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

[Nitin John Raj via llvm-commits]

================
@@ -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 {
----------------
nitinjohnraj wrote:

I abandoned using these generic instructions. If you look at the next comment, you'll see they were deleted; I didn't squash the comment so that I could preserve that version in case we decided to revert to that.

In the future, would it be better if I squashed such changed?

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