bdd8c64a2a
Add value-preserving folds mirroring LLVM's InstructionSimplify for the integer division and remainder ops: ``` divui/divsi/ceildivui/ceildivsi/floordivsi(0, x) -> 0 divui/divsi/ceildivui/ceildivsi/floordivsi(x, x) -> 1 remui/remsi(0, x) -> 0 remui/remsi(x, x) -> 0 ``` The self and zero-dividend cases are valid refinements because division or remainder by zero is undefined behaviour; no overflow flags are required. The folds return a scalar or splat constant and bail out on shaped types with a dynamic shape. Folding `x / 0` and `x % 0` to poison is left as a TODO: it would make the arith dialect depend on the ub dialect to materialize `ub.poison`. LLVM performs the same simplifications: https://godbolt.org/z/dzTjYjs4e Verified with Alive2: | Fold | udiv | sdiv | urem | srem | | :--- | :---: | :---: | :---: | :---: | | `x / x -> 1`, `x % x -> 0` | [✓](https://alive2.llvm.org/ce/z/YjZCEA) | [✓](https://alive2.llvm.org/ce/z/BSWQrm) | [✓](https://alive2.llvm.org/ce/z/gx5sRH) | [✓](https://alive2.llvm.org/ce/z/VUYkr4) | | `0 / x -> 0`, `0 % x -> 0` | [✓](https://alive2.llvm.org/ce/z/keqeCZ) | [✓](https://alive2.llvm.org/ce/z/jyf5wm) | [✓](https://alive2.llvm.org/ce/z/fZa6ND) | [✓](https://alive2.llvm.org/ce/z/fo6ss8) | ---- Code generated by Claude Code. Signed-off-by: Víctor Pérez Carrasco <victor.pc.upm@gmail.com> |
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| llvm | ||
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| offload | ||
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| CODE_OF_CONDUCT.md | ||
| CONTRIBUTING.md | ||
| LICENSE.TXT | ||
| pyproject.toml | ||
| README.md | ||
| SECURITY.md | ||
The LLVM Compiler Infrastructure
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.
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