[PATCH] D157972: [DAG] SimplifyDemandedBits - add sra(shl(x,c1),c1) -> sign_extend_inreg(x) demanded elts fold

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon added inline comments.


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Comment at: llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp:1948
 
+      // fold (sra (shl x, c1), c1) -> sext_inreg for some c1 and target
+      // supports sext_inreg.
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pengfei wrote:
> Did we check the constant `c1` some where?
Yes - the `*InnerSA == ShAmt` check on line 1959


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