[fpc-devel] LEA instruction speed

[J. Gareth Moreton]

I don't think any of them currently fit, although Zen 3 is later than 
Ice Lake, but I'm not sure if it has a faster LEA or not. I'll do some 
investigation.  I'll take up Tomas' offer on the 486 test though.  
Personally I think the best test might actually be one of the 
recently-optimised cryptographic functions.

Kit

On 03/10/2023 08:02, Florian Klämpfl via fpc-devel wrote:
>
>> Am 03.10.2023 um 03:32 schrieb J. Gareth Moreton via fpc-devel <fpc-devel at lists.freepascal.org>:
>>
>> Hi everyone,
>>
>> This is mainly to Florian, but also to anyone else who can answer the question - at which point did a complex LEA instruction (using all three input operands and some other specific circumstances) get slow?
> Maybe check Agner’s list?
>
>> Preliminary research suggests the 486 was when it gained extra latency, and then Sandy Bridge when it got particularly bad.  Icy Lake seems to be the architecture where faster LEA instructions are reintroduced, but I'm not sure about AMD processors.
>>
>> Should I introduce a new x86 subprocessor named "ICYLAKE" or is there a better name or does it fall under one of our categories already (CORE_AVX2 or ZEN3)?
> If it doesn’t fit in the existing ones, you can always add new ones
>
>> Kit
>>
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