[gcc r12-1785] libstdc++: Fix condition when AVX512F ldexp implementation is used

[Jonathan Wakely <redi@gcc.gnu.org>]

https://gcc.gnu.org/g:5014f12509980d51cfbb34bb61b1605356592afd

commit r12-1785-g5014f12509980d51cfbb34bb61b1605356592afd
Author: Matthias Kretz <m.kretz@gsi.de>
Date:   Thu Jun 24 14:20:15 2021 +0100

    libstdc++: Fix condition when AVX512F ldexp implementation is used
    
    This improves codegen of ldexp if AVX512VL is available.
    
    Signed-off-by: Matthias Kretz <m.kretz@gsi.de>
    
    libstdc++-v3/ChangeLog:
    
            * include/experimental/bits/simd_x86.h (_S_ldexp): The AVX512F
            implementation doesn't require a _VecBltnBtmsk ABI tag, it
            requires either a 64-Byte input (in which case AVX512F must be
            available) or AVX512VL.

Diff:
---
 libstdc++-v3/include/experimental/bits/simd_x86.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/libstdc++-v3/include/experimental/bits/simd_x86.h b/libstdc++-v3/include/experimental/bits/simd_x86.h
index 305d7a9fa54..5706bf63845 100644
--- a/libstdc++-v3/include/experimental/bits/simd_x86.h
+++ b/libstdc++-v3/include/experimental/bits/simd_x86.h
@@ -2611,13 +2611,14 @@ template <typename _Abi>
       _S_ldexp(_SimdWrapper<_Tp, _Np> __x,
 	       __fixed_size_storage_t<int, _Np> __exp)
       {
-	if constexpr (__is_avx512_abi<_Abi>())
+	if constexpr (sizeof(__x) == 64 || __have_avx512vl)
 	  {
 	    const auto __xi = __to_intrin(__x);
 	    constexpr _SimdConverter<int, simd_abi::fixed_size<_Np>, _Tp, _Abi>
 	      __cvt;
 	    const auto __expi = __to_intrin(__cvt(__exp));
-	    constexpr auto __k1 = _Abi::template _S_implicit_mask_intrin<_Tp>();
+	    using _Up = __bool_storage_member_type_t<_Np>;
+	    constexpr _Up __k1 = _Np < sizeof(_Up) * __CHAR_BIT__ ? _Up((1ULL << _Np) - 1) : ~_Up();
 	    if constexpr (sizeof(__xi) == 16)
 	      {
 		if constexpr (sizeof(_Tp) == 8)