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.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@78563 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SimpleHazardRecognizer.h b/lib/CodeGen/SimpleHazardRecognizer.h
new file mode 100644
index 0000000..f69feaf
--- /dev/null
+++ b/lib/CodeGen/SimpleHazardRecognizer.h
@@ -0,0 +1,89 @@
+//=- llvm/CodeGen/SimpleHazardRecognizer.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 SimpleHazardRecognizer class, which
+// implements hazard-avoidance heuristics for scheduling, based on the
+// scheduling itineraries specified for the target.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CODEGEN_SIMPLEHAZARDRECOGNIZER_H
+#define LLVM_CODEGEN_SIMPLEHAZARDRECOGNIZER_H
+
+#include "llvm/CodeGen/ScheduleHazardRecognizer.h"
+#include "llvm/CodeGen/ScheduleDAG.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetInstrInfo.h"
+
+namespace llvm {
+ /// SimpleHazardRecognizer - A *very* simple hazard recognizer. It uses
+ /// a coarse classification and attempts to avoid that instructions of
+ /// a given class aren't grouped too densely together.
+ class SimpleHazardRecognizer : public ScheduleHazardRecognizer {
+ /// Class - A simple classification for SUnits.
+ enum Class {
+ Other, Load, Store
+ };
+
+ /// Window - The Class values of the most recently issued
+ /// instructions.
+ Class Window[8];
+
+ /// getClass - Classify the given SUnit.
+ Class getClass(const SUnit *SU) {
+ const MachineInstr *MI = SU->getInstr();
+ const TargetInstrDesc &TID = MI->getDesc();
+ if (TID.mayLoad())
+ return Load;
+ if (TID.mayStore())
+ return Store;
+ return Other;
+ }
+
+ /// Step - Rotate the existing entries in Window and insert the
+ /// given class value in position as the most recent.
+ void Step(Class C) {
+ std::copy(Window+1, array_endof(Window), Window);
+ Window[array_lengthof(Window)-1] = C;
+ }
+
+ public:
+ SimpleHazardRecognizer() : Window() {
+ Reset();
+ }
+
+ virtual HazardType getHazardType(SUnit *SU) {
+ Class C = getClass(SU);
+ if (C == Other)
+ return NoHazard;
+ unsigned Score = 0;
+ for (unsigned i = 0; i != array_lengthof(Window); ++i)
+ if (Window[i] == C)
+ Score += i + 1;
+ if (Score > array_lengthof(Window) * 2)
+ return Hazard;
+ return NoHazard;
+ }
+
+ virtual void Reset() {
+ for (unsigned i = 0; i != array_lengthof(Window); ++i)
+ Window[i] = Other;
+ }
+
+ virtual void EmitInstruction(SUnit *SU) {
+ Step(getClass(SU));
+ }
+
+ virtual void AdvanceCycle() {
+ Step(Other);
+ }
+ };
+}
+
+#endif