Andrea Di Biagio 2ce3ac8dd8 Teach DAGCombiner how to canonicalize dags according to the rule ...

(shl (zext (shr A, X)), X) => (zext (shl (shr A, X), X)).

The rule only triggers when there are no other uses of the
zext to avoid materializing more instructions.

This helps the DAGCombiner understand that the shl/shr
sequence can then be converted into an and instruction.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191393 91177308-0d34-0410-b5e6-96231b3b80d8

2013-09-25 19:01:01 +00:00

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