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Get rid of address to pointer conversion in LoopRotate which is present just to avoid the address phi absence assert

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This commit is contained in:
Meghana Gupta
2022-08-24 13:26:58 -07:00
parent 2e3be7da07
commit 9007fca45b
1 changed files with 12 additions and 55 deletions
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67
lib/SILOptimizer/LoopTransforms/LoopRotate.cpp
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@@ -147,9 +147,7 @@ static void mapOperands(SILInstruction *inst,
static void updateSSAForUseOfValue(
SILSSAUpdater &updater, SmallVectorImpl<SILPhiArgument *> &insertedPhis,
const llvm::DenseMap<ValueBase *, SILValue> &valueMap,
SILBasicBlock *Header, SILBasicBlock *EntryCheckBlock, SILValue Res,
SmallVectorImpl<std::pair<SILBasicBlock *, unsigned>>
&accumulatedAddressPhis) {
SILBasicBlock *Header, SILBasicBlock *EntryCheckBlock, SILValue Res) {
// Find the mapped instruction.
assert(valueMap.count(Res) && "Expected to find value in map!");
SILValue MappedValue = valueMap.find(Res)->second;
@@ -179,14 +177,13 @@ static void updateSSAForUseOfValue(
if (user->getParent() == Header)
continue;
assert(user->getParent() != EntryCheckBlock
&& "The entry check block should dominate the header");
assert(user->getParent() != EntryCheckBlock &&
"The entry check block should dominate the header");
updater.rewriteUse(*use);
}
// Canonicalize inserted phis to avoid extra BB Args and if we find an address
// phi, stash it so we can handle it after we are done rewriting.
bool hasOwnership = Header->getParent()->hasOwnership();
for (SILPhiArgument *arg : insertedPhis) {
if (SILValue inst = replaceBBArgWithCast(arg)) {
arg->replaceAllUsesWith(inst);
@@ -195,30 +192,24 @@ static void updateSSAForUseOfValue(
// SimplifyCFG deletes the dead BB arg.
continue;
}
// If we didn't simplify and have an address phi, stash the value so we can
// fix it up.
if (hasOwnership && arg->getType().isAddress())
accumulatedAddressPhis.emplace_back(arg->getParent(), arg->getIndex());
}
}
static void updateSSAForUseOfInst(
SILSSAUpdater &updater, SmallVectorImpl<SILPhiArgument *> &insertedPhis,
const llvm::DenseMap<ValueBase *, SILValue> &valueMap,
SILBasicBlock *header, SILBasicBlock *entryCheckBlock, SILInstruction *inst,
SmallVectorImpl<std::pair<SILBasicBlock *, unsigned>>
&accumulatedAddressPhis) {
static void
updateSSAForUseOfInst(SILSSAUpdater &updater,
SmallVectorImpl<SILPhiArgument *> &insertedPhis,
const llvm::DenseMap<ValueBase *, SILValue> &valueMap,
SILBasicBlock *header, SILBasicBlock *entryCheckBlock,
SILInstruction *inst) {
for (auto result : inst->getResults())
updateSSAForUseOfValue(updater, insertedPhis, valueMap, header,
entryCheckBlock, result, accumulatedAddressPhis);
entryCheckBlock, result);
}
/// Rewrite the code we just created in the preheader and update SSA form.
static void rewriteNewLoopEntryCheckBlock(
SILBasicBlock *header, SILBasicBlock *entryCheckBlock,
const llvm::DenseMap<ValueBase *, SILValue> &valueMap) {
SmallVector<std::pair<SILBasicBlock *, unsigned>, 8> accumulatedAddressPhis;
SmallVector<SILPhiArgument *, 8> insertedPhis;
SILSSAUpdater updater(&insertedPhis);
@@ -227,7 +218,7 @@ static void rewriteNewLoopEntryCheckBlock(
for (unsigned i : range(header->getNumArguments())) {
auto *arg = header->getArguments()[i];
updateSSAForUseOfValue(updater, insertedPhis, valueMap, header,
entryCheckBlock, arg, accumulatedAddressPhis);
entryCheckBlock, arg);
}
auto instIter = header->begin();
@@ -236,43 +227,9 @@ static void rewriteNewLoopEntryCheckBlock(
while (instIter != header->end()) {
auto &inst = *instIter;
updateSSAForUseOfInst(updater, insertedPhis, valueMap, header,
entryCheckBlock, &inst, accumulatedAddressPhis);
entryCheckBlock, &inst);
++instIter;
}
// Then see if any of our phis were address phis. In such a case, rewrite the
// address to be a smuggled through raw pointer. We do this late to
// conservatively not interfere with the previous code's invariants.
//
// We also translate the phis into a BasicBlock, Index form so we are careful
// with invalidation issues around branches/args.
auto rawPointerTy =
SILType::getRawPointerType(header->getParent()->getASTContext());
auto rawPointerUndef = SILUndef::get(rawPointerTy, header->getModule());
auto loc = RegularLocation::getAutoGeneratedLocation();
while (!accumulatedAddressPhis.empty()) {
SILBasicBlock *block;
unsigned argIndex;
std::tie(block, argIndex) = accumulatedAddressPhis.pop_back_val();
auto *arg = cast<SILPhiArgument>(block->getArgument(argIndex));
assert(arg->getType().isAddress() && "Not an address phi?!");
for (auto *predBlock : block->getPredecessorBlocks()) {
Operand *predUse = arg->getIncomingPhiOperand(predBlock);
SILBuilderWithScope builder(predUse->getUser());
auto *newIncomingValue =
builder.createAddressToPointer(loc, predUse->get(), rawPointerTy);
predUse->set(newIncomingValue);
}
SILBuilderWithScope builder(arg->getNextInstruction());
SILType oldArgType = arg->getType();
auto *phiShim = builder.createPointerToAddress(
loc, rawPointerUndef, oldArgType, true /*isStrict*/,
false /*is invariant*/);
arg->replaceAllUsesWith(phiShim);
SILArgument *newArg = block->replacePhiArgument(
argIndex, rawPointerTy, OwnershipKind::None, nullptr);
phiShim->setOperand(newArg);
}
}
/// Update the dominator tree after rotating the loop.