[PATCH] D112085: [DAGCombiner] fold bit-hack form of usubsat

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon added inline comments.


================
Comment at: llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:5653
+
+  // (i8 X ^ 128) & (i8 X s>> 7) --> usubsat X, 128
+  SDLoc DL(N);
----------------
foad wrote:
> What about the same thing with X +/- 128 instead of X ^ 128? Do they already get canonicalized to the XOR version?
I think instcombine will have canonicalized them: https://alive2.llvm.org/ce/z/n2TfRo


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  https://reviews.llvm.org/D112085/new/

https://reviews.llvm.org/D112085