mc-3780-tar.c-Cleanup-compiler-aggressive-loop-optimizations-warning.patch

From 0f551ab4dccba214bb7217be284428115ce02a10 Mon Sep 17 00:00:00 2001
From: Andreas Mohr <and@gmx.li>
Date: Wed, 10 May 2017 19:22:06 +0000
Subject: [PATCH] (tar.c) Cleanup compiler aggressive-loop-optimizations warning

tar.c: In function 'tar_checksum':
tar.c:403:44: error: iteration 8u invokes undefined behavior [-Werror=aggressive-loop-optimizations]
         sum -= 0xFF & header->header.chksum[i];
                                            ^
tar.c:401:5: note: containing loop
     for (i = sizeof (header->header.chksum); i-- >= 0;)
     ^
Signed-off-by: Andreas Mohr <and@gmx.li>
---
 src/vfs/tar/tar.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/vfs/tar/tar.c b/src/vfs/tar/tar.c
index 9016a3d..8e9446f 100644
--- a/src/vfs/tar/tar.c
+++ b/src/vfs/tar/tar.c
@@ -387,7 +387,7 @@ tar_checksum (const union record *header)
 
     recsum = tar_from_oct (8, header->header.chksum);
 
-    for (i = sizeof (*header); i-- >= 0;)
+    for (i = sizeof (*header); --i >= 0;)
     {
         /*
          * We can't use unsigned char here because of old compilers,
@@ -398,7 +398,7 @@ tar_checksum (const union record *header)
     }
 
     /* Adjust checksum to count the "chksum" field as blanks. */
-    for (i = sizeof (header->header.chksum); i-- >= 0;)
+    for (i = sizeof (header->header.chksum); --i >= 0;)
     {
         sum -= 0xFF & header->header.chksum[i];
         signed_sum -= (char) header->header.chksum[i];