Extract LaneBitmask into a separate type

Specifically avoid implicit conversions from/to integral types to
avoid potential errors when changing the underlying type. For example,
a typical initialization of a "full" mask was "LaneMask = ~0u", which
would result in a value of 0x00000000FFFFFFFF if the type was extended
to uint64_t.

Differential Revision: https://reviews.llvm.org/D27454

llvm-svn: 289820

llvm/lib/CodeGen/PeepholeOptimizer.cpp

@@ -1833,8 +1833,8 @@ ValueTrackerResult ValueTracker::getNextSourceFromInsertSubreg() {
   // sub-register we are tracking.
   const TargetRegisterInfo *TRI = MRI.getTargetRegisterInfo();
   if (!TRI ||
-      (TRI->getSubRegIndexLaneMask(DefSubReg) &
-       TRI->getSubRegIndexLaneMask(InsertedReg.SubIdx)) != 0)
+      !(TRI->getSubRegIndexLaneMask(DefSubReg) &
+        TRI->getSubRegIndexLaneMask(InsertedReg.SubIdx)).none())
     return ValueTrackerResult();
   // At this point, the value is available in v0 via the same subreg
   // we used for Def.