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NVPTX: Avoid implicit iterator conversions, NFC 

Avoid implicit conversions from MachineInstrBundleIterator to
MachineInstr* in the NVPTX backend, mainly by preferring MachineInstr&
over MachineInstr* when a pointer isn't nullable and using range-based
for loops.

There was one piece of questionable code in
NVPTXInstrInfo::AnalyzeBranch, where a condition checked a pointer
converted from an iterator for nullptr.  Since this case is impossible
(moreover, the code above guarantees that the iterator is valid), I
removed the check when I changed the pointer to a reference.

Despite that case, there should be no functionality change here.

llvm-svn: 274931
This commit is contained in:
Duncan P. N. Exon Smith 2016-07-08 21:10:58 +00:00
parent 1002373946
commit 68f499a6fa
3 changed files with 21 additions and 22 deletions
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2
llvm/lib/Target/NVPTX/NVPTXFrameLowering.cpp
View File

@ -34,7 +34,7 @@ void NVPTXFrameLowering::emitPrologue(MachineFunction &MF,
MachineBasicBlock &MBB) const {
if (MF.getFrameInfo()->hasStackObjects()) {
assert(&MF.front() == &MBB && "Shrink-wrapping not yet supported");
MachineInstr *MI = MBB.begin();
MachineInstr *MI = &MBB.front();
MachineRegisterInfo &MR = MF.getRegInfo();
// This instruction really occurs before first instruction

32
llvm/lib/Target/NVPTX/NVPTXInstrInfo.cpp
View File

@ -155,17 +155,17 @@ bool NVPTXInstrInfo::AnalyzeBranch(
return false;
// Get the last instruction in the block.
MachineInstr *LastInst = I;
MachineInstr &LastInst = *I;
// If there is only one terminator instruction, process it.
if (I == MBB.begin() || !isUnpredicatedTerminator(*--I)) {
if (LastInst->getOpcode() == NVPTX::GOTO) {
TBB = LastInst->getOperand(0).getMBB();
if (LastInst.getOpcode() == NVPTX::GOTO) {
TBB = LastInst.getOperand(0).getMBB();
return false;
} else if (LastInst->getOpcode() == NVPTX::CBranch) {
} else if (LastInst.getOpcode() == NVPTX::CBranch) {
// Block ends with fall-through condbranch.
TBB = LastInst->getOperand(1).getMBB();
Cond.push_back(LastInst->getOperand(0));
TBB = LastInst.getOperand(1).getMBB();
Cond.push_back(LastInst.getOperand(0));
return false;
}
// Otherwise, don't know what this is.
@ -173,26 +173,26 @@ bool NVPTXInstrInfo::AnalyzeBranch(
}
// Get the instruction before it if it's a terminator.
MachineInstr *SecondLastInst = I;
MachineInstr &SecondLastInst = *I;
// If there are three terminators, we don't know what sort of block this is.
if (SecondLastInst && I != MBB.begin() && isUnpredicatedTerminator(*--I))
if (I != MBB.begin() && isUnpredicatedTerminator(*--I))
return true;
// If the block ends with NVPTX::GOTO and NVPTX:CBranch, handle it.
if (SecondLastInst->getOpcode() == NVPTX::CBranch &&
LastInst->getOpcode() == NVPTX::GOTO) {
TBB = SecondLastInst->getOperand(1).getMBB();
Cond.push_back(SecondLastInst->getOperand(0));
FBB = LastInst->getOperand(0).getMBB();
if (SecondLastInst.getOpcode() == NVPTX::CBranch &&
LastInst.getOpcode() == NVPTX::GOTO) {
TBB = SecondLastInst.getOperand(1).getMBB();
Cond.push_back(SecondLastInst.getOperand(0));
FBB = LastInst.getOperand(0).getMBB();
return false;
}
// If the block ends with two NVPTX:GOTOs, handle it. The second one is not
// executed, so remove it.
if (SecondLastInst->getOpcode() == NVPTX::GOTO &&
LastInst->getOpcode() == NVPTX::GOTO) {
TBB = SecondLastInst->getOperand(0).getMBB();
if (SecondLastInst.getOpcode() == NVPTX::GOTO &&
LastInst.getOpcode() == NVPTX::GOTO) {
TBB = SecondLastInst.getOperand(0).getMBB();
I = LastInst;
if (AllowModify)
I->eraseFromParent();

9
llvm/lib/Target/NVPTX/NVPTXPrologEpilogPass.cpp
View File

@ -55,11 +55,10 @@ bool NVPTXPrologEpilogPass::runOnMachineFunction(MachineFunction &MF) {
calculateFrameObjectOffsets(MF);
for (MachineFunction::iterator BB = MF.begin(), E = MF.end(); BB != E; ++BB) {
for (MachineBasicBlock::iterator I = BB->begin(); I != BB->end(); ++I) {
MachineInstr *MI = I;
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
if (!MI->getOperand(i).isFI())
for (MachineBasicBlock &MBB : MF) {
for (MachineInstr &MI : MBB) {
for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) {
if (!MI.getOperand(i).isFI())
continue;
TRI.eliminateFrameIndex(MI, 0, i, nullptr);
Modified = true;