unsigned DefOpEnd = MI->getNumOperands();
if (MI->isCall()) {
- // Spill all virtregs before a call. This serves two purposes: 1. If an
+ // Spill all virtregs before a call. This serves one purpose: If an
// exception is thrown, the landing pad is going to expect to find
- // registers in their spill slots, and 2. we don't have to wade through
- // all the <imp-def> operands on the call instruction.
- DefOpEnd = VirtOpEnd;
+ // registers in their spill slots.
+ // Note: although this is appealing to just consider all definitions
+ // as call-clobbered, this is not correct because some of those
+ // definitions may be used later on and we do not want to reuse
+ // those for virtual registers in between.
DEBUG(dbgs() << " Spilling remaining registers before call.\n");
spillAll(MI);