[PATCH] D66498: [GlobalISel] Import patterns containing INSERT_SUBREG

[Jessica Paquette via Phabricator via llvm-commits]

paquette added a comment.

For some reason, I thought `llvm::sort` was stable. So, what was happening is that sometimes you would end up with different register classes in `getSuperRegForSubReg`. As a result, when match tables are optimized, sometimes you would end up missing entire cases in the generated C++. (It would sometimes take a few tries to get it to fail, which is why I wasn't seeing it.)

Changing the `llvm::sort` to `llvm::stable_sort` fixes this on my end.

Recommitted in r370084. Hopefully this will make the bots happy. :)


Repository:
  rL LLVM

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  https://reviews.llvm.org/D66498/new/

https://reviews.llvm.org/D66498