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[Bugfix] Recover code for flexible parallel #1032

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Merged
merged 2 commits into from
Oct 14, 2025
Merged

[Bugfix] Recover code for flexible parallel #1032

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9aeba45
recover flex parallel process
Hamerlate Oct 14, 2025
73ad4d3
lint fix
Hamerlate Oct 14, 2025
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105 changes: 57 additions & 48 deletions src/op/parallel.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -307,8 +307,10 @@ LayoutMap ParallelOpNode::InferLayout(const LayoutInferArgs &T,
// (const index frag_a interacts with non-const index frag_b)
// - No propagation needed: shared_a[i] = frag_a[0]
// (const index frag_a with non-fragment buffer)

bool allow_layout_propgate =
fragment_buffers.size() > const_index_fragment_buffer.size();
const_index_fragment_buffer.empty() ||
(fragment_buffers.size() > const_index_fragment_buffer.size());

// Step 1: try to infer loop's partition from a source fragment
Buffer source_buffer, read_source_buffer;
Expand Down Expand Up @@ -361,7 +363,15 @@ LayoutMap ParallelOpNode::InferLayout(const LayoutInferArgs &T,
PrimExpr loop_var_to_thread =
src_layout->ForwardThread(indice_map_[buffer], rep);
loop_var_to_thread = analyzer_.Simplify(loop_var_to_thread);

PostOrderVisit(loop_var_to_thread, [&](const ObjectRef &objref) {
if (auto opt_var = objref.as<Var>();
opt_var && inner_vars_.count(*opt_var)) {
std::ostringstream oss;
oss << "loop_var_to_thread = " << loop_var_to_thread
<< "contains inner var" << *opt_var;
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⚠️ Potential issue | 🟡 Minor

Fix spacing in error message.

The error message is missing a space before "contains", which will concatenate the expression value with the text.

Apply this diff:

-        << "contains inner var" << *opt_var;
+        << " contains inner var " << *opt_var;
📝 Committable suggestion

‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.

Suggested change
<< "contains inner var" << *opt_var;
<< " contains inner var " << *opt_var;
🤖 Prompt for AI Agents 
In src/op/parallel.cc around line 369, the error message concatenates the
previous expression value with the string "contains inner var" due to a missing
leading space; update the string so there is a space before "contains" (e.g.,
change to " contains inner var") ensuring the formatted output separates the
expression value and the message.

throw LayoutConflictException(oss.str());
}
});
result = Fragment(loop_vars_, {}, loop_var_to_thread, rep_iter)
->BindThreadRange(T.thread_bounds);
}
Expand All @@ -379,57 +389,46 @@ LayoutMap ParallelOpNode::InferLayout(const LayoutInferArgs &T,
if (source_buffer.defined() && allow_layout_propgate) {
loop_layout_ = compute_loop_layout_from_buffer(source_buffer);
} else if (level == InferLevel::kFree) {
// For free layout inference
// If replication exists and buffer has cross-thread shared memory access,
// add predicate
bool has_cross_thread_access = false;
PostOrderVisit(root_, [&](const ObjectRef &obj) {
if (const auto *store = obj.as<BufferStoreNode>()) {
// check if scope is shared or global
if (store->buffer.scope() == "shared" ||
store->buffer.scope() == "shared.dyn" ||
store->buffer.scope() == "global") {
has_cross_thread_access = true;
}
} else if (const auto *load = obj.as<BufferLoadNode>()) {
// check if scope is shared or global
if (load->buffer.scope() == "shared" ||
load->buffer.scope() == "shared.dyn" ||
load->buffer.scope() == "global") {
has_cross_thread_access = true;
}
}
});

// check if loop body contains a "pure" buffer store (i.e., direct
// assignment, not compound update)
bool has_pure_buffer_store = false;
PostOrderVisit(root_, [&](const ObjectRef &obj) {
if (const auto *store = obj.as<BufferStoreNode>()) {
// Check if the value is a direct load from another buffer (i.e., b[i]
// = a[i])
if (const auto *load = store->value.as<BufferLoadNode>()) {
has_pure_buffer_store = true;
}
}
});

if (read_source_buffer.defined() && allow_layout_propgate) {
loop_layout_ = compute_loop_layout_from_buffer(read_source_buffer);
// // Loop don't need to be replicated.
// if (!is_one(loop_layout_->ReplicateExtent()))
// loop_layout_ = loop_layout_->DeReplicate();

// For free layout inference
// If replication exists and buffer has cross-thread shared memory access,
// add predicate
bool has_cross_thread_access = false;
PostOrderVisit(root_, [&](const ObjectRef &obj) {
if (const auto *store = obj.as<BufferStoreNode>()) {
// check if scope is shared or global
if (store->buffer.scope() == "shared" ||
store->buffer.scope() == "shared.dyn" ||
store->buffer.scope() == "global") {
has_cross_thread_access = true;
}
} else if (const auto *load = obj.as<BufferLoadNode>()) {
// check if scope is shared or global
if (load->buffer.scope() == "shared" ||
load->buffer.scope() == "shared.dyn" ||
load->buffer.scope() == "global") {
has_cross_thread_access = true;
}
}
});

// check if loop body contains a "pure" buffer store (i.e., direct
// assignment, not compound update)
bool has_pure_buffer_store = false;
PostOrderVisit(root_, [&](const ObjectRef &obj) {
if (const auto *store = obj.as<BufferStoreNode>()) {
// Check if the value is a direct load from another buffer (i.e., b[i]
// = a[i])
if (const auto *load = store->value.as<BufferLoadNode>()) {
has_pure_buffer_store = true;
}
}
});

if (!is_one(loop_layout_->ReplicateExtent()) && has_cross_thread_access &&
!has_pure_buffer_store) {
auto inv = loop_layout_->Inverse();
Array<PrimExpr> fwd;
for (size_t i = 0; i < loop_layout_->OutputDim(); i++)
fwd.push_back(0);
fwd.push_back(InputPlaceholder(0) - T.thread_bounds->min);
auto rep = inv->Forward(fwd).back();
AddPredicate(EQ(rep, 0));
}
}

if (!loop_layout_.defined()) {
Expand Down Expand Up @@ -478,6 +477,16 @@ LayoutMap ParallelOpNode::InferLayout(const LayoutInferArgs &T,
DLOG(INFO) << "[PlanLoopPartition] loop_layout_ = "
<< loop_layout_->DebugOutput() << '\n';
}
if (!is_one(loop_layout_->ReplicateExtent()) && has_cross_thread_access &&
!has_pure_buffer_store) {
auto inv = loop_layout_->Inverse();
Array<PrimExpr> fwd;
for (size_t i = 0; i < loop_layout_->OutputDim(); i++)
fwd.push_back(0);
fwd.push_back(InputPlaceholder(0) - T.thread_bounds->min);
auto rep = inv->Forward(fwd).back();
AddPredicate(EQ(rep, 0));
}
} else {
return {};
}
Expand Down
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