Hexagon backend support

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146412 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/Hexagon/HexagonSplitTFRCondSets.cpp

@@ -0,0 +1,136 @@
+//===---- HexagonSplitTFRCondSets.cpp - split TFR condsets into xfers -----===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//
+//===----------------------------------------------------------------------===////
+// This pass tries to provide opportunities for better optimization of muxes.
+// The default code generated for something like: flag = (a == b) ? 1 : 3;
+// would be:
+//
+//   {p0 = cmp.eq(r0,r1)}
+//   {r3 = mux(p0,#1,#3)}
+//
+// This requires two packets.  If we use .new predicated immediate transfers, 
+// then we can do this in a single packet, e.g.:
+//
+//   {p0 = cmp.eq(r0,r1)
+//    if (p0.new) r3 = #1
+//    if (!p0.new) r3 = #3}
+//
+// Note that the conditional assignments are not generated in .new form here.
+// We assume opptimisically that they will be formed later.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "xfer"
+#include "llvm/CodeGen/Passes.h"
+#include "llvm/CodeGen/LatencyPriorityQueue.h"
+#include "llvm/CodeGen/SchedulerRegistry.h"
+#include "llvm/CodeGen/MachineDominators.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/MachineLoopInfo.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/CodeGen/ScheduleHazardRecognizer.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetInstrInfo.h"
+#include "llvm/Target/TargetRegisterInfo.h"
+#include "llvm/Support/Compiler.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/Support/MathExtras.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "HexagonTargetMachine.h"
+#include "HexagonSubtarget.h"
+#include "HexagonMachineFunctionInfo.h"
+#include <map>
+#include <iostream>
+
+#include "llvm/Support/CommandLine.h"
+#define DEBUG_TYPE "xfer"
+
+
+using namespace llvm;
+
+namespace {
+
+class HexagonSplitTFRCondSets : public MachineFunctionPass {
+    HexagonTargetMachine& QTM;
+    const HexagonSubtarget &QST;
+
+ public:
+    static char ID;
+    HexagonSplitTFRCondSets(HexagonTargetMachine& TM) :
+      MachineFunctionPass(ID), QTM(TM), QST(*TM.getSubtargetImpl()) {}
+
+    const char *getPassName() const {
+      return "Hexagon Split TFRCondSets";
+    }
+    bool runOnMachineFunction(MachineFunction &Fn);
+};
+
+
+char HexagonSplitTFRCondSets::ID = 0;
+
+
+bool HexagonSplitTFRCondSets::runOnMachineFunction(MachineFunction &Fn) {
+
+  const TargetInstrInfo *TII = QTM.getInstrInfo();
+
+  // Loop over all of the basic blocks.
+  for (MachineFunction::iterator MBBb = Fn.begin(), MBBe = Fn.end();
+       MBBb != MBBe; ++MBBb) {
+    MachineBasicBlock* MBB = MBBb;
+    // Traverse the basic block.
+    for (MachineBasicBlock::iterator MII = MBB->begin(); MII != MBB->end();
+         ++MII) {
+      MachineInstr *MI = MII;
+      int Opc = MI->getOpcode();
+      if (Opc == Hexagon::TFR_condset_rr) {
+
+        int DestReg = MI->getOperand(0).getReg();
+        int SrcReg1 = MI->getOperand(2).getReg();
+        int SrcReg2 = MI->getOperand(3).getReg();
+
+        // Minor optimization: do not emit the predicated copy if the source and
+        // the destination is the same register
+        if (DestReg != SrcReg1) {
+          BuildMI(*MBB, MII, MI->getDebugLoc(), TII->get(Hexagon::TFR_cPt),
+                  DestReg).addReg(MI->getOperand(1).getReg()).addReg(SrcReg1);
+        }
+        if (DestReg != SrcReg2) {
+          BuildMI(*MBB, MII, MI->getDebugLoc(), TII->get(Hexagon::TFR_cNotPt),
+                  DestReg).addReg(MI->getOperand(1).getReg()).addReg(SrcReg2);
+        }
+        MII = MBB->erase(MI);
+        --MII;
+      } else if (Opc == Hexagon::TFR_condset_ii) {
+        int DestReg = MI->getOperand(0).getReg();
+        int SrcReg1 = MI->getOperand(1).getReg();
+        int Immed1 = MI->getOperand(2).getImm();
+        int Immed2 = MI->getOperand(3).getImm();
+        BuildMI(*MBB, MII, MI->getDebugLoc(), TII->get(Hexagon::TFRI_cPt),
+                DestReg).addReg(SrcReg1).addImm(Immed1);
+        BuildMI(*MBB, MII, MI->getDebugLoc(), TII->get(Hexagon::TFRI_cNotPt),
+                DestReg).addReg(SrcReg1).addImm(Immed2);
+        MII = MBB->erase(MI);
+        --MII;
+      }
+    }
+  }
+
+  return true;
+}
+
+}
+
+//===----------------------------------------------------------------------===//
+//                         Public Constructor Functions
+//===----------------------------------------------------------------------===//
+
+FunctionPass *llvm::createHexagonSplitTFRCondSets(HexagonTargetMachine &TM) {
+  return new HexagonSplitTFRCondSets(TM);
+}