
OK?

Bye,
Ulrich


ChangeLog:
	
	PR middle-end/15054
	* expr.c (expand_expr_real): Do not call preserve_temp_slots 
	on a TARGET_EXPR temp.
	* function.c (assign_stack_temp_for_type): Set 'keep' flag for
	TARGET_EXPR temp slots.

testsuite/ChangeLog:

	PR middle-end/15054
	* g++.dg/opt/pr15054.C: New test.

Index: gcc/expr.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/expr.c,v
retrieving revision 1.639
diff -c -p -r1.639 expr.c
*** gcc/expr.c	25 Apr 2004 23:52:13 -0000	1.639
--- gcc/expr.c	30 Apr 2004 12:52:18 -0000
*************** expand_expr_real (tree exp, rtx target, 
*** 8525,8532 ****
  	    else
  	      {
  		target = assign_temp (type, 2, 0, 1);
- 		/* All temp slots at this level must not conflict.  */
- 		preserve_temp_slots (target);
  		SET_DECL_RTL (slot, target);
  		if (TREE_ADDRESSABLE (slot))
  		  put_var_into_stack (slot, /*rescan=*/false);
--- 8525,8530 ----
Index: gcc/function.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/function.c,v
retrieving revision 1.513
diff -c -p -r1.513 function.c
*** gcc/function.c	28 Apr 2004 20:40:44 -0000	1.513
--- gcc/function.c	30 Apr 2004 12:52:19 -0000
*************** assign_stack_temp_for_type (enum machine
*** 780,786 ****
    if (keep == 2)
      {
        p->level = target_temp_slot_level;
!       p->keep = 0;
      }
    else if (keep == 3)
      {
--- 780,786 ----
    if (keep == 2)
      {
        p->level = target_temp_slot_level;
!       p->keep = 1;
      }
    else if (keep == 3)
      {
*** /dev/null	Mon Mar 15 14:37:15 2004
--- gcc/testsuite/g++.dg/opt/pr15054.C	Thu Apr 29 04:06:20 2004
***************
*** 0 ****
--- 1,36 ----
+ // PR middle-end/15054
+ // This used to abort due to overlapping stack temporaries.
+ 
+ // { dg-do run }
+ // { dg-options "-O" }
+ 
+ extern "C" void abort (void);
+ 
+ struct pointer
+ {
+   void* ptr;
+ 
+   pointer(void* x = 0) : ptr(x) {}
+   pointer(const pointer& x) : ptr(x.ptr) {}
+ };
+ 
+ struct element
+ {
+   int canary;
+ 
+   element() : canary(123) { }
+   ~element() { pointer(); if (canary != 123) abort (); }
+ };
+ 
+ inline pointer
+ insert(const element& x)
+ {
+   return pointer(new element(x));
+ }
+ 
+ int
+ main (void)
+ {
+   insert(element());
+   return 0;
+ }

-- 
  Dr. Ulrich Weigand
  weigand@informatik.uni-erlangen.de