Massive performance regression from switching to gcc 4.5

[Jan Hubicka]

> 
> (it is regression at 4.5 branch, forgot to mention)
PR44694

GiNaC indeed shows interesting behaviour.  Just the first test on 4.3 is:
timing commutative expansion and substitution....
        size:   100     200     400     800
        time/s: 0.064   0.30    1.4     6.2

for 4.5
timing commutative expansion and substitution....
        size:   100     200     400     800
        time/s: 0.080   0.36    1.6     7.4
and for 4.6
timing commutative expansion and substitution....
        size:   100     200     400     800
        time/s: 0.076   0.37    1.7     8.2

I assume that the numbers are times in second, so it is indeed not good.  Can I
easilly run the individual tests by hand?  Do you have any idea what is going
wrong here?

Honza