| Issue |
143529
|
| Summary |
Missed optimization: propagate not of `trunc nuw ... it1` equalities
|
| Labels |
new issue
|
| Assignees |
|
| Reporter |
yashnator
|
Not of `trunc nuw iN ... to i1` equalities can be propagated.
For example, `store i8 %v, ptr %p, align 8` -> `store i8 0, ptr %p, align 8` in
```ll
define i8 @src(ptr %p, i8 %v, i1 %cond) {
%trunc = trunc nuw i8 %v to i1
%not = xor i1 %trunc, true
%and = and i1 %not, %cond
br i1 %and, label %3, label %common.ret
common.ret:
ret i8 0
3:
store i8 %v, ptr %p, align 8
br label %common.ret
}
```
should be optimized to:
```ll
define i8 @src(ptr %p, i8 %v, i1 %cond) {
%trunc = trunc nuw i8 %v to i1
%not = xor i1 %trunc, true
%and = and i1 %not, %cond
br i1 %and, label %3, label %common.ret
common.ret:
ret i8 0
3:
store i8 0, ptr %p, align 8
br label %common.ret
}
```
[Alive2 and opt](https://alive2.llvm.org/ce/z/AbsgX_)
Discussed in #143273
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