Re: [PATCH v2 12/36] tcg: Use tcg_constant_i32 with icount expander

["Alex Bennée" <alex.bennee@linaro.org>]

Richard Henderson <richard.henderson@linaro.org> writes:

> We must do this before we adjust how tcg_out_movi_i32,
> lest the under-the-hood poking that we do be broken.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>

> ---
>  include/exec/gen-icount.h | 25 +++++++++++++------------
>  1 file changed, 13 insertions(+), 12 deletions(-)
>
> diff --git a/include/exec/gen-icount.h b/include/exec/gen-icount.h
> index 822c43cfd3..404732518a 100644
> --- a/include/exec/gen-icount.h
> +++ b/include/exec/gen-icount.h
> @@ -34,7 +34,7 @@ static inline void gen_io_end(void)
>  
>  static inline void gen_tb_start(TranslationBlock *tb)
>  {
> -    TCGv_i32 count, imm;
> +    TCGv_i32 count;
>  
>      tcg_ctx->exitreq_label = gen_new_label();
>      if (tb_cflags(tb) & CF_USE_ICOUNT) {
> @@ -48,15 +48,13 @@ static inline void gen_tb_start(TranslationBlock *tb)
>                     offsetof(ArchCPU, env));
>  
>      if (tb_cflags(tb) & CF_USE_ICOUNT) {
> -        imm = tcg_temp_new_i32();
> -        /* We emit a movi with a dummy immediate argument. Keep the insn index
> -         * of the movi so that we later (when we know the actual insn count)
> -         * can update the immediate argument with the actual insn count.  */
> -        tcg_gen_movi_i32(imm, 0xdeadbeef);
> +        /*
> +         * We emit a sub with a dummy immediate argument. Keep the insn index
> +         * of the sub so that we later (when we know the actual insn count)
> +         * can update the argument with the actual insn count.
> +         */
> +        tcg_gen_sub_i32(count, count, tcg_constant_i32(0));
>          icount_start_insn = tcg_last_op();
> -
> -        tcg_gen_sub_i32(count, count, imm);
> -        tcg_temp_free_i32(imm);
>      }
>  
>      tcg_gen_brcondi_i32(TCG_COND_LT, count, 0, tcg_ctx->exitreq_label);
> @@ -74,9 +72,12 @@ static inline void gen_tb_start(TranslationBlock *tb)
>  static inline void gen_tb_end(TranslationBlock *tb, int num_insns)
>  {
>      if (tb_cflags(tb) & CF_USE_ICOUNT) {
> -        /* Update the num_insn immediate parameter now that we know
> -         * the actual insn count.  */
> -        tcg_set_insn_param(icount_start_insn, 1, num_insns);
> +        /*
> +         * Update the num_insn immediate parameter now that we know
> +         * the actual insn count.
> +         */
> +        tcg_set_insn_param(icount_start_insn, 2,
> +                           tcgv_i32_arg(tcg_constant_i32(num_insns)));
>      }
>  
>      gen_set_label(tcg_ctx->exitreq_label);


-- 
Alex Bennée