🚀 go-pugleaf

The following code, when compiled with GCC 1.35 (with Michael
Meissner's M88k patches installed) resulted in bogus code.
Specifically, although the store into the volatile int
pointed to by "vip" *was* generated correctly, the subsequent
load was *not* properly generated, and instead, the value
(of 7) which was still in a register was reused.  That's not
right!  Since "vip" points to a volatile word, that word
should be referenced again for the final executable statement
shown below.

volatile int vi;

void test ()
{
	volatile int * vip = (volatile int *) 99;

	*vip = 7;
	vi = *vip;
}

I tracked this problem down into reload1.c.  Here is a trivial
(but correct) fix that solved the problem.


diff -rc2 1.35-/reload1.c 1.35+/reload1.c
*** 1.35-/reload1.c	Thu Mar 23 08:03:42 1989
--- 1.35+/reload1.c	Sat May 13 22:06:38 1989
***************
*** 1071,1074 ****
--- 1071,1075 ----
        {
  	rtx addr = XEXP (x, 0);
+ 	rtx mem;
  	FIX_FRAME_POINTER_ADDRESS (addr, depth);
  	/* These MEMs are normally shared.  Make a changed copy;
***************
*** 1075,1079 ****
  	   don't alter the shared MEM, since it needs to be altered
  	   differently each time it occurs (since DEPTH varies).  */
! 	return gen_rtx (MEM, GET_MODE (x), addr);
        }
  
--- 1076,1082 ----
  	   don't alter the shared MEM, since it needs to be altered
  	   differently each time it occurs (since DEPTH varies).  */
! 	mem = gen_rtx (MEM, GET_MODE (x), addr);
! 	MEM_VOLATILE_P (mem) = MEM_VOLATILE_P (x);
! 	return mem;
        }