Re: [1/1] tcg/mips: Fix SoftTLB comparison on mips backend

[Philippe Mathieu-Daudé]

On 4/1/21 12:04 PM, Kele Huang wrote:
> The addrl used to compare with SoftTLB entry should be sign-extended
> in common case, and it will cause constant failing in SoftTLB
> comparisons for the addrl whose address is over 0x80000000 on the
> emulation of 32-bit guest on 64-bit host.

Apparently missed in commit f0d703314ec
("tcg-mips: Adjust qemu_ld/st for mips64").

> 
> This is an important performance bug fix. Spec2000 gzip rate increase
> from ~45 to ~140 on Loongson 3A4000 (MIPS compatible platform).
> 
> Signed-off-by: Kele Huang <kele.hwang@gmail.com>

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

> ---
>  tcg/mips/tcg-target.c.inc | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tcg/mips/tcg-target.c.inc b/tcg/mips/tcg-target.c.inc
> index 8738a3a581..8b16726242 100644
> --- a/tcg/mips/tcg-target.c.inc
> +++ b/tcg/mips/tcg-target.c.inc
> @@ -1201,13 +1201,13 @@ static void tcg_out_tlb_load(TCGContext *s, TCGReg 
> base, TCGReg addrl,
>             load the tlb addend for the fast path.  */
>          tcg_out_ld(s, TCG_TYPE_PTR, TCG_TMP2, TCG_TMP3, add_off);
>      }
> -    tcg_out_opc_reg(s, OPC_AND, TCG_TMP1, TCG_TMP1, addrl);
>  
>      /* Zero extend a 32-bit guest address for a 64-bit host. */
>      if (TCG_TARGET_REG_BITS > TARGET_LONG_BITS) {
>          tcg_out_ext32u(s, base, addrl);
>          addrl = base;
>      }
> +    tcg_out_opc_reg(s, OPC_AND, TCG_TMP1, TCG_TMP1, addrl);
>  
>      label_ptr[0] = s->code_ptr;
>      tcg_out_opc_br(s, OPC_BNE, TCG_TMP1, TCG_TMP0);
>