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Re: Setting -frounding-math by default
Richard Guenther wrote:
The middle-end knows about an explicit association barrier (only
used from the Fortran FE sofar), a PAREN_EXPR. Would exposing
that to C/C++ be of any help? For example it would, even with
-ffast-math, avoid constant folding for (x + FLT_EPS) - FLT_EPS
(which FLT_EPS such that proper rounding to the nearest integer
value is performed).
Off the top of my head, I don't see anything both really useful
and not-surprising in C/C++ here, but I may well miss something.
There are some C++0x features, axiom and constexpr, which are
related to this area. It's not clear yet to me how all this
will interact, but I have good hope to see some connections
there (like modeling some associativity rules with axioms).
--
Sylvain Pion
INRIA Sophia-Antipolis
Geometrica Project-Team
CGAL, http://cgal.org/