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Re: [gfortran] Exponentiation by integral exponents
- From: Andrew Pinski <pinskia at physics dot uc dot edu>
- To: Tobias Schlüter <tobias dot schlueter at physik dot uni-muenchen dot de>
- Cc: GCC Fortran mailing list <fortran at gcc dot gnu dot org>, "gcc at gcc dot gnu dot org list" <gcc at gcc dot gnu dot org>, Andrew Pinski <pinskia at physics dot uc dot edu>
- Date: Tue, 27 Apr 2004 18:14:28 -0400
- Subject: Re: [gfortran] Exponentiation by integral exponents
- References: <408ECD52.2090709@physik.uni-muenchen.de> <23B628D8-9891-11D8-9EA6-000393A6D2F2@physics.uc.edu> <408ED9A7.5060603@physik.uni-muenchen.de>
On Apr 27, 2004, at 18:07, Tobias Schlüter wrote:
Andrew Pinski wrote:
On Apr 27, 2004, at 17:14, Tobias Schlüter wrote:
FYI I have ported Andy's code for exponentiation by an integral
exponent to our tree. This is an implementation of Knuth's algorithm
...
You should not need it if you use __builtin_pow and you turn on
flag_unsafe_math_optimizations on. Maybe the best way is to have
another flag
to say expand __builtin_pow always.
Does the builtin recognize the case pow(x,(float)i), where i is an
integer? Then this sounds like a very good idea.
Yes it does except that flag_unsafe_math_optimizations has to be true
but we can
easily change that.
Thanks,
Andrew Pinski