[Bug libstdc++/115575] experimental/simd/pr115454_find_last_set.cc FAILs

[mkretz at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115575

--- Comment #5 from Matthias Kretz (Vir) <mkretz at gcc dot gnu.org> ---
Still trying to somehow verify on SPARC...

diff --git a/libstdc++-v3/testsuite/experimental/simd/pr115454_find_last_set.cc
b/libstdc++-v3/testsuite/experimental/simd/pr115454_find_last_set.cc
index b47f19d3067..25a713b4e94 100644
--- a/libstdc++-v3/testsuite/experimental/simd/pr115454_find_last_set.cc
+++ b/libstdc++-v3/testsuite/experimental/simd/pr115454_find_last_set.cc
@@ -1,7 +1,7 @@
 // { dg-options "-std=gnu++17" }
 // { dg-do run { target *-*-* } }
 // { dg-require-effective-target c++17 }
-// { dg-additional-options "-march=x86-64-v4" { target avx512f } }
+// { dg-additional-options "-march=x86-64-v4" { target avx512f_runtime } }
 // { dg-require-cmath "" }

 #include <experimental/simd>
@@ -25,7 +25,9 @@ namespace stdx
 {
   using M8 = typename V<short, 8>::mask_type;
   using M4 = typename V<int, 4>::mask_type;
-  if constexpr (sizeof(M8) == sizeof(M4))
+  if constexpr (sizeof(M8) == sizeof(M4)
+                 && !std::is_same_v<M4, stdx::fixed_size_simd_mask<int, 4>>)
+    // fixed_size invariant: padding bits of masks are zero, the memcpy would
violate that
     {
       M4 k;
       __builtin_memcpy(&__data(k), &__data(M8(true)), sizeof(M4));