optimization/6798: [3.2/3.3/3.4 regression] very long compile time with large case-statement

[Wolfgang Bangerth]

> > Volker, you said you saw this on Linux?  I don't see this bug on
> > i586-linux, so I hope you can confirm this so we can close this PR, or
> > else we should try to find out if this is a target-specific problem.
> > 
> > Greetz
> > Steven
> 
> Sorry, but that was Wolfgang and not me

Yes, I could reproduce this with mainline. I just checked again, it's fine 
now on mainline, but it still takes forever on the 3.3 branch. However, 
for well known reasons I can't update my 3.3 copy, which is still of 
2003-03-05. Likewise, my 3.2 copy (from 2003-01-24).

So, it seems as if this is fixed on mainline. I'll change the synopsis 
accordingly. Can anyone double check with the other two branches and newer 
versions than mine?

Thanks
  W.

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Wolfgang Bangerth             email:            bangerth@ticam.utexas.edu
                              www: http://www.ticam.utexas.edu/~bangerth/