Re: [PATCH] x86: minor improvements to optimize_imm() (part III)

["H.J. Lu" <hjl.tools@gmail.com>]

On Fri, Oct 28, 2022 at 5:35 AM Jan Beulich <jbeulich@suse.com> wrote:
>
> Earlier tidying still missed an opportunity: There's no need for the
> "anyimm" static variable. Instead of using it in the loop to mask
> "allowed" (which is necessary to satisfy operand_type_or()'s assertions)
> simply use "mask", requiring it to be calculated first. That way the
> post-loop masking by "mask" ahead of the operand_type_all_zero() can be
> dropped.
>
> --- a/gas/config/tc-i386.c
> +++ b/gas/config/tc-i386.c
> @@ -1906,7 +1906,6 @@ operand_type_xor (i386_operand_type x, i
>
>  static const i386_operand_type disp16_32 = OPERAND_TYPE_DISP16_32;
>  static const i386_operand_type anydisp = OPERAND_TYPE_ANYDISP;
> -static const i386_operand_type anyimm = OPERAND_TYPE_ANYIMM;
>  static const i386_operand_type regxmm = OPERAND_TYPE_REGXMM;
>  static const i386_operand_type imm8 = OPERAND_TYPE_IMM8;
>  static const i386_operand_type imm8s = OPERAND_TYPE_IMM8S;
> @@ -5812,13 +5811,6 @@ optimize_imm (void)
>               const insn_template *t = current_templates->start;
>
>               operand_type_set (&mask, 0);
> -             allowed = t->operand_types[op];
> -
> -             while (++t < current_templates->end)
> -               {
> -                 allowed = operand_type_and (allowed, anyimm);
> -                 allowed = operand_type_or (allowed, t->operand_types[op]);
> -               }
>               switch (guess_suffix)
>                 {
>                 case QWORD_MNEM_SUFFIX:
> @@ -5837,7 +5829,14 @@ optimize_imm (void)
>                 default:
>                   break;
>                 }
> -             allowed = operand_type_and (mask, allowed);
> +
> +             allowed = operand_type_and (t->operand_types[op], mask);
> +             while (++t < current_templates->end)
> +               {
> +                 allowed = operand_type_or (allowed, t->operand_types[op]);
> +                 allowed = operand_type_and (allowed, mask);

mask isn't changed in the loop.  Can the AND operation be moved after
the loop?

> +               }
> +
>               if (!operand_type_all_zero (&allowed))
>                 i.types[op] = operand_type_and (i.types[op], mask);
>             }
> --- a/opcodes/i386-gen.c
> +++ b/opcodes/i386-gen.c
> @@ -537,8 +537,6 @@ static initializer operand_type_init[] =
>      "Imm32|Imm32S|Imm64|Disp32" },
>    { "OPERAND_TYPE_IMM32_32S_64_DISP32_64",
>      "Imm32|Imm32S|Imm64|Disp32|Disp64" },
> -  { "OPERAND_TYPE_ANYIMM",
> -    "Imm1|Imm8|Imm8S|Imm16|Imm32|Imm32S|Imm64" },
>  };
>
>  typedef struct bitfield



-- 
H.J.