ca93dd399e
Previous commit message: > Original commit message: > >>When users explicitly specify a PTX version via -mattr=+ptxNN that's insufficient for their target SM, we now emit a fatal error. Previously, we silently upgraded the PTX version to the minimum required for the target SM. >> >>When no SM or PTX version is specified, we now use PTX 3.2 (the minimum for the default SM 3.0) instead of PTX 6.0. > >The following commits should fix the failures that arose when I previously tried to land this commit: > >9fc5fd0ad6should address the llvm-nvptx*-nvidia-* build failures: https://github.com/llvm/llvm-project/pull/174834#issuecomment-3742242651 > >600514a637should address the MLIR failures --- The previous commit was reverted with d23cb79ba497281de050ef609cb91b91058bf323 because the [mlir-nvidia](https://lab.llvm.org/buildbot/#/builders/138/builds/24797) and [mlir-nvidia-gcc7](https://lab.llvm.org/buildbot/#/builders/116/builds/23929) Buildbots were failing. Those tests failed because MLIR's default SM was 5.0, which caused NVPTX to target PTX ISA v4.0, which did not support the intrinsics used in the failing tests. 243f011577193c99358ccc4142b296d4fa80ea11 should address this by bumping MLIR's default SM to 7.5. Now, using MLIR's new default SM, NVPTX targets the PTX ISA v6.3, which supports the intrinsics used in the failing tests.
Flang
Flang is a ground-up implementation of a Fortran front end written in modern C++. It started off as the f18 project (https://github.com/flang-compiler/f18) with an aim to replace the previous flang project (https://github.com/flang-compiler/flang) and address its various deficiencies. F18 was subsequently accepted into the LLVM project and rechristened as Flang.
Please note that flang is not ready yet for production usage.
Getting Started
Read more about flang in the docs directory. Start with the compiler overview.
To better understand Fortran as a language and the specific grammar accepted by flang, read Fortran For C Programmers and flang's specifications of the Fortran grammar and the OpenMP grammar.
Treatment of language extensions is covered in this document.
To understand the compilers handling of intrinsics, see the discussion of intrinsics.
To understand how a flang program communicates with libraries at runtime, see the discussion of runtime descriptors.
If you're interested in contributing to the compiler, read the style guide and also review how flang uses modern C++ features.
If you are interested in writing new documentation, follow LLVM's Markdown style guide.
Consult the Getting Started with Flang for information on building and running flang.