| commit | 57dc71352c75f88e6819314b2b0e81a62bf285e9 | [log] [tgz] |
|---|---|---|
| author | lorenzo chelini <l.chelini@icloud.com> | Tue Mar 18 01:42:43 2025 -0600 |
| committer | GitHub <noreply@github.com> | Tue Mar 18 08:42:43 2025 +0100 |
| tree | 80c853cb4d051344448fb425f4613b11ab7a475d | |
| parent | 58dd3eda4e3d0e8a4dd3a5f1267ee259cdb5442c [diff] |
[MLIR][Bufferization] Retire `enforce-aliasing-invariants` (#130929)
Why? This option can lead to incorrect IR if used in isolation, for
example, consider the IR below:
```mlir
func.func @loop_with_aliasing(%arg0: tensor<5xf32>, %arg1: index, %arg2: index) -> tensor<5xf32> {
%c1 = arith.constant 1 : index
%cst = arith.constant 1.000000e+00 : f32
%0 = tensor.empty() : tensor<5xf32>
%1 = linalg.fill ins(%cst : f32) outs(%0 : tensor<5xf32>) -> tensor<5xf32>
// The BufferizableOpInterface says that %2 alias with %arg0 or be a newly
// allocated buffer
%2 = scf.for %arg3 = %arg1 to %arg2 step %c1 iter_args(%arg4 = %arg0) -> (tensor<5xf32>) {
scf.yield %1 : tensor<5xf32>
}
%cst_0 = arith.constant 1.000000e+00 : f32
%inserted = tensor.insert %cst_0 into %1[%c1] : tensor<5xf32>
return %2 : tensor<5xf32>
}
```
If we bufferize with: enforce-aliasing-invariants=false, we get:
```
func.func @loop_with_aliasing(%arg0: memref<5xf32, strided<[?], offset: ?>>, %arg1: index, %arg2: index) -> memref<5xf32, strided<[?], offset: ?>> {
%c1 = arith.constant 1 : index
%cst = arith.constant 1.000000e+00 : f32
%alloc = memref.alloc() {alignment = 64 : i64} : memref<5xf32>
linalg.fill ins(%cst : f32) outs(%alloc : memref<5xf32>)
%0 = scf.for %arg3 = %arg1 to %arg2 step %c1 iter_args(%arg4 = %arg0) -> (memref<5xf32, strided<[?], offset: ?>>) {
%cast = memref.cast %alloc : memref<5xf32> to memref<5xf32, strided<[?], offset: ?>>
scf.yield %cast : memref<5xf32, strided<[?], offset: ?>>
}
%cst_0 = arith.constant 1.000000e+00 : f32
memref.store %cst_0, %alloc[%c1] : memref<5xf32>
return %0 : memref<5xf32, strided<[?], offset: ?>>
}
```
Which is not correct IR since the loop yields the allocation.
I am using this option. What do I need to do now?
If you are using this option in isolation, you are possibly generating
incorrect IR, so you need to revisit your bufferization strategy. If you
are using it together with `copyBeforeWrite,` you simply need to retire
the `enforceAliasingInvariants` option.
Co-authored-by: Matthias Springer <mspringer@nvidia.com>
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.
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.
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.