Improve gdb.base/float128.exp failure message
If the "print large128" sub-test fails in a manner that typically
indicates internal overflow due to GDB being built without MPFR
support, explicitly state this in the failure message.
gdb/testsuite/ChangeLog:
2018-06-20 Ulrich Weigand <uweigand@de.ibm.com>
* gdb.base/float128.exp: Add comment and improved fail message
to the failure case of "print large128" test.
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index e981535..df218ef 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2018-06-20 Ulrich Weigand <uweigand@de.ibm.com>
+
+ * gdb.base/float128.exp: Add comment and improved fail message
+ to the failure case of "print large128" test.
+
2018-06-19 Simon Marchi <simon.marchi@ericsson.com>
* configure.ac: Remove AC_PREREQ.
diff --git a/gdb/testsuite/gdb.base/float128.exp b/gdb/testsuite/gdb.base/float128.exp
index 4c322b8..26cabac 100644
--- a/gdb/testsuite/gdb.base/float128.exp
+++ b/gdb/testsuite/gdb.base/float128.exp
@@ -75,5 +75,19 @@
gdb_test "print f128" ".* = 20\\.375.*" "the value of f128 is changed to 20.375"
# Test that we can correctly handle the largest IEEE-128 value
-gdb_test "print large128" ".* = 1\\.18973149535723176508575932662800702e\\+4932" "print large128"
+# Note: If we get "inf" instead of the correct result, we may have run into
+# an internal overflow. This typically happens on host platforms without
+# native IEEE-128 support where GDB was built without MPFR support.
+set test "print large128"
+gdb_test_multiple "print large128" "$test" {
+ -re ".* = 1\\.18973149535723176508575932662800702e\\+4932.*$gdb_prompt $" {
+ pass "$test"
+ }
+ -re ".* = inf.*$gdb_prompt $" {
+ fail "$test (GDB may be missing MPFR support!)"
+ }
+ -re ".*$gdb_prompt $" {
+ fail "$test"
+ }
+}
