Re: [PATCH] Hexagon (target/hexagon) TCG generation cleanup

[Richard Henderson <richard.henderson@linaro.org>]

On 3/14/21 10:54 PM, Taylor Simpson wrote:
> Simplify TCG generation of hex_reg_written
> 
> Address feedback from Richard Henderson <<richard.henderson@linaro.org>
> 
> Signed-off-by: Taylor Simpson <tsimpson@quicinc.com>
> ---
>   target/hexagon/genptr.c | 12 +++++++++---
>   1 file changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/target/hexagon/genptr.c b/target/hexagon/genptr.c
> index 7481f4c..0ad63fe 100644
> --- a/target/hexagon/genptr.c
> +++ b/target/hexagon/genptr.c
> @@ -43,9 +43,15 @@ static inline void gen_log_predicated_reg_write(int rnum, TCGv val, int slot)
>       tcg_gen_movcond_tl(TCG_COND_EQ, hex_new_value[rnum], slot_mask, zero,
>                              val, hex_new_value[rnum]);
>   #if HEX_DEBUG
> -    /* Do this so HELPER(debug_commit_end) will know */
> -    tcg_gen_movcond_tl(TCG_COND_EQ, hex_reg_written[rnum], slot_mask, zero,
> -                       one, hex_reg_written[rnum]);
> +    /*
> +     * Do this so HELPER(debug_commit_end) will know
> +     *
> +     * Note that slot_mask indicates the value is not written
> +     * (i.e., slot was cancelled), so we negate the value before
> +     * or'ing with hex_reg_written[rnum].
> +     */
> +    tcg_gen_xori_tl(slot_mask, slot_mask, 1 << slot);
> +    tcg_gen_or_tl(hex_reg_written[rnum], hex_reg_written[rnum], slot_mask);

reg_written appears to be a boolean, not a mask of any kind.
I think you want

     tcg_gen_setcond_i32(TCG_COND_EQ, slot_mask, slot_mask, zero);

and not the xor.


r~