Re: [PATCH 11/24] tcg/ppc: Use the Set Boolean Extension

[Nicholas Piggin]

On Tue Aug 8, 2023 at 1:11 PM AEST, Richard Henderson wrote:
> The SETBC family of instructions requires exactly two insns for
> all comparisions, saving 0-3 insns per (neg)setcond.
>

Nice patch. Tested on a POWER10.

Tested-by: Nicholas Piggin <npiggin@gmail.com>

> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  tcg/ppc/tcg-target.c.inc | 22 ++++++++++++++++++++++
>  1 file changed, 22 insertions(+)
>
> diff --git a/tcg/ppc/tcg-target.c.inc b/tcg/ppc/tcg-target.c.inc
> index 10448aa0e6..090f11e71c 100644
> --- a/tcg/ppc/tcg-target.c.inc
> +++ b/tcg/ppc/tcg-target.c.inc
> @@ -447,6 +447,11 @@ static bool tcg_target_const_match(int64_t val, TCGType 
> type, int ct)
>  #define TW     XO31( 4)
>  #define TRAP   (TW | TO(31))
>  
> +#define SETBC    XO31(384)  /* v3.10 */
> +#define SETBCR   XO31(416)  /* v3.10 */
> +#define SETNBC   XO31(448)  /* v3.10 */
> +#define SETNBCR  XO31(480)  /* v3.10 */
> +
>  #define NOP    ORI  /* ori 0,0,0 */
>  
>  #define LVX        XO31(103)
> @@ -1624,6 +1629,23 @@ static void tcg_out_setcond(TCGContext *s, TCGType 
> type, TCGCond cond,
>          arg2 = (uint32_t)arg2;
>      }
>  
> +    /* With SETBC/SETBCR, we can always implement with 2 insns. */
> +    if (have_isa_3_10) {
> +        tcg_insn_unit bi, opc;
> +
> +        tcg_out_cmp(s, cond, arg1, arg2, const_arg2, 7, type);
> +
> +        /* Re-use tcg_to_bc for BI and BO_COND_{TRUE,FALSE}. */
> +        bi = tcg_to_bc[cond] & (0x1f << 16);
> +        if (tcg_to_bc[cond] & BO(8)) {
> +            opc = neg ? SETNBC : SETBC;
> +        } else {
> +            opc = neg ? SETNBCR : SETBCR;
> +        }
> +        tcg_out32(s, opc | RT(arg0) | bi);
> +        return;
> +    }
> +
>      /* Handle common and trivial cases before handling anything else.  */
>      if (arg2 == 0) {
>          switch (cond) {