3 files changed, 9 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/LiveInterval.cpp b/llvm/lib/CodeGen/LiveInterval.cpp
index d75e4417cb0..3dc4113c639 100644
--- a/llvm/lib/CodeGen/LiveInterval.cpp
+++ b/llvm/lib/CodeGen/LiveInterval.cpp
@@ -1110,6 +1110,8 @@ void LiveInterval::verify(const MachineRegisterInfo *MRI) const {
 
     // subrange mask should not contained in maximum lane mask for the vreg.
     assert((Mask & ~MaxMask) == 0);
+    // empty subranges must be removed.
+    assert(!SR.empty());
 
     SR.verify();
     // Main liverange should cover subrange.
diff --git a/llvm/lib/CodeGen/LiveIntervalAnalysis.cpp b/llvm/lib/CodeGen/LiveIntervalAnalysis.cpp
index ee7c1d30315..9738dac65ad 100644
--- a/llvm/lib/CodeGen/LiveIntervalAnalysis.cpp
+++ b/llvm/lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -403,9 +403,14 @@ bool LiveIntervals::shrinkToUses(LiveInterval *li,
          && "Can only shrink virtual registers");
 
   // Shrink subregister live ranges.
+  bool NeedsCleanup = false;
   for (LiveInterval::SubRange &S : li->subranges()) {
     shrinkToUses(S, li->reg);
+    if (S.empty())
+      NeedsCleanup = true;
   }
+  if (NeedsCleanup)
+    li->removeEmptySubRanges();
 
   // Find all the values used, including PHI kills.
   ShrinkToUsesWorkList WorkList;
diff --git a/llvm/lib/CodeGen/MachineVerifier.cpp b/llvm/lib/CodeGen/MachineVerifier.cpp
index ca35ec5fdcf..a5e5bc992ef 100644
--- a/llvm/lib/CodeGen/MachineVerifier.cpp
+++ b/llvm/lib/CodeGen/MachineVerifier.cpp
@@ -1671,6 +1671,8 @@ void MachineVerifier::verifyLiveInterval(const LiveInterval &LI) {
       report("Lane masks of sub ranges overlap in live interval", MF, LI);
     if ((SR.LaneMask & ~MaxMask) != 0)
       report("Subrange lanemask is invalid", MF, LI);
+    if (SR.empty())
+      report("Subrange must not be empty", MF, SR, LI.reg, SR.LaneMask);
     Mask |= SR.LaneMask;
     verifyLiveRange(SR, LI.reg, SR.LaneMask);
     if (!LI.covers(SR))