1 files changed, 25 insertions, 0 deletions
diff --git a/lib/CodeGen/AggressiveAntiDepBreaker.cpp b/lib/CodeGen/AggressiveAntiDepBreaker.cpp
index 91c1314..58b87e1 100644
--- a/lib/CodeGen/AggressiveAntiDepBreaker.cpp
+++ b/lib/CodeGen/AggressiveAntiDepBreaker.cpp
@@ -296,6 +296,16 @@ void AggressiveAntiDepBreaker::HandleLastUse(unsigned Reg, unsigned KillIdx,
   std::multimap<unsigned, AggressiveAntiDepState::RegisterReference>&
     RegRefs = State->GetRegRefs();
 
+  // FIXME: We must leave subregisters of live super registers as live, so that
+  // we don't clear out the register tracking information for subregisters of
+  // super registers we're still tracking (and with which we're unioning
+  // subregister definitions).
+  for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI)
+    if (TRI->isSuperRegister(Reg, *AI) && State->IsLive(*AI)) {
+      DEBUG(if (!header && footer) dbgs() << footer);
+      return;
+    }
+
   if (!State->IsLive(Reg)) {
     KillIndices[Reg] = KillIdx;
     DefIndices[Reg] = ~0u;
@@ -673,6 +683,21 @@ bool AggressiveAntiDepBreaker::FindSuitableFreeRegisters(
           goto next_super_reg;
       }
 
+      // We cannot rename 'Reg' to 'NewReg' if one of the uses of 'Reg' also
+      // defines 'NewReg' via an early-clobber operand.
+      auto Range = RegRefs.equal_range(Reg);
+      for (auto Q = Range.first, QE = Range.second; Q != QE; ++Q) {
+        auto UseMI = Q->second.Operand->getParent();
+        int Idx = UseMI->findRegisterDefOperandIdx(NewReg, false, true, TRI);
+        if (Idx == -1)
+          continue;
+
+        if (UseMI->getOperand(Idx).isEarlyClobber()) {
+          DEBUG(dbgs() << "(ec)");
+          goto next_super_reg;
+        }
+      }
+
       // Record that 'Reg' can be renamed to 'NewReg'.
       RenameMap.insert(std::pair<unsigned, unsigned>(Reg, NewReg));
     }