Fix a bug in the 'shuffle(undef,x,mask) -> shuffle(x, undef,mask')' xform Make the insert/extract elt -> shuffle code more aggressive.
Fix a bug in the 'shuffle(undef,x,mask) -> shuffle(x, undef,mask')' xform
Make the insert/extract elt -> shuffle code more aggressive.

This fixes CodeGen/PowerPC/vec_shuffle.ll


git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@27728 91177308-0d34-0410-b5e6-96231b3b80d8

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