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[Bugfix] Fix missing reg alloc in custom warp specialization #1084

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Merged
merged 1 commit into from
Oct 20, 2025
Merged

[Bugfix] Fix missing reg alloc in custom warp specialization #1084

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11 changes: 4 additions & 7 deletions src/transform/annotate_warp_group_reg_alloc.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -95,8 +95,7 @@ class SetMaxNRegInjector : public StmtExprMutator {
private:
Stmt VisitStmt_(const EvaluateNode *op) final {
if (const CallNode *call = op->value.as<CallNode>()) {
if (call->op.same_as(set_max_nreg()) ||
call->op.same_as(no_set_max_nreg())) {
if (call->op.same_as(no_set_max_nreg())) {
// Remove the original set_max_nreg calls as they will be re-inserted
// at appropriate locations
return Evaluate(0);
Comment on lines +98 to 101
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⚠️ Potential issue | 🟡 Minor

Update the misleading comment.

The comment on lines 99-100 claims to "Remove the original set_max_nreg calls" but the code now only removes no_set_max_nreg() calls. Original set_max_nreg() calls are preserved in this version.

Apply this diff to correct the comment:

       if (call->op.same_as(no_set_max_nreg())) {
-        // Remove the original set_max_nreg calls as they will be re-inserted
-        // at appropriate locations
+        // Remove no_set_max_nreg() calls to allow injection of default hints
+        // if no explicit register hints were provided
         return Evaluate(0);
       }
📝 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
if (call->op.same_as(no_set_max_nreg())) {
// Remove the original set_max_nreg calls as they will be re-inserted
// at appropriate locations
return Evaluate(0);
if (call->op.same_as(no_set_max_nreg())) {
// Remove no_set_max_nreg() calls to allow injection of default hints
// if no explicit register hints were provided
return Evaluate(0);
🤖 Prompt for AI Agents 
In src/transform/annotate_warp_group_reg_alloc.cc around lines 98 to 101, the
comment incorrectly states that "Remove the original set_max_nreg calls" while
the code only removes no_set_max_nreg() calls; update the comment to accurately
state that only no_set_max_nreg() calls are removed (or similar wording) so it
reflects the current behavior, e.g., change the comment to indicate removal of
no_set_max_nreg() calls which will be re-inserted later.

Expand Down Expand Up @@ -136,11 +135,9 @@ class SetMaxNRegInjector : public StmtExprMutator {
// Only inject if we have valid register hints and no SIMT copy
bool has_simt_copy = SimtCopyDetector::Detect(producer_body);

if (dec_reg >= 0 && inc_reg >= 0 && !has_simt_copy) {
auto inc_reg_num =
IntImm(DataType::Int(32), inc_reg == 0 ? 240 : inc_reg);
auto dec_reg_num =
IntImm(DataType::Int(32), dec_reg == 0 ? 24 : dec_reg);
if (dec_reg == 0 && inc_reg == 0 && !has_simt_copy) {
auto inc_reg_num = IntImm(DataType::Int(32), 240);
auto dec_reg_num = IntImm(DataType::Int(32), 24);
inc_reg_stmt = Evaluate(
Call(DataType::Handle(), set_max_nreg(), {inc_reg_num, 1}));
dec_reg_stmt = Evaluate(
Expand Down