Re: [PATCH] MIPS/gas: LQC2, LDC3 and SQC2 macro !microMIPS assertions

["Maciej W. Rozycki" <macro at codesourcery dot com>]

On Mon, 25 Aug 2014, Richard Sandiford wrote:

> >  This adds missing !microMIPS assertions for the LQC2, LDC3 and SQC2 
> > macros whose underlying instructions have no microMIPS encoding.
> 
> I don't really see the need for these kinds of asserts.  If the instruction
> isn't available we're going to assert later anyway.  The problem with asserting
> here too is that (as this patch proves) it's very hard to maintain the
> consistent duplication of information without some kind of automatic help.
> 
> I'd prefer to go for consistency the other way and remove
> !mips_opts.micromips asserts that are only there because there's no
> underlying microMIPS instruction.  This includes the one in the earlier
> SAA(D) patch.

 I missed this e-mail from you because unlike the other three it wasn't 
delivered to me for some reason, I now only noticed it on the mailing list 
(and pulled a copy).  So I pushed the SAA(D) patch without seeing your 
concern, sorry about that.

 I think you're actually right, why didn't I realise that before making 
these changes?  The thing is these asserts were really needed with the old 
INSERT_OPERAND CPP macro that would do something really silly if used for 
an unsupported ISA.  Now they could have really gone with your removal of 
old code:

commit e077a1c8de38e8ad1ce26e127b24ed4ecf77a840
Author: Richard Sandiford <rdsandiford@googlemail.com>
Date:   Sun Jul 14 13:37:51 2013 +0000

however I suppose you didn't want to mess with things more than necessary 
with that change and then the issue got forgotten somehow.

 So I think I can clean this stuff up easily throughout `macro', though 
I'll make some checks first as to what happens if some of these synthetic 
instruction macros are indeed inserted into an opcode table of the wrong 
ISA.

 Thanks for your feedback.

  Maciej