It turns out that the testcase in question uncovered subreg-handling bug.
Add assert in asmprinter to catch such cases and xfail the tests.
PR is to be filled.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86375 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/AsmPrinter/ARMAsmPrinter.cpp b/lib/Target/ARM/AsmPrinter/ARMAsmPrinter.cpp
index a3f52cd..c130ced 100644
--- a/lib/Target/ARM/AsmPrinter/ARMAsmPrinter.cpp
+++ b/lib/Target/ARM/AsmPrinter/ARMAsmPrinter.cpp
@@ -347,9 +347,7 @@
                                                &ARM::DPR_VFP2RegClass);
       O << getRegisterName(DReg) << '[' << (RegNum & 1) << ']';
     } else {
-      if (unsigned SubReg = MO.getSubReg())
-        Reg = TRI->getSubReg(Reg, SubReg);
-
+      assert(!MO.getSubReg() && "Subregs should be eliminated!");
       O << getRegisterName(Reg);
     }
     break;