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

1 files changed, 3 insertions, 3 deletions

diff --git a/llvm/lib/CodeGen/VirtRegMap.cpp b/llvm/lib/CodeGen/VirtRegMap.cpp
index 57aa740..c181bc0 100644
--- a/llvm/lib/CodeGen/VirtRegMap.cpp
+++ b/llvm/lib/CodeGen/VirtRegMap.cpp
@@ -266,7 +266,7 @@ void VirtRegRewriter::addLiveInsForSubRanges(const LiveInterval &LI,
     SlotIndex MBBBegin = MBBI->first;
     // Advance all subrange iterators so that their end position is just
     // behind MBBBegin (or the iterator is at the end).
-    LaneBitmask LaneMask = 0;
+    LaneBitmask LaneMask;
     for (auto &RangeIterPair : SubRanges) {
       const LiveInterval::SubRange *SR = RangeIterPair.first;
       LiveInterval::const_iterator &SRI = RangeIterPair.second;
@@ -277,7 +277,7 @@ void VirtRegRewriter::addLiveInsForSubRanges(const LiveInterval &LI,
       if (SRI->start <= MBBBegin)
         LaneMask |= SR->LaneMask;
     }
-    if (LaneMask == 0)
+    if (LaneMask.none())
       continue;
     MachineBasicBlock *MBB = MBBI->second;
     MBB->addLiveIn(PhysReg, LaneMask);
@@ -342,7 +342,7 @@ bool VirtRegRewriter::readsUndefSubreg(const MachineOperand &MO) const {
   LaneBitmask UseMask = TRI->getSubRegIndexLaneMask(SubRegIdx);
   // See if any of the relevant subregister liveranges is defined at this point.
   for (const LiveInterval::SubRange &SR : LI.subranges()) {
-    if ((SR.LaneMask & UseMask) != 0 && SR.liveAt(BaseIndex))
+    if (!(SR.LaneMask & UseMask).none() && SR.liveAt(BaseIndex))
       return false;
   }
   return true;