This is the mail archive of the binutils@sourceware.org mailing list for the binutils project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [PATCH] x86: Expand Broadcast to 3 bits


On Thu, Jul 26, 2018 at 7:58 AM, Jan Beulich <JBeulich@suse.com> wrote:
>>>> On 26.07.18 at 00:05, <hongjiu.lu@intel.com> wrote:
>> @@ -5008,6 +5010,22 @@ optimize_disp (void)
>>        }
>>  }
>>
>> +/* Return 1 if there is a match in broadcast bytes between operand
>> +   GIVEN and instruction template T.   */
>> +
>> +static INLINE int
>> +match_broadcast_size (const insn_template *t, unsigned int given)
>> +{
>> +  return ((t->opcode_modifier.broadcast == BYTE_BROADCAST
>> +        && i.types[given].bitfield.byte)
>> +       || (t->opcode_modifier.broadcast == WORD_BROADCAST
>> +           && i.types[given].bitfield.word)
>> +       || (t->opcode_modifier.broadcast == DWORD_BROADCAST
>> +           && i.types[given].bitfield.dword)
>> +       || (t->opcode_modifier.broadcast == QWORD_BROADCAST
>> +           && i.types[given].bitfield.qword));
>> +}
>> +
>>  /* Check if operands are valid for the instruction.  */
>>
>>  static int
>> @@ -5126,23 +5144,29 @@ check_VecOperands (const insn_template *t)
>>        i386_operand_type type, overlap;
>>
>>        /* Check if specified broadcast is supported in this instruction,
>> -      and it's applied to memory operand of DWORD or QWORD type.  */
>> +      and its broadcast bytes match the memory operand.  */
>>        op = i.broadcast->operand;
>>        if (!t->opcode_modifier.broadcast
>>         || !i.types[op].bitfield.mem
>>         || (!i.types[op].bitfield.unspecified
>> -           && (t->operand_types[op].bitfield.dword
>> -               ? !i.types[op].bitfield.dword
>> -               : !i.types[op].bitfield.qword)))
>> +           && !match_broadcast_size (t, op)))
>>       {
>>       bad_broadcast:
>>         i.error = unsupported_broadcast;
>>         return 1;
>>       }
>>
>> +      i.broadcast->bytes = ((1 << (t->opcode_modifier.broadcast - 1))
>> +                         * i.broadcast->type);
>
> So if you moved this up ahead of the earlier if(), and if you used
> i.broadcast->bytes in place of t->opcode_modifier.broadcast in
> match_broadcast_size(), I think you could get away without the
> extension to 3 bits in the templates.

i.broadcast->bytes is set from t->opcode_modifier.broadcast.
I'd like to avoid check byte, word, dword, qword to compute
i.broadcast->bytes.

> Also, wouldn't you better clear ->bytes again in case the function later
> returns an error, leading to the next template to be looked at?

Good point.  I will take a look.


-- 
H.J.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]