Summary:
Conversions between float and half are only available when the
taraget has the half-precision extension. Guard these intrinsics
so that they don't cause crashes in the backend.
Fixes PR27550.
Reviewers: rengolin, t.p.northover
Subscribers: cfe-commits, aemerson, t.p.northover, rengolin
Differential Revision: http://reviews.llvm.org/D19665
llvm-svn: 268047
Silviu Baranga