On April 24, 2017 2:49:04 PM GMT+02:00, Marc Glisse <marc.gli...@inria.fr> wrote: >On Mon, 24 Apr 2017, Jakub Jelinek wrote: > >> On Mon, Apr 24, 2017 at 09:41:01AM +0200, Richard Biener wrote: >>> On Sun, Apr 23, 2017 at 11:38 PM, Marc Glisse <marc.gli...@inria.fr> >wrote: >>>> Hello, >>>> >>>> this patches teaches tree_expr_nonzero_warnv_p to handle SSA_NAME >using >>>> range information and known (non-)zero bits, by delegating to >>>> expr_not_equal_to which already knows how to handle all that. >>>> >>>> This makes one strict overflow warning disappear. It isn't >particularly >>>> surprising, since the new code makes tree_expr_nonzero_warnv_p >return true >>>> without warning (we do not remember if the range information was >obtained >>>> using strict overflow). In my opinion, improving code generation is >more >>>> important than this specific warning. >>>> >>>> Bootstrap+regtest on powerpc64le-unknown-linux-gnu. >>> >>> Hmm, I think you need to guard this with a INTEGRAL_TYPE_P check >>> given the comment on tree_single_nonzero_warnv_p also talks about >>> FP. > >The SSA_NAME case in expr_not_equal_to starts with > > if (!INTEGRAL_TYPE_P (TREE_TYPE (t))) > return false; > >Do you still want the extra check in tree_single_nonzero_warnv_p before > >calling expr_not_equal_to?
Yes because you create a wide int with TYPE_PRECISION. Richard. >> I vaguely remember there were issues with that, because VRP uses >> the *_nonzero_warnv* functions to compute the ranges and now those >> functions would use range info. But it has been some time ago and >maybe this >> patch is different enough from what I've been trying back then. > >I hope it is safe, but we'll see. > >> So just please watch carefully for any fallout. > >Ok.
