@@ -685,7 +685,7 @@ static void fixupPrivateMemoryPFWILambdaCaptures(CallInst *PFWICall) {
685685
686686// Go through "byval" parameters which are passed as AS(0) pointers
687687// and: (1) create local shadows for them (2) and initialize them from the
688- // leader's copy and (3) replace usages with pointer to the shadow
688+ // leader's copy and (3) materialize the value in the local variable before use
689689//
690690// Do the same for 'this' pointer which points to PFWG lamda object which is
691691// allocated in the caller. Caller is a kernel function which is generated by
@@ -707,7 +707,7 @@ static void sharePFWGPrivateObjects(Function &F, const Triple &TT) {
707707 BasicBlock *LeaderBB = EntryBB->splitBasicBlock (SplitPoint, " leader"
708708 BasicBlock *MergeBB = LeaderBB->splitBasicBlock (&LeaderBB->front (), " merge"
709709
710- // 1) rewire the above basic blocks so that LeaderBB is executed only for the
710+ // Rewire the above basic blocks so that LeaderBB is executed only for the
711711 // leader workitem
712712 guardBlockWithIsLeaderCheck (EntryBB, LeaderBB, MergeBB,
713713 EntryBB->back ().getDebugLoc (), TT);
@@ -719,50 +719,34 @@ static void sharePFWGPrivateObjects(Function &F, const Triple &TT) {
719719 IRBuilder<> Builder (Ctx);
720720 Builder.SetInsertPoint (&LeaderBB->front ());
721721
722- // 2) create the shared copy - "shadow" - for current arg
722+ // Create the shared copy - "shadow" - for current arg
723723 GlobalVariable *Shadow = nullptr ;
724- Value *RepVal = nullptr ;
725724 if (Arg.hasByValAttr ()) {
726725 assert (Arg.getType ()->getPointerAddressSpace () ==
727726 asUInt (spirv::AddrSpace::Private));
728727 T = Arg.getParamByValType ();
729728 Shadow = spirv::createWGLocalVariable (*F.getParent (), T, " ArgShadow"
730- RepVal = Shadow;
731- if (TT.isNVPTX ()) {
732- // For NVPTX target address space inference for kernel arguments and
733- // allocas is happening in the backend (NVPTXLowerArgs and
734- // NVPTXLowerAlloca passes). After the frontend these pointers are in
735- // LLVM default address space 0 which is the generic address space for
736- // NVPTX target.
737- assert (Arg.getType ()->getPointerAddressSpace () == 0 );
738-
739- // Cast a pointer in the shared address space to the generic address
740- // space.
741- RepVal = ConstantExpr::getPointerBitCastOrAddrSpaceCast (Shadow,
742- Arg.getType ());
743- }
744729 }
745730 // Process 'this' pointer which points to PFWG lambda object
746731 else if (Arg.getArgNo () == 0 ) {
747732 PointerType *PtrT = dyn_cast<PointerType>(Arg.getType ());
748733 assert (PtrT && " Expected this pointer as the first argument"
749734 T = PtrT->getElementType ();
750735 Shadow = spirv::createWGLocalVariable (*F.getParent (), T, " ArgShadow"
751- RepVal =
752- Builder.CreatePointerBitCastOrAddrSpaceCast (Shadow, Arg.getType ());
753736 }
754737
755- if (!Shadow || !RepVal )
738+ if (!Shadow)
756739 continue ;
757740
758- // 3) replace argument with shadow in all uses
759- for (auto *U : Arg.users ())
760- U->replaceUsesOfWith (&Arg, RepVal);
761-
762741 copyBetweenPrivateAndShadow (&Arg, Shadow, Builder,
763742 true /* private->shadow*/
743+ // Materialize the value in the local variable before use
744+ Builder.SetInsertPoint (&MergeBB->front ());
745+ copyBetweenPrivateAndShadow (&Arg, Shadow, Builder,
746+ false /* shadow->private*/
764747 }
765- // 5) make sure workers use up-to-date shared values written by the leader
748+ // Insert barrier to make sure workers use up-to-date shared values written by
749+ // the leader
766750 spirv::genWGBarrier (MergeBB->front (), TT);
767751}
768752
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