https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100855
--- Comment #10 from Nadav Halahmi ---
(In reply to Dominique d'Humieres from comment #9)
> I don't know if the test is coming from a real world problem. The modified
> test
>
> program power
> implicit none
>
> real :: sum, sum1, n,
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100855
Dominique d'Humieres changed:
What|Removed |Added
Resolution|--- |INVALID
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100855
--- Comment #8 from Dominique d'Humieres ---
> So gnu is indeed faster for real(8), but the result was changed.
What OS are you using? In any sensible library REAL(4° should be faster than
REAL(8).
> notice the result was also changed
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100855
--- Comment #7 from Nadav Halahmi ---
(In reply to Dominique d'Humieres from comment #6)
> On a MacOS, Corei9, 2.4Ghz, the program runs in ~1s, almost indpendtly of
> the option level.
>
> This PR remind me an old problem in which the
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100855
--- Comment #6 from Dominique d'Humieres ---
On a MacOS, Corei9, 2.4Ghz, the program runs in ~1s, almost indpendtly of the
option level.
This PR remind me an old problem in which the transcendental functions were
almost slower for REAL(4) then
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100855
--- Comment #5 from Nadav Halahmi ---
(In reply to Richard Biener from comment #3)
> Might be interesting to see whether ifort does any expression simplification
> here. Can you share the produced assembly?
ifort pow.f90 -O3 -no-vec -S -o
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100855
--- Comment #4 from Nadav Halahmi ---
(In reply to Richard Biener from comment #3)
> Might be interesting to see whether ifort does any expression simplification
> here. Can you share the produced assembly?
gfortran pow.f90 -O3
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100855
--- Comment #3 from Richard Biener ---
Might be interesting to see whether ifort does any expression simplification
here. Can you share the produced assembly?
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100855
--- Comment #2 from anlauf at gcc dot gnu.org ---
If you do not care about correct rounding, you can replace
sum = sum + (i ** (0.05 + n))
by
sum = sum + exp (log (real(i)) * (0.05 + n))
I think __builtin_powf and powf do care.
I do
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100855
kargl at gcc dot gnu.org changed:
What|Removed |Added
Priority|P3 |P4
Last reconfirmed|
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