[all-commits] [llvm/llvm-project] 42263f: [mlir][MemRef] Make reinterpret_cast(extract_strid...

[qcolombet via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 42263fb52d627e19a5d00fe57dcd2fe607732ff9
      https://github.com/llvm/llvm-project/commit/42263fb52d627e19a5d00fe57dcd2fe607732ff9
  Author: Quentin Colombet <quentin.colombet at gmail.com>
  Date:   2022-11-14 (Mon, 14 Nov 2022)

  Changed paths:
    M mlir/include/mlir/Dialect/MemRef/IR/MemRefOps.td
    M mlir/lib/Dialect/MemRef/IR/MemRefOps.cpp
    M mlir/test/Dialect/MemRef/canonicalize.mlir

  Log Message:
  -----------
  [mlir][MemRef] Make reinterpret_cast(extract_strided_metadata) more robust

Prior to this patch the canonicalization pattern that turns
`reinterpret_cast(extract_strided_metadata)` into cast was only applied
when all the input operands of the `reinterpret_cast` are exactly all the
output results of the `extract_strided_metadata`.

This missed simplification opportunities when the values would have hold
the same constant values, but yet, come from different actual values.

E.g., prior to this patch, a pattern of the form:
```
%base, %offset = extract_strided_metadata %source : memref<i16>
reinterpret_cast %base to offset:[0]
```
Wouldn't have been simplified into a simple cast, because %offset is not
directly the same value object as 0.

This patch teaches this pattern how to check if the constant values
match what the results of the `extract_strided_metadata` operation would
have hold.

Differential Revision: https://reviews.llvm.org/D135736