[SystemZ] NFC refactoring in SystemZHazardRecognizer.

Handle the not-taken branch in emitInstruction() where the TakenBranch
argument is available. This is cleaner than relying on EmitInstruction().

Review: Ulrich Weigand

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@326879 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/SystemZ/SystemZHazardRecognizer.cpp

@@ -283,17 +283,14 @@ EmitInstruction(SUnit *SU) {
           << LastFPdOpCycleIdx << "\n";);
   }
 
-  bool GroupEndingBranch =
-    (CurrGroupSize >= 1 && isBranchRetTrap(SU->getInstr()));
-
   // Insert SU into current group by increasing number of slots used
   // in current group.
   CurrGroupSize += getNumDecoderSlots(SU);
   assert (CurrGroupSize <= 3);
 
   // Check if current group is now full/ended. If so, move on to next
   // group to be ready to evaluate more candidates.
-  if (CurrGroupSize == 3 || SC->EndGroup || GroupEndingBranch)
+  if (CurrGroupSize == 3 || SC->EndGroup)
     nextGroup();
 }
 
@@ -386,8 +383,15 @@ void SystemZHazardRecognizer::emitInstruction(MachineInstr *MI,
     }
   }
 
+  unsigned GroupSizeBeforeEmit = CurrGroupSize;
   EmitInstruction(&SU);
 
+  if (!TakenBranch && isBranchRetTrap(MI)) {
+    // NT Branch on second slot ends group.
+    if (GroupSizeBeforeEmit == 1)
+      nextGroup();
+  }
+
   if (TakenBranch && CurrGroupSize > 0)
     nextGroup();