Give a better assertion if we see a use before a def.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16135 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/LiveVariables.cpp b/lib/CodeGen/LiveVariables.cpp
index f6d00f702ac4f5d3d74b6aeb2c9b731008954f26..630477d7b654cae1d87264ffc166e6ea84a90020 100644 (file)
--- a/lib/CodeGen/LiveVariables.cpp
+++ b/lib/CodeGen/LiveVariables.cpp
@@ -82,6 +82,8 @@ void LiveVariables::MarkVirtRegAliveInBlock(VarInfo &VRInfo,
 
 void LiveVariables::HandleVirtRegUse(VarInfo &VRInfo, MachineBasicBlock *MBB,
                                      MachineInstr *MI) {
+  assert(VRInfo.DefInst && "Register use before def!");
+
   // Check to see if this basic block is already a kill block...
   if (!VRInfo.Kills.empty() && VRInfo.Kills.back()->getParent() == MBB) {
     // Yes, this register is killed in this basic block already.  Increase the