Give a better message for a common assertion failure.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@17887 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/LiveInterval.cpp b/lib/CodeGen/LiveInterval.cpp
index 174b4830d01180068c65ad5ce4032389dfba4960..8306116b1a84c9f5a9687c20457d9e9b7479aa45 100644 (file)
--- a/lib/CodeGen/LiveInterval.cpp
+++ b/lib/CodeGen/LiveInterval.cpp
@@ -214,7 +214,8 @@ LiveInterval::addRangeFrom(LiveRange LR, Ranges::iterator From) {
       // Check to make sure that we are not overlapping two live ranges with
       // different ValId's.
       assert(B->end <= Start &&
-             "Cannot overlap two LiveRanges with differing ValID's");
+             "Cannot overlap two LiveRanges with differing ValID's"
+             " (did you def the same reg twice in a MachineInstr?)");
     }
   }