combine.c (simplify_logical, case AND): Only call ...

[Jim Wilson]

This fixes a bug that showed up in a 32 bit hosted cross compiler to a 64 bit
target.

Combine converted
  x = (and:DI (ashiftrt:DI (ashift:DI (subreg:DI (reg:SI 336) 0)
                                      (const_int 32))
                           (const_int 32))
              (const_int -0x80000000))
to
      (and:DI (subreg:DI (reg:SI 336) 0) (const_int -0x80000000))
which is wrong, because the sign-extension of (reg:SI 336) has been lost.

Mon Jun 14 12:57:38 1999  David Mosberger  <davidm@hpl.hp.com>

        * combine.c (simplify_logical, case AND): Only call
        simplify_and_const_int if the mode is no wider than HOST_WIDE_INT
	or the constant is positive.

Index: combine.c
===================================================================
RCS file: /egcs/carton/cvsfiles/egcs/gcc/combine.c,v
retrieving revision 1.62
diff -p -r1.62 combine.c
*** combine.c	1999/03/25 16:54:31	1.62
--- combine.c	1999/06/14 20:05:35
*************** simplify_logical (x, last)
*** 4902,4908 ****
  	  && ! side_effects_p (op1))
  	x = gen_binary (AND, mode, XEXP (XEXP (op0, 0), 0), op1);
  
!       if (GET_CODE (op1) == CONST_INT)
  	{
  	  x = simplify_and_const_int (x, mode, op0, INTVAL (op1));
  
--- 4902,4913 ----
  	  && ! side_effects_p (op1))
  	x = gen_binary (AND, mode, XEXP (XEXP (op0, 0), 0), op1);
  
!       /* We can call simplify_and_const_int only if we don't lose
! 	 any (sign) bits when converting INTVAL (op1) to
! 	 "unsigned HOST_WIDE_INT".  */
!       if (GET_CODE (op1) == CONST_INT
! 	  && (GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT
! 	      || INTVAL (op1) > 0))
  	{
  	  x = simplify_and_const_int (x, mode, op0, INTVAL (op1));