Phase 3: Remove hardcoded DtRobust system from compiler

[ztripez]

Phase 3: Remove Hardcoded DtRobust System

Part of Epic #247

Objective

Remove all hardcoded DtRobust logic from the compiler IR, making it operator-agnostic and letting the standard library be authoritative.

Tasks

Remove Type Definitions

• Remove DtRobustOperator enum from types.rs
• Remove IntegrationMethod enum from types.rs
• Remove DtRobustCall variant from CompiledExpr
• Remove DtRobustCall from SsaInstruction

Remove Hardcoded Parsing

• Remove parse_dt_robust_operator() function from lower/expr.rs
• Remove hardcoded dt-robust check in expression lowering
• Remove dt-robust precedence over kernel function lookup
• Update dt_robust_operator_name() in codegen.rs (or remove entirely)

Remove Execution Logic

• Remove execute_dt_robust() from vectorized/mod.rs
• Remove dt-robust handling from SSA execution
• Remove pattern matching on DtRobust variants

Update Related Code

• Remove dt-robust imports across the codebase
• Update any documentation referencing hardcoded operators
• Remove or update related test files

Validation

• Ensure no compilation errors after removal
• Verify fallback to kernel function calls works
• Test with simple dt-robust function calls

Files to Modify

• crates/kernels/ir/src/types.rs
• crates/kernels/ir/src/expressions.rs
• crates/kernels/ir/src/ssa/types.rs
• crates/kernels/ir/src/lower/expr.rs
• crates/kernels/ir/src/vectorized/mod.rs
• crates/kernels/ir/src/codegen.rs
• Various test files

Success Criteria

• No hardcoded dt-robust logic in compiler
• Compiler builds successfully
• DtRobust functions route to stdlib instead
• All tests pass (updated for new behavior)

Dependencies

• Requires Phase 2 (complete stdlib implementation)

Breaking Changes

• DtRobustOperator and related types removed from public API
• DSL must use kernel. prefix for dt-robust functions

Estimated Time: 1 week

[ztripez]

✅ Phase 3 Complete!

Summary

Removed the hardcoded DtRobust system from the compiler and routed dt-robust operations through standard kernel calls. All SSA, analysis, and execution paths now treat these as regular kernel functions, removing the special IR constructs.

✅ Completed Work

1) Removed DtRobust Types

• Deleted DtRobustOperator enum and IntegrationMethod from types.rs
• Removed CompiledExpr::DtRobustCall and SsaInstruction::DtRobustCall
• Updated all type-based match arms and helpers

2) Removed Hardcoded Parsing

• Deleted parse_dt_robust_operator() from lower/expr.rs
• Removed dt-robust precedence; kernel calls now require kernel. prefix
• Cleaned up leftover doc comments and imports

3) Updated SSA & Analysis Pipeline

• SSA lowering now emits only KernelCall for dt-robust functions
• Updated pattern extraction to match KernelCall names (decay, integrate, relax, smooth)
• Updated dimensional analysis to validate integrate* and decay via kernel names
• Removed dt-robust special cases from validation, fusion, compile passes

4) Vectorized Executor Cleanup

• Removed execute_dt_robust and dt-robust dispatch from L2 executor
• Added kernel-registry fallback for any kernel function (scalar evaluation)
• L2 now resolves kernel.integrate, kernel.decay, kernel.smooth via registry

5) Tests Updated & Passing

• Updated SSA tests and vectorized tests to use KernelCall
• Updated pattern tests to use KernelCall
• All continuum-ir tests pass (144 total)

Files Updated

• crates/kernels/ir/src/types.rs
• crates/kernels/ir/src/expressions.rs
• crates/kernels/ir/src/ssa/types.rs
• crates/kernels/ir/src/lower/expr.rs
• crates/kernels/ir/src/lower/signals.rs
• crates/kernels/ir/src/vectorized/mod.rs
• crates/kernels/ir/src/analysis/dimensions.rs
• crates/kernels/ir/src/patterns.rs
• crates/kernels/ir/src/ssa/lower.rs
• crates/kernels/ir/src/ssa/tests.rs
• crates/kernels/ir/src/vectorized/tests.rs
• crates/kernels/ir/src/compile.rs
• crates/kernels/ir/src/fusion.rs
• crates/kernels/ir/src/validate.rs
• crates/kernels/ir/src/codegen.rs
• crates/kernels/ir/src/interpret/mod.rs
• crates/kernels/ir/src/interpret/member_interp.rs

✅ Result

The compiler is now operator-agnostic. Dt-robust functions are only recognized via standard library kernel calls. No hardcoded operators remain in IR, SSA, or L2 execution.

Ready for Phase 4: execution pipeline + DSL migration updates.