From 8c189909642bb045e256ebd791ae5f94d7f50300 Mon Sep 17 00:00:00 2001
From: "Y. Srinivas Ramakrishna" <ysr@openjdk.org>
Date: Tue, 15 Sep 2009 16:50:50 -0700
Subject: [PATCH] 6861557: G1: assert(top() == bottom() || zfs ==
 Allocated,"Region must be empty, or ...")

Druing heap shrinking, check for emptiness of a region before modifying its ZF status.

Reviewed-by: tonyp
---
 hotspot/src/share/vm/gc_implementation/g1/heapRegionSeq.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hotspot/src/share/vm/gc_implementation/g1/heapRegionSeq.cpp b/hotspot/src/share/vm/gc_implementation/g1/heapRegionSeq.cpp
index 4e89c8cf979..79a40355adf 100644
--- a/hotspot/src/share/vm/gc_implementation/g1/heapRegionSeq.cpp
+++ b/hotspot/src/share/vm/gc_implementation/g1/heapRegionSeq.cpp
@@ -302,9 +302,9 @@ MemRegion HeapRegionSeq::shrink_by(size_t shrink_bytes,
     if (cur->isHumongous()) {
       return MemRegion(last_start, end);
     }
-    cur->reset_zero_fill();
     assert(cur == _regions.top(), "Should be top");
     if (!cur->is_empty()) break;
+    cur->reset_zero_fill();
     shrink_bytes -= cur->capacity();
     num_regions_deleted++;
     _regions.pop();