Files
archived-llvm/lib/Target/PowerPC/PPCPreEmitPeephole.cpp
Nemanja Ivanovic 649870608e [PowerPC] Fix for PR35688 - handle out-of-range values for r+r to r+i conversion
Revision 320791 introduced a pass that transforms reg+reg instructions to
reg+imm if they're fed by "load immediate". However, it didn't
handle out-of-range shifts correctly as reported in PR35688.
This patch fixes that and therefore the PR.

Furthermore, there was undefined behaviour in the patch where the RHS of an
initialization expression was 32 bits and constant `1` was shifted left 32
bits. This was fixed by ensuring the RHS is 64 bits just like the LHS.

Differential Revision: https://reviews.llvm.org/D41369


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@321551 91177308-0d34-0410-b5e6-96231b3b80d8
2017-12-29 12:22:27 +00:00

96 lines
3.1 KiB
C++

//===--------- PPCPreEmitPeephole.cpp - Late peephole optimizations -------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// A pre-emit peephole for catching opportunities introduced by late passes such
// as MachineBlockPlacement.
//
//===----------------------------------------------------------------------===//
#include "PPC.h"
#include "PPCInstrInfo.h"
#include "PPCSubtarget.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/CodeGen/LivePhysRegs.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Support/Debug.h"
using namespace llvm;
#define DEBUG_TYPE "ppc-pre-emit-peephole"
STATISTIC(NumRRConvertedInPreEmit,
"Number of r+r instructions converted to r+i in pre-emit peephole");
STATISTIC(NumRemovedInPreEmit,
"Number of instructions deleted in pre-emit peephole");
static cl::opt<bool>
RunPreEmitPeephole("ppc-late-peephole", cl::Hidden, cl::init(true),
cl::desc("Run pre-emit peephole optimizations."));
namespace {
class PPCPreEmitPeephole : public MachineFunctionPass {
public:
static char ID;
PPCPreEmitPeephole() : MachineFunctionPass(ID) {
initializePPCPreEmitPeepholePass(*PassRegistry::getPassRegistry());
}
void getAnalysisUsage(AnalysisUsage &AU) const override {
MachineFunctionPass::getAnalysisUsage(AU);
}
MachineFunctionProperties getRequiredProperties() const override {
return MachineFunctionProperties().set(
MachineFunctionProperties::Property::NoVRegs);
}
bool runOnMachineFunction(MachineFunction &MF) override {
if (skipFunction(MF.getFunction()) || !RunPreEmitPeephole)
return false;
bool Changed = false;
const PPCInstrInfo *TII = MF.getSubtarget<PPCSubtarget>().getInstrInfo();
SmallVector<MachineInstr *, 4> InstrsToErase;
for (MachineBasicBlock &MBB : MF) {
for (MachineInstr &MI : MBB) {
MachineInstr *DefMIToErase = nullptr;
if (TII->convertToImmediateForm(MI, &DefMIToErase)) {
Changed = true;
NumRRConvertedInPreEmit++;
DEBUG(dbgs() << "Converted instruction to imm form: ");
DEBUG(MI.dump());
if (DefMIToErase) {
InstrsToErase.push_back(DefMIToErase);
}
}
}
}
for (MachineInstr *MI : InstrsToErase) {
DEBUG(dbgs() << "PPC pre-emit peephole: erasing instruction: ");
DEBUG(MI->dump());
MI->eraseFromParent();
NumRemovedInPreEmit++;
}
return Changed;
}
};
}
INITIALIZE_PASS(PPCPreEmitPeephole, DEBUG_TYPE, "PowerPC Pre-Emit Peephole",
false, false)
char PPCPreEmitPeephole::ID = 0;
FunctionPass *llvm::createPPCPreEmitPeepholePass() {
return new PPCPreEmitPeephole();
}