[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");
----------------
farzonl wrote:

I was also going to say just put everything in the assert and avoid the conditional entirely 

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