Avoid commuting a def MI in order to coalesce a copy instruction away if any use of the same val# is a copy instruction that has already been coalesced.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48833 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 1 insertions, 0 deletions

diff --git a/lib/CodeGen/VirtRegMap.cpp b/lib/CodeGen/VirtRegMap.cpp
index f89ef9a8b5..264ab14569 100644
--- a/lib/CodeGen/VirtRegMap.cpp
+++ b/lib/CodeGen/VirtRegMap.cpp
@@ -1593,6 +1593,7 @@ void LocalSpiller::RewriteMBB(MachineBasicBlock &MBB, VirtRegMap &VRM) {
         }
       }
 
+      assert(PhysReg && "VR not assigned a physical register?");
       RegInfo->setPhysRegUsed(PhysReg);
       unsigned RReg = SubIdx ? TRI->getSubReg(PhysReg, SubIdx) : PhysReg;
       ReusedOperands.markClobbered(RReg);