[PATCH] D103269: [RISCV] Reserve an emergency spill slot for any RVV spills

[Fraser Cormack via Phabricator via llvm-commits]

frasercrmck added a comment.

Ah that's interesting, thanks both for the input. I've actually done both of those things in other backends and wasn't a huge fan of either approach. I found the flag to be quite brittle and didn't like how we had to clean up the redundant addressing instructions to get the best code.

I don't anticipate a large increase in compile time, since it's only called once per function and should have early exits. One thing I forgot to include was that `hasRVVSpillWithFIs` can (presumably) safely return `false` if `!Subtarget.hasStdExtV()`. That will limit the impact on non-V code. The flag would no doubt be faster, of course, in terms of compile time. I can run some tests on the larger kernels we're producing if you like.


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https://reviews.llvm.org/D103269