Simplify a bunch of isVirtualRegister() and isPhysicalRegister() logic.

These functions not longer assert when passed 0, but simply return false instead.

No functional change intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123155 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMBaseInstrInfo.cpp b/lib/Target/ARM/ARMBaseInstrInfo.cpp
index 046ba8e..a53d8cb 100644
--- a/lib/Target/ARM/ARMBaseInstrInfo.cpp
+++ b/lib/Target/ARM/ARMBaseInstrInfo.cpp
@@ -234,8 +234,7 @@
   if (LV) {
     for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
       MachineOperand &MO = MI->getOperand(i);
-      if (MO.isReg() && MO.getReg() &&
-          TargetRegisterInfo::isVirtualRegister(MO.getReg())) {
+      if (MO.isReg() && TargetRegisterInfo::isVirtualRegister(MO.getReg())) {
         unsigned Reg = MO.getReg();
 
         LiveVariables::VarInfo &VI = LV->getVarInfo(Reg);