From cbada1a1b218c1ef61d0eb4363fad7598e6509d6 Mon Sep 17 00:00:00 2001
From: Martin Jansa <Martin.Jansa@gmail.com>
Date: Sun, 30 Sep 2018 09:16:48 +0000
Subject: [PATCH] locale: prevent maybe-uninitialized errors with -Os [BZ
 #19444]

Fixes following error when building for aarch64 with -Os:
| In file included from strcoll_l.c:43:
| strcoll_l.c: In function '__strcoll_l':
| ../locale/weight.h:31:26: error: 'seq2.back_us' may be used uninitialized in this function [-Werror=maybe-uninitialized]
|    int_fast32_t i = table[*(*cpp)++];
|                           ^~~~~~~~~
| strcoll_l.c:304:18: note: 'seq2.back_us' was declared here
|    coll_seq seq1, seq2;
|                   ^~~~
| In file included from strcoll_l.c:43:
| ../locale/weight.h:31:26: error: 'seq1.back_us' may be used uninitialized in this function [-Werror=maybe-uninitialized]
|    int_fast32_t i = table[*(*cpp)++];
|                           ^~~~~~~~~
| strcoll_l.c:304:12: note: 'seq1.back_us' was declared here
|    coll_seq seq1, seq2;
|             ^~~~

        Partial fix for [BZ #23716]
        * locale/weight.h: Fix build with -Os.

Work around the issue instead of removing -O like we do with
SELECTED_OPTIMIZATION

Upstream-Status: Submitted [https://www.sourceware.org/ml/libc-alpha/2018-09/msg00539.html]

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
---
 ChangeLog       | 4 ++++
 locale/weight.h | 7 +++++++
 2 files changed, 11 insertions(+)

diff --git a/ChangeLog b/ChangeLog
index 216336edc9..84fbbf47ed 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2018-09-30  Martin Jansa  <Martin.Jansa@gmail.com>
+	Partial fix for [BZ #23716]
+	* locale/weight.h: Fix build with -Os.
+
 2018-09-30  Martin Jansa  <Martin.Jansa@gmail.com>
 	Partial fix for [BZ #23716]
 	* sysdeps/ieee754/soft-fp/s_fdiv.c: Fix build with -O.
diff --git a/locale/weight.h b/locale/weight.h
index 6028d3595e..10bcea25e5 100644
--- a/locale/weight.h
+++ b/locale/weight.h
@@ -28,7 +28,14 @@ findidx (const int32_t *table,
 	 const unsigned char *extra,
 	 const unsigned char **cpp, size_t len)
 {
+  /* With GCC 8 when compiling with -Os the compiler warns that
+     seq1.back_us and seq2.back_us might be used uninitialized.
+     This uninitialized use is impossible for the same reason
+     as described in comments in locale/weightwc.h.  */
+  DIAG_PUSH_NEEDS_COMMENT;
+  DIAG_IGNORE_Os_NEEDS_COMMENT (8, "-Wmaybe-uninitialized");
   int_fast32_t i = table[*(*cpp)++];
+  DIAG_POP_NEEDS_COMMENT;
   const unsigned char *cp;
   const unsigned char *usrc;