Re: [PATCH] x86: don't allow invalid operand combinations for VGATHER

["Jan Beulich" <JBeulich at suse dot com>]

>>> On 30.07.12 at 18:10, "H.J. Lu" <hjl.tools@gmail.com> wrote:
> On Tue, Jul 24, 2012 at 7:18 AM, Jan Beulich <JBeulich@suse.com> wrote:
>> The VGATHER group of instructions requires that all three involved
>> xmm/ymm registers are distinct. This patch adds code to check for this,
>> and at once eliminates a superfluous check for not using PC-relative
>> addressing for these instructions (the fact that an index register is
>> required here already excludes valid PC-relative addresses).
>>
> 
> The assembler should only check the operands which can't be
> encoded.  It should shouldn't check if operands are functional
> correct.  However, I don't mind to issue an error which is controlled
> by a command line option.

Hmm, not sure. Is there any precedent to such behavior? I as a
programmer would appreciate if the assembler rejected anything
that's invalid.

In the case you stay on that position, would making the new
diagnostic an unconditional warning be acceptable instead?

Jan