Re: [PATCH] libstdc++: ppc: conditionalize vsx-only simd intrinsics

[Alexandre Oliva <oliva@adacore.com>]

On Apr 28, 2022, Segher Boessenkool <segher@kernel.crashing.org> wrote:

> On Thu, Apr 28, 2022 at 03:09:54AM -0300, Alexandre Oliva wrote:

>> +# ifdef __VSX__

> No space after # (here and everywhere else).

'k, thanks

>> +		  "no __intrinsic_type support for [long] double on PPC w/o VSX");

> This change isn't in the changelog.

It is, it's just that long double is dealt with differently from the
other types, so requiring VSX for it takes a different form:

> 	* include/experimental/bits/simd.h [__ALTIVEC__]: Require VSX
> 	for double, long long, and 64-bit long and 64-bit long double
> 	intrinsic types.                           ^^^^^^^^^^^^^^^^^^



> The message should not say "long
> double" without qualifying it as "64-bit long double".

How about qualifying both such messages as in this incremental patchlet:

@@ -2456,11 +2456,11 @@ template <typename _Tp, size_t _Bytes>
     static constexpr bool _S_is_ldouble = is_same_v<_Tp, long double>;
     // allow _Tp == long double with -mlong-double-64
     static_assert(!(_S_is_ldouble && sizeof(long double) > sizeof(double)),
-		  "no __intrinsic_type support for long double on PPC");
+		  "no __intrinsic_type support for 128-bit floating point on PPC");
 #ifndef __VSX__
     static_assert(!(is_same_v<_Tp, double>
 		    || (_S_is_ldouble && sizeof(long double) == sizeof(double))),
-		  "no __intrinsic_type support for [long] double on PPC w/o VSX");
+		  "no __intrinsic_type support for 64-bit floating point on PPC w/o VSX");
 #endif
     using type =
       typename __intrinsic_type_impl<

> Okay for trunk without this part of the patch, and the spaces after the
> hash signs deleted.  Or send a new patch with the "[long] double" thing
> fixed?

Thanks, awaiting feedback on the suggestion above to post the consolidated patch.

-- 
Alexandre Oliva, happy hacker                https://FSFLA.org/blogs/lxo/
   Free Software Activist                       GNU Toolchain Engineer
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