From a372ea889b3491192d80439ad3bf45fa10ce759b Mon Sep 17 00:00:00 2001
From: ebotcazou <ebotcazou@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Fri, 15 Sep 2017 17:11:47 +0000
Subject: [PATCH] 	* c-pragma.c (handle_pragma_scalar_storage_order):
 Expand on error 	message for non-uniform endianness and issue a warning
 in C++.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@252831 138bc75d-0d04-0410-961f-82ee72b054a4
---
 gcc/c-family/ChangeLog       |  5 +++++
 gcc/c-family/c-pragma.c      | 14 +++++++++++++-
 gcc/testsuite/ChangeLog      |  7 ++++++-
 gcc/testsuite/g++.dg/sso-1.C |  8 ++++++++
 gcc/testsuite/g++.dg/sso-2.C |  6 ++++++
 5 files changed, 38 insertions(+), 2 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/sso-1.C
 create mode 100644 gcc/testsuite/g++.dg/sso-2.C

diff --git a/gcc/c-family/ChangeLog b/gcc/c-family/ChangeLog
index 4fffa315644..a3f990d49fd 100644
--- a/gcc/c-family/ChangeLog
+++ b/gcc/c-family/ChangeLog
@@ -1,3 +1,8 @@
+2017-09-15  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* c-pragma.c (handle_pragma_scalar_storage_order): Expand on error
+	message for non-uniform endianness and issue a warning in C++.
+
 2017-09-15  Jakub Jelinek  <jakub@redhat.com>
 
 	* c.opt (Wc++1z-compat): Change from option to undocumented alias.
diff --git a/gcc/c-family/c-pragma.c b/gcc/c-family/c-pragma.c
index a2ffdbacbbb..f7b59b34807 100644
--- a/gcc/c-family/c-pragma.c
+++ b/gcc/c-family/c-pragma.c
@@ -415,7 +415,19 @@ handle_pragma_scalar_storage_order (cpp_reader *ARG_UNUSED(dummy))
   tree x;
 
   if (BYTES_BIG_ENDIAN != WORDS_BIG_ENDIAN)
-    error ("scalar_storage_order is not supported");
+    {
+      error ("scalar_storage_order is not supported because endianness "
+	     "is not uniform");
+      return;
+    }
+
+  if (c_dialect_cxx ())
+    {
+      if (warn_unknown_pragmas > in_system_header_at (input_location))
+	warning (OPT_Wunknown_pragmas,
+		 "%<#pragma scalar_storage_order%> is not supported for C++");
+      return;
+    }
 
   token = pragma_lex (&x);
   if (token != CPP_NAME)
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index bdc79b61e04..303f700c451 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,4 +1,9 @@
-2017-09-13  Paolo Carlini  <paolo.carlini@oracle.com>
+2017-09-15  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* g++.dg/sso-1.C: New test.
+	* g++.dg/sso-2.C: Likewise.
+
+2017-09-15  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	PR c++/78648
 	* g++.dg/cpp0x/lambda/lambda-ice21.C: New.
diff --git a/gcc/testsuite/g++.dg/sso-1.C b/gcc/testsuite/g++.dg/sso-1.C
new file mode 100644
index 00000000000..0f59d0c4069
--- /dev/null
+++ b/gcc/testsuite/g++.dg/sso-1.C
@@ -0,0 +1,8 @@
+/* Test support of scalar_storage_order attribute */
+
+/* { dg-do compile } */
+
+struct __attribute__((scalar_storage_order("little-endian"))) Rec /* { dg-warning "attribute ignored" } */
+{
+  int i;
+};
diff --git a/gcc/testsuite/g++.dg/sso-2.C b/gcc/testsuite/g++.dg/sso-2.C
new file mode 100644
index 00000000000..402a61e3b47
--- /dev/null
+++ b/gcc/testsuite/g++.dg/sso-2.C
@@ -0,0 +1,6 @@
+/* Test support of scalar_storage_order pragma */
+
+/* { dg-do compile } */
+/* { dg-options "-Wall" } */
+
+#pragma scalar_storage_order little-endian /* { dg-warning "not supported" } */
-- 
2.11.4.GIT