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/RegAllocPBQP.cpp b/lib/CodeGen/RegAllocPBQP.cpp
index 984aab2..2722490 100644
--- a/lib/CodeGen/RegAllocPBQP.cpp
+++ b/lib/CodeGen/RegAllocPBQP.cpp
@@ -208,8 +208,6 @@
     mri->setPhysRegUsed(Reg);
   }
 
-  BitVector reservedRegs = tri->getReservedRegs(*mf);
-
   // Iterate over vregs.
   for (RegSet::const_iterator vregItr = vregs.begin(), vregEnd = vregs.end();
        vregItr != vregEnd; ++vregItr) {
@@ -227,7 +225,7 @@
     ArrayRef<uint16_t> rawOrder = trc->getRawAllocationOrder(*mf);
     for (unsigned i = 0; i != rawOrder.size(); ++i) {
       unsigned preg = rawOrder[i];
-      if (reservedRegs.test(preg))
+      if (mri->isReserved(preg))
         continue;
 
       // vregLI crosses a regmask operand that clobbers preg.