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Commit 6eb8fc92 authored by Simon Pilgrim's avatar Simon Pilgrim
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[X86] Add some missing dependency-breaking zero idiom patterns to scheduler models

Many of the x86 scheduler models are not accounting for their microarch's ability to handle dependency-breaking zero idioms (pxor xmm0,xmm0 etc.), which is causing some notable differences when comparing llvm-mca reports to iaca, uops.info etc.

These are based on the Intel AoMs and Agner's docs which list the instructions handled on each cpu model - there may be more, although tbh the xor/pxor/xorps/xorpd are by far the most commonly encountered.

Once this is in place we also need to review missing support for 'allones' idioms and reg-reg move elimination, but this needs fixing first.

@lebedev.ri The Barcelona test changes are due to the cpu still being tagged as using the SandyBridge model, if/when you get back to D63628 these will need to be addressed.

Based on an original patch by @andreadb (Andrea Di Biagio)

Differential Revision: https://reviews.llvm.org/D117497
parent 42a68215
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