About João Saffran

• I work on HLSL language support in Clang.
• I'm on the DirectX Shader Compiler team at Microsoft since 2024.
• I am a contributor to Clang and DirectX, SPIR-V backends in LLVM.
• Curated Contributions:
  • llvm/llvm-project:
    • Root Signature Support: Implemented Root Signature support in the DirectX backend.
    • HLSL intrinsics: Added matrix type overloads for HLSL intrinsics.
    • HLSL support to Vulkan: Added an opt flag to run the SPIR-V structurizer pass in isolation; Added support for hlsl instrinsics in vulkan.
  • microsoft/DirectXShaderCompiler:
    • auto type: Contributed to HLSL auto type deduction in DXC.
    • HLK tests: Extended HLK driver-compiler tests to validate Long Vector operations.
    • Vulkan SDK Release: Contributed fixes, test coverage and CI/CD pipelines to DXC Vulkan SDK releases.
  • microsoft/hlsl-specs:
    • Root Signature spec: Contributed to the formal specification of Root Signature syntax and semantics for the next HLSL language revision.
    • Vulkan SDK release spec: Contributed HLSL-to-SPIR-V behavior specifications aligned with the Vulkan SDK release cycle.
  • llvm/offload-test-suite:
    • HLSL intrinsics tests: Added end-to-end execution tests for HLSL intrinsics and language features.
    • Cross-IHV validation: Audited and fixed the test suite to validate shader correctness across hardware from AMD, Intel, and NVIDIA.
• Before joining Microsoft, I was a compiler and HPC researcher:
  • On-line synthesis of parsers for string events — J. Saffran, H. Barbosa, F. M. Q. Pereira, S. Vladamani. Journal of Computer Languages, 2021.
  • NeurOMP: Automated code parallelization using Reinforcement Learning — J. Saffran, R. C. O. Rocha, L. F. W. Góes. SSCAD, 2019.
  • A low-cost energy-efficient Raspberry Pi cluster for data mining — J. Saffran, G. Garcia, M. Souza, P. H. Penna, M. Castro, L. F. Góes, H. C. Freitas. Euro-Par Workshops, 2016.
• Find me at:
  • GitHub: @joaosaffran
  • Email: joaosaffranllvm@gmail.com