Hexagon backend support
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146412 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/Hexagon/HexagonOptimizeSZExtends.cpp b/lib/Target/Hexagon/HexagonOptimizeSZExtends.cpp
new file mode 100644
index 0000000..1229aca
--- /dev/null
+++ b/lib/Target/Hexagon/HexagonOptimizeSZExtends.cpp
@@ -0,0 +1,129 @@
+//===-- HexagonOptimizeSZExtends.cpp - Identify and remove sign and -------===//
+//===-- zero extends. -------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Constants.h"
+#include "llvm/PassSupport.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/CodeGen/Passes.h"
+#include "llvm/CodeGen/MachineDominators.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/CodeGen/MachineLoopInfo.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/CodeGen/RegisterScavenging.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/CodeGen/MachineFunctionAnalysis.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Target/TargetInstrInfo.h"
+#include <algorithm>
+#include "Hexagon.h"
+#include "HexagonTargetMachine.h"
+
+using namespace llvm;
+
+namespace {
+ struct HexagonOptimizeSZExtends : public MachineFunctionPass {
+
+ public:
+ static char ID;
+ HexagonOptimizeSZExtends() : MachineFunctionPass(ID) {}
+
+ bool runOnMachineFunction(MachineFunction &MF);
+
+ const char *getPassName() const {
+ return "Hexagon remove redundant zero and size extends";
+ }
+
+ void getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.addRequired<MachineFunctionAnalysis>();
+ AU.addPreserved<MachineFunctionAnalysis>();
+ MachineFunctionPass::getAnalysisUsage(AU);
+ }
+
+ private:
+ };
+}
+
+char HexagonOptimizeSZExtends::ID = 0;
+
+// This is a brain dead pass to get rid of redundant sign extends for the
+// following case:
+//
+// Transform the following pattern
+// %vreg170<def> = SXTW %vreg166
+// ...
+// %vreg176<def> = COPY %vreg170:subreg_loreg
+//
+// Into
+// %vreg176<def> = COPY vreg166
+
+bool HexagonOptimizeSZExtends::runOnMachineFunction(MachineFunction &MF) {
+ DenseMap<unsigned, unsigned> SExtMap;
+
+ // Loop over all of the basic blocks
+ for (MachineFunction::iterator MBBb = MF.begin(), MBBe = MF.end();
+ MBBb != MBBe; ++MBBb) {
+ MachineBasicBlock* MBB = MBBb;
+ SExtMap.clear();
+
+ // Traverse the basic block.
+ for (MachineBasicBlock::iterator MII = MBB->begin(); MII != MBB->end();
+ ++MII) {
+ MachineInstr *MI = MII;
+ // Look for sign extends:
+ // %vreg170<def> = SXTW %vreg166
+ if (MI->getOpcode() == Hexagon::SXTW) {
+ assert (MI->getNumOperands() == 2);
+ MachineOperand &Dst = MI->getOperand(0);
+ MachineOperand &Src = MI->getOperand(1);
+ unsigned DstReg = Dst.getReg();
+ unsigned SrcReg = Src.getReg();
+ // Just handle virtual registers.
+ if (TargetRegisterInfo::isVirtualRegister(DstReg) &&
+ TargetRegisterInfo::isVirtualRegister(SrcReg)) {
+ // Map the following:
+ // %vreg170<def> = SXTW %vreg166
+ // SExtMap[170] = vreg166
+ SExtMap[DstReg] = SrcReg;
+ }
+ }
+ // Look for copy:
+ // %vreg176<def> = COPY %vreg170:subreg_loreg
+ if (MI->isCopy()) {
+ assert (MI->getNumOperands() == 2);
+ MachineOperand &Dst = MI->getOperand(0);
+ MachineOperand &Src = MI->getOperand(1);
+
+ // Make sure we are copying the lower 32 bits.
+ if (Src.getSubReg() != Hexagon::subreg_loreg)
+ continue;
+
+ unsigned DstReg = Dst.getReg();
+ unsigned SrcReg = Src.getReg();
+ if (TargetRegisterInfo::isVirtualRegister(DstReg) &&
+ TargetRegisterInfo::isVirtualRegister(SrcReg)) {
+ // Try to find in the map.
+ if (unsigned SextSrc = SExtMap.lookup(SrcReg)) {
+ // Change the 1st operand.
+ MI->RemoveOperand(1);
+ MI->addOperand(MachineOperand::CreateReg(SextSrc, false));
+ }
+ }
+ }
+ }
+ }
+ return true;
+}
+
+FunctionPass *llvm::createHexagonOptimizeSZExtends() {
+ return new HexagonOptimizeSZExtends();
+}