sendFusion gets emask either by dmask & ce0 or cmp. As using dmask

isn't always safe (code using vmask, etc) and reading ce0 might have
issues.  This change will always use cmp to get emask.

Instruction count wise, cmp approach needs 2 insts where dmask&ce0 approach
needs just 1 instructions, per each basic block.

Change-Id: Ic426e0806e955827714b3977118c1cabfde75322

Author: jgu222

visa/SendFusion.cpp

@@ -145,8 +145,18 @@ namespace vISA
               FlagDefPerBB(nullptr),
               WAce0Read(false)
         {
-            WAce0Read = VISA_WA_CHECK(Builder->getPWaTable(), Wa_1406950495) ;
-            initDMaskModInfo();
+            // Using "dmask (sr0.2) And ce0.0" for emask for each BB is not very safe
+            // for the following reasons:
+            //    1) shader may use vmask; or
+            //    2) reading ce might be unsafe (for example, hardware issue)
+            // Thus, we set WAce0Read to true to force using "cmp r0, r0" to create emask
+            // always, and no dmask would be used at all!
+            //WAce0Read = VISA_WA_CHECK(Builder->getPWaTable(), Wa_1406950495) ;
+            WAce0Read = true;
+            if (!WAce0Read)
+            {
+                initDMaskModInfo();
+            }
         }
 
         bool run(G4_BB* BB);
@@ -1248,7 +1258,7 @@ void SendFusion::createFlagPerBB(G4_BB* bb, INST_LIST_ITER InsertBeforePos)
     }
     else
     {
-        // (W) and (|M0) tmp<1>:ud ce0.0<0;1,0>:ud DMaskUD:ud
+        // (W) and (1|M0) tmp<1>:ud ce0.0<0;1,0>:ud DMaskUD:ud
         G4_SrcRegRegion *ce0Src = Builder->createSrcRegRegion(
             Mod_src_undef, Direct, Builder->phyregpool.getMask0Reg(), 0, 0, scalar, Type_UD);
         G4_SrcRegRegion *dmaskSrc = Builder->createSrcRegRegion(