[rfc] Moving bbs back to pools

[Daniel Berlin]

On 6/7/07, Zdenek Dvorak <rakdver@kam.mff.cuni.cz> wrote:
> Hello,
>
> as discussed in http://gcc.gnu.org/ml/gcc-patches/2007-05/msg01133.html,
> it might be a good idea to try moving cfg to alloc pools.  The patch
> below does that for basic blocks (each function has a separate pool
> from that its basic blocks are allocated).  At the moment, the patch
> breaks precompiled headers, but otherwise bootstraps and passes
> regtesting.
>
> The problem is, that it does not give any speedups (it is almost
> completely compile-time neutral for compilation of preprocessed
> gcc sources).

It was mainly on sources that allocate a lot of bb's that this mattered.
If you have a small number of bb's, it just doesn't matter how you
allocate them.

None of the gcc sources (except for insn-*) ever end up with that many
basic blocks.