Differentiate FIR and basic support for Fortran MLIR by vchuravy · Pull Request #2969 · EnzymeAD/Enzyme

vchuravy · 2026-07-22T15:47:33Z

Differentiate the basic FIR constructs.

🤖 Generated with Claude Code

Extends the StoreLikeInterface generalization to the remaining store sites in ActivityAnalysis and gates the pointer-like type check on the type interface, so out-of-tree dialects (e.g. FIR/HLFIR) participate fully in activity analysis without hard-coded dyn_casts. These are the Fortran-independent pieces of #2969. - isConstantValue: besides LLVM ptr / memref, treat any type whose AutoDiffTypeInterface reports isMutable() (e.g. !fir.ref) as a reference that carries active memory. Behavior-preserving in-tree: among core dialects only memref and LLVM pointer report isMutable(), and both are already matched by the existing isa<> check. - isOperationInactiveFromOrigin: dialect-agnostic store branch mirroring the LLVM::StoreOp case (inactive iff stored value or pointer is constant). - isValueActivelyStoredOrReturned: dialect-agnostic store branch mirroring the LLVM::StoreOp case. Deliberately excludes the Fortran-coupled / behavior-changing parts of #2969 (FIR/HLFIR models, flang plugin, the CoreDialects registration TU split, and dropping tensor/linalg from the pass dependent dialects). Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

vchuravy · 2026-07-23T16:00:41Z

+//
+// Enzyme autodiff support for FIR's by-reference memory model, so whole Fortran
+// functions differentiate: their arguments and locals are !fir.ref<T> and the
+// body is fir.load / hlfir.assign / fir.alloca / hlfir.declare over that


Use https://github.com/EnzymeAD/Enzyme/pull/2980 for fir.alloca

vchuravy · 2026-07-23T16:01:23Z

This should be on flang-plugin-sketch

vchuravy · 2026-07-23T16:02:37Z

+    $<TARGET_FILE:MLIREnzymeAutoDiffInterface>
+    -Wl,--end-group)
+  target_link_options(FlangEnzymeMLIR-${LLVM_VERSION_MAJOR} PRIVATE
+    -Wl,--allow-shlib-undefined)


This should be on flang-plugin-sketch partially

…lugins Sets up the flang-dependent autodiff layer and its delivery vehicles for differentiating by-reference Fortran (arguments/locals are !fir.ref<T>): * FIRAutoDiffOpInterfaceImpl.cpp + FIRDerivatives.td -- !fir.ref<T> as active memory: AutoDiffTypeInterface (mutable, parallel-ref shadow), the FIR/HLFIR memory ops as active-memory identities (fir.load/store, fir.alloca, hlfir.declare/assign), StoreLikeInterface, and hand-written reverse adjoints for fir.load/store, hlfir.assign, hlfir.declare (mirroring the LLVM dialect). Added to the flang-dependent MLIREnzymeHLFIRImplementations library. * fir-enzyme-opt registers the core + FIR autodiff interfaces. * enzyme-fir-plugin.cpp (FIREnzyme) -- the fir-opt dialect+pass plugin for a shared-libMLIR build; HLFIRFlangPluginRegistration.cpp (FlangEnzymeMLIR) -- the -load'able plugin that registers the Enzyme passes into flang's own codegen pipeline via fir::registerPassPipelineConfigCallback. * %firenzyme / %firopt / %flang_enzyme lit substitutions. The Tier-1 hlfir.* array-intrinsic models (hlfir.matmul) attach on top of this layer in a follow-up. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01BkvJByk8nTti2GiF4RudNG

Two core activity-analysis generalizations so whole by-reference Fortran functions differentiate, kept free of any FIR/HLFIR dependency: * ActivityAnalysis.cpp queries enzyme::StoreLikeInterface alongside the existing memref/LLVM store cases, so activity propagates from an active stored value to the pointer written for fir.store / hlfir.assign. * isConstantValue's pointer-type gate now also admits any type whose AutoDiffTypeInterface::isMutable() is true (fir.ref, and any out-of-tree mutable reference), so a local fir.alloca result buffer enters the memory-based activity search. The memory-identity forward handler inverts a constant mutable operand rather than erroring. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01BkvJByk8nTti2GiF4RudNG

fir-enzyme-opt FileCheck tests for !fir.ref forward and reverse modes through the by-reference memory model (fir_ref_fwd/rev, fir_ref_function_result_fwd/rev), a smoke test for the FIR+Enzyme wiring, and end-to-end flang-plugin tests (flang_plugin_lower/emit_llvm/executable) that drive `flang -fc1` with the FlangEnzymeMLIR plugin on a scalar function. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01BkvJByk8nTti2GiF4RudNG

FIR_README.md (fir-enzyme-opt / plugin delivery vehicles, the static-LLVM cl::opt constraint) and plan_fortran.md (the flang+plugin end-to-end plan and op-level Tier-1/2/3 breakdown). Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01BkvJByk8nTti2GiF4RudNG

This entry point is implemented and used by this layer (FIRAutoDiffOpInterfaceImpl.cpp, fir-enzyme-opt), so declare it here rather than in the base plugin header. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

vchuravy · 2026-07-23T16:20:41Z

+# fir-opt (from the Flang/LLVM build) plus the FIREnzyme dialect+pass plugin, so
+# hlfir.* array intrinsics can be differentiated while still ops. %firenzyme is
+# the two --load-*-plugin flags; %firopt is fir-opt already carrying them.
+firenzyme_plugin = (config.enzyme_obj_root
+                    + "/Enzyme/MLIR/FIREnzyme-" + config.llvm_ver
+                    + config.llvm_shlib_ext)
+if len("@ENZYME_BINARY_DIR@") == 0:
+  firenzyme_plugin = (os.path.dirname(os.path.abspath(__file__))
+                      + "/../FIREnzyme-" + config.llvm_ver + config.llvm_shlib_ext)
+firenzyme_flags = (" --load-dialect-plugin=" + firenzyme_plugin
+                   + " --load-pass-plugin=" + firenzyme_plugin)
+config.substitutions.append(('%firenzyme', firenzyme_flags))
+config.substitutions.append(('%firopt', config.llvm_tools_dir + "/fir-opt" + firenzyme_flags))
+if os.path.exists(config.llvm_tools_dir + "/fir-opt") and os.path.exists(firenzyme_plugin):
+  config.available_features.add('fir_enzyme_plugin')
+


This should likely be on flang-plugin-sketch

vchuravy mentioned this pull request Jul 22, 2026

[MLIR] Add StoreLikeInterface to decouple activity analysis from stores #2978

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vchuravy force-pushed the flang-plugin-sketch branch from 919ab16 to 3f67afa Compare July 23, 2026 10:09

vchuravy force-pushed the flang-fir-plugin branch from 37683b4 to 9b544ae Compare July 23, 2026 10:09

vchuravy force-pushed the flang-plugin-sketch branch from 3f67afa to 2cac952 Compare July 23, 2026 12:02

vchuravy force-pushed the flang-fir-plugin branch 4 times, most recently from bfff057 to a5daaf1 Compare July 23, 2026 15:39

vchuravy force-pushed the flang-plugin-sketch branch from 5c556a3 to 290e091 Compare July 23, 2026 15:39

vchuravy force-pushed the flang-fir-plugin branch from a5daaf1 to eef53d0 Compare July 23, 2026 15:41

vchuravy force-pushed the flang-plugin-sketch branch from 290e091 to 0a0078a Compare July 23, 2026 15:41

vchuravy force-pushed the flang-plugin-sketch branch from 0a0078a to 74585c6 Compare July 23, 2026 15:48

vchuravy force-pushed the flang-fir-plugin branch from eef53d0 to 90369f2 Compare July 23, 2026 15:48

vchuravy commented Jul 23, 2026

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Comment thread enzyme/Enzyme/MLIR/enzyme-fir-plugin.cpp

vchuravy Jul 23, 2026

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This should be on flang-plugin-sketch

vchuravy commented Jul 23, 2026

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Comment thread enzyme/Enzyme/MLIR/Implementations/HLFIRFlangPluginRegistration.cpp

vchuravy commented Jul 23, 2026

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vchuravy and others added 5 commits July 23, 2026 18:15

vchuravy force-pushed the flang-fir-plugin branch from e63b5cc to e086584 Compare July 23, 2026 16:17

Delete plan_fortran.md

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vchuravy commented Jul 23, 2026

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vchuravy changed the title ~~Differentiate HLFIR array intrinsics via Enzyme-MLIR (fir-opt tool + flang plugin)~~ Differentiate FIR and basic support for Fortran MLIR Jul 23, 2026

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Differentiate FIR and basic support for Fortran MLIR#2969

Differentiate FIR and basic support for Fortran MLIR#2969
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vchuravy commented Jul 22, 2026 •

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vchuravy commented Jul 22, 2026 •

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