From 7a80a882ab838b037ca7afc4c14e2a098ce07493 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Przemys=C5=82aw=20Czerpak?= <druzus@poczta.onet.pl>
Date: Sat, 1 Aug 2015 13:14:30 +0200
Subject: [PATCH] 2015-08-01 13:14 UTC+0200 Przemyslaw Czerpak
 (druzus/at/poczta.onet.pl)   * src/vm/asort.c     * restored original loop
 and added different workaround which for       the problem in 64 bit MinGW we
 exploited. It's dummy function call       inside a loop so probably link time
 optimization (LTO is enabled       by -O4 in the newest GCC versions) ignore
 it and the problem will       reappear. Anyhow it only temporary solution
 which should give time       to create self contain example and report the
 problem to MinGW       authors - it's highly possible that also other code
 exploited this       problem so be careful with MinGW64.     % fixed index
 range checking to eliminate unnecessary index verification

---
 ChangeLog.txt  | 12 ++++++++++++
 src/vm/asort.c | 11 ++++++++---
 2 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/ChangeLog.txt b/ChangeLog.txt
index 8a4e7712bf..fe81270daf 100644
--- a/ChangeLog.txt
+++ b/ChangeLog.txt
@@ -10,6 +10,18 @@
      * Change, ! Fix, % Optimization, + Addition, - Removal, ; Comment
  */
 
+2015-08-01 13:14 UTC+0200 Przemyslaw Czerpak (druzus/at/poczta.onet.pl)
+  * src/vm/asort.c
+    * restored original loop and added different workaround which for
+      the problem in 64 bit MinGW we exploited. It's dummy function call
+      inside a loop so probably link time optimization (LTO is enabled
+      by -O4 in the newest GCC versions) ignore it and the problem will
+      reappear. Anyhow it only temporary solution which should give time
+      to create self contain example and report the problem to MinGW
+      authors - it's highly possible that also other code exploited this
+      problem so be careful with MinGW64.
+    % fixed index range checking to eliminate unnecessary index verification
+
 2015-08-01 01:28 UTC+0200 Przemyslaw Czerpak (druzus/at/poczta.onet.pl)
   * src/vm/asort.c
     * added workaround for bug in 64 bit MinGW builds
diff --git a/src/vm/asort.c b/src/vm/asort.c
index 00e4266941..2f7bd0db6a 100644
--- a/src/vm/asort.c
+++ b/src/vm/asort.c
@@ -280,9 +280,14 @@ static void hb_arraySortStart( PHB_BASEARRAY pBaseArray, PHB_ITEM pBlock,
    HB_SIZE * pBuffer, * pDest, * pPos, nPos, nTo;
 
    pBuffer = ( HB_SIZE * ) hb_xgrab( sizeof( HB_SIZE ) * 2 * nCount );
-   nPos = nCount;
-   while( nPos-- )
+   for( nPos = 0; nPos < nCount; ++nPos )
+   {
+#ifdef __MINGW64__
+      /* added dummy function call to disable buggy optimization in MinGW64 */
+      hb_gcDummyMark( NULL );
+#endif
       pBuffer[ nPos ] = nStart + nPos;
+   }
 
    if( hb_arraySortDO( pBaseArray, pBlock, pBuffer, &pBuffer[ nCount ], nCount ) )
       pPos = ( pDest = pBuffer ) + nCount;
@@ -290,7 +295,7 @@ static void hb_arraySortStart( PHB_BASEARRAY pBaseArray, PHB_ITEM pBlock,
       pDest = ( pPos = pBuffer ) + nCount;
 
    /* protection against array resizing by user codeblock */
-   if( nStart + nCount >= pBaseArray->nLen )
+   if( nStart + nCount > pBaseArray->nLen )
    {
       if( pBaseArray->nLen > nStart )
       {