DAG Combiner: Fold SelectCC When Cond is UNDEF
DAG Combiner: Fold SelectCC When Cond is UNDEF

In case folding a node end up with a NaN as operand for the select, 
the folding of the condition of the selectcc node returns "UNDEF".

Differential Revision: http://reviews.llvm.org/D6889



git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@225952 91177308-0d34-0410-b5e6-96231b3b80d8

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