[fpc-devel] Finally fixed that MOVZX/SX optimisation!

J. Gareth Moreton gareth at moreton-family.com
Wed Feb 19 01:40:12 CET 2020

Ah, I understand, thank you.

I chose those two tests in particular because the design with multiple 
typecasts opens it up to a lot of peephole optimisations.

Gareth aka. Kit

On 18/02/2020 23:12, Joost van der Sluis wrote:
> Op 18-02-2020 om 23:04 schreef J. Gareth Moreton:
>> It seems that not all regressions are caught when you run the test 
>> suite conventionally, and you have to specify additional options like 
>> "-O4", which may cause other failures to occur if a test is not 
>> expecting any kind of intense optimisation, for example.  In 
>> response, over here at https://bugs.freepascal.org/view.php?id=36687, 
>> I've introduced two new tests that are copies of the ones that 
>> failed, but which explicitly add -O4 to the default compiler options.
> In fact, *all* test should succeed with an option like -O4. So, 
> following your approach we have to add copies for all tests, with all 
> possible combination of compiler-options. That's undo-able and that is 
> why this isn't done.
> So when you are working on optimizations, it might be a good idea to 
> run the complete test-suite with optimizations enabled (-O4) on your 
> local system.
> We also realize that it is undo-able to test with all 
> optimization-settings, but to make our live easier, there are nightly 
> (daily) tests with all sort of options. You can find the results here:
> https://www.freepascal.org/testsuite/cgi-bin/testsuite.cgi
> For example, the latest x86_64-linux run with -O4:
> https://www.freepascal.org/testsuite/cgi-bin/testsuite.cgi?run1id=488056&run2id=&previousrunid=487938&failedonly=1&action=Show%2FCompare 
> Regards,
> Joost.
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