floating point
Henry Cejtin
henry@sourcelight.com
Mon, 13 Aug 2001 15:03:44 -0500
I decided to look some more at why gcc was generating such bad code, and now
I am slightly nervous. There is a `-ffast-math' option which they warn you
should NOT be turned on by any optimization level because it is not
sufficiently ANSI or IEEE compliant. Then you turn it on, the code looks
like MLton's does now.
If you look at the info pages, they talk about one of the things this does is
allow the compiler to assume that args to sqrt are non-negative and that no
arg is a NaN. I don't see why this would matter since I assume, perhaps
incorrectly, that if the arg is negative or NaN then the sqrt instruction
would give me a NaN result.
Any way, whet are the requirements, if any, for SML? I don't see any thing
in the standard except for the usual pointer to the still-does-not-exist
basis book.