[Autobackout][FuncReg]Revert of change: 7d42c37

Structurizer requires that the last BB is a return BB. Make sure this condition is met before invoking the structurizer. It not ( should not happen), non-structurized code (goto/join) will be generated instead.
HSD/Radar: n/a

Change-Id: Iffae3b5d18b50c189df2dd32dcc4d820176f141d

Author: jgu222

visa/FlowGraph.cpp

@@ -893,9 +893,7 @@ void FlowGraph::constructFlowGraph(INST_LIST& instlist)
     setPhysicalPredSucc();
     if (hasGoto)
     {
-        // If the last BB isn't a return block, do not invoke structurizer.
-        if (builder->getOption(vISA_EnableStructurizer) &&
-            isLastBBReturnOrExit())
+        if (builder->getOption(vISA_EnableStructurizer))
         {
             if (builder->getOption(vISA_DumpDotAll))
             {

visa/FlowGraph.h

@@ -1094,20 +1094,6 @@ class FlowGraph
         }
     }
 
-    bool isLastBBReturnOrExit() const
-    {
-        G4_BB* lastBB = back();
-        if (lastBB->size() > 0)
-        {
-            G4_INST* I = lastBB->back();
-            if (I->isReturn() || I->isFReturn() || I->isExit())
-            {
-                return true;
-            }
-        }
-        return false;
-    }
-
 private:
     //
     // Flow group traversal routines

visa/Gen4_IR.hpp

@@ -632,7 +632,6 @@ class G4_INST
     bool isFCall() const { return op == G4_pseudo_fcall; }
     bool isReturn() const { return op == G4_return; }
     bool isFReturn() const { return (op == G4_pseudo_fret); }
-    bool isExit() const { return (op == G4_pseudo_exit);  }
     bool isMath() const { return op == G4_math; }
     bool isIntrinsic() const { return op == G4_intrinsic; }
     bool isSend() const { return op == G4_send || op == G4_sendc || op == G4_sends || op == G4_sendsc; }