LiveInterval: Document and enforce rules about empty subranges.

[oota-llvm.git] / lib / CodeGen / LiveInterval.cpp

diff --git a/lib/CodeGen/LiveInterval.cpp b/lib/CodeGen/LiveInterval.cpp
index d75e4417cb0366f0bc492881d5e0fff5e2b33e2e..3dc4113c6396854ca37afbac8f79b7c4b468584c 100644 (file)
--- a/lib/CodeGen/LiveInterval.cpp
+++ b/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.