Switch most getReservedRegs() clients to the MRI equivalent.

Using the cached bit vector in MRI avoids comstantly allocating and
recomputing the reserved register bit vector.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165983 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/LiveVariables.cpp b/lib/CodeGen/LiveVariables.cpp
index 7359bb9..6ea933d 100644
--- a/lib/CodeGen/LiveVariables.cpp
+++ b/lib/CodeGen/LiveVariables.cpp
@@ -503,8 +503,6 @@
   MRI = &mf.getRegInfo();
   TRI = MF->getTarget().getRegisterInfo();
 
-  ReservedRegisters = TRI->getReservedRegs(mf);
-
   unsigned NumRegs = TRI->getNumRegs();
   PhysRegDef  = new MachineInstr*[NumRegs];
   PhysRegUse  = new MachineInstr*[NumRegs];
@@ -588,7 +586,7 @@
         unsigned MOReg = UseRegs[i];
         if (TargetRegisterInfo::isVirtualRegister(MOReg))
           HandleVirtRegUse(MOReg, MBB, MI);
-        else if (!ReservedRegisters[MOReg])
+        else if (!MRI->isReserved(MOReg))
           HandlePhysRegUse(MOReg, MI);
       }
 
@@ -601,7 +599,7 @@
         unsigned MOReg = DefRegs[i];
         if (TargetRegisterInfo::isVirtualRegister(MOReg))
           HandleVirtRegDef(MOReg, MI);
-        else if (!ReservedRegisters[MOReg])
+        else if (!MRI->isReserved(MOReg))
           HandlePhysRegDef(MOReg, MI, Defs);
       }
       UpdatePhysRegDefs(MI, Defs);