[llvm-commits] CVS: llvm/lib/CodeGen/SelectionDAG/ScheduleDAG.cpp

[Jim Laskey]

Changes in directory llvm/lib/CodeGen/SelectionDAG:

ScheduleDAG.cpp updated: 1.51 -> 1.52
---
Log message:

Create a strong dependency for loads following stores.  This will leave a
latency period between the two.


---
Diffs of the changes:  (+6 -2)

 ScheduleDAG.cpp |    8 ++++++--
 1 files changed, 6 insertions(+), 2 deletions(-)


Index: llvm/lib/CodeGen/SelectionDAG/ScheduleDAG.cpp
diff -u llvm/lib/CodeGen/SelectionDAG/ScheduleDAG.cpp:1.51 llvm/lib/CodeGen/SelectionDAG/ScheduleDAG.cpp:1.52
--- llvm/lib/CodeGen/SelectionDAG/ScheduleDAG.cpp:1.51	Sun Dec 18 16:20:05 2005
+++ llvm/lib/CodeGen/SelectionDAG/ScheduleDAG.cpp	Mon Dec 19 10:30:13 2005
@@ -281,7 +281,9 @@
   InstrStage    *StageBegin;            // First stage in itinerary
   InstrStage    *StageEnd;              // Last+1 stage in itinerary
   unsigned      Latency;                // Total cycles to complete instruction
-  bool          IsCall;                 // Is function call
+  bool          IsCall : 1;             // Is function call
+  bool          IsLoad : 1;             // Is memory load
+  bool          IsStore : 1;            // Is memory store
   unsigned      Slot;                   // Node's time slot
   NodeGroup     *Group;                 // Grouping information
   unsigned      VRBase;                 // Virtual register base
@@ -756,6 +758,8 @@
         // Get machine opcode
         MachineOpCode TOpc = Node->getTargetOpcode();
         NI->IsCall = TII.isCall(TOpc);
+        NI->IsLoad = TII.isLoad(TOpc);
+        NI->IsStore = TII.isStore(TOpc);
 
         if (TII.isLoad(TOpc))              NI->StageBegin = &LoadStage;
         else if (TII.isStore(TOpc))        NI->StageBegin = &StoreStage;
@@ -857,7 +861,7 @@
 /// I.E., B must wait for latency of A.
 bool SimpleSched::isStrongDependency(NodeInfo *A, NodeInfo *B) {
   // If A defines for B then it's a strong dependency
-  return isDefiner(A, B);
+  return isDefiner(A, B) || (A->IsStore && B->IsLoad);
 }
 
 /// isWeakDependency Return true if node A produces a result that will