Add new intrinsic is_constant and optimize pow#114390
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Centri3 wants to merge 11 commits intorust-lang:masterfrom
Closed
Add new intrinsic is_constant and optimize pow#114390Centri3 wants to merge 11 commits intorust-lang:masterfrom
is_constant and optimize pow#114390Centri3 wants to merge 11 commits intorust-lang:masterfrom
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This was suggested in #114254. This basically lets LLVM know that it can evaluate the next few statements at compile-time, and thus can completely remove them. This allows us to select a path at compile-time, and with optimizations on, the other will be entirely removed. This will likely be a bit slower in debug mode but this should be ok.
I've done this for the integer's
powmethods as was done in #114254 and it works great!We should probably restrict the types that can be passed to it, though,
llvm.is.constantcan be passed any type but some ICE. (So far, I know that all ZSTs cause an ICE)cc @rust-lang/lang; I highly doubt this shouldn't be insta-
const, but I think discussion should be warranted anyway.