[PATCH] D122269: Modify DXILPrepare to emit no-op bitcasts

[Xiang Li via Phabricator via llvm-commits]

python3kgae added inline comments.


================
Comment at: llvm/lib/Target/DirectX/DXILPrepare.cpp:123
+            }
+            // Insert bitcasts at the top of the block...
+            Builder.SetInsertPoint(Inst->getParent(),
----------------
Why bitcasts need to be at top of the block?
Could there be phi at top of the block?


================
Comment at: llvm/lib/Target/DirectX/DXILPrepare.cpp:136
+          if (auto Inst = dyn_cast_or_null<StoreInst>(&I)) {
+            // Omit bitcasts if we only have one type
+            auto It = PointerTypes.find(Inst->getPointerOperand());
----------------
Cannot find the check for only have one type.
Does it hide in PointerTypes.find ?



================
Comment at: llvm/lib/Target/DirectX/DXILPrepare.cpp:137-142
+            auto It = PointerTypes.find(Inst->getPointerOperand());
+            if (It != PointerTypes.end()) {
+              if (cast<TypedPointerType>(It->second)->getElementType() ==
+                  Inst->getValueOperand()->getType())
+                continue;
+            }
----------------
Could we have shouldOmit function and createNoOpBitcast function? The same code happened 3 times.



Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D122269/new/

https://reviews.llvm.org/D122269