Post RA scheduler changes. Introduce a hazard recognizer that uses the target schedule information to accurately model the pipeline. Update the scheduler to correctly handle multi-issue targets.

llvm-svn: 78563

1 files changed, 61 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/ExactHazardRecognizer.h b/llvm/lib/CodeGen/ExactHazardRecognizer.h
new file mode 100644
index 00000000000..71ac979e6cd
--- /dev/null
+++ b/llvm/lib/CodeGen/ExactHazardRecognizer.h
@@ -0,0 +1,61 @@
+//=- llvm/CodeGen/ExactHazardRecognizer.h - Scheduling Support -*- C++ -*-=//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the ExactHazardRecognizer class, which
+// implements hazard-avoidance heuristics for scheduling, based on the
+// scheduling itineraries specified for the target.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CODEGEN_EXACTHAZARDRECOGNIZER_H
+#define LLVM_CODEGEN_EXACTHAZARDRECOGNIZER_H
+
+#include "llvm/CodeGen/ScheduleHazardRecognizer.h"
+#include "llvm/CodeGen/ScheduleDAG.h"
+#include "llvm/Target/TargetInstrItineraries.h"
+
+namespace llvm {
+  class ExactHazardRecognizer : public ScheduleHazardRecognizer {
+    // Itinerary data for the target.
+    const InstrItineraryData &ItinData;
+
+    // Scoreboard to track function unit usage. Scoreboard[0] is a
+    // mask of the FUs in use in the cycle currently being
+    // schedule. Scoreboard[1] is a mask for the next cycle. The
+    // Scoreboard is used as a circular buffer with the current cycle
+    // indicated by ScoreboardHead.
+    unsigned *Scoreboard;
+
+    // The maximum number of cycles monitored by the Scoreboard. This
+    // value is determined based on the target itineraries to ensure
+    // that all hazards can be tracked.
+    unsigned ScoreboardDepth;
+
+    // Indices into the Scoreboard that represent the current cycle.
+    unsigned ScoreboardHead;
+
+    // Return the scoreboard index to use for 'offset' cycles in the
+    // future. 'offset' of 0 returns ScoreboardHead.
+    unsigned getFutureIndex(unsigned offset);
+
+    // Print the scoreboard.
+    void dumpScoreboard();
+
+  public:
+    ExactHazardRecognizer(const InstrItineraryData &ItinData);
+    ~ExactHazardRecognizer();
+    
+    virtual HazardType getHazardType(SUnit *SU);
+    virtual void Reset();
+    virtual void EmitInstruction(SUnit *SU);
+    virtual void AdvanceCycle();
+  };
+}
+
+#endif