[llvm] [DirectX] Make DXILOpLowering split vector coordinates, offsets, and gradient operands (PR #223091)

[Joshua Batista via llvm-commits]

================
@@ -946,49 +987,23 @@ class OpLowerer {
   static std::array<Value *, 4> splitStoreData(IRBuilder<> &IRB, Value *Data,
                                                uint64_t NumElements,
                                                bool FillWithUndef) {
-    Type *DataTy = Data->getType();
-    Type *ScalarTy = DataTy->getScalarType();
-
     std::array<Value *, 4> DataElements{nullptr, nullptr, nullptr, nullptr};
-    if (DataTy == ScalarTy)
-      DataElements[0] = Data;
-    else {
-      // Since we're post-scalarizer, if we see a vector here it's likely
-      // constructed solely for the argument of the store. Just use the scalar
-      // values from before they're inserted into the temporary.
-      auto *IEI = dyn_cast<InsertElementInst>(Data);
-      while (IEI) {
-        auto *IndexOp = dyn_cast<ConstantInt>(IEI->getOperand(2));
-        if (!IndexOp)
-          break;
-        size_t IndexVal = IndexOp->getZExtValue();
-        assert(IndexVal < 4 && "Too many elements for resource store");
-        DataElements[IndexVal] = IEI->getOperand(1);
-        IEI = dyn_cast<InsertElementInst>(IEI->getOperand(0));
-      }
-    }
-
-    // If for some reason we weren't able to forward the arguments from the
-    // scalarizer artifact, then we may need to actually extract elements from
-    // the vector.
-    for (uint64_t I = 0, E = NumElements; I < E; ++I)
-      if (DataElements[I] == nullptr)
-        DataElements[I] = IRB.CreateExtractElement(
-            Data, ConstantInt::get(IRB.getInt32Ty(), I));
+    extractElementsIntoArgs(IRB, DataElements, 0, Data, 4);
 
     // For any elements beyond the length of the vector, we should fill it up
     // with undef - however, for typed UAVs we repeat the first element to
     // match DXC.
     for (uint64_t I = NumElements, E = 4; I < E; ++I)
       if (DataElements[I] == nullptr)
         DataElements[I] =
-            FillWithUndef ? UndefValue::get(ScalarTy) : DataElements[0];
+            FillWithUndef ? UndefValue::get(Data->getType()->getScalarType())
----------------
bob80905 wrote:

Are we really guaranteed all results of getType() will have a method getScalarType()?

https://github.com/llvm/llvm-project/pull/223091