yields "i == -16382" when the assertion fails
--- coreutils-6.9.92/gnulib-tests/test-printf-frexpl.c
+++ coreutils-6.9.92/gnulib-tests/test-printf-frexpl.c
@@ -93,6 +93,9 @@
       int exp = -9999;
       long double mantissa = printf_frexpl (x, &exp);
       ASSERT (exp == LDBL_MIN_EXP - 1);
+      if (mantissa != my_ldexp (1.0L, i - LDBL_MIN_EXP)) {
+              printf("i == %d\n",i);
+      }
       ASSERT (mantissa == my_ldexp (1.0L, i - LDBL_MIN_EXP));
     }