RegisterCoalescer: Cleanup empty subranges after shrinkToUses()

A call to removeEmptySubranges() is necessary after every operation that
potentially removes all segments from a subregister range; this case in
the register coalescer was missing.

llvm-svn: 241027

1 files changed, 1 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/RegisterCoalescer.cpp b/llvm/lib/CodeGen/RegisterCoalescer.cpp
index 7b7c7502172..7afea2a4f6f 100644
--- a/llvm/lib/CodeGen/RegisterCoalescer.cpp
+++ b/llvm/lib/CodeGen/RegisterCoalescer.cpp
@@ -1449,6 +1449,7 @@ bool RegisterCoalescer::joinCopy(MachineInstr *CopyMI, bool &Again) {
                    << format("%04X", S.LaneMask) << ")\n");
       LIS->shrinkToUses(S, LI.reg);
     }
+    LI.removeEmptySubRanges();
   }
   if (ShrinkMainRange) {
     LiveInterval &LI = LIS->getInterval(CP.getDstReg());