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Re: What is acceptable for -ffast-math? (Was: associative law in combine)
- To: Linus Torvalds <torvalds at transmeta dot com>
- Subject: Re: What is acceptable for -ffast-math? (Was: associative law in combine)
- From: Gabriel Dos Reis <gdr at codesourcery dot com>
- Date: 01 Aug 2001 05:54:55 +0200
- Cc: Gabriel Dos Reis <gdr at codesourcery dot com>, <dewar at gnat dot com>, <aoliva at redhat dot com>, <amylaar at redhat dot com>, <gcc at gcc dot gnu dot org>, <moshier at moshier dot ne dot mediaone dot net>, <tprince at computer dot org>
- Organization: CodeSourcery, LLC
- References: <Pine.LNX.4.33.0107310945000.1188-100000@penguin.transmeta.com>
Linus Torvalds <torvalds@transmeta.com> writes:
| Look again:
|
| {"fast-math", &flag_fast_math, 1,
| "Improve FP speed by violating ANSI & IEEE rules" },
|
| and realize that even something simple as "double" doesn't historcially
| have an exact meaning in C (ie you can _not_ assume specific ranges or
| specific IEEE rounding in traditional C - it was left up to the
| implementor to do as best he could with what hardware was available).
|
| That means that traditionally, you don't even know what overflows or not,
You don't need to have an IEEE implementation before speaking of
overflow. That is the point you seem to miss.
| you're arguing for small-mindedness everywhere. ]
like yours?
-- Gaby