Merging r368164:

------------------------------------------------------------------------
r368164 | s.desmalen | 2019-08-07 14:41:38 +0200 (Wed, 07 Aug 2019) | 13 lines

[AArch64][WinCFI] Do not pair callee-save instructions in LoadStoreOptimizer

Prevent the LoadStoreOptimizer from pairing any load/store instructions with
instructions from the prologue/epilogue if the CFI information has encoded the
operations as separate instructions.  This would otherwise lead to a mismatch
of the actual prologue size from the size as recorded in the Windows CFI.

Reviewers: efriedma, mstorsjo, ssijaric

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D65817

------------------------------------------------------------------------

llvm-svn: 370438