Re: [PATCH] libstdc++: Correct NTTP and simd_mask ctor call

[Alexandre Oliva <oliva@adacore.com>]

Hello, Matthias,

On May 26, 2023, Matthias Kretz via Libstdc++ <libstdc++@gcc.gnu.org> wrote:

> OK for master and all backports (after 11.4 is done)?
> tested on powerpc64le-linux-gnu and x86_64-pc-linux-gnu

> 	* testsuite/experimental/simd/pr109822_cast_functions.cc: New
> 	test.

This testcase fails to compile on PowerPC targets without VSX: 64-bit
integer and floating-point types cannot be vectorized.

I wonder if the test is malformed (and should be amended to test for
available simd types), or whether a patch like this would be desirable
to make simd constructs more portable.  I'm not sure about the
requirements.


[libstdc++] [simd] [ppc] use nonvector intrinsic fallback types

From: Alexandre Oliva <oliva@adacore.com>

Compiling such tests as pr109822_cast_functions.cc on powerpc targets
that don't support VSX fails because some intrinsic types that are
expected to be vectorizable are not defined without VSX.

Introduce fallback non-vector types to enable the code to compile.


for  libstdc++-v3/ChangeLog

	* include/experimental/bits/simd.h: Introduce fallback
	non-vector intrinsic_type_impl specializations for PowerPC
	without VSX.
---
 libstdc++-v3/include/experimental/bits/simd.h |   12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/libstdc++-v3/include/experimental/bits/simd.h b/libstdc++-v3/include/experimental/bits/simd.h
index 834fe923065bd..2691823e869e8 100644
--- a/libstdc++-v3/include/experimental/bits/simd.h
+++ b/libstdc++-v3/include/experimental/bits/simd.h
@@ -2431,9 +2431,14 @@ template <typename _Tp>
 #define _GLIBCXX_SIMD_PPC_INTRIN(_Tp)                                          \
   template <>                                                                  \
     struct __intrinsic_type_impl<_Tp> { using type = __vector _Tp; }
+#define _GLIBCXX_SIMD_PPC_INTRIN_NOVEC(_Tp)				       \
+  template <>                                                                  \
+    struct __intrinsic_type_impl<_Tp> { using type = _Tp; }
 _GLIBCXX_SIMD_PPC_INTRIN(float);
 #ifdef __VSX__
 _GLIBCXX_SIMD_PPC_INTRIN(double);
+#else
+_GLIBCXX_SIMD_PPC_INTRIN_NOVEC(double);
 #endif
 _GLIBCXX_SIMD_PPC_INTRIN(signed char);
 _GLIBCXX_SIMD_PPC_INTRIN(unsigned char);
@@ -2444,12 +2449,19 @@ _GLIBCXX_SIMD_PPC_INTRIN(unsigned int);
 #if defined __VSX__ || __SIZEOF_LONG__ == 4
 _GLIBCXX_SIMD_PPC_INTRIN(signed long);
 _GLIBCXX_SIMD_PPC_INTRIN(unsigned long);
+#else
+_GLIBCXX_SIMD_PPC_INTRIN_NOVEC(signed long);
+_GLIBCXX_SIMD_PPC_INTRIN_NOVEC(unsigned long);
 #endif
 #ifdef __VSX__
 _GLIBCXX_SIMD_PPC_INTRIN(signed long long);
 _GLIBCXX_SIMD_PPC_INTRIN(unsigned long long);
+#else
+_GLIBCXX_SIMD_PPC_INTRIN_NOVEC(signed long long);
+_GLIBCXX_SIMD_PPC_INTRIN_NOVEC(unsigned long long);
 #endif
 #undef _GLIBCXX_SIMD_PPC_INTRIN
+#undef _GLIBCXX_SIMD_PPC_INTRIN_NOVEC
 
 template <typename _Tp, size_t _Bytes>
   struct __intrinsic_type<_Tp, _Bytes, enable_if_t<__is_vectorizable_v<_Tp> && _Bytes <= 16>>


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