Ownership Fusion special types

[mdavis36]

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[mdavis36]

!test

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Review updated until commit 1588d37

Description

• Moved special values (zero_val_, one_val_, true_val_, false_val_, magic_zero_val_) from IrContainer to Fusion class

• Implemented lazy creation pattern for all special value accessors in Fusion

• Updated Fusion copy/swap/clear operations to handle per-Fusion special values

• Added StatementGuard support to prevent dangling special value pointers

• Removed special value methods from IrContainer class

• Added regression test for lazy special vals with StatementGuard

Changes walkthrough

	Relevant files
Enhancement	fusion.cpp Move special values to Fusion with lazy creation                  csrc/fusion.cpp Added includes for type.h, ir/builder.h, ir/internal_nodes.h Updated swap() to handle per-Fusion special values Updated copy() to remap cached special val pointers Updated clear() to reset special value pointers Updated removeVal() to protect cached special vals Added removeStatementsCreatedAfter() with special value cache handling Implemented lazy creation accessors for all special values Added metadataOf(), axioms(), assumePositive(), assumeNonNegative() methods +211/-0  container.cpp Remove special value methods from IrContainer                        csrc/ir/container.cpp Removed all special value methods (zeroVal, oneVal, etc.) Removed axioms and metadata methods Removed removeStatementsCreatedAfter() method Updated swap() to not handle special values (now in Fusion) Updated copy() to not copy special values (now in Fusion) Updated removeVal() to not check for special values Updated clear() to not clear special values +2/-180  utils.cpp Optimize SubstituteInExpr to skip unnecessary mutations    csrc/ir/utils.cpp Added check to avoid unnecessary mutations in SubstituteInExpr +3/-1      statement_guard.cpp Update StatementGuard for new numVals() signature                csrc/statement_guard.cpp Changed numVals() call to not pass include_shortcuts parameter +1/-1      fusion.h Add special value members and methods to Fusion class        csrc/fusion.h Added NamedScalar forward declaration Moved special value accessors from IrContainer to Fusion Added new member variables for per-Fusion special values Added axioms and metadata member variables to Fusion Updated method declarations for moved functionality +25/-46  container.h Remove special value methods from IrContainer interface    csrc/ir/container.h Removed all special value method declarations Removed axioms and metadata method declarations Removed removeStatementsCreatedAfter() method declaration Removed member variables for special values, axioms, and metadata Updated numVals() to not have include_shortcuts parameter +2/-50
Tests	test_indexing.cpp Update test expectations for reshape test                                tests/cpp/test_indexing.cpp Updated expected string output for reshape test +2/-2      test_statement_guard.cpp Add regression test for lazy special vals with StatementGuard tests/cpp/test_statement_guard.cpp Added LazySpecialValsNotDangling regression test Test verifies special vals work correctly with StatementGuard rollback +51/-0

PR Reviewer Guide

Here are some key observations to aid the review process:

🧪 PR contains tests

⚡ Recommended focus areas for review

Memory Management The PR moves special value ownership from IrContainer to Fusion, but I need to verify that the memory management is correct. The special values are now stored as raw pointers in Fusion, and there's careful handling in copy/swap/clear operations. The lazy creation pattern in methods like zeroVal() looks correct, but I should verify there are no memory leaks or dangling pointers. Val* Fusion::zeroVal() { if (!zero_val_) { zero_val_ = IrBuilder::createInContainer<Val>(this, 0L, DataType::Index); } return zero_val_; } Val* Fusion::oneVal() { if (!one_val_) { one_val_ = IrBuilder::createInContainer<Val>(this, 1L, DataType::Index); } return one_val_; } Val* Fusion::falseVal() { if (!false_val_) { false_val_ = IrBuilder::createInContainer<Val>(this, false, DataType::Bool); } return false_val_; } Val* Fusion::trueVal() { if (!true_val_) { true_val_ = IrBuilder::createInContainer<Val>(this, true, DataType::Bool); } return true_val_; } NamedScalar* Fusion::magicZeroVal() { if (!magic_zero_val_) { magic_zero_val_ = IrBuilder::createInContainer<NamedScalar>( this, kMagicZeroName, DataType::Index); } return magic_zero_val_; } StatementGuard Integration The removeStatementsCreatedAfter function now nulls out special value caches to prevent dangling pointers when special vals are lazily created inside a StatementGuard scope. This is a critical fix, but I need to verify the logic is sound and that the test case properly exercises this scenario. // Null out any special value caches that point to vals about to be destroyed. // This prevents dangling pointers when special vals are lazily created inside // a StatementGuard scope. while (std::ssize(c->vals_up_) > num_vals_before) { Val* v = c->vals_up_.back().get(); if (v == zero_val_) { zero_val_ = nullptr; } else if (v == one_val_) { one_val_ = nullptr; } else if (v == true_val_) { true_val_ = nullptr; } else if (v == false_val_) { false_val_ = nullptr; } else if (v == magic_zero_val_) { magic_zero_val_ = nullptr; } c->vals_.erase(v); c->vals_up_.pop_back(); } API Consistency The PR removes shortcut methods from IrContainer and moves them to Fusion. This breaks the existing API where users could call container->zeroVal(). I need to check if this is intentional and if there are any remaining calls to the old API that need to be updated. IrCloner IrContainer::copy(const IrContainer* from, IrContainer* to) { to->clear(); IrCloner ir_cloner(to->parent()); // Copy values in deterministic order for (auto val : from->deterministic_vals()) { if (from->vals().count(val) > 0) { to->vals_.insert(ir_cloner.clone(val)); } } // Copy expressions in deterministic order for (auto expr : from->deterministic_exprs()) { if (from->unordered_exprs().count(expr) > 0) { to->exprs_.insert(ir_cloner.clone(expr)); } } to->val_type_name_map_ = from->val_type_name_map_; to->expr_name_counter_ = from->expr_name_counter_; return ir_cloner; }

[mdavis36]

!test

[mdavis36]

!test

[mdavis36]

!test