[llvm] [RISCV][GlobalISel] Select G_GLOBAL_VALUE for medlow code model (PR #68380)

[Nitin John Raj via llvm-commits]

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@@ -2032,6 +2032,28 @@ def : Pat<(binop_allwusers<add> GPR:$rs1, (AddiPair:$rs2)),
                  (AddiPairImmSmall AddiPair:$rs2))>;
 }
 
+//===----------------------------------------------------------------------===//
+// GlobalISel generic instruction definitions
+/* /===----------------------------------------------------------------------===//
+
+class RISCVGenericInstruction : GenericInstruction {
+  let Namespace = "RISCV";
+}
+
+def G_ADD_LO : RISCVGenericInstruction {
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nitinjohnraj wrote:

If we decide to go with the generic instruction approach, I will rename them accordingly, though, it does make things much clearer.

https://github.com/llvm/llvm-project/pull/68380