MI-Sched: schedule physreg copies.

The register allocator expects minimal physreg live ranges. Schedule
physreg copies accordingly. This is slightly tricky when they occur in
the middle of the scheduling region. For now, this is handled by
rescheduling the copy when its associated instruction is
scheduled. Eventually we may instead bundle them, but only if we can
preserve the bundles as parallel copies during regalloc.

llvm-svn: 179449

2 files changed, 17 insertions, 13 deletions

diff --git a/llvm/include/llvm/CodeGen/MachineScheduler.h b/llvm/include/llvm/CodeGen/MachineScheduler.h
index 57febe77464..99cbd870ec3 100644
--- a/llvm/include/llvm/CodeGen/MachineScheduler.h
+++ b/llvm/include/llvm/CodeGen/MachineScheduler.h
@@ -297,6 +297,10 @@ public:
   /// reorderable instructions.
   virtual void schedule();
 
+  /// Change the position of an instruction within the basic block and update
+  /// live ranges and region boundary iterators.
+  void moveInstruction(MachineInstr *MI, MachineBasicBlock::iterator InsertPos);
+
   /// Get current register pressure for the top scheduled instructions.
   const IntervalPressure &getTopPressure() const { return TopPressure; }
   const RegPressureTracker &getTopRPTracker() const { return TopRPTracker; }
@@ -362,7 +366,6 @@ protected:
 
   void updateScheduledPressure(const std::vector<unsigned> &NewMaxPressure);
 
-  void moveInstruction(MachineInstr *MI, MachineBasicBlock::iterator InsertPos);
   bool checkSchedLimit();
 
   void findRootsAndBiasEdges(SmallVectorImpl<SUnit*> &TopRoots,
diff --git a/llvm/include/llvm/CodeGen/ScheduleDAG.h b/llvm/include/llvm/CodeGen/ScheduleDAG.h
index 8c959da696d..e13636c2504 100644
--- a/llvm/include/llvm/CodeGen/ScheduleDAG.h
+++ b/llvm/include/llvm/CodeGen/ScheduleDAG.h
@@ -302,6 +302,7 @@ namespace llvm {
     bool isCallOp         : 1;          // Is a function call operand.
     bool isTwoAddress     : 1;          // Is a two-address instruction.
     bool isCommutable     : 1;          // Is a commutable instruction.
+    bool hasPhysRegUses   : 1;          // Has physreg uses.
     bool hasPhysRegDefs   : 1;          // Has physreg defs that are being used.
     bool hasPhysRegClobbers : 1;        // Has any physreg defs, used or not.
     bool isPending        : 1;          // True once pending.
@@ -331,10 +332,10 @@ namespace llvm {
         NodeQueueId(0), NumPreds(0), NumSuccs(0), NumPredsLeft(0),
         NumSuccsLeft(0), WeakPredsLeft(0), WeakSuccsLeft(0), NumRegDefsLeft(0),
         Latency(0), isVRegCycle(false), isCall(false), isCallOp(false),
-        isTwoAddress(false), isCommutable(false), hasPhysRegDefs(false),
-        hasPhysRegClobbers(false), isPending(false), isAvailable(false),
-        isScheduled(false), isScheduleHigh(false), isScheduleLow(false),
-        isCloned(false), SchedulingPref(Sched::None),
+        isTwoAddress(false), isCommutable(false), hasPhysRegUses(false),
+        hasPhysRegDefs(false), hasPhysRegClobbers(false), isPending(false),
+        isAvailable(false), isScheduled(false), isScheduleHigh(false),
+        isScheduleLow(false), isCloned(false), SchedulingPref(Sched::None),
         isDepthCurrent(false), isHeightCurrent(false), Depth(0), Height(0),
         TopReadyCycle(0), BotReadyCycle(0), CopyDstRC(NULL), CopySrcRC(NULL) {}
 
@@ -345,10 +346,10 @@ namespace llvm {
         NodeQueueId(0), NumPreds(0), NumSuccs(0), NumPredsLeft(0),
         NumSuccsLeft(0), WeakPredsLeft(0), WeakSuccsLeft(0), NumRegDefsLeft(0),
         Latency(0), isVRegCycle(false), isCall(false), isCallOp(false),
-        isTwoAddress(false), isCommutable(false), hasPhysRegDefs(false),
-        hasPhysRegClobbers(false), isPending(false), isAvailable(false),
-        isScheduled(false), isScheduleHigh(false), isScheduleLow(false),
-        isCloned(false), SchedulingPref(Sched::None),
+        isTwoAddress(false), isCommutable(false), hasPhysRegUses(false),
+        hasPhysRegDefs(false), hasPhysRegClobbers(false), isPending(false),
+        isAvailable(false), isScheduled(false), isScheduleHigh(false),
+        isScheduleLow(false), isCloned(false), SchedulingPref(Sched::None),
         isDepthCurrent(false), isHeightCurrent(false), Depth(0), Height(0),
         TopReadyCycle(0), BotReadyCycle(0), CopyDstRC(NULL), CopySrcRC(NULL) {}
 
@@ -358,10 +359,10 @@ namespace llvm {
         NodeQueueId(0), NumPreds(0), NumSuccs(0), NumPredsLeft(0),
         NumSuccsLeft(0), WeakPredsLeft(0), WeakSuccsLeft(0), NumRegDefsLeft(0),
         Latency(0), isVRegCycle(false), isCall(false), isCallOp(false),
-        isTwoAddress(false), isCommutable(false), hasPhysRegDefs(false),
-        hasPhysRegClobbers(false), isPending(false), isAvailable(false),
-        isScheduled(false), isScheduleHigh(false), isScheduleLow(false),
-        isCloned(false), SchedulingPref(Sched::None),
+        isTwoAddress(false), isCommutable(false), hasPhysRegUses(false),
+        hasPhysRegDefs(false), hasPhysRegClobbers(false), isPending(false),
+        isAvailable(false), isScheduled(false), isScheduleHigh(false),
+        isScheduleLow(false), isCloned(false), SchedulingPref(Sched::None),
         isDepthCurrent(false), isHeightCurrent(false), Depth(0), Height(0),
         TopReadyCycle(0), BotReadyCycle(0), CopyDstRC(NULL), CopySrcRC(NULL) {}