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[NFC][LoopIdiom] Make for loops more readable 

Patch simplifies for loops in LIR following LLVM guidelines: https://llvm.org/docs/CodingStandards.html#use-range-based-for-loops-wherever-possible.

Differential Revision: https://reviews.llvm.org/D112077
This commit is contained in:
Dawid Jurczak 2021-10-21 12:07:07 +02:00
parent 05a2d17668
commit 9ba5bb4309
1 changed files with 19 additions and 27 deletions
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46
llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
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@ -625,8 +625,8 @@ bool LoopIdiomRecognize::runOnLoopBlock(
// We can only promote stores in this block if they are unconditionally
// executed in the loop. For a block to be unconditionally executed, it has
// to dominate all the exit blocks of the loop. Verify this now.
for (unsigned i = 0, e = ExitBlocks.size(); i != e; ++i)
if (!DT->dominates(BB, ExitBlocks[i]))
for (BasicBlock *ExitBlock : ExitBlocks)
if (!DT->dominates(BB, ExitBlock))
return false;
bool MadeChange = false;
@ -750,16 +750,13 @@ bool LoopIdiomRecognize::processLoopStores(SmallVectorImpl<StoreInst *> &SL,
bool Changed = false;
// For stores that start but don't end a link in the chain:
for (SetVector<StoreInst *>::iterator it = Heads.begin(), e = Heads.end();
it != e; ++it) {
if (Tails.count(*it))
for (StoreInst *I : Heads) {
if (Tails.count(I))
continue;
// We found a store instr that starts a chain. Now follow the chain and try
// to transform it.
SmallPtrSet<Instruction *, 8> AdjacentStores;
StoreInst *I = *it;
StoreInst *HeadStore = I;
unsigned StoreSize = 0;
@ -1020,9 +1017,8 @@ mayLoopAccessLocation(Value *Ptr, ModRefInfo Access, Loop *L,
// which will then no-alias a store to &A[100].
MemoryLocation StoreLoc(Ptr, AccessSize);
for (Loop::block_iterator BI = L->block_begin(), E = L->block_end(); BI != E;
++BI)
for (Instruction &I : **BI)
for (BasicBlock *B : L->blocks())
for (Instruction &I : *B)
if (IgnoredInsts.count(&I) == 0 &&
isModOrRefSet(
intersectModRef(AA.getModRefInfo(&I, StoreLoc), Access)))
@ -1675,24 +1671,22 @@ static bool detectPopcountIdiom(Loop *CurLoop, BasicBlock *PreCondBB,
// step 4: Find the instruction which count the population: cnt2 = cnt1 + 1
{
CountInst = nullptr;
for (BasicBlock::iterator Iter = LoopEntry->getFirstNonPHI()->getIterator(),
IterE = LoopEntry->end();
Iter != IterE; Iter++) {
Instruction *Inst = &*Iter;
if (Inst->getOpcode() != Instruction::Add)
for (Instruction &Inst : llvm::make_range(
LoopEntry->getFirstNonPHI()->getIterator(), LoopEntry->end())) {
if (Inst.getOpcode() != Instruction::Add)
continue;
ConstantInt *Inc = dyn_cast<ConstantInt>(Inst->getOperand(1));
ConstantInt *Inc = dyn_cast<ConstantInt>(Inst.getOperand(1));
if (!Inc || !Inc->isOne())
continue;
PHINode *Phi = getRecurrenceVar(Inst->getOperand(0), Inst, LoopEntry);
PHINode *Phi = getRecurrenceVar(Inst.getOperand(0), &Inst, LoopEntry);
if (!Phi)
continue;
// Check if the result of the instruction is live of the loop.
bool LiveOutLoop = false;
for (User *U : Inst->users()) {
for (User *U : Inst.users()) {
if ((cast<Instruction>(U))->getParent() != LoopEntry) {
LiveOutLoop = true;
break;
@ -1700,7 +1694,7 @@ static bool detectPopcountIdiom(Loop *CurLoop, BasicBlock *PreCondBB,
}
if (LiveOutLoop) {
CountInst = Inst;
CountInst = &Inst;
CountPhi = Phi;
break;
}
@ -1801,22 +1795,20 @@ static bool detectShiftUntilZeroIdiom(Loop *CurLoop, const DataLayout &DL,
// plus "cnt0". Currently it is not optimized.
// This step could be used to detect POPCNT instruction:
// cnt.next = cnt + (x.next & 1)
for (BasicBlock::iterator Iter = LoopEntry->getFirstNonPHI()->getIterator(),
IterE = LoopEntry->end();
Iter != IterE; Iter++) {
Instruction *Inst = &*Iter;
if (Inst->getOpcode() != Instruction::Add)
for (Instruction &Inst : llvm::make_range(
LoopEntry->getFirstNonPHI()->getIterator(), LoopEntry->end())) {
if (Inst.getOpcode() != Instruction::Add)
continue;
ConstantInt *Inc = dyn_cast<ConstantInt>(Inst->getOperand(1));
ConstantInt *Inc = dyn_cast<ConstantInt>(Inst.getOperand(1));
if (!Inc || (!Inc->isOne() && !Inc->isMinusOne()))
continue;
PHINode *Phi = getRecurrenceVar(Inst->getOperand(0), Inst, LoopEntry);
PHINode *Phi = getRecurrenceVar(Inst.getOperand(0), &Inst, LoopEntry);
if (!Phi)
continue;
CntInst = Inst;
CntInst = &Inst;
CntPhi = Phi;
break;
}