diff -r ff9031a745d9 -r bcf55c5acf4e hotspot/src/share/vm/gc_implementation/g1/heapRegion.cpp
--- a/hotspot/src/share/vm/gc_implementation/g1/heapRegion.cpp	Wed Jul 05 17:11:12 2017 +0200
+++ b/hotspot/src/share/vm/gc_implementation/g1/heapRegion.cpp	Tue May 11 14:35:43 2010 -0700
@@ -290,7 +290,7 @@
   // Recalculate the region size to make sure it's a power of
   // 2. This means that region_size is the largest power of 2 that's
   // <= what we've calculated so far.
-  region_size = 1 << region_size_log;
+  region_size = ((uintx)1 << region_size_log);
 
   // Now make sure that we don't go over or under our limits.
   if (region_size < MIN_REGION_SIZE) {