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Re: [RFC] third liveness pass

On Sun, May 26, 2002 at 02:21:47PM +0200, Jan Hubicka wrote:
> But interestingly the only C++ benchamrk, eon shows different figures.
> The savings are about 2.2% in code size and 1.6% performance (*).

Interesting.  I wonder if someone with an interest in C++ can
corroborate with "real" applications.

> Similary I think the liveness costs can be made much lower, since
> currently we don't compute bitmaps of local properties, instead re-scan
> every time that can be expensive especially when dead store removal has
> been added.

How can we, when the local property is dependent on which
insns are deleted as dead code?

> Perhaps the dead code removal is better done using DU/UD chains and
> curent ssa-dce code converted to these, but I am not sure how popular
> step this can be.

I wouldn't have a prolem with that at all, if it is faster.

You'd have to rewrite the autoinc portions of life_analysis
at the same time, but it should be fairly straight-forward
to re-implement the existing algorithms with DU/UD chains.


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