Re-apply r175088 for bug fix 13622: Add paired register support for
inline asm with 64-bit data on ARM

Update test case to use -mtriple=arm-linux-gnueabi


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175186 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMAsmPrinter.cpp b/lib/Target/ARM/ARMAsmPrinter.cpp
index 986dfb7..58c7798 100644
--- a/lib/Target/ARM/ARMAsmPrinter.cpp
+++ b/lib/Target/ARM/ARMAsmPrinter.cpp
@@ -342,6 +342,11 @@
     unsigned Reg = MO.getReg();
     assert(TargetRegisterInfo::isPhysicalRegister(Reg));
     assert(!MO.getSubReg() && "Subregs should be eliminated!");
+    if(ARM::GPRPairRegClass.contains(Reg)) {
+      const MachineFunction &MF = *MI->getParent()->getParent();
+      const TargetRegisterInfo *TRI = MF.getTarget().getRegisterInfo();
+      Reg = TRI->getSubReg(Reg, ARM::gsub_0);
+    }
     O << ARMInstPrinter::getRegisterName(Reg);
     break;
   }
@@ -530,14 +535,12 @@
       const MachineOperand &MO = MI->getOperand(OpNum);
       if (!MO.isReg())
         return true;
-      const TargetRegisterClass &RC = ARM::GPRRegClass;
       const MachineFunction &MF = *MI->getParent()->getParent();
       const TargetRegisterInfo *TRI = MF.getTarget().getRegisterInfo();
-
-      unsigned RegIdx = TRI->getEncodingValue(MO.getReg());
-      RegIdx |= 1; //The odd register is also the higher-numbered one of a pair.
-
-      unsigned Reg = RC.getRegister(RegIdx);
+      unsigned Reg = MO.getReg();
+      if(!ARM::GPRPairRegClass.contains(Reg))
+        return false;
+      Reg = TRI->getSubReg(Reg, ARM::gsub_1);
       O << ARMInstPrinter::getRegisterName(Reg);
       return false;
     }