[PPC] Lower load acquire/seq_cst trailing fence to cmp + bne + isync.
Summary:
This fixes pr32392.
The lowering pipeline is:
llvm.ppc.cfence in IR -> PPC::CFENCE8 in isel -> Actual instructions in
expandPostRAPseudo.
The reason why expandPostRAPseudo is chosen is because previous passes
are likely eliminating instructions like cmpw 3, 3 (early CSE) and bne-
7, .+4 (some branch pass(s)).
Differential Revision: https://reviews.llvm.org/D32763
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@303205 91177308-0d34-0410-b5e6-96231b3b80d8
10 files changed