Add appropriate predicate to mov when sample is split

When we split a predicated sample, we create 2 predicated samples and
copies from sample write back message to original variable. The copies
must use same predicate as the sample. Otherwise semantics are incorrect
if such a split occurs in a loop.

Author: pratikashar

visa/BuildIR.h

@@ -1759,7 +1759,8 @@ class IR_Builder {
   // emask is InstOption
   void Copy_SrcRegRegion_To_Payload(G4_Declare *payload, unsigned int &regOff,
                                     G4_SrcRegRegion *src, G4_ExecSize execSize,
-                                    uint32_t emask);
+                                    uint32_t emask,
+                                    G4_Predicate *pred = nullptr);
   unsigned int getByteOffsetSrcRegion(G4_SrcRegRegion *srcRegion);
 
   // only used in TranslateSend3D, maybe consider moving there if no

visa/VisaToG4/TranslateMisc.cpp

@@ -391,13 +391,15 @@ void IR_Builder::Copy_SrcRegRegion_To_Payload(G4_Declare *payload,
                                               unsigned int &regOff,
                                               G4_SrcRegRegion *src,
                                               G4_ExecSize execSize,
-                                              uint32_t emask) {
+                                              uint32_t emask,
+                                              G4_Predicate* pred) {
   auto payloadDstRgn = createDst(payload->getRegVar(), (short)regOff, 0, 1,
                                  payload->getElemType());
 
   G4_SrcRegRegion *srcRgn = createSrcRegRegion(*src);
   srcRgn->setType(*this, payload->getElemType());
-  createMov(execSize, payloadDstRgn, srcRgn, emask, true);
+  createMov(duplicateOperand(pred), execSize, payloadDstRgn, srcRgn, emask,
+            true);
   if (TypeSize(payload->getElemType()) == 2) {
     // for half float each source occupies 1 GRF regardless of execution size
     regOff++;

visa/VisaToG4/TranslateSend3D.cpp

@@ -2159,7 +2159,7 @@ int IR_Builder::splitSampleInst(
         createMov(execSize, dst, tmpSrcPnt, MovInstOpt, true);
       } else {
         Copy_SrcRegRegion_To_Payload(originalDstDcl, regOff, tmpSrcPnt,
-                                     execSize, MovInstOpt);
+                                     execSize, MovInstOpt, pred);
       }
     }
   }
@@ -2199,7 +2199,7 @@ int IR_Builder::splitSampleInst(
         createMov(execSize, dst, tmpSrcPnt, MovInstOpt, true);
       } else {
         Copy_SrcRegRegion_To_Payload(originalDstDcl, regOff, tmpSrcPnt,
-                                     execSize, MovInstOpt);
+                                     execSize, MovInstOpt, pred);
       }
     }
   }