On Fri, Mar 03, 2023 at 03:35:44PM -0600, Segher Boessenkool wrote:
> Hi!
>
> On Fri, Feb 03, 2023 at 12:53:05AM -0500, Michael Meissner wrote:
> > This patch reworks how the complex multiply and divide built-in functions
> > are
> > done.
>
> > I tested all 3 patchs for PR target/107299 on:
>
> Is this part of the proposed commit message? As Ke Wen pointed out, it
> is wrong. Most of your mail does not belong in a commit message at all,
> but some probably does? Please do this clearer with future patches.
>
> > * config/rs6000/rs6000.cc (create_complex_muldiv): Delete.
> > (init_float128_ieee): Delete code to switch complex multiply and divide
> > for long double.
>
> I like this kind of patch :-)
>
> > +/* Internal function to return the built-in function id for the complex
> > + multiply operation for a given mode. */
> > +
> > +static inline built_in_function
> > +complex_multiply_builtin_code (machine_mode mode)
> > +{
> > + return (built_in_function) (BUILT_IN_COMPLEX_MUL_MIN + mode
> > + - MIN_MODE_COMPLEX_FLOAT);
> > +}
>
> There should be an assert that the mode is as expected
> gcc_assert (IN_RANGE (mode, MIN_MODE_COMPLEX_FLOAT,
> MAX_MODE_COMPLEX_FLOAT));
> or such.
Ok.
> Using more temporaries should make this simpler as well, obviate the
> need for explicit casts, and make everything fit on short lines.
>
> > +static inline built_in_function
> > +complex_divide_builtin_code (machine_mode mode)
> > +{
> > + return (built_in_function) (BUILT_IN_COMPLEX_DIV_MIN + mode
> > + - MIN_MODE_COMPLEX_FLOAT);
> > +}
>
> Ditto ofc.
>
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/powerpc/divic3-1.c
> > @@ -0,0 +1,18 @@
> > +/* { dg-do compile { target { powerpc*-*-* } } } */
>
> Leave the target clause out.
Ok.
> > +/* { dg-require-effective-target powerpc_p8vector_ok } */
> > +/* { dg-require-effective-target longdouble128 } */
> > +/* { dg-require-effective-target ppc_float128_sw } */
> > +/* { dg-options "-O2 -mpower8-vector -mabi=ieeelongdouble -Wno-psabi" } */
>
> It would be nice if you did not try to add -mpower8-vector in more
> testcases :-(
Yep.
> Is -Wno-psabi needed here? What is the error you get without it / on
> which configurations? Cargo-culting hiding the warnings makes you see
> fewer warnings, but that is the opposite of a good idea.
>
> > +/* { dg-final { scan-assembler "bl __divtc3" } } */
>
> This name depends on what object format and ABI is in use (some have an
> extra leading underscore, or a dot, or whatever).
Yes it is needed if GCC is configured against an older GLIBC before the full
IEEE 128-bit support was added. For example, on my big endian test system, you
get warnings if you switch the floating point format. I would imagine it would
also fail on little endian system with older libraries.
--
Michael Meissner, IBM
PO Box 98, Ayer, Massachusetts, USA, 01432
email: meiss...@linux.ibm.com
