Various cleanups to this pass, no functionality change

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@24846 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 43 insertions, 46 deletions

diff --git a/lib/Target/Sparc/FPMover.cpp b/lib/Target/Sparc/FPMover.cpp
index 41346144d1..feeadc52a7 100644
--- a/lib/Target/Sparc/FPMover.cpp
+++ b/lib/Target/Sparc/FPMover.cpp
@@ -7,7 +7,7 @@
 //
 //===----------------------------------------------------------------------===//
 //
-// Turns FpMOVD instructions into FMOVS pairs after regalloc.
+// Expand FpMOVD/FpABSD/FpNEGD instructions into their single-precision pieces.
 //
 //===----------------------------------------------------------------------===//
 
@@ -19,8 +19,8 @@
 using namespace llvm;
 
 namespace {
-  Statistic<> NumFpMOVDs ("fpmover", "# FpMOVD instructions translated");
-  Statistic<> SkippedFpMOVDs ("fpmover", "# FpMOVD instructions skipped");
+  Statistic<> NumFpDs("fpmover", "Number of instructions translated");
+  Statistic<> NoopFpDs("fpmover", "Number of noop instructions removed");
 
   struct FPMover : public MachineFunctionPass {
     /// Target machine description which we query for reg. names, data
@@ -28,18 +28,18 @@ namespace {
     ///
     TargetMachine &TM;
 
-    FPMover (TargetMachine &tm) : TM (tm) { }
+    FPMover(TargetMachine &tm) : TM(tm) { }
 
-    virtual const char *getPassName () const {
+    virtual const char *getPassName() const {
       return "SparcV8 Double-FP Move Fixer";
     }
 
-    bool runOnMachineBasicBlock (MachineBasicBlock &MBB);
-    bool runOnMachineFunction (MachineFunction &F) {
+    bool runOnMachineBasicBlock(MachineBasicBlock &MBB);
+    bool runOnMachineFunction(MachineFunction &F) {
       bool Changed = false;
-      for (MachineFunction::iterator FI = F.begin (), FE = F.end ();
+      for (MachineFunction::iterator FI = F.begin(), FE = F.end();
            FI != FE; ++FI)
-        Changed |= runOnMachineBasicBlock (*FI);
+        Changed |= runOnMachineBasicBlock(*FI);
       return Changed;
     }
 
@@ -49,66 +49,63 @@ namespace {
 /// createSparcV8FPMoverPass - Returns a pass that turns FpMOVD
 /// instructions into FMOVS instructions
 ///
-FunctionPass *llvm::createSparcV8FPMoverPass (TargetMachine &tm) {
-  return new FPMover (tm);
+FunctionPass *llvm::createSparcV8FPMoverPass(TargetMachine &tm) {
+  return new FPMover(tm);
 }
 
-static void doubleToSingleRegPair(unsigned doubleReg, unsigned &singleReg1,
-                                  unsigned &singleReg2) {
-  const unsigned EvenHalvesOfPairs[] = {
+/// getDoubleRegPair - Given a DFP register, return the even and odd FP
+/// registers that correspond to it.
+static void getDoubleRegPair(unsigned DoubleReg, unsigned &EvenReg,
+                             unsigned &OddReg) {
+  static const unsigned EvenHalvesOfPairs[] = {
     V8::F0, V8::F2, V8::F4, V8::F6, V8::F8, V8::F10, V8::F12, V8::F14,
     V8::F16, V8::F18, V8::F20, V8::F22, V8::F24, V8::F26, V8::F28, V8::F30
   };
-  const unsigned OddHalvesOfPairs[] = {
+  static const unsigned OddHalvesOfPairs[] = {
     V8::F1, V8::F3, V8::F5, V8::F7, V8::F9, V8::F11, V8::F13, V8::F15,
     V8::F17, V8::F19, V8::F21, V8::F23, V8::F25, V8::F27, V8::F29, V8::F31
   };
-  const unsigned DoubleRegsInOrder[] = {
+  static const unsigned DoubleRegsInOrder[] = {
     V8::D0, V8::D1, V8::D2, V8::D3, V8::D4, V8::D5, V8::D6, V8::D7, V8::D8,
     V8::D9, V8::D10, V8::D11, V8::D12, V8::D13, V8::D14, V8::D15
   };
   for (unsigned i = 0; i < sizeof(DoubleRegsInOrder)/sizeof(unsigned); ++i)
-    if (DoubleRegsInOrder[i] == doubleReg) {
-      singleReg1 = EvenHalvesOfPairs[i];
-      singleReg2 = OddHalvesOfPairs[i];
+    if (DoubleRegsInOrder[i] == DoubleReg) {
+      EvenReg = EvenHalvesOfPairs[i];
+      OddReg = OddHalvesOfPairs[i];
       return;
     }
-  assert (0 && "Can't find reg");
+  assert(0 && "Can't find reg");
 }
 
 /// runOnMachineBasicBlock - Fixup FpMOVD instructions in this MBB.
 ///
-bool FPMover::runOnMachineBasicBlock (MachineBasicBlock &MBB) {
+bool FPMover::runOnMachineBasicBlock(MachineBasicBlock &MBB) {
   bool Changed = false;
-  for (MachineBasicBlock::iterator I = MBB.begin (); I != MBB.end (); ++I)
-    if (V8::FpMOVD == I->getOpcode ()) {
-      unsigned NewSrcReg0 = 0, NewSrcReg1 = 0, NewDestReg0 = 0, NewDestReg1 = 0;
-      doubleToSingleRegPair (I->getOperand (0).getReg (), NewDestReg0,
-                             NewDestReg1);
-      doubleToSingleRegPair (I->getOperand (1).getReg (), NewSrcReg0,
-                             NewSrcReg1);
-      MachineBasicBlock::iterator J = I;
-      ++J;
-      if (!(NewDestReg0 == NewSrcReg0 && NewDestReg1 == NewSrcReg1)) {
-        I->setOpcode (V8::FMOVS);
-        I->SetMachineOperandReg (0, NewDestReg0);
-        I->SetMachineOperandReg (1, NewSrcReg0);
-        DEBUG (std::cerr << "FPMover: new dest reg. is: " << NewDestReg0
-                         << "; modified instr is: " << *I);
+  for (MachineBasicBlock::iterator I = MBB.begin(); I != MBB.end(); ) {
+    MachineInstr *MI = I++;
+    if (MI->getOpcode() == V8::FpMOVD) {
+      unsigned DestDReg = MI->getOperand(0).getReg();
+      unsigned SrcDReg  = MI->getOperand(1).getReg();
+      if (DestDReg != SrcDReg || MI->getOpcode() != V8::FpMOVD) {
+        unsigned EvenSrcReg = 0, OddSrcReg = 0, EvenDestReg = 0, OddDestReg = 0;
+        getDoubleRegPair(DestDReg, EvenDestReg, OddDestReg);
+        getDoubleRegPair(SrcDReg, EvenSrcReg, OddSrcReg);
+
+        I->setOpcode(V8::FMOVS);
+        I->SetMachineOperandReg(0, EvenDestReg);
+        I->SetMachineOperandReg(1, EvenSrcReg);
+        DEBUG(std::cerr << "FPMover: the modified instr is: " << *I);
         // Insert copy for the other half of the double:
-        MachineInstr *MI2 =
-          BuildMI (MBB, J, V8::FMOVS, 1, NewDestReg1).addReg (NewSrcReg1);
-        DEBUG (std::cerr << "FPMover: new dest reg. is " << NewDestReg1
-                         << "; inserted instr is: " << *MI2);
-        ++NumFpMOVDs;
-        I = J;
-        --I;
+        MI = BuildMI(MBB, I, V8::FMOVS, 1, OddDestReg).addReg(OddSrcReg);
+        DEBUG(std::cerr << "FPMover: the inserted instr is: " << *MI);
+        ++NumFpDs;
       } else {
-        MBB.erase (I);
-        ++SkippedFpMOVDs;
-        I = J;
+        MBB.erase(MI);
+        ++NoopFpDs;
       }
       Changed = true;
     }
+  }
   return Changed;
 }