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Re: [PATCH, v2] gas/x86: don't allow invalid operand combinations for VGATHER
- From: "H.J. Lu" <hjl dot tools at gmail dot com>
- To: Jan Beulich <JBeulich at suse dot com>
- Cc: binutils at sourceware dot org
- Date: Tue, 7 Aug 2012 06:21:06 -0700
- Subject: Re: [PATCH, v2] gas/x86: don't allow invalid operand combinations for VGATHER
- References: <500ECADF0200007800090386@nat28.tlf.novell.com> <CAMe9rOohHAP2sk2PuMFspXtHCmda4WQoJzpbRf1iUau+7sR5XQ@mail.gmail.com> <5017AA390200007800091775@nat28.tlf.novell.com> <CAMe9rOoiaQgwu-ounpDeP_C9Hkx0w967tQjNMTx6fwZbHVA9TA@mail.gmail.com> <502109F902000078000932A7@nat28.tlf.novell.com>
On Tue, Aug 7, 2012 at 3:28 AM, Jan Beulich <JBeulich@suse.com> wrote:
>>>> On 31.07.12 at 17:43, "H.J. Lu" <firstname.lastname@example.org> wrote:
>> On Tue, Jul 31, 2012 at 12:49 AM, Jan Beulich <JBeulich@suse.com> wrote:
>>>>>> On 30.07.12 at 18:10, "H.J. Lu" <email@example.com> wrote:
>>>> 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?
>> Can you also add a command line option to turn it off and
>> turn warning into error?
> How about this then?
> 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
> severity of the resulting diagnostics can be controlled via command
> line option or directive.
can't be used? XMM2 can be used for both mask and