[Beignet] [PATCH] structuralize bug fix: check the loop successor before merge.

[xionghu.luo at intel.com]

From: Luo Xionghu <xionghu.luo at intel.com>

self loop header should have a successor to itself, check this before merge.
this could fix Opencv case opencv_perf_imgproc/OCL_CvtColorFixture_CvtColor causes GPU hang.

Signed-off-by: Luo Xionghu <xionghu.luo at intel.com>
---
 backend/src/ir/structurizer.cpp | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/backend/src/ir/structurizer.cpp b/backend/src/ir/structurizer.cpp
index 82bb56b..6c4e455 100644
--- a/backend/src/ir/structurizer.cpp
+++ b/backend/src/ir/structurizer.cpp
@@ -812,6 +812,13 @@ namespace ir {
     if(loopBBs.empty())
       return 0;
 
+    if(loopSets.size() == 1) {
+    //self loop header should have a successor to itself, check this before merged.
+      Block* lblock = *loopSets.begin();
+      if(lblock->successors().find(lblock) == lblock->successors().end())
+        return 0;
+    }
+
     Block* mergedBB = mergeLoopBlock(loopBBs);
     if(mergedBB == NULL)
       return 0;
-- 
1.9.1