On Tue, 29 Sep 2020, Segher Boessenkool wrote:
> Hi Raoni,
>
> Some of this isn't an rs6000 patch, but the subject says it is, so it
> might well not draw the attention it needs.
>
> Adding some Cc:s.
>
> On Fri, Sep 04, 2020 at 12:52:30PM -0300, Raoni Fassina Firmino wrote:
> > There is one pending question raised by Segher, It is about adding
> > documentation, I am not sure if it is needed and if so, where it
> > should be. I will quote the relevant part of the conversation[2] from
> > the v1 thread for context:
> >
> > > > > +OPTAB_D (fegetround_optab, "fegetround$a")
> > > > > +OPTAB_D (feclearexcept_optab, "feclearexcept$a")
> > > > > +OPTAB_D (feraiseexcept_optab, "feraiseexcept$a")
> > > >?
> > > > Should those be documented somewhere? (In gcc/doc/ somewhere).
> > >
> > > I am lost on that one. I took a look on the docs (I hope looking on the
> > > online docs was good enough) and I didn't find a place where i feel it
> > > sits well. On the PowerPC target specific sections (6.60.22 Basic
> > > PowerPC Built-in Functions), I didn't found it mentioning builtins that
> > > are optimizations for the standard library functions, but we do have
> > > many of these for Power. Then, on the generic section (6.59 Other
> > > Built-in Functions Provided by GCC) it mentions C99 functions that have
> > > builtins but it seems like it mentions builtins that have target
> > > independent implementation, or at least it dos not say that some
> > > builtins may be implemented on only some targets. And in this case
> > > there is no implementation (for now) for any other target that is not
> > > PowerPc.
> > >
> > > So, I don't know if or where this should be documented.
>
> I don't see much about optabs in the docs either. Add some text to
> optabs.def itself then?
All optabs are documented in doc/md.texi as 'instruction patterns'
This is where new optabs need to be documented.
> > +(define_expand "feclearexceptsi"
> > + [(use (match_operand:SI 1 "const_int_operand" "n"))
> > + (set (match_operand:SI 0 "gpc_reg_operand")
> > + (const_int 0))]
> > + "TARGET_HARD_FLOAT"
> > +{
> > + switch (INTVAL (operands[1]))
> > + {
> > + case 0x2000000: /* FE_INEXACT */
> > + case 0x4000000: /* FE_DIVBYZERO */
> > + case 0x8000000: /* FE_UNDERFLOW */
> > + case 0x10000000: /* FE_OVERFLOW */
>
> Please write 0x02000000 etc. instead?
>
> > +;; int fegraiseexcept(int excepts)
>
> (typo)
>
> > +/* { dg-do run } */
> > +/* { dg-require-effective-target fenv_exceptions } */
> > +/* { dg-options "-lm -fno-builtin" } */
>
> That -fno-builtin looks very strange... Comment what it is for?
>
> > +#define FAIL(v, e) printf("ERROR, __builtin_fegetround() returned %d," \
> > + " not the expecected value %d\n", v, e);
>
> (Typo, "expected")
>
> The rs6000 part is okay for trunk (with those modifications), after the
> generic parts is approved. Thanks!
>
>
> Segher
>
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