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/CodeGen/VirtRegMap.cpp b/lib/CodeGen/VirtRegMap.cpp
index df8a021..82c64f3 100644
--- a/lib/CodeGen/VirtRegMap.cpp
+++ b/lib/CodeGen/VirtRegMap.cpp
@@ -115,11 +115,10 @@
 unsigned VirtRegMap::getRegAllocPref(unsigned virtReg) {
   std::pair<unsigned, unsigned> Hint = MRI->getRegAllocationHint(virtReg);
   unsigned physReg = Hint.second;
-  if (physReg &&
-      TargetRegisterInfo::isVirtualRegister(physReg) && hasPhys(physReg))
+  if (TargetRegisterInfo::isVirtualRegister(physReg) && hasPhys(physReg))
     physReg = getPhys(physReg);
   if (Hint.first == 0)
-    return (physReg && TargetRegisterInfo::isPhysicalRegister(physReg))
+    return (TargetRegisterInfo::isPhysicalRegister(physReg))
       ? physReg : 0;
   return TRI->ResolveRegAllocHint(Hint.first, physReg, *MF);
 }