-/// GetValueInMiddleOfBlock - Construct SSA form, materializing a value that
-/// is live in the middle of the specified block.
-///
-/// GetValueInMiddleOfBlock is the same as GetValueAtEndOfBlock except in one
-/// important case: if there is a definition of the rewritten value after the
-/// 'use' in BB. Consider code like this:
-///
-/// X1 = ...
-/// SomeBB:
-/// use(X)
-/// X2 = ...
-/// br Cond, SomeBB, OutBB
-///
-/// In this case, there are two values (X1 and X2) added to the AvailableVals
-/// set by the client of the rewriter, and those values are both live out of
-/// their respective blocks. However, the use of X happens in the *middle* of
-/// a block. Because of this, we need to insert a new PHI node in SomeBB to
-/// merge the appropriate values, and this value isn't live out of the block.
-///