If a goto is uniform and it is in divergent BB, this goto

will affect divergence (goto BB to its target are divergent).
If it is uniform and not in divergent BB, it does not affect
divergence.

Change-Id: I83efb23b0569c7b7c76e6d63f979819a95cb9dc0

Author: jgu222

visa/FlowGraph.cpp

@@ -2994,9 +2994,8 @@ void FlowGraph::markDivergentBBs()
                         continue;
                     }
                     G4_INST* tmpInst = BB1->back();
-                    if ((tmpInst->opcode() == G4_break || tmpInst->opcode() == G4_goto) &&
-                        !tmpInst->asCFInst()->isUniform())
-                    {
+                    if (tmpInst->opcode() == G4_break || tmpInst->opcode() == G4_goto)
+                    {   // Assume divergent. todo: going over loop twice to find if it's divergent.
                         G4_BB* newJoinBB = joinBB;
                         if (tmpInst->opcode() == G4_goto)
                         {
@@ -3035,14 +3034,16 @@ void FlowGraph::markDivergentBBs()
 
             G4_INST* lastInst = BB->back();
             if (((lastInst->opcode() == G4_goto && !lastInst->asCFInst()->isBackward()) ||
-                 lastInst->opcode() == G4_break) && !lastInst->asCFInst()->isUniform())
+                 lastInst->opcode() == G4_break) &&
+                (!lastInst->asCFInst()->isUniform() || BB->isDivergent()))
             {
                 // forward goto/break : the last Succ BB is our target BB
                 // For break, it should be the BB right after while inst.
                 G4_BB* joinBB = BB->Succs.back();
                 pushJoin(joinBB);
             }
-            else if (lastInst->opcode() == G4_if && !lastInst->asCFInst()->isUniform())
+            else if (lastInst->opcode() == G4_if &&
+                (!lastInst->asCFInst()->isUniform() || BB->isDivergent()))
             {
                 G4_Label* labelInst = lastInst->asCFInst()->getUip();
                 G4_BB* joinBB = findLabelBB(IT, IE, labelInst->getLabel());