[Bug fortran/19925] Implied do-loop in an initialization expression is broken

[dominiq at lps dot ens dot fr]

------- Comment #20 from dominiq at lps dot ens dot fr  2008-02-01 15:31 -------
With the patch in comment #18, on a Core2Duo 2.16Ghz I get:

    5000      0.54   secs
  10000      1.82
  20000      6.74
  40000    36.5
  60000  206
  65535  258
  65536     68         <--   Error: Initialization expression didn't reduce (1)
  80000  149                                            Ditto
100000  281                                            Ditto

So the threshold seems to be 2**16. While the timings in comment #18 seem more
or less cubic in n, on the Core2duo, they start more or less quadratic in n up
to 20000, then grow up much faster with n, as if they were the addition of one
quadratic behavior and one cubic (or faster) with prefactors depending on the
processor.

Note that the patch in #18, is not needed below some value of n: n=10000 pass
on unpatched ppc.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19925