Add more constantness in BlockFrequencyInfo.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136816 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/MachineBlockFrequencyInfo.cpp

@@ -55,6 +55,7 @@ bool MachineBlockFrequencyInfo::runOnMachineFunction(MachineFunction &F) {
 /// that we should not rely on the value itself, but only on the comparison to
 /// the other block frequencies. We do this to avoid using of floating points.
 ///
-BlockFrequency MachineBlockFrequencyInfo::getBlockFreq(MachineBasicBlock *MBB) {
+BlockFrequency MachineBlockFrequencyInfo::
+getBlockFreq(MachineBasicBlock *MBB) const {
   return MBFI->getBlockFreq(MBB);
 }