Compilation time has more than doubled on some Polyhedron tests

[dominiq at lps dot ens dot fr (Dominique Dhumieres)]

I have the following timing for the compilation of the polyhedron tests 
on a 1.8Ghz G5 with:

gfortran -w -O3 -ftree-loop-linear -ffast-math -funroll-loops 

for the following snapshots patched with the Paul Thomas' optimization of
dot_product.

snapshot     12/24     12/31     01/07     01/14
	     
ac            5.8s      6.0s     24.7s     23.0s    +
aermod      223.9s    227.3s    485.8s    467.6s    +
air          21.0s     21.6s      8.2s      8.0s    -
capacita      4.6s      4.7s      5.8s      5.6s
channel       2.5s      2.5s     17.6s     17.7s    +
doduc        19.7s     20.0s     38.6s     37.0s    +
fatigue      15.0s     15.4s      7.2s      6.8s    -
gas_dyn       8.6s      8.8s     19.6s     18.5s    +
induct       28.1s     28.7s     66.1s     61.6s    +
kepler        0.6s      0.6s      1.1s      1.0s    +
linpk         1.4s      1.4s      1.4s      1.4s
mdbx          5.3s      5.4s      6.9s      6.5s
nf            3.6s      3.6s      4.4s      4.3s
protein      15.5s     15.9s     15.9s     14.5s
rnflow       11.4s     11.6s     12.6s     12.7s
test_fpu      8.4s      8.5s      8.8s      8.5s
tfft          1.3s      1.3s      1.8s      1.7s

I only noticed it today, but there has been a noticable change in the 
compilation time between the 20051231 and 20060107 snapshots:
air.f90 and fatigue.f90 compile twice faster, but aermode.f90, 
doduc.f90, gas_dyn.f90, induct.f90, and kepler.f90 compile twice slower, 
while ac.f90 takes four more time and channel.f90 takes seven more time.

Am I the only one to see that? If not, does any one has any idea of what 
caused this slow down in compilation?

Using the François-Xavier's builds I have narrowed the problem between the
05/01 and the 06/01:

[scala] gfortran/2006> time irun/bin/gfortran -v -O3 -ffast-math -funroll-loops induct.f90
...
GNU F95 version 4.2.0 20060105 (experimental) (x86_64-unknown-linux-gnu)
...
19.375u 0.250s 0:20.39 96.2%    0+0k 0+0io 0pf+0w

[scala] gfortran/2006> time irun/bin/gfortran -v -O3 -ffast-math -funroll-loops induct.f90
...
GNU F95 version 4.2.0 20060106 (experimental) (x86_64-unknown-linux-gnu)
...
33.865u 0.362s 0:35.09 97.5%    0+0k 0+0io 0pf+0w

TIA

Dominique

On the induct.f90 test I get with the latest snapshot:

                     options                        compile   exec
		     
-O3 -ftree-loop-linear -ffast-math -funroll-loops     62.7    66.7
-O3 -ffast-math -funroll-loops                        61.0    66.6
-O3 -ffast-math                                       59.5    72.0
-O3 -funroll-loops                                    60.1    81.1
-O3                                                   59.5    81.4
-O2 -ffast-math -funroll-loops                        60.1    67.0
-O2 -ffast-math                                       54.3   154.5
-O2 -funroll-loops                                    58.7    81.0
-O2                                                   55.2   112.3
-O1 -ffast-math -funroll-loops                        14.6    80.5
-O1 -ffast-math                                       12.6   160.3
-O1 -funroll-loops                                    14.4   105.7
-O1                                                   12.7   164.4
-O0 -ffast-math -funroll-loops                         3.3   638.0
-O0                                                    3.4   634.4