[dataflow] speed up bitmap_ior_and_compl and other functions

Paolo Bonzini paolo.bonzini@lu.unisi.ch
Tue Mar 27 13:24:00 GMT 2007


This patch speeds up some bitmap functions that
are used on dataflow branch to solve dataflow equation.
In particular, the computation of A | (B & ~C) is done
directly, without going through a temporary bitmap for
B & ~C.

It changes the profile on a tramp3d compilation from

3967      0.2535  bitmap_elt_clear_from
2312      0.1477  bitmap_ior
2152      0.1375  bitmap_and_compl

to

3576      0.2286  bitmap_elt_clear_from
2382      0.1523  bitmap_ior_and_compl

and it improves bootstrapping time by ~0.5%.

Bootstrapped/regtested on df-branch, i686-pc-linux-gnu,
also with some debugging code to compare the results
with the old implementation and to check the correctness
of the "changed" result.

Ok for the branch?

Paolo
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