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

[Craig Topper via Phabricator via llvm-commits]

craig.topper 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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nemanjai wrote:
> 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.
I think I may need to rebase the patch do to a lot of KnownBits related changed lately. I'll do that tonight or tomorrow


https://reviews.llvm.org/D31724