[llvm] [DirectX] Add support for Raw Buffer Loads and Stores for scalars and vectors of doubles and i64s in SM6.2 and earlier (PR #146627)

[Farzon Lotfi via llvm-commits]

================
@@ -630,46 +663,52 @@ static bool expandTypedBufferLoadIntrinsic(CallInst *Orig) {
   return true;
 }
 
-static bool expandTypedBufferStoreIntrinsic(CallInst *Orig) {
+static bool expandBufferStoreIntrinsic(CallInst *Orig, bool IsRaw) {
   IRBuilder<> Builder(Orig);
 
-  Type *BufferTy = Orig->getFunctionType()->getParamType(2);
+  Type *BufferTy = Orig->getFunctionType()->getParamType(IsRaw ? 3 : 2);
   Type *ScalarTy = BufferTy->getScalarType();
   bool IsDouble = ScalarTy->isDoubleTy();
   assert((IsDouble || ScalarTy->isIntegerTy(64)) &&
          "Only expand double or int64 scalars or vectors");
 
   // Determine if we're dealing with a vector or scalar
   bool IsVector = isa<FixedVectorType>(BufferTy);
-  if (IsVector) {
-    assert(cast<FixedVectorType>(BufferTy)->getNumElements() == 2 &&
-           "TypedBufferStore vector must be size 2");
+  unsigned ExtractNum = 2;
+  unsigned VecLen = 0;
+  if (auto *VT = dyn_cast<FixedVectorType>(BufferTy)) {
+    if (!IsRaw)
+      assert(VT->getNumElements() == 2 &&
+             "TypedBufferStore vector must be size 2");
+    VecLen = VT->getNumElements();
+    ExtractNum = VecLen * 2;
   }
 
   // Create the appropriate vector type for the result
   Type *Int32Ty = Builder.getInt32Ty();
-  Type *ResultTy = VectorType::get(Int32Ty, IsVector ? 4 : 2, false);
+  Type *ResultTy = VectorType::get(Int32Ty, ExtractNum, false);
   Value *Val = PoisonValue::get(ResultTy);
 
   Type *SplitElementTy = Int32Ty;
   if (IsVector)
-    SplitElementTy = VectorType::get(SplitElementTy, 2, false);
+    SplitElementTy = VectorType::get(SplitElementTy, VecLen, false);
 
   Value *LowBits = nullptr;
   Value *HighBits = nullptr;
   // Split the 64-bit values into 32-bit components
   if (IsDouble) {
     auto *SplitTy = llvm::StructType::get(SplitElementTy, SplitElementTy);
     Value *Split = Builder.CreateIntrinsic(SplitTy, Intrinsic::dx_splitdouble,
-                                           {Orig->getOperand(2)});
+                                           {Orig->getOperand(IsRaw ? 3 : 2)});
----------------
farzonl wrote:

we are repeating this terinary a bunch: `IsRaw ? 3 : 2`. Lets just store the operand index somewhere so we don't have to keep doing this.

https://github.com/llvm/llvm-project/pull/146627