[llvm] r289456 - [LiveRangeEdit] Add assert string and descriptive comment.

[Geoff Berry via llvm-commits]

Author: gberry
Date: Mon Dec 12 13:12:41 2016
New Revision: 289456

URL: http://llvm.org/viewvc/llvm-project?rev=289456&view=rev
Log:
[LiveRangeEdit] Add assert string and descriptive comment.

Modified:
    llvm/trunk/lib/CodeGen/LiveRangeEdit.cpp

Modified: llvm/trunk/lib/CodeGen/LiveRangeEdit.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/LiveRangeEdit.cpp?rev=289456&r1=289455&r2=289456&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/LiveRangeEdit.cpp (original)
+++ llvm/trunk/lib/CodeGen/LiveRangeEdit.cpp Mon Dec 12 13:12:41 2016
@@ -273,7 +273,9 @@ void LiveRangeEdit::eliminateDeadDef(Mac
   bool isOrigDef = false;
   unsigned Dest;
   if (VRM && MI->getOperand(0).isReg() && MI->getOperand(0).isDef()) {
-    assert(MI->getDesc().getNumDefs() == 1);
+    // It is assumed that callers of eliminateDeadDefs() will never pass in dead
+    // instructions with multiple virtual register defs.
+    assert(MI->getDesc().getNumDefs() == 1 && "Unexpected instruction with multiple defs.");
     Dest = MI->getOperand(0).getReg();
     unsigned Original = VRM->getOriginal(Dest);
     LiveInterval &OrigLI = LIS.getInterval(Original);