[ARM] Split out ARMv8-A semaphores and atomics and ARMv7 clrex as separate features

llvm-svn: 257877
diff --git a/llvm/lib/Target/ARM/ARMSubtarget.cpp b/llvm/lib/Target/ARM/ARMSubtarget.cpp
index bb6ae28..c676f9f 100644
--- a/llvm/lib/Target/ARM/ARMSubtarget.cpp
+++ b/llvm/lib/Target/ARM/ARMSubtarget.cpp
@@ -154,6 +154,8 @@
   UseNaClTrap = false;
   GenLongCalls = false;
   UnsafeFPMath = false;
+  HasV7Clrex = false;
+  HasAcquireRelease = false;
 
   // MCAsmInfo isn't always present (e.g. in opt) so we can't initialize this
   // directly from it, but we can try to make sure they're consistent when both