[PATCH, V4 09/14] opcodes: i386: new marker for insns that implicitly update stack pointer

[Indu Bhagat]

On 1/5/24 06:05, Jan Beulich wrote:
> On 03.01.2024 08:43, Indu Bhagat wrote:
>> --- a/opcodes/i386-opc.h
>> +++ b/opcodes/i386-opc.h
>> @@ -750,6 +750,9 @@ enum
>>     /* No CSPAZO flags update indication.  */
>>     NF,
>>   
>> +  /* Instruction updates stack pointer implicitly.  */
>> +  ImplicitStackOp,
>> +
>>     /* The last bitfield in i386_opcode_modifier.  */
>>     Opcode_Modifier_Num
>>   };
>> @@ -796,6 +799,7 @@ typedef struct i386_opcode_modifier
>>     unsigned int isa64:2;
>>     unsigned int noegpr:1;
>>     unsigned int nf:1;
>> +  unsigned int implicitstackop:1;
>>   } i386_opcode_modifier;
> 
> I'm not happy to see a new attribute be introduced for this (a new
> OperandConstraint enumerator would seem more appropriate), while at
> the same time I can see that the Rex2 attribute used in two of the
> affected insns presently makes this impossible. However, with no
> other way out, I'd rather see Rex2 become a standalone attribute,
> and this one be another operand constraint.
> 

To be sure I understand clearly, the ask here is to:
   - Use unsigned int rex2:1 in struct i386_opcode_modifier instead
   - Add a new OperandConstraint=IMPLICIT_STACK_OP
   - Remove the OperandConstraint=REX2_REQUIRED

Is this right ?

Indu