[llvm] [NVPTX] support immediate values in st.param instructions (PR #91523)

[Artem Belevich via llvm-commits]

================
@@ -2182,6 +2182,84 @@ bool NVPTXDAGToDAGISel::tryStoreRetval(SDNode *N) {
   return true;
 }
 
+// Helpers for constructing opcode (ex: NVPTX::StoreParamV4F32_iiri)
+#define getOpcV2H(ty, op0, op1) NVPTX::StoreParamV2##ty##_##op0##op1
+
+#define getOpcV2H1(ty, op0, op1)                                               \
+  (op1) ? getOpcV2H(ty, op0, i) : getOpcV2H(ty, op0, r)
+
+#define getOpcodeForVectorStParamV2(ty, isimm)                                 \
+  (isimm[0]) ? getOpcV2H1(ty, i, isimm[1]) : getOpcV2H1(ty, r, isimm[1])
+
+#define getOpcV4H(ty, op0, op1, op2, op3)                                      \
+  NVPTX::StoreParamV4##ty##_##op0##op1##op2##op3
+
+#define getOpcV4H3(ty, op0, op1, op2, op3)                                     \
+  (op3) ? getOpcV4H(ty, op0, op1, op2, i) : getOpcV4H(ty, op0, op1, op2, r)
+
+#define getOpcV4H2(ty, op0, op1, op2, op3)                                     \
+  (op2) ? getOpcV4H3(ty, op0, op1, i, op3) : getOpcV4H3(ty, op0, op1, r, op3)
+
+#define getOpcV4H1(ty, op0, op1, op2, op3)                                     \
+  (op1) ? getOpcV4H2(ty, op0, i, op2, op3) : getOpcV4H2(ty, op0, r, op2, op3)
+
+#define getOpcodeForVectorStParamV4(ty, isimm)                                 \
+  (isimm[0]) ? getOpcV4H1(ty, i, isimm[1], isimm[2], isimm[3])                 \
+             : getOpcV4H1(ty, r, isimm[1], isimm[2], isimm[3])
+
+#define getOpcodeForVectorStParam(n, ty, isimm)                                \
+  (n == 2) ? getOpcodeForVectorStParamV2(ty, isimm)                            \
+           : getOpcodeForVectorStParamV4(ty, isimm)
+
+static std::optional<unsigned>
----------------
Artem-B wrote:

What's the contract here for returned nullopt ?

https://github.com/llvm/llvm-project/pull/91523