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
Summary:
As disscused in https://bugs.llvm.org/show_bug.cgi?id=43219,
i believe it may be somewhat useful to show //some// aggregates
over all the sea of statistics provided.
Example:
```
Average Wait times (based on the timeline view):
[0]: Executions
[1]: Average time spent waiting in a scheduler's queue
[2]: Average time spent waiting in a scheduler's queue while ready
[3]: Average time elapsed from WB until retire stage
[0] [1] [2] [3]
0. 3 1.0 1.0 4.7 vmulps %xmm0, %xmm1, %xmm2
1. 3 2.7 0.0 2.3 vhaddps %xmm2, %xmm2, %xmm3
2. 3 6.0 0.0 0.0 vhaddps %xmm3, %xmm3, %xmm4
3 3.2 0.3 2.3 <total>
```
I.e. we average the averages.
Reviewers: andreadb, mattd, RKSimon
Reviewed By: andreadb
Subscribers: gbedwell, arphaman, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D68714
llvm-svn: 374361
This copies the Sandy Bridge zero idiom support to later CPUs. Adding the AVX2 and AVX512F/VL instructions as appropriate.
Differential Revision: https://reviews.llvm.org/D62360
llvm-svn: 361690
Simon Pilgrim