llvm/lib/Target/SparcV8/FPMover.cpp
Brian Gaeke 8ee6a2fb16 When FpMOVDs appeared in pairs, we were mistakenly skipping over the latter of
each pair. I think this fixes that.

One of these days, I swear I'm going to get the hang of C++ iterators.
Really.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@18734 91177308-0d34-0410-b5e6-96231b3b80d8
2004-12-10 04:42:45 +00:00

106 lines
4.0 KiB
C++

//===-- FPMover.cpp - SparcV8 double-precision floating point move fixer --===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Turns FpMOVD instructions into FMOVS pairs after regalloc.
//
//===----------------------------------------------------------------------===//
#include "SparcV8.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Support/Debug.h"
using namespace llvm;
namespace {
Statistic<> NumFpMOVDs ("fpmover", "# FpMOVD instructions translated");
Statistic<> SkippedFpMOVDs ("fpmover", "# FpMOVD instructions skipped");
struct FPMover : public MachineFunctionPass {
/// Target machine description which we query for reg. names, data
/// layout, etc.
///
TargetMachine &TM;
FPMover (TargetMachine &tm) : TM (tm) { }
virtual const char *getPassName () const {
return "SparcV8 Double-FP Move Fixer";
}
bool runOnMachineBasicBlock (MachineBasicBlock &MBB);
bool runOnMachineFunction (MachineFunction &F) {
bool Changed = false;
for (MachineFunction::iterator FI = F.begin (), FE = F.end ();
FI != FE; ++FI)
Changed |= runOnMachineBasicBlock (*FI);
return Changed;
}
};
} // end of anonymous namespace
/// createSparcV8FPMoverPass - Returns a pass that turns FpMOVD
/// instructions into FMOVS instructions
///
FunctionPass *llvm::createSparcV8FPMoverPass (TargetMachine &tm) {
return new FPMover (tm);
}
static void doubleToSingleRegPair(unsigned doubleReg, unsigned &singleReg1, unsigned &singleReg2) {
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[] = { 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[] = { 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];
return;
}
assert (0 && "Can't find reg");
}
/// runOnMachineBasicBlock - Fixup FpMOVD instructions in this 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, NewSrcReg1, NewDestReg0, NewDestReg1;
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);
// 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;
} else {
MBB.erase (I);
++SkippedFpMOVDs;
I = J;
}
Changed = true;
}
return Changed;
}