Summary: In some cases, shufflevector instruction can be transformed involving insert_subvector instructions. The ARM backend was missing some insert_subvector patterns, causing a failure during instruction selection. AArch64 has similar patterns.
Reviewers: t.p.northover, olista01, javed.absar, rengolin
Reviewed By: javed.absar
Subscribers: aemerson, kristof.beyls, llvm-commits
Differential Revision: https://reviews.llvm.org/D36796
llvm-svn: 311543