tree c527644aa9db20bc889c6d49cb6c923816d08b6d
parent 1d505f62ade3acbc13eb15e83953f6afcd4c2e0c
author Ryotaro Kasuga <kasuga.ryotaro@fujitsu.com> 1771605682 +0900
committer GitHub <noreply@github.com> 1771605682 +0900
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[DA] Add test for RDIV misses dependency due to "minor algebra" (NFC) (#179653)

The function `testRDIV` contains the following comments:

```
// With minor algebra, this test can also be used for things like
// [c1 + a1*i + a2*j][c2].
```

```
// we have 3 possible situations here:
//   1) [a*i + b] and [c*j + d]
//   2) [a*i + c*j + b] and [d]
//   3) [b] and [a*i + c*j + d]
// We need to find what we've got and get organized
```

In case `2)`, it moves `c*j` from `Src` to `Dst` and performs dependence
testing between `[a*i + b]` and `[-c*j + d]`. Similar algebraic
manipulations are applied in case `3)`. This "minor algebra" is unsound
in LLVM because whether wraps occur can change. This patch adds a test
case to illustrate the issue.