continue;
SlotIndex Idx = getInstructionIndex(UseMI).getUseIndex();
VNInfo *VNI = li->getVNInfoAt(Idx);
- assert(VNI && "Live interval not live into reading instruction");
+ if (!VNI) {
+ // This shouldn't happen: readsVirtualRegister returns true, but there is
+ // no live value. It is likely caused by a target getting <undef> flags
+ // wrong.
+ DEBUG(dbgs() << Idx << '\t' << *UseMI
+ << "Warning: Instr claims to read non-existent value in "
+ << *li << '\n');
+ continue;
+ }
if (VNI->def == Idx) {
// Special case: An early-clobber tied operand reads and writes the
// register one slot early.