[fpc-devel] FPC trunk compiler slower than 3.0.4

Jonas Maebe jonas at freepascal.org
Mon May 21 17:55:13 CEST 2018

On 21/05/18 17:42, Florian Klämpfl wrote:
> Am 18.05.2018 um 17:32 schrieb Ondrej Pokorny:
>> I observe that FPC trunk compiler is about 65-70% (factor 1.65-1.7) slower than FPC 3.0.4 compiler.
>> E.g. building Lazarus IDE takes on my machine:
>> 1:00 with FPC 3.0.4
>> 1:40 with FPC trunk
>> Do you observe the same? Any hints why?
> New features? E.g. helpers made fpc a lot slower (or are they already in 3.0.x?) Optimizer improved
> and made the compiler slower etc.

The new typed constant generator is also much slower than the old "just 
emit sequences of bytes" approach. On the other hand, it's much less 
error prone (no more alignment issues), much more portable and higher 
level. It's been in trunk for four years already though.


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