Add a cast to avoid signed integer overflow.

* vm_trace.c (recalc_remove_ruby_vm_event_flags): Add a cast to
  avoid signed integer overflow.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@54873 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,8 @@
+Mon May  2 00:41:53 2016  Tanaka Akira  <akr@fsij.org>
+
+	* vm_trace.c (recalc_remove_ruby_vm_event_flags): Add a cast to
+	  avoid signed integer overflow.
+
 Mon May  2 00:06:04 2016  Tanaka Akira  <akr@fsij.org>
 
 	* test/lib/envutil.rb: Define Integer::{FIXNUM_MIN,FIXNUM_MAX}.

vm_trace.c

@@ -81,7 +81,7 @@ recalc_remove_ruby_vm_event_flags(rb_event_flag_t events)
     ruby_vm_event_flags = 0;
 
     for (i=0; i<MAX_EVENT_NUM; i++) {
-	if (events & (1 << i)) {
+	if (events & ((rb_event_flag_t)1 << i)) {
 	    ruby_event_flag_count[i]--;
 	}
 	ruby_vm_event_flags |= ruby_event_flag_count[i] ? (1<<i) : 0;