From 886459456c58695fe30dbf5b91954aa36a7a3674 Mon Sep 17 00:00:00 2001
From: Evan Cheng <evan.cheng@apple.com>
Date: Fri, 18 Jun 2010 23:11:35 +0000
Subject: [PATCH] Thumb2 hazard recognizer.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106347 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/ARM/Thumb2HazardRecognizer.cpp | 50 +++++++++++++++++++++++
 lib/Target/ARM/Thumb2HazardRecognizer.h   | 40 ++++++++++++++++++
 2 files changed, 90 insertions(+)
 create mode 100644 lib/Target/ARM/Thumb2HazardRecognizer.cpp
 create mode 100644 lib/Target/ARM/Thumb2HazardRecognizer.h

diff --git a/lib/Target/ARM/Thumb2HazardRecognizer.cpp b/lib/Target/ARM/Thumb2HazardRecognizer.cpp
new file mode 100644
index 00000000000..1614422a365
--- /dev/null
+++ b/lib/Target/ARM/Thumb2HazardRecognizer.cpp
@@ -0,0 +1,50 @@
+//===-- Thumb2HazardRecognizer.cpp - Thumb2 postra hazard recognizer ------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ARM.h"
+#include "Thumb2HazardRecognizer.h"
+#include "llvm/CodeGen/MachineInstr.h"
+#include "llvm/CodeGen/ScheduleDAG.h"
+using namespace llvm;
+
+ScheduleHazardRecognizer::HazardType
+Thumb2HazardRecognizer::getHazardType(SUnit *SU) {
+  if (ITBlockSize) {
+    MachineInstr *MI = SU->getInstr();
+    if (MI != ITBlockMIs[ITBlockSize-1])
+      return Hazard;
+  }
+
+  return PostRAHazardRecognizer::getHazardType(SU);
+}
+
+void Thumb2HazardRecognizer::Reset() {
+  ITBlockSize = 0;
+  PostRAHazardRecognizer::Reset();
+}
+
+void Thumb2HazardRecognizer::EmitInstruction(SUnit *SU) {
+  MachineInstr *MI = SU->getInstr();
+  unsigned Opcode = MI->getOpcode();
+  if (ITBlockSize) {
+    --ITBlockSize;
+  } else if (Opcode == ARM::t2IT) {
+    unsigned Mask = MI->getOperand(1).getImm();
+    unsigned NumTZ = CountTrailingZeros_32(Mask);
+    assert(NumTZ <= 3 && "Invalid IT mask!");
+    ITBlockSize = 4 - NumTZ;
+    MachineBasicBlock::iterator I = MI;
+    for (unsigned i = 0; i < ITBlockSize; ++i) {
+      ++I;
+      ITBlockMIs[ITBlockSize-1-i] = &*I;
+    }
+  }
+
+  PostRAHazardRecognizer::EmitInstruction(SU);
+}
diff --git a/lib/Target/ARM/Thumb2HazardRecognizer.h b/lib/Target/ARM/Thumb2HazardRecognizer.h
new file mode 100644
index 00000000000..472665862e4
--- /dev/null
+++ b/lib/Target/ARM/Thumb2HazardRecognizer.h
@@ -0,0 +1,40 @@
+//===-- Thumb2HazardRecognizer.h - Thumb2 Hazard Recognizers ----*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines hazard recognizers for scheduling Thumb2 functions on
+// ARM processors.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef THUMB2HAZARDRECOGNIZER_H
+#define THUMB2HAZARDRECOGNIZER_H
+
+#include "llvm/CodeGen/PostRAHazardRecognizer.h"
+
+namespace llvm {
+
+class MachineInstr;
+
+class Thumb2HazardRecognizer : public PostRAHazardRecognizer {
+  unsigned ITBlockSize;  // No. of MIs in current IT block yet to be scheduled.
+  MachineInstr *ITBlockMIs[4];
+
+public:
+  Thumb2HazardRecognizer(const InstrItineraryData &ItinData) :
+    PostRAHazardRecognizer(ItinData) {}
+
+  virtual HazardType getHazardType(SUnit *SU);
+  virtual void Reset();
+  virtual void EmitInstruction(SUnit *SU);
+};
+
+
+} // end namespace llvm
+
+#endif // THUMB2HAZARDRECOGNIZER_H