[fpc-devel] Kit's ambitions!

[Florian Klämpfl]

Am 21.05.2018 um 21:05 schrieb J. Gareth Moreton:
> Would you object to me trying anyway, Florian? 

No, feel free to go ahead, but it needs to be done step by step.

> It might be that I run into the same problems you had and it's too 
> unsafe, but I'm going by a conservative philosophy in that if it spots something that it can't work out (e.g. an 
> instruction that it's not programmed to handle) or is potentially unsafe (e.g. reading and writing to a block of memory 
> that it doesn't have control over, due to multi-threading issues), then it just stops optimising and drops all 
> assumptions that it has made at that point.
> 
> As a small test case, I'm attempting to see if I can spot and optimise, for example, "mov %rax, %rbx; lea %rcx, 
> -8(%rsp); mov %rbx, 8(%rsp)", where a pipeline stall occurs due to a read-after-write penalty (with %rbx in this case).  

Things like this are fine, it gets hairy though as soon as memory locations are involved.