EXCEEDS logo
Exceeds
Sayan Saha

PROFILE

Sayan Saha

Over 16 months, contributed to llvm/torch-mlir and ROCm/tensorflow-upstream by building robust compiler infrastructure for deep learning models. Focused on Torch-to-TOSA and Torch-to-Linalg lowering, implemented features such as quantized inference, dynamic shape handling, and cross-platform CI workflows. Used C++, MLIR, and Python to enhance tensor operation correctness, optimize build systems, and improve quantization flows. Addressed edge cases in dynamic tensor shapes, improved numerical accuracy, and expanded test coverage to ensure reliability across Windows and Linux. The work emphasized maintainable code, configurability for resource-constrained hardware, and seamless integration with PyTorch and TensorFlow model pipelines.

Overall Statistics

Feature vs Bugs

59%Features

Repository Contributions

32Total
Bugs
11
Commits
32
Features
16
Lines of code
6,845
Activity Months16

Work History

June 2026

2 Commits • 1 Features

Jun 1, 2026

June 2026 monthly summary for llvm/torch-mlir: - Key features delivered: - Torch-to-TOSA: Fix crashes and invalid IR generation when handling dynamic tensor shapes. Added explicit checks to bail out on unsupported dynamic shapes and updated reshape handling; introduced new tests to validate robust error handling. - Torch-to-Linalg: Optimize slice conversion by properly handling INT64_MAX sentinel to avoid materializing large index constants, improving compatibility with 32-bit index targets; added tests for dynamic slice behavior. - Major bugs fixed: - Resolved crashes and invalid IR emission in Torch-to-TOSA legalization for dynamic dimensions; ensured stable lowering paths with safe fallbacks and improved test coverage. - Overall impact and accomplishments: - Increased stability and reliability of dynamic-shape conversions, reducing runtime crashes in production pipelines. - Improved cross-target compatibility (including 32-bit index targets) for Torch-to-Linalg slice operations. - Strengthened test suite with targeted dynamic-shape and slice-edge-case tests, boosting regression protection. - Technologies/skills demonstrated: - MLIR-based lowering passes, dynamic shape analysis, error handling, test-driven development, and cross-path integration between Torch, TOSA, and Linalg backends. - Commits linked: - bddd9e6c360f7dd5eefb0bb1aa9a1c021430337f: "[tosa] Fix dynamic dims crashes in torch tosa legalization (#4622)" — fixed crashes for dynamic dims, added checks, and robust tests. - 626f533bc8efb39d2f56a1d2509a06126597376b: "[TorchToLinalg] slice: use dimSize for INT64_MAX end sentinel (#4623)" — avoids large constant materialization for 32-bit targets, with added tests for dynamic slices.

May 2026

3 Commits • 1 Features

May 1, 2026

In May 2026, advanced 16-bit quantized inference capabilities and importer reliability across the Torch-MLIR stack, delivering tangible business value through memory-efficient execution and improved interoperability. Key work spanned the reference backend ABI, conv path optimizations, and ONNX-to-Torch import correctness, with tests and diagnostics enhancing long-term maintainability and quality.

March 2026

3 Commits • 1 Features

Mar 1, 2026

2026-03 Monthly Summary (llvm/torch-mlir): Delivered a configurable, safer Torch-to-TOSA lowering path and fixed quantization accuracy issues to enable production-grade deployments on resource-constrained hardware. Key features delivered: - Torch to TOSA conversion enhancements: Introduced a common base class TorchToTosaOpConversionPattern with a final matchAndRewrite and a virtual matchAndRewriteImpl hook. Enforced zero-sized dimension checks before legalization to prevent errors across all Torch→TOSA conversions. Implemented configurability to selectively enable/disable specific conversion patterns for resource-constrained environments, reducing memory pressure on embedded HW. - Pattern configurability for resource-constrained deployments: Added an option to enable/disable specific conversion patterns so the TOSA path can be tuned per target HW, with fallbacks to the linalg path when needed. Major bugs fixed: - Quantization casting order fix: Adjusted quantize_per_tensor lowering to perform integer casting after all computations and ZP addition, improving numerical accuracy and preventing premature casting. Overall impact and accomplishments: - Robust, configurable Torch→TOSA lowering that can be tuned for hardware constraints, improving deployment feasibility on embedded devices while preserving correctness. - Improved numerical accuracy for quantized models, contributing to higher model fidelity in production. Technologies/skills demonstrated: - MLIR-based pattern design and C++ implementation (base class pattern, final methods, virtual hooks). - Cross-dialect lowering considerations (Torch, TOSA, and linalg paths) and memory footprint awareness. - Code quality, maintainability, and testability through centralized, reusable conversion patterns.

February 2026

2 Commits

Feb 1, 2026

February 2026 monthly recap for llvm/torch-mlir: 1) Key features delivered - Fixed dynamic tensor shape handling in makeTorchShapeCompatible to support Torch-MLIR TOSA conversion when shapes are dynamic, preventing incorrect modifications and asserts during TensorType construction. Commit: 9a7cd961c16e85002201511e5c6a600b35017d45. 2) Major bugs fixed - Improved CI reliability on Windows for TOSA conversion by updating the tosa.const_shape LIT test to use CHECK-DAG to verify output shapes in a DAG, addressing Windows CI failures. Commit: b9f84d6fb61c2c371ce652c466a518a5da0a7177. 3) Overall impact and accomplishments - These fixes remove a critical edge-case in dynamic shape handling and reduce Windows CI noise, leading to more reliable builds and correct TensorType construction in the Torch-MLIR TOSA path. The changes align with the existing usage patterns of makeTorchShapeCompatible and preserve correctness across ~60 other usages. 4) Technologies/skills demonstrated - C++/MLIR internals, Torch-MLIR integration, TOSA conversion workflow, LIT testing, and Windows CI debugging (CHECK-DAG usage).

January 2026

1 Commits • 1 Features

Jan 1, 2026

Implemented unsigned-to-signed integer conversion support across multiple bit widths in TOSA for ROCm/tensorflow-upstream, with end-to-end tests, file renaming for clarity, and scale recalculation based on zero points to improve unsigned data handling in ML models.

December 2025

1 Commits • 1 Features

Dec 1, 2025

December 2025: Focused work on MLIR/TOSA quantization path in ROCm/tensorflow-upstream. Delivered enhanced QuantizedType legalization by incorporating signed information, with new helper functions and updates to existing logic to correctly handle signed quantized types. This improvement enhances accuracy and efficiency of quantized tensor operations and aligns with upstream goals for ROCm/tensorflow-upstream. Key commit: 2175701ae9313dd73f0cebceb482ef941cb1f933; PR: "[tosa] : Use QuantizedType signed info for legalization. (#105376)".

November 2025

4 Commits • 2 Features

Nov 1, 2025

November 2025 monthly summary for llvm/torch-mlir. Key features delivered include end-to-end quantized matmul support in the Torch MLIR/TOSA path, with per-tensor quantization on the TOSA backend, and pooling operation canonicalization to support flexible input shapes. Major bugs fixed include stabilization of Windows builds by pinning the Ninja build tool to an older, compatible version. Overall impact includes enabling quantized inference paths, improving model portability across devices, and reducing CI/build disruptions. Technologies and skills demonstrated span MLIR/TOSA quantization flows, operator legalization for quantize/dequantize and per-tensor quantization, and Windows CI/build-hardening practices.

September 2025

2 Commits • 1 Features

Sep 1, 2025

Month: 2025-09 — Build System Improvement: LLVM Python Dependencies Management for llvm/torch-mlir. Refactored the build to leverage LLVM's Python requirements and added llvm/python requirements.txt to the Bazel work directory, ensuring Python dependencies for LLVM are available during builds. This reduces build flakiness, improves CI reliability, and aligns with upstream LLVM dependency management. Key accomplishments (top 3-5): - Adopted LLVM Python requirements in the build process (commit 03da86187083846e257597135177442233923d28). - Copied LLVM Python requirements.txt to the Bazel workdir to ensure Python dependencies are available during builds (commit ed166d4dc3a7072e021c6ab3aef673b9151011f7). - Enhanced CI reproducibility and reduced build instability by standardizing Python packaging with LLVM's requirements. Major bugs fixed: Stabilized the build environment by ensuring Python dependencies are resolved through LLVM requirements, reducing sporadic build failures due to missing Python packages. Overall impact and accomplishments: Improved build reliability and reproducibility for llvm/torch-mlir in September 2025, enabling faster PR validation and onboarding. The changes reduce CI churn, cut debugging time related to Python deps, and align with LLVM's upstream dependency management, translating into measurable efficiency gains for the development and release cycle. Technologies/skills demonstrated: Bazel build configurations, LLVM Python packaging, Python dependency management, CI/CD alignment, reproducible build practices, and contributor onboarding facilitation.

August 2025

1 Commits

Aug 1, 2025

August 2025 (llvm/torch-mlir) focused on quality and stability with no new user-facing features. Key outcomes included (1) clearer, codebase-wide error messages to speed debugging, and (2) updated PyTorch nightly to 2.9.0.dev20250820 to maintain compatibility with nightly changes. These efforts improve developer productivity, reduce incident resolution time, and enhance build reproducibility across the repo.

July 2025

2 Commits • 1 Features

Jul 1, 2025

July 2025 monthly summary for llvm/torch-mlir. Focused on enhancing numerical robustness in the TOSA dialect to improve model accuracy and PyTorch compatibility. Delivered two critical changes in the TOSA lowering path: (1) improved convolution bias type handling and a bias initialization helper ensuring bias tensors use the correct output type; (2) aligned MatMul accumulator type with PyTorch specifications to ensure correct lowering of aten.mm to tosa.matmul. These changes reduce type-related errors, improve numerical stability, and lay groundwork for more reliable integration with PyTorch models. Commits captured: 386bba4a92898b3e37184db754fc439b370f7d5f and 0bf6e9ca41d4577a00730d7143969ae9bb214f04.

May 2025

1 Commits • 1 Features

May 1, 2025

May 2025 monthly summary for llvm/torch-mlir. Delivered a focused feature to enhance TOSA tensor operations by normalizing operand ranks in the tosa.select operation and enabling dynamic-batch input slicing for static spatial dimensions in convolution, improving flexibility, correctness, and serving reliability. The work is recorded in commit 1682ce22d0240a4a6a528ddae05df7073eb545e5 (#4162). This contributes to more robust dynamic shapes handling and reduces downstream integration risks, aligning with our roadmap for TOSA performance.

March 2025

2 Commits • 1 Features

Mar 1, 2025

March 2025 monthly summary for llvm/torch-mlir: Consolidated Windows CI enhancements and dtype robustness to accelerate cross-platform development and improve tensor-operation reliability. Key features delivered include a Windows CI workflow with LIT unit tests and build caching, expanding Windows test coverage and speeding iteration cycles. Major bug fixes focus on correct dtype handling for empty tensor creation via a new dtype inference utility, reducing type-related failures during tensor operations.

February 2025

1 Commits • 1 Features

Feb 1, 2025

February 2025 monthly summary for llvm/torch-mlir: Focused on expanding pooling functionality by enabling AvgPool2d CHW input compatibility and flexible kernel/stride expansion, with changes aligned to the TOSA framework. Delivered a robust feature to broaden model compatibility and reduce preprocessing overhead.

January 2025

2 Commits • 1 Features

Jan 1, 2025

January 2025 performance summary for llvm/torch-mlir focused on strengthening the Torch-to-TOSA backend with new operation support and correctness improvements. Delivered practical features enabling broader model coverage and improved numerical accuracy, backed by tests and code updates.

December 2024

3 Commits • 2 Features

Dec 1, 2024

December 2024 monthly summary for llvm/torch-mlir focusing on delivering core conv/MLIR improvements, with notable refactor and bug fix contributions.

October 2024

2 Commits • 1 Features

Oct 1, 2024

Month: 2024-10. This period focused on stabilizing cross-platform builds and expanding tensor indexing capabilities within llvm/torch-mlir. Key features delivered include: 1) Windows build stability for STABLEHLO: disabled building STABLEHLO on Windows and added a USE_MATH_DEFINES definition to resolve a math-related build error, reducing platform-specific failures. 2) Negative indexing support in tensor indexing: introduced support for negative indices in index.tensor and index.Tensor_hacked_twin for TorchToTosa lowering, including a new wrap-negative-indices utility, updates to related tensor operations, and tests to verify correctness. Overall impact: improved reliability of Windows CI, parity in indexing semantics across TorchToTosa, and stronger test coverage. Technologies/skills demonstrated: cross-platform build configuration and maintenance (C++/LLVM), TorchToTosa lowering, tensor operation updates, and test-driven development."

Activity

Loading activity data...

Quality Metrics

Correctness93.8%
Maintainability81.2%
Architecture86.2%
Performance81.8%
AI Usage33.2%

Skills & Technologies

Programming Languages

BashC++CMakeMLIRPythonShellYAML

Technical Skills

Build SystemsC++C++ DevelopmentC++ ProgrammingC++ developmentCI/CDCMakeCompiler DesignCompiler DevelopmentContinuous IntegrationDeep Learning FrameworksDependency ManagementDevOpsMLIRMLIR Development

Repositories Contributed To

2 repos

Overview of all repositories you've contributed to across your timeline

llvm/torch-mlir

Oct 2024 Jun 2026
14 Months active

Languages Used

C++CMakeMLIRShellPythonBashYAML

Technical Skills

Build SystemsC++ developmentCMakeMLIRShell Scriptingtensor operations

ROCm/tensorflow-upstream

Dec 2025 Jan 2026
2 Months active

Languages Used

C++MLIR

Technical Skills

compiler designmachine learningquantizationtensor operationsCompiler DesignMLIR