nikic requested changes to this revision. nikic added a comment. This revision now requires changes to proceed.
This doesn't looks like a wasm specific problem. You get essentially the same issue on any target that has a rotate instruction but no funnel shift instruction. Here are just a couple examples: https://godbolt.org/z/8v6nfaax9 I believe this needs to be either solved by preventing demanded bits simplifications that break a rotate pattern (though I'm not sure if that would break any other optimizations we care about) or by adding a special case for this in the backend when lowering FSH to ROT. Lowering to a rotate intrinsic only "solves" this for wasm and will at the same time make these rotates completely opaque to optimization -- heck, it looks like we don't even support constant folding for these intrinsics (https://llvm.godbolt.org/z/hMWG16b9W). Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D150670/new/ https://reviews.llvm.org/D150670 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
