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Re: What is acceptable for -ffast-math? (Was: associative law in combine)
- To: Neil Booth <neil at daikokuya dot demon dot co dot uk>
- Subject: Re: What is acceptable for -ffast-math? (Was: associative law in combine)
- From: Alexandre Oliva <aoliva at redhat dot com>
- Date: 30 Jul 2001 20:02:46 -0300
- Cc: Linus Torvalds <torvalds at transmeta dot com>, dewar at gnat dot com, moshier at moshier dot ne dot mediaone dot net, gcc at gcc dot gnu dot org, tprince at computer dot org
- Organization: GCC Team, Red Hat
- References: <20010730234518.B11200@daikokuya.demon.co.uk>
On Jul 30, 2001, Neil Booth <neil@daikokuya.demon.co.uk> wrote:
> Alexandre Oliva wrote:-
>> But we could use new tokens, say (( )) and ((( ))) to mark expressions
>> the preprocessor and the compiler shouldn't muck up with.
> You can't be serious? Any non-trivial CPP expansion tends to have
> multiple redundant parentheses all over the place.
I am serious. The preprocessor should protect individual parentheses
from becoming consecutive by introducing whitespace. We should tell:
((foo))
from
#define a (foo)
#define b (a)
b
so that the latter expands to say:
( (foo) )
This is something the preprocessor already does in certain cases, to
prevent certain sequences of characters from becoming different
tokens. I'm just suggesting that we do this for parentheses too, so
that we can recognize sequences of parentheses explicitly introduced
by the user, as optimization barriers.
--
Alexandre Oliva Enjoy Guarana', see http://www.ic.unicamp.br/~oliva/
Red Hat GCC Developer aoliva@{cygnus.com, redhat.com}
CS PhD student at IC-Unicamp oliva@{lsd.ic.unicamp.br, gnu.org}
Free Software Evangelist *Please* write to mailing lists, not to me