diff --git a/gdb/testsuite/lib/compiler.c b/gdb/testsuite/lib/compiler.c
index 58750413466..7160591a93c 100644
--- a/gdb/testsuite/lib/compiler.c
+++ b/gdb/testsuite/lib/compiler.c
@@ -68,5 +68,5 @@ set compiler_info [join {hpacc __HP_aCC} -]
 #if defined (__xlc__)
 /* IBM'x xlc compiler. NOTE:  __xlc__ expands to a double quoted string of four
    numbers seperated by '.'s: currently "7.0.0.0" */
-regsub -all {\.} [join {xlc __xlc__} -] - compiler_info
+set need_a_set [regsub -all {\.} [join {xlc __xlc__} -] - compiler_info]
 #endif
diff --git a/gdb/testsuite/lib/compiler.cc b/gdb/testsuite/lib/compiler.cc
index eea1df46949..60319007bc1 100644
--- a/gdb/testsuite/lib/compiler.cc
+++ b/gdb/testsuite/lib/compiler.cc
@@ -56,5 +56,5 @@ set compiler_info [join {hpacc __HP_aCC} -]
 #if defined (__xlc__)
 /* IBM'x xlc compiler. NOTE:  __xlc__ expands to a double quoted string of four
    numbers seperated by '.'s: currently "7.0.0.0" */
-regsub -all {\.} [join {xlc __xlc__} -] - compiler_info
+set need_a_set [regsub -all {\.} [join {xlc __xlc__} -] - compiler_info]
 #endif