Hi Richard,
> switch (code)
> {
> case MULT_EXPR:
> if (!convert_mult_to_widen (stmt, &gsi)
> && !convert_expand_mult_copysign (stmt, &gsi)
> && convert_mult_to_fma (stmt,
> gimple_assign_rhs1 (stmt),
> gimple_assign_rhs2 (stmt)))
>
> given you likely do not want x * copysign (1, y) + z to be transformed into
> FMA but still use xorsign?Ah yes, that's correct, thanks! > > I am also eventually missing a single-use check on the copysign result. If > the > result of copysign is used in multiple places do we want to keep the multiply > or is the xorsign much cheaper? > The only eventual disadvantage would be higher register pressure if y and > copysing (1, y) were not live at the same time before. No the transformation should be limited for single use, I've updated the patch accordingly. Thanks, Tamar > > > > gcc/ > > 2017-08-03 Tamar Christina <tamar.christ...@arm.com> > > Andrew Pinski <pins...@gmail.com> > > > > PR middle-end/19706 > > * internal-fn.def (XORSIGN): New. > > * optabs.def (xorsign_optab): New. > > * tree-ssa-math-opts.c (is_copysign_call_with_1): New. > > (convert_expand_mult_copysign): New. > > (pass_optimize_widening_mul::execute): Call > convert_expand_mult_copysign. > > > > > > -- > Richard Biener <rguent...@suse.de> > SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, > HRB 21284 (AG Nuernberg)
xorsign-math-sp2.patch
Description: xorsign-math-sp2.patch
