From fb47a163d48e8364bf61a99246ff5e79bc46836e Mon Sep 17 00:00:00 2001
From: Vladislav Vaintroub <wlad@montyprogram.com>
Date: Sat, 12 Feb 2011 17:17:19 +0100
Subject: [PATCH] Fix MYSQL Bug#60057  : sel_arg_range_seq_next loops in
 optimized compilation/VS2010

When mariadb 5.3 is compiler with VS2010, several tests would enter infinite loop in
sel_arg_range_seq_next(). The reason is compiler backend bug. This bug is not
present in either VS2008  or VS2010 SP1 RC.

Workaround is to compile this function without most aggresive optimization flag
 (-Og )  using #pragma optimize ("g", {on|off}) for this version of MSVC compiler.
---
 sql/opt_range_mrr.cc | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/sql/opt_range_mrr.cc b/sql/opt_range_mrr.cc
index e5da9577f7f..2047f6f250c 100644
--- a/sql/opt_range_mrr.cc
+++ b/sql/opt_range_mrr.cc
@@ -120,6 +120,14 @@ static void step_down_to(SEL_ARG_RANGE_SEQ *arg, SEL_ARG *key_tree)
     TRUE   No more ranges in the sequence
 */
 
+#if (_MSC_FULL_VER == 160030319)
+/*
+   Workaround Visual Studio 2010 RTM compiler backend bug, the function enters 
+   infinite loop.
+ */
+#pragma optimize("g", off)
+#endif
+
 bool sel_arg_range_seq_next(range_seq_t rseq, KEY_MULTI_RANGE *range)
 {
   SEL_ARG *key_tree;
@@ -273,6 +281,12 @@ walk_up_n_right:
   return 0;
 }
 
+#if (_MSC_FULL_VER == 160030319)
+/* VS2010 compiler bug workaround */
+#pragma optimize("g", on)
+#endif
+
+
 /****************************************************************************
   MRR Range Sequence Interface implementation that walks array<QUICK_RANGE>
  ****************************************************************************/