Re-enable memory fence scheduling and do not schedule it beyond branches.

Author: weiyu-chen

visa/Optimizer.cpp

@@ -6907,7 +6907,7 @@ bool Optimizer::foldPseudoAndOr(G4_BB* bb, INST_LIST_ITER& ii)
         for (auto E = bb->end(); I != E; ++I)
         {
             G4_INST* inst = *I;
-            if (inst->isSend() || inst->isOptBarrier())
+            if (inst->isSend() || inst->isCFInst() || inst->isLabel() || inst->isOptBarrier())
             {
                 break;
             }
@@ -6951,6 +6951,7 @@ bool Optimizer::foldPseudoAndOr(G4_BB* bb, INST_LIST_ITER& ii)
                 builder.phyregpool.getNullReg(), 0, 0, 1, fenceDcl->getElemType());
             G4_SrcRegRegion* movSrc = builder.Create_Src_Opnd_From_Dcl(fenceDcl, builder.createRegionDesc(8, 8, 1));
             G4_INST* movInst = builder.createMov(g4::SIMD8, movDst, movSrc, InstOpt_WriteEnable, false);
+            movInst->setComments("memory fence commit");
             bb->insertBefore(nextIter, movInst);
         }
         return true;

visa/include/VISAOptions.def

@@ -75,7 +75,7 @@ DEF_VISA_OPTION(vISA_reassociate,           ET_BOOL, "-noreassoc",   UNUSED, tru
 DEF_VISA_OPTION(vISA_split4GRFVar,          ET_BOOL, "-no4GRFSplit", UNUSED, true)
 DEF_VISA_OPTION(vISA_divergentBB,           ET_BOOL, "-divergentBB", UNUSED, true)
 DEF_VISA_OPTION(vISA_splitInstructions,     ET_BOOL, "-noSplitInstructions", UNUSED, true)
-DEF_VISA_OPTION(vISA_scheduleFenceCommit,   ET_BOOL, NULLSTR, UNUSED, false)
+DEF_VISA_OPTION(vISA_scheduleFenceCommit,   ET_BOOL, NULLSTR, UNUSED, true)
 
 //=== code gen options ===
 DEF_VISA_OPTION(vISA_noSrc1Byte,          ET_BOOL, "-nosrc1byte",         UNUSED, false)