When folding addressing modes in CodeGenPrepare, attempt to look through PHI nodes if all the operands of the PHI are equivalent.  This allows CodeGenPrepare to undo unprofitable PRE transforms.
When folding addressing modes in CodeGenPrepare, attempt to look through PHI nodes
if all the operands of the PHI are equivalent.  This allows CodeGenPrepare to undo
unprofitable PRE transforms.


git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@119853 91177308-0d34-0410-b5e6-96231b3b80d8

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