Merging r339536:

Merging r339536:
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r339536 | ctopper | 2018-08-13 08:53:49 +0200 (Mon, 13 Aug 2018) | 3 lines

[SelectionDAG] In PromoteFloatOp_BITCAST, insert a bitcast after the fp_to_fp16 in case the result type isn't a scalar integer.

This is another variation of PR38533. In this case, the result type of the bitcast is legal and 16-bits wide, but not a scalar integer. So we need to emit the convert to i16 and then bitcast it to the true result type. This new bitcast will be further type legalized if necessary.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_70@339857 91177308-0d34-0410-b5e6-96231b3b80d8