[llvm-dev] How to write LLVM backend pass after every LLVM's internal pass?

[Nicholas Krause via llvm-dev]

On 11/28/19 12:16 AM, Casper Sun via llvm-dev wrote:
> Currently I’m writing a X86 backend pass for my research project. I inserted a few instructions in MachineBasicBlocks, but then llc optimized my code, and deleted some of it. So how to so backend pass after all machine level optimizations?
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I don't have enough details to really help out here but my first 
assumption is that costs of selections are being merged in the llc.
You should note that's normal and generally a good thing or other forms 
of combining or merging instructions in the llc.

So based on that I'm curious as to why your concerned about the llc 
deleted parts of it,

Nick