[llvm] [NVPTX] Attempt to load params using symbol addition node directly (PR #119935)

[Kevin McAfee via llvm-commits]

================
@@ -2473,17 +2473,27 @@ bool NVPTXDAGToDAGISel::SelectDirectAddr(SDValue N, SDValue &Address) {
 }
 
 // symbol+offset
-bool NVPTXDAGToDAGISel::SelectADDRsi_imp(
-    SDNode *OpNode, SDValue Addr, SDValue &Base, SDValue &Offset, MVT mvt) {
-  if (Addr.getOpcode() == ISD::ADD) {
-    if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(Addr.getOperand(1))) {
-      SDValue base = Addr.getOperand(0);
-      if (SelectDirectAddr(base, Base)) {
-        Offset = CurDAG->getTargetConstant(CN->getZExtValue(), SDLoc(OpNode),
-                                           mvt);
-        return true;
+bool NVPTXDAGToDAGISel::SelectADDRsi_imp(SDNode *OpNode, SDValue Addr,
+                                         SDValue &Base, SDValue &Offset,
+                                         MVT mvt) {
+  std::function<std::optional<uint64_t>(SDValue, uint64_t)>
+      FindRootAddressAndTotalOffset =
+          [&](SDValue Addr,
+              uint64_t AccumulatedOffset) -> std::optional<uint64_t> {
+    if (Addr.getOpcode() == ISD::ADD) {
+      if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(Addr.getOperand(1))) {
+        SDValue base = Addr.getOperand(0);
----------------
kalxr wrote:

I went for `PossibleBaseAddr` since the base address is what we're looking for and what `SelectDirectAddr` is checking.

https://github.com/llvm/llvm-project/pull/119935