[PATCH] D31724: [SelectionDAG] Remove special call to LHS computeKnownBits for ANDs with constant RHS.

[Nemanja Ivanovic via Phabricator via llvm-commits]

nemanjai added inline comments.


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Comment at: test/CodeGen/PowerPC/rlwimi-and.ll:33
+; CHECK: rlwimi [[R1:[0-9]+]], {{[0-9]+}}, 8, 16, 23
+; CHECK: andi. {{[0-9]+}}, [[R1]], 257
 
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It's hard to tell exactly what's going on without context (i.e. being able to produce the code with this patch). I tried applying this patch to do so but it appears this patch may depend on the previous patches (not upstream yet).

Semantically these instruction sequences are the same. Take bits 23 and 31 from two different inputs (with the former input being shifted right 8 bits). Performance wise there isn't any real difference either. So this LGTM.


https://reviews.llvm.org/D31724