GHC.Cmm.Opt: Handle MO_XX_Conv
This MachOp was introduced by 2c959a18 but a wildcard match in cmmMachOpFoldM hid the fact that it wasn't handled. Ideally we would eliminate the match but this appears to be a larger task. Fixes #18141.
This MachOp was introduced by 2c959a18 but a wildcard match in cmmMachOpFoldM hid the fact that it wasn't handled. Ideally we would eliminate the match but this appears to be a larger task. Fixes #18141.