Google Git
Sign in
llvm / llvm-project / 56910a8b1b302ebf37e9d30bd200091fd23dc232
commit56910a8b1b302ebf37e9d30bd200091fd23dc232[log] [tgz]
authorAlex MacLean <amaclean@nvidia.com>Mon Apr 21 15:55:06 2025 -0700
committerGitHub <noreply@github.com>Mon Apr 21 15:55:06 2025 -0700
tree5b8f58e19de3aa5769a667b10339716a4f21474e
parentc40d3a411ce3f0a35ae4f3d2f0e1e7df45673856 [diff]
[NVPTX] Improve kernel byval parameter lowering (#136008)

This change introduces a new pattern for lowering kernel byval
parameters in `NVPTXLowerArgs`. Each byval argument is wrapped in a call
to a new intrinsic, `@llvm.nvvm.internal.addrspace.wrap`. This intrinsic
explicitly equates to no instructions and is removed during operation
legalization in SDAG. However, it allows us to change the addrspace of
the arguments to 101 to reflect the fact that they will occupy this
space when lowered by `LowerFormalArgs` in `NVPTXISelLowering`.
Optionally, if a generic pointer to a param is needed, a standard
`addrspacecast` is used. This approach offers several advantages:

- Exposes addrspace optimizations: By using a standard `addrspacecast`
back to generic space we allow InferAS to optimize this instruction,
potentially sinking it through control flow or in other ways unsupported
by `NVPTXLowerArgs`. This is demonstrated in several existing tests.

- Clearer, more consistent semantics: Previously an `addrspacecast` from
generic to param space was implicitly a no-op. This is problematic
because it's not reciprocal with the inverse cast, violating LLVM
semantics. Further it is very confusing given the existence of
`cvta.to.param`. After this change the cast equates to this instruction.

- Allow for the removal of all nvvm.ptr.* intrinsics: In a follow-up
change the nvvm.ptr.gen.to.param and nvvm.ptr.param.to.gen intrinsics
may be removed.
13 files changed
tree: 5b8f58e19de3aa5769a667b10339716a4f21474e
  1. .ci/
  2. .github/
  3. bolt/
  4. clang/
  5. clang-tools-extra/
  6. cmake/
  7. compiler-rt/
  8. cross-project-tests/
  9. flang/
  10. flang-rt/
  11. libc/
  12. libclc/
  13. libcxx/
  14. libcxxabi/
  15. libunwind/
  16. lld/
  17. lldb/
  18. llvm/
  19. llvm-libgcc/
  20. mlir/
  21. offload/
  22. openmp/
  23. polly/
  24. pstl/
  25. runtimes/
  26. third-party/
  27. utils/
  28. .clang-format
  29. .clang-format-ignore
  30. .clang-tidy
  31. .git-blame-ignore-revs
  32. .gitattributes
  33. .gitignore
  34. .mailmap
  35. CODE_OF_CONDUCT.md
  36. CONTRIBUTING.md
  37. LICENSE.TXT
  38. pyproject.toml
  39. README.md
  40. SECURITY.md
README.md

The LLVM Compiler Infrastructure

OpenSSF Scorecard OpenSSF Best Practices libc++

Welcome to the LLVM project!

This repository contains the source code for LLVM, a toolkit for the construction of highly optimized compilers, optimizers, and run-time environments.

The LLVM project has multiple components. The core of the project is itself called “LLVM”. This contains all of the tools, libraries, and header files needed to process intermediate representations and convert them into object files. Tools include an assembler, disassembler, bitcode analyzer, and bitcode optimizer.

C-like languages use the Clang frontend. This component compiles C, C++, Objective-C, and Objective-C++ code into LLVM bitcode -- and from there into object files, using LLVM.

Other components include: the libc++ C++ standard library, the LLD linker, and more.

Getting the Source Code and Building LLVM

Consult the Getting Started with LLVM page for information on building and running LLVM.

For information on how to contribute to the LLVM project, please take a look at the Contributing to LLVM guide.

Getting in touch

Join the LLVM Discourse forums, Discord chat, LLVM Office Hours or Regular sync-ups.

The LLVM project has adopted a code of conduct for participants to all modes of communication within the project.