diff mbox series

x86: simplify and slightly correct XCHG vs NOP checking

Message ID 35539292-53a8-292d-2f5d-f65ad02a36bb@suse.com
State Accepted
Headers
Series x86: simplify and slightly correct XCHG vs NOP checking |

Checks

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

Commit Message

Jan Beulich Dec. 1, 2022, 9:11 a.m. UTC 
  For one, because of CheckRegSize, there's no need to check the size of
both (register) operands. And then in process_suffix() check opcode
space rather than the (potentially ambiguous) extension opcode.

Comments

H.J. Lu Dec. 1, 2022, 4:43 p.m. UTC | #1 
On Thu, Dec 1, 2022 at 1:11 AM Jan Beulich <jbeulich@suse.com> wrote:
>
> For one, because of CheckRegSize, there's no need to check the size of
> both (register) operands. And then in process_suffix() check opcode
> space rather than the (potentially ambiguous) extension opcode.
>
> --- a/gas/config/tc-i386.c
> +++ b/gas/config/tc-i386.c
> @@ -6686,8 +6686,7 @@ match_template (char mnem_suffix)
>               && t->opcode_modifier.opcodespace == SPACE_BASE
>               && i.types[0].bitfield.instance == Accum
>               && i.types[0].bitfield.dword
> -             && i.types[1].bitfield.instance == Accum
> -             && i.types[1].bitfield.dword)
> +             && i.types[1].bitfield.instance == Accum)
>             continue;
>           /* xrelease mov %eax, <disp> is another special case. It must not
>              match the accumulator-only encoding of mov.  */
> @@ -7408,11 +7407,10 @@ process_suffix (void)
>              need rex64. */
>           && ! (i.operands == 2
>                 && i.tm.base_opcode == 0x90
> -               && i.tm.extension_opcode == None
> +               && i.tm.opcode_modifier.opcodespace == SPACE_BASE
>                 && i.types[0].bitfield.instance == Accum
>                 && i.types[0].bitfield.qword
> -               && i.types[1].bitfield.instance == Accum
> -               && i.types[1].bitfield.qword))
> +               && i.types[1].bitfield.instance == Accum))
>         i.rex |= REX_W;
>
>        break;

OK.

Thanks.
diff mbox series

Patch

--- a/gas/config/tc-i386.c
+++ b/gas/config/tc-i386.c
@@ -6686,8 +6686,7 @@  match_template (char mnem_suffix)
 	      && t->opcode_modifier.opcodespace == SPACE_BASE
 	      && i.types[0].bitfield.instance == Accum
 	      && i.types[0].bitfield.dword
-	      && i.types[1].bitfield.instance == Accum
-	      && i.types[1].bitfield.dword)
+	      && i.types[1].bitfield.instance == Accum)
 	    continue;
 	  /* xrelease mov %eax, <disp> is another special case. It must not
 	     match the accumulator-only encoding of mov.  */
@@ -7408,11 +7407,10 @@  process_suffix (void)
 	     need rex64. */
 	  && ! (i.operands == 2
 		&& i.tm.base_opcode == 0x90
-		&& i.tm.extension_opcode == None
+		&& i.tm.opcode_modifier.opcodespace == SPACE_BASE
 		&& i.types[0].bitfield.instance == Accum
 		&& i.types[0].bitfield.qword
-		&& i.types[1].bitfield.instance == Accum
-		&& i.types[1].bitfield.qword))
+		&& i.types[1].bitfield.instance == Accum))
 	i.rex |= REX_W;
 
       break;