Re: [PATCH v2 2/7] target/ppc: optimize hreg_compute_pmu_hflags_value

[Nicholas Piggin]

On Thu May 23, 2024 at 3:14 PM AEST, Harsh Prateek Bora wrote:
> Cache env->spr[SPR_POWER_MMCR0] in a local variable as used in multiple
> conditions to avoid multiple indirect accesses.
>
> Signed-off-by: Harsh Prateek Bora <harshpb@linux.ibm.com>

Compiler might cache it in a reg, but anyway I like it.

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

> ---
>  target/ppc/helper_regs.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/target/ppc/helper_regs.c b/target/ppc/helper_regs.c
> index 945fa1a596..d09dcacd5e 100644
> --- a/target/ppc/helper_regs.c
> +++ b/target/ppc/helper_regs.c
> @@ -50,15 +50,16 @@ void hreg_swap_gpr_tgpr(CPUPPCState *env)
>  static uint32_t hreg_compute_pmu_hflags_value(CPUPPCState *env)
>  {
>      uint32_t hflags = 0;
> -
>  #if defined(TARGET_PPC64)
> -    if (env->spr[SPR_POWER_MMCR0] & MMCR0_PMCC0) {
> +    target_ulong mmcr0 = env->spr[SPR_POWER_MMCR0];
> +
> +    if (mmcr0 & MMCR0_PMCC0) {
>          hflags |= 1 << HFLAGS_PMCC0;
>      }
> -    if (env->spr[SPR_POWER_MMCR0] & MMCR0_PMCC1) {
> +    if (mmcr0 & MMCR0_PMCC1) {
>          hflags |= 1 << HFLAGS_PMCC1;
>      }
> -    if (env->spr[SPR_POWER_MMCR0] & MMCR0_PMCjCE) {
> +    if (mmcr0 & MMCR0_PMCjCE) {
>          hflags |= 1 << HFLAGS_PMCJCE;
>      }
>