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<p>Hi everyone,</p>
<p>Just thought I'd give a heads-up on my latest mad experiments!</p>
<p>I'm currently working to see if I can improve auto-vectorisation
within the compiler. I'm using x86_64 as my starting point since
SSE2 is guaranteed to be present, but aiming to make it as
cross-platform as possible so it can be ported to AArch64 and the
like.</p>
<p>Current status:<br>
</p>
<ul>
<li>Currently it compiles and works but it generally performs
worse than without auto-vectorisation because the compiler
forces everything into memory (its usual fall-back when it
doesn't quite know what to do wih a storage type).<br>
</li>
<li>I'm using the ucomplex.pp unit as my test case while also
telling it to use 'vectorcall' in all of the routines. Because
the complex type is just two Doubles, this is perfectly suited
for XMM.</li>
<li>I tried to reuse LOC_SUBSETREG and LOC_CSUBSETREG for
locations that occupied specific lanes of an MM register, but
this caused problems since the type is designed only for integer
registers, so I have created a new LOC_MMLANE and LOC_CMMLANE
type and associated structure within the TLocation union, which
are specifically designed for MM registers (and so doesn't have
to handle bitpacking). This also allows me to write new methods
like a_loadmm_reg_lane instead of re-using and over-complicating
existing ones. (I also made sure to follow the convention of
keeping LOC_REFERENCE and LOC_CREFERENCE last).<br>
</li>
<li>Currently I'm only supporting 128-bit MM types. 256-bit and
above will come at a later date.</li>
<li>Currently auto-vectorisation is always attempted, but later
will disable it if it's not -O2 or -O3 (haven't decided which
yet).<br>
</li>
</ul>
<p>Kit<br>
</p>
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