On 10/18/2013 01:18 PM, Richard Biener wrote: > Index: gcc/fold-const.c > =================================================================== > --- gcc/fold-const.c (revision 203267) > +++ gcc/fold-const.c (working copy) > @@ -7270,8 +7270,8 @@ fold_plusminus_mult_expr (location_t loc, enum tre > HOST_WIDE_INT int01, int11, tmp; > bool swap = false; > tree maybe_same; > - int01 = TREE_INT_CST_LOW (arg01); > - int11 = TREE_INT_CST_LOW (arg11); > + int01 = int_cst_value (arg01); > + int11 = int_cst_value (arg11); > > this is not correct - it will mishandle all large unsigned numbers. > > The real issue is that we rely on twos-complement arithmetic to work > when operating on pointer offsets (because we convert them all to > unsigned sizetype). That makes interpreting the offsets or expressions > that compute offsets hard (or impossible in some cases), as you can > see from the issues in IVOPTs.
I still have patches to keep pointer types in ivopts (using a new POINTER_PLUSV_EXPR). Would that help in this case? Last time I posted them they met an unenthusiastic reception so I've never bothered to repost them. Bernd
