[PATCH] D79492: [RISCV] Improve constant materialization

[Alex Bradbury via Phabricator via llvm-commits]

asb added a comment.

Thanks, this is a good improvement. Two thoughts, mainly for discussion rather than blocking issues:

1. I don't want to unreasonably expand the scope of this patch, but I do note that at least the srli transformation may be beneficial on RV32 as well for code size (still two instructions, but more compressible). Did you consider adding this or look at other RVC considerations?

2. Although it has the advantage that mistakes in edge cases etc won't lead to regressions in terms of longer instruction sequences, I'm slightly wary of the "generate and see if it's shorter" approach. Though perhaps this is going to come way down the list on any compile-time profiling vs all the other analyses+transformations being done. Any thoughts on this?


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https://reviews.llvm.org/D79492