🚀 go-pugleaf

Here is a patch to a typo in fold-const.c (GCC 2.3.1, sparc).  On a sparc, the
expression (HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT - 1) evaluates to
1<<31, which is a signed integer overflow.  Replacing it with (-1)<<31 fixes
the problem.

This is the only constant expression signed integer overflow that I found in
GCC 2.3.1 itself (sparc, SunOS 4.1.2).

Thu Nov  5 01:53:38 1992  Paul Eggert  (eggert@twinsun.com)

	* fold-const.c (fold_convert): Avoid signed integer overflow in 1<<N.

===================================================================
RCS file: fold-const.c,v
retrieving revision 2.3.1.5
retrieving revision 2.3.1.6
diff -c -r2.3.1.5 -r2.3.1.6
*** fold-const.c	1992/11/05 01:27:21	2.3.1.5
--- fold-const.c	1992/11/05 01:53:38	2.3.1.6
***************
*** 1530,1536 ****
  	    if (d >= (REAL_VALUE_TYPE) half_word * half_word / 2)
  	      {
  		low = d - (REAL_VALUE_TYPE) half_word * half_word / 2;
! 		low |= (HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT - 1);
  	      }
  	    else
  	      low = (HOST_WIDE_INT) d;
--- 1530,1536 ----
  	    if (d >= (REAL_VALUE_TYPE) half_word * half_word / 2)
  	      {
  		low = d - (REAL_VALUE_TYPE) half_word * half_word / 2;
! 		low |= (HOST_WIDE_INT) -1 << (HOST_BITS_PER_WIDE_INT - 1);
  	      }
  	    else
  	      low = (HOST_WIDE_INT) d;