expected_value_to_br_prob buglet

[Richard Henderson]

Glibc is now using __builtin_expect in ld.so, which showed
up this bit of laziness.



r~

        * predict.c (expected_value_to_br_prob): Don't bomb if op1 of
        the collected condition is not a constant.

Index: gcc/predict.c
===================================================================
RCS file: /cvs/gcc/egcs/gcc/predict.c,v
retrieving revision 1.6
diff -c -p -d -r1.6 predict.c
*** predict.c	2000/04/21 16:19:20	1.6
--- predict.c	2000/04/22 18:30:01
*************** expected_value_to_br_prob ()
*** 248,256 ****
  	}
  
        /* Collect the branch condition, hopefully relative to EV_REG.  */
        cond = XEXP (SET_SRC (PATTERN (insn)), 0);
        cond = canonicalize_condition (insn, cond, 0, NULL, ev_reg);
!       if (! cond || XEXP (cond, 0) != ev_reg)
  	continue;
  
        /* Substitute and simplify.  Given that the expression we're 
--- 248,266 ----
  	}
  
        /* Collect the branch condition, hopefully relative to EV_REG.  */
+       /* ???  At present we'll miss things like
+ 		(expected_value (eq r70 0))
+ 		(set r71 -1)
+ 		(set r80 (lt r70 r71))
+ 		(set pc (if_then_else (ne r80 0) ...))
+ 	 as canonicalize_condition will render this to us as 
+ 		(lt r70, r71)
+ 	 Could use cselib to try and reduce this further.  */
        cond = XEXP (SET_SRC (PATTERN (insn)), 0);
        cond = canonicalize_condition (insn, cond, 0, NULL, ev_reg);
!       if (! cond
! 	  || XEXP (cond, 0) != ev_reg
! 	  || GET_CODE (XEXP (cond, 1)) != CONST_INT)
  	continue;
  
        /* Substitute and simplify.  Given that the expression we're