flambda-backend: Initial refactoring of To_cmm (#619)

Author: mshinwell

utils/target_system.ml

@@ -20,6 +20,18 @@ let architecture () : architecture =
   | "riscv" -> Riscv
   | arch -> Misc.fatal_errorf "Unknown architecture `%s'" arch
 
+let is_64_bit =
+  match architecture () with
+  | X86_64
+  | AArch64
+  | POWER
+  | Z
+  | Riscv -> true
+  | IA32
+  | ARM -> false
+
+let is_32_bit = not is_64_bit
+
 type derived_system =
   | Linux
   | MinGW_32

utils/target_system.mli

@@ -9,6 +9,10 @@ type architecture =
 
 val architecture : unit -> architecture
 
+val is_64_bit : bool
+
+val is_32_bit : bool
+
 type derived_system =
   | Linux
   | MinGW_32