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Re: question regarding div / std::div implementation
- From: Paul Eggert <eggert at cs dot ucla dot edu>
- To: Daniel Gutson <daniel dot gutson at tallertechnologies dot com>
- Cc: Adhemerval Zanella <adhemerval dot zanella at linaro dot org>, GNU C Library <libc-alpha at sourceware dot org>
- Date: Wed, 20 Apr 2016 15:10:28 -0700
- Subject: Re: question regarding div / std::div implementation
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- References: <CAF5HaEXKZ7j-gbZPiWPhDpx7=R0zm1xYvXNYCNUMG4WeZS532Q at mail dot gmail dot com> <5717DF65 dot 5060606 at linaro dot org> <CAF5HaEWdpAGiXtCO36u3F0QGAXfVHL+qkY+RLsszpv7paPVdMg at mail dot gmail dot com> <5717E68D dot 2020905 at linaro dot org> <CAF5HaEWuSS7dEEM6ogU6TCqQ-Y7OM9DC1HFCeuuAGL0vKtL2Kw at mail dot gmail dot com> <5717EB44 dot 5020508 at linaro dot org> <CAF5HaEVWnU9_8Ae3gCR9Ns8sD_B8QoD794sp59XQNrqEw034EQ at mail dot gmail dot com> <5717F6BD dot 90705 at cs dot ucla dot edu> <CAF5HaEW-qiGwkpJCSHbptsMZzq--RJSOKoijx6qKiMRpXoYsvA at mail dot gmail dot com>
On 04/20/2016 02:55 PM, Daniel Gutson wrote:
That fools the compiler.
Yes, bizarre C code can fool the compiler. I was talking about realistic
code, not contrived examples.
glibc itself uses % and / in places where div/ldiv/lldiv might plausibly
be used internally, and this is portable and maintainable and efficient
and there is no real reason to change this, even if div/ldiv/lldiv were
tuned. Similarly for other C applications.