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Re: Patch for stricter implicit conversions between vectors
- From: Ian Lance Taylor <iant at google dot com>
- To: Andrew Pinski <pinskia at gmail dot com>
- Cc: Mark Shinwell <shinwell at codesourcery dot com>, gcc patches <gcc-patches at gcc dot gnu dot org>
- Date: 14 Nov 2006 10:04:49 -0800
- Subject: Re: Patch for stricter implicit conversions between vectors
- References: <4559B33A.5050406@codesourcery.com> <1163522856.7128.12.camel@celery.andrew.com>
Andrew Pinski <pinskia@gmail.com> writes:
> On Tue, 2006-11-14 at 12:14 +0000, Mark Shinwell wrote:
> > - Adds a new flag -flax-vector-conversions to suppress the extra checking
> > in the first two points above.
>
> I really really don't want a flag that allows people to create non
> portable code. Also this is just a real regression of accepting invalid
> code, why don't we have a flag for the other cases where we now reject
> the code?
We do have such flags. For example, -fpermissive and
-ffriend-injection.
I feel very strongly that these sorts of flags are required. Many
people must compile code which they did not write. When earlier
versions of the compiler accepted code, I believe that we must make a
reasonable effort to help convert their code. That includes providing
options to permit their code to compile without requiring them to
change the code.
Of course, I don't mean that we should do this in every case. We
shouldn't do it when providing the option would be complex, or
potentially buggy, or would slow down the compiler, or would cause
other problems. But in a case like this, adding the option costs
almost nothing.
You have to think about the whole range of compiler users, not just
compiler developers.
I also think it is OK to remove these sorts of flags after a few
releases. By "a few" I mean more than three.
Ian