When checking whether a def of an aliased register is dead, ask the

machineinstr whether the aliased register is dead, rather than the original
register is dead. This allows it to get the correct answer when examining
an instruction like this:
  CALLpcrel32 <ga:foo>, %AL<imp-def>, %EAX<imp-def,dead>
where EAX is dead but a subregister of it is still live. This fixes PR5294.

llvm-svn: 85135

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/ScheduleDAGInstrs.cpp b/llvm/lib/CodeGen/ScheduleDAGInstrs.cpp
index 43454dd1cbe..880782e2817 100644
--- a/llvm/lib/CodeGen/ScheduleDAGInstrs.cpp
+++ b/llvm/lib/CodeGen/ScheduleDAGInstrs.cpp
@@ -208,7 +208,7 @@ void ScheduleDAGInstrs::BuildSchedGraph(AliasAnalysis *AA) {
           SUnit *DefSU = DefList[i];
           if (DefSU != SU &&
               (Kind != SDep::Output || !MO.isDead() ||
-               !DefSU->getInstr()->registerDefIsDead(Reg)))
+               !DefSU->getInstr()->registerDefIsDead(*Alias)))
             DefSU->addPred(SDep(SU, Kind, AOLatency, /*Reg=*/ *Alias));
         }
       }