diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/vmemitcodes.ml | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/kernel/vmemitcodes.ml b/kernel/vmemitcodes.ml index e70285d9ab..5849641c20 100644 --- a/kernel/vmemitcodes.ml +++ b/kernel/vmemitcodes.ml @@ -135,6 +135,16 @@ let out env opcode = let is_immed i = Uint63.le (Uint63.of_int i) Uint63.maxuint31 +(* Detect whether the current value of the accu register is no longer + needed (i.e., the register is written before being read). If so, the + register can be used freely; no need to save and restore it. *) +let is_accu_dead = function + | [] -> false + | c :: _ -> + match c with + | Kacc _ | Kenvacc _ | Kconst _ | Koffsetclosure _ | Kgetglobal _ -> true + | _ -> false + let out_int env n = out_word env n (n asr 8) (n asr 16) (n asr 24) @@ -399,6 +409,9 @@ let rec emit env insns remaining = match insns with | Kpush :: Kconst const :: c -> out env opPUSHGETGLOBAL; slot_for_const env const; emit env c remaining + | Kpushfields 1 :: c when is_accu_dead c -> + out env opGETFIELD0; + emit env (Kpush :: c) remaining | Kpop n :: Kjump :: c -> out env opRETURN; out_int env n; emit env c remaining | Ksequence c1 :: c -> |