libsupc++: Fix handling of m68k extended real in <compare>

	PR libstdc++/116513
	* libsupc++/compare (_S_fp_bits) [__fmt == _M68k_80bit]: Shift
	padding out of exponent word.

diff --git a/libstdc++-v3/libsupc++/compare b/libstdc++-v3/libsupc++/compare
index 686aa6d218fe54646a21d29e882d729f00cc8577..63ad6b5c23e95c7e5c1ba7457382092b0b41830e 100644 (file)
--- a/libstdc++-v3/libsupc++/compare
+++ b/libstdc++-v3/libsupc++/compare
@@ -838,7 +838,7 @@ namespace std _GLIBCXX_VISIBILITY(default)
              using enum _Fp_fmt;
 #endif
              constexpr auto __fmt = _S_fp_fmt<_Tp>();
-             if constexpr (__fmt == _X86_80bit || __fmt == _M68k_80bit)
+             if constexpr (__fmt == _X86_80bit)
                {
                  if constexpr (sizeof(_Tp) == 3 * sizeof(int32_t))
                    {
@@ -851,6 +851,11 @@ namespace std _GLIBCXX_VISIBILITY(default)
                      return _Int<int16_t>(__ival._M_hi, __ival._M_lo);
                    }
                }
+             else if constexpr (__fmt == _M68k_80bit)
+               {
+                 auto __ival = __builtin_bit_cast(_Int<int32_t>, __val);
+                 return _Int<int16_t>(__ival._M_hi >> 16, __ival._M_lo);
+               }
              else if constexpr (sizeof(_Tp) == 2 * sizeof(int64_t))
                {
 #if __SIZEOF_INT128__