[fpc-devel] FPC/Lazarus Rebuild performance

Jonas Maebe jonas.maebe at elis.ugent.be
Sun Sep 12 16:15:35 CEST 2010

On 12 Sep 2010, at 14:50, Martin Schreiber wrote:

> Hmm. ;-)
> Please take it with humor. :-)

No humor is necessary. Delphi probably uses a linear scan register allocator, which (as I mentioned before) in general generates somewhat worse code in the general case (assuming an implementation of equal quality of both), but which is much faster than graph colouring (especially for very large procedures, of which tw2242 is an extreme test case).

On 12 Sep 2010, at 16:10, Sergei Gorelkin wrote:

> Does that happen because of the SSA? I mean, it looks like a new register is allocated for every statement until limit of 16384 is hit.

No, that's unrelated to SSA (or even graph colouring). Also, I think the limit is 65535 rather than 16384.


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