diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 47c68cbde03..bd74aa55e5b 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2020-11-24  Joel Brobecker  <brobecker@adacore.com>
+
+	* unittests/gmp-utils-selftests.c (write_fp_test): Use mpq_set_si
+	instead of mpq_set_ui to initialize our GMP rational.
+
 2020-11-23  Tom de Vries  <tdevries@suse.de>
 
 	* debuginfod-support.c (debuginfod_source_query)
diff --git a/gdb/unittests/gmp-utils-selftests.c b/gdb/unittests/gmp-utils-selftests.c
index af5bc65d2f9..175ab3f9827 100644
--- a/gdb/unittests/gmp-utils-selftests.c
+++ b/gdb/unittests/gmp-utils-selftests.c
@@ -400,7 +400,7 @@ write_fp_test (int numerator, unsigned int denominator,
   memset (buf, 0, len);
 
   gdb_mpq v;
-  mpq_set_ui (v.val, numerator, denominator);
+  mpq_set_si (v.val, numerator, denominator);
   mpq_canonicalize (v.val);
   v.write_fixed_point (buf, len, byte_order, 0, scaling_factor);