[PATCH] D62818: [InstCombine] Allow ((X << Y) & SignMask) != 0 to be optimized as (X << Y) s< 0.

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri added a comment.

In D62818#1529921 <https://reviews.llvm.org/D62818#1529921>, @huihuiz wrote:

> The other approach could be changing the order of folding. Move foldICmpBinOpEqualityWithConstant to the very beginning of foldICmpInstWithConstant. 
>  foldICmpBinOpEqualityWithConstant has rules to replace (and X, (1 << size(X)-1) != 0) with x s< 0.
>  Let me know if this approach is more preferable?


You want (1+1*2)*2 = 6 folds: https://rise4fun.com/Alive/Y8Ct


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