diff mbox series

x86: minor improvements to optimize_imm() (part III)

Message ID eb0e1bff-675e-72db-b8b1-b0f0e50b7121@suse.com
State Accepted
Headers
Series x86: minor improvements to optimize_imm() (part III) |

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Context Check Description
snail/binutils-gdb-check success Github commit url

Commit Message

Jan Beulich Oct. 28, 2022, 12:35 p.m. UTC 
  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.

Comments

H.J. Lu Oct. 28, 2022, 4:03 p.m. UTC | #1 
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
Jan Beulich Oct. 31, 2022, 10:11 a.m. UTC | #2 
On 28.10.2022 18:03, H.J. Lu wrote:
> 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?

Initially I thought it could, yes, but it cannot: As said in the
description the AND-ing "is necessary to satisfy operand_type_or()'s
assertions".

Jan
H.J. Lu Oct. 31, 2022, 4:24 p.m. UTC | #3 
On Mon, Oct 31, 2022 at 3:11 AM Jan Beulich <jbeulich@suse.com> wrote:
>
> On 28.10.2022 18:03, H.J. Lu wrote:
> > 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?
>
> Initially I thought it could, yes, but it cannot: As said in the
> description the AND-ing "is necessary to satisfy operand_type_or()'s
> assertions".
>
> Jan

OK.

Thanks.
diff mbox series

Patch

--- 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);
+		}
+
 	      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