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Re: [PATCH] Fix PR28268, ICE building vector const { 1, 1 }
On Thu, 6 Jul 2006, Paolo Bonzini wrote:
>
> > This makes me uncomfortable. The number zero seems like a special
> > case which merits special handling. The number one does not. What
> > you are looking for is a function which returns the multiplicative
> > identity for TYPE. Currently you are getting it by calling
> > fold_convert (TYPE, integer_one_node). Suppose you write the
> > multiplicative identify function, and handle VECTOR_TYPE there, rather
> > than making the number one a special case in fold_convert?
>
> I agree, and there is indeed already get_one_constant in tree-ssa-math-opts.c.
/* Return the LHS of a RDIV_EXPR that computes a reciprocal in type TYPE.
*/
static tree
get_constant_one (tree type)
;)
well, ok - more like writing a general one. And I'd call it
build_cst_one? (or even build_one_cst to mimic build_int_cst).
> I'd suggest that you move it to fold-const.c and use it.
>
> I think -1 is way more "special" than 1. It is not stretching the argument as
> much as 1, because it is always "all ones".
It depends on what transformations you are after.
Richard.
--
Richard Guenther <rguenther@suse.de>
Novell / SUSE Labs