[all-commits] [llvm/llvm-project] 06ca0a: [InstCombine] (~a & b & c) | ~(a | b | c) -> ~(a |...

[Stanislav Mekhanoshin via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 06ca0a273308112c660dddf14c92fe14957bd468
      https://github.com/llvm/llvm-project/commit/06ca0a273308112c660dddf14c92fe14957bd468
  Author: Stanislav Mekhanoshin <Stanislav.Mekhanoshin at amd.com>
  Date:   2021-12-09 (Thu, 09 Dec 2021)

  Changed paths:
    M llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
    M llvm/test/Transforms/InstCombine/and-xor-or.ll

  Log Message:
  -----------
  [InstCombine] (~a & b & c) | ~(a | b | c) -> ~(a | (b ^ c))

Transform
```
(~a & b & c) | ~(a | b | c) -> ~(a | (b ^ c))
```
And swapped case:
```
(~a | b | c) & ~(a & b & c) -> ~a | (b ^ c)
```

```
----------------------------------------
define i4 @src(i4 %a, i4 %b, i4 %c) {
%0:
  %or1 = or i4 %b, %a
  %or2 = or i4 %or1, %c
  %not1 = xor i4 %or2, 15
  %not2 = xor i4 %a, 15
  %and1 = and i4 %b, %not2
  %and2 = and i4 %and1, %c
  %or3 = or i4 %and2, %not1
  ret i4 %or3
}
=>
define i4 @tgt(i4 %a, i4 %b, i4 %c) {
%0:
  %1 = xor i4 %c, %b
  %2 = or i4 %1, %a
  %or3 = xor i4 %2, 15
  ret i4 %or3
}
Transformation seems to be correct!
```
```
----------------------------------------
define i4 @src(i4 %a, i4 %b, i4 %c) {
%0:
  %and1 = and i4 %b, %a
  %and2 = and i4 %and1, %c
  %not1 = xor i4 %and2, 15
  %not2 = xor i4 %a, 15
  %or1 = or i4 %not2, %b
  %or2 = or i4 %or1, %c
  %and3 = and i4 %or2, %not1
  ret i4 %and3
}
=>
define i4 @tgt(i4 %a, i4 %b, i4 %c) {
%0:
  %xor = xor i4 %b, %c
  %not = xor i4 %a, 15
  %or = or i4 %xor, %not
  ret i4 %or
}
Transformation seems to be correct!
```

Differential Revision: https://reviews.llvm.org/D112966