Tighten the conditions under which we do PRE, remove some unneeded code, and correct our preserved analyses list, since we do now change the CFG by splitting critical edges during PRE.
Tighten the conditions under which we do PRE, remove some unneeded code, and correct our preserved analyses list, since we
do now change the CFG by splitting critical edges during PRE.


git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@52631 91177308-0d34-0410-b5e6-96231b3b80d8

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