Yet another PREFERRED_STACK_BOUNDARY fix and sanity check

[Jan Hubicka <hubicka at atrey dot karlin dot mff dot cuni dot cz>]

Hi
This patch adds more sanity checking to calls.c to verify that stack
pointer really is aligned before emit_call_1 is called.
This don't hold in one case - when nested call is done and pending_stack_adjust
is nonzero so no alignment instruction is necessary for the outer call.
Then NO_DEFER_POP is not called and stack gets missaligned by aligning it
for nested call.
I've fixed it by doing NO_DEFER_POP unconditionally now.  Note that I am
aware, that this penalize nested calls even on non-i386 architectures,
but I have proper fix for this, that require quite grand revamps in the
calls.c that I want to delay until the code is more stable and other pending
stuff is done (such as emit_library_call_value_1 merger).

Honza

Fri Apr  7 13:57:16 MET DST 2000  Jan Hubicka  <jh@suse.cz>
	* calls.c (expand_call): Do NO_DEFER_POP unconditionally once
	stack is propertly aligned; add sanity checking for aligned
	stack pointer.
	(expand_library_call_value_1): Add sanity checking for aligned
	stack pointer.

Index: egcs/gcc/calls.c
===================================================================
RCS file: /cvs/gcc/egcs/gcc/calls.c,v
retrieving revision 1.115
diff -c -3 -p -r1.115 calls.c
*** calls.c	2000/04/05 01:52:54	1.115
--- calls.c	2000/04/07 11:56:37
*************** expand_call (exp, target, ignore)
*** 2671,2678 ****
  					- unadjusted_args_size));
  	  /* Now that the stack is properly aligned, pops can't safely
  	     be deferred during the evaluation of the arguments.  */
- 	  NO_DEFER_POP;
  	}
  #endif
  
        /* Don't try to defer pops if preallocating, not even from the first arg,
--- 2671,2678 ----
  					- unadjusted_args_size));
  	  /* Now that the stack is properly aligned, pops can't safely
  	     be deferred during the evaluation of the arguments.  */
  	}
+       NO_DEFER_POP;
  #endif
  
        /* Don't try to defer pops if preallocating, not even from the first arg,
*************** expand_call (exp, target, ignore)
*** 2798,2803 ****
--- 2798,2809 ----
        /* All arguments and registers used for the call must be set up by
  	 now!  */
  
+       /* Stack ought to be propertly aligned now.  */
+ #ifdef PREFERRED_STACK_BOUNDARY
+       if (stack_pointer_delta & (preferred_stack_boundary / BITS_PER_UNIT - 1))
+ 	abort();
+ #endif
+ 
        /* Generate the actual call instruction.  */
        emit_call_1 (funexp, fndecl, funtype, unadjusted_args_size,
  		   args_size.constant, struct_value_size,
*************** emit_library_call_value_1 (retval, orgfu
*** 3681,3686 ****
--- 3687,3698 ----
    /* Don't allow popping to be deferred, since then
       cse'ing of library calls could delete a call and leave the pop.  */
    NO_DEFER_POP;
+ 
+   /* Stack ought to be propertly aligned now.  */
+ #ifdef PREFERRED_STACK_BOUNDARY
+   if (stack_pointer_delta & (PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT - 1))
+     abort();
+ #endif
  
    /* We pass the old value of inhibit_defer_pop + 1 to emit_call_1, which
       will set inhibit_defer_pop to that value.  */