Subzero: Slight improvement to phi lowering.

src/IceCfg.cpp

Index: src/IceCfg.cpp
diff --git a/src/IceCfg.cpp b/src/IceCfg.cpp
index c19d01a464020bc5ce4c9d5750f7907531a82293..183336a5132fbb5fe08cfd13b4468c5c298656cb 100644
--- a/src/IceCfg.cpp
+++ b/src/IceCfg.cpp
@@ -273,9 +273,6 @@ void Cfg::advancedPhiLowering() {
       InstNumberT FirstInstNum = getNextInstNumber();
       (*I)->renumberInstructions();
       InstNumberT LastInstNum = getNextInstNumber() - 1;
-      // TODO(stichnot): May be able to speed up liveness and live range
-      // calculation by having it consider only pre-colored or infinite-weight
-      // variables.  Could also simplify LinearScan::initForInfOnly() that way.
       (*I)->liveness(getLiveness());
       (*I)->livenessAddIntervals(getLiveness(), FirstInstNum, LastInstNum);
     }