Re: How to gimplify_build a FMA_EXPR since it was removed?

[Andrew Pinski <pinskia@gmail.com>]

On Mon, Feb 4, 2019 at 3:13 PM Laurent Thévenoux <lrnt@thvnx.com> wrote:
>
> Hi,
>
> Thanks for pointing this me out. Nevertheless, I’m not sure this can apply in my case since gimple_build_call_internal() returns a gimple data type while gimplify_build3() returns a tree data type. I’ll try to figure how faisable is to use it in my case. For more context, see the code snippet below.

You need to create a new temp ssa name to hold the FMA results.  There
are few examples in the tree-ssa-phi-opt.c code for on how to use this
way instead of using gimplify_build3.

Thanks,
Andrew Pinski

>
> ```
> static void
> some_fn (gimple_stmt_iterator *gsi, tree inner_type, tree ar, tree ai, tree br, tree bi)
> {
>   tree rr, ri, pr1;
>
>   p1r = gimplify_build2 (gsi, MULT_EXPR, inner_type, ar, ar);
>   rr  = gimplify_build3 (gsi, FMA_EXPR, inner_type, ai, ai, p1r);
>   ri  = build_real (inner_type, dconst0);
>   update_complex_assignment (gsi, rr, ri);
> }
>
> ```
>
> > Le 4 févr. 2019 à 23:38, Andrew Pinski <pinskia@gmail.com> a écrit :
> >
> > On Mon, Feb 4, 2019 at 4:47 AM Laurent Thévenoux <lrnt@thvnx.com> wrote:
> >>
> >> Sorry for duplicate, gcc-help was not the right mailing list for this one.
> >>
> >>
> >> -------- Original Message --------
> >> Subject: How to gimplify_build a FMA_EXPR since it was removed?
> >> Date: Monday, February 04, 2019 13:28 CET
> >> From: Laurent Thévenoux <lrnt@thvnx.com>
> >> To: gcc-help@gcc.gnu.org
> >> CC: richard.sandiford@linaro.org
> >>
> >>
> >>
> >> Hi,
> >>
> >> I've developed some code in gcc/tree-complex.c. I was using the
> >> FMA_EXPR to generate fma operations such as in:
> >>
> >> ```
> >> rr  = gimplify_build3 (gsi, FMA_EXPR, inner_type, ai, ai, p1r);```
> >>
> >> FMA_EXPR was removed in https://gcc.gnu.org/ml/gcc-patches/2018-05/msg00570.html.
> >>
> >> Is there an easy way to gimplify FMAs with the new functions
> >> introduced in the patch below?
> >
> > From that patch (e.g. rs6000_gimple_fold_builtin):
> >
> > - gimple *g = gimple_build_assign (lhs, FMA_EXPR, arg0, arg1, arg2);
> > + gcall *g = gimple_build_call_internal (IFN_FMA, 3, arg0, arg1, arg2);
> > + gimple_call_set_lhs (g, lhs);
> > + gimple_call_set_nothrow (g, true);
> >
> >
> > Thanks,
> > Andrew Pinski
> >
> >
> >>
> >> Thanks,
> >> Laurent
>