[PATCH] ada: Do not raise Use_Error in Reset if mode isn't changed

[Samuel Tardieu]

Regtested on i686-pc-linux-gnu.

Note that the existing comment above the change does describe the code...
after this patch is applied :)

    gcc/ada/
	PR ada/22255
	* s-fileio.adb (Reset): Do not raise Use_Error if mode isn't changed.

    gcc/testsuite/
	PR ada/22255
	* test_direct_io.adb: New file.
---
 gcc/ada/s-fileio.adb                     |    9 +++++----
 gcc/testsuite/gnat.dg/test_direct_io.adb |   15 +++++++++++++++
 2 files changed, 20 insertions(+), 4 deletions(-)
 create mode 100644 gcc/testsuite/gnat.dg/test_direct_io.adb

diff --git a/gcc/ada/s-fileio.adb b/gcc/ada/s-fileio.adb
index e2c0e3d..f44eaa2 100644
--- a/gcc/ada/s-fileio.adb
+++ b/gcc/ada/s-fileio.adb
@@ -1077,10 +1077,11 @@ package body System.File_IO is
       --  Change of mode not allowed for shared file or file with no name
       --  or file that is not a regular file, or for a system file.
 
-      if File.Shared_Status = Yes
-        or else File.Name'Length <= 1
-        or else File.Is_System_File
-        or else (not File.Is_Regular_File)
+      if Mode /= File.Mode
+        and then (File.Shared_Status = Yes
+                    or else File.Name'Length <= 1
+                    or else File.Is_System_File
+                    or else (not File.Is_Regular_File))
       then
          raise Use_Error;
 
diff --git a/gcc/testsuite/gnat.dg/test_direct_io.adb b/gcc/testsuite/gnat.dg/test_direct_io.adb
new file mode 100644
index 0000000..0eb8aa2
--- /dev/null
+++ b/gcc/testsuite/gnat.dg/test_direct_io.adb
@@ -0,0 +1,15 @@
+-- { dg-do run }
+with Ada.Direct_IO;
+
+procedure Test_Direct_IO is
+
+   package BDIO is new Ada.Direct_IO (Boolean);
+   use BDIO;
+
+   FD : File_Type;
+
+begin
+   Create (FD, Form => "shared=yes");
+   Reset (FD);
+   Close (FD);
+end Test_Direct_IO;
-- 
1.5.3.6