[gcc r17-507] libstdc++: Mark gencanon_eng_neg test as unsupported if __float128 is not available.

[Tomasz Kaminski]

https://gcc.gnu.org/g:5d17eec7d83445ba4f960c81c386be33baee52a4

commit r17-507-g5d17eec7d83445ba4f960c81c386be33baee52a4
Author: Tomasz Kamiński <tkaminsk@redhat.com>
Date:   Thu May 14 09:46:14 2026 +0200

    libstdc++: Mark gencanon_eng_neg test as unsupported if __float128 is not available.
    
    As DejaGnu reads all lines, the { dg-error } still expected error,
    even if the code was removed by preprocessor checks.
    
    libstdc++-v3/ChangeLog:
    
            * testsuite/26_numerics/random/uniform_real_distribution/operators/gencanon_eng_neg.cc:
            Removed preprocessor checks, add dg-require-effective-target.
    
    Reviewed-by: Jonathan Wakely <jwakely@redhat.com>
    Signed-off-by: Tomasz Kamiński <tkaminsk@redhat.com>

Diff:
---
 .../operators/gencanon_eng_neg.cc                      | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/libstdc++-v3/testsuite/26_numerics/random/uniform_real_distribution/operators/gencanon_eng_neg.cc b/libstdc++-v3/testsuite/26_numerics/random/uniform_real_distribution/operators/gencanon_eng_neg.cc
index 8b241fee7edf..e3b4540bf2b6 100644
--- a/libstdc++-v3/testsuite/26_numerics/random/uniform_real_distribution/operators/gencanon_eng_neg.cc
+++ b/libstdc++-v3/testsuite/26_numerics/random/uniform_real_distribution/operators/gencanon_eng_neg.cc
@@ -1,4 +1,7 @@
 // { dg-do compile { target { c++11 } } }
+// { dg-require-effective-target __float128 }
+// { dg-require-effective-target base_quadfloat_support }
+// { dg-add-options __float128 }
 
 #include <random>
 #include <cstdint>
@@ -45,13 +48,12 @@ test_pow2()
 
 int main()
 {
-// For 128bit floating points, generator emitting a range, which size is 
-// not power of two, but of width of B bits, such that for any N:
-// N * B < 113 (bits in ieee128)
-// (N+1) * B > 128
-// are not supported, as they would require integer with more than 127 bits.
-#ifndef _GLIBCXX_GENERATE_CANONICAL_STRICT
-#  ifdef __SIZEOF_FLOAT128__
+  // For 128bit floating points, generator emitting a range, which size is 
+  // not power of two, but of width of B bits, such that for any N:
+  // N * B < 113 (bits in ieee128)
+  // (N+1) * B > 128
+  // are not supported, as they would require integer with more than 127 bits.
+
   // N == 3: B in [43, 57)
   test_non_pow2<__float128, 42>(); // 3 calls
   test_non_pow2<__float128, 43>(); // { dg-error "from here" }
@@ -81,8 +83,6 @@ int main()
   test_non_pow2<__float128, 22>(); // { dg-error "from here" }
   test_non_pow2<__float128, 23>(); // 5 calls
   test_pow2<__float128, 22>();
-#  endif
-#endif 
 }
 
 // { dg-prune-output "no type named 'type' in 'struct std::__detail::_Select_uint_least_t" }