| Issue |
64613
|
| Summary |
Miscompile with attributor-light and dse
|
| Labels |
miscompilation,
llvm:optimizations
|
| Assignees |
|
| Reporter |
bevin-hansson
|
In the following case, running `attributor-light` followed by `dse` results in a miscompilation:
```
define dso_local ptr @fun(ptr noundef %p) {
entry:
%p.addr = alloca ptr, align 1
store ptr %p, ptr %p.addr, align 1
%0 = load ptr, ptr %p.addr, align 1
ret ptr %0
}
define dso_local i16 @test_it() {
entry:
%x = alloca i16, align 1
%p = alloca ptr, align 1
call void @llvm.lifetime.start.p0(i64 2, ptr %x)
store i16 42, ptr %x, align 1
call void @llvm.lifetime.start.p0(i64 2, ptr %p)
%call = call ptr @fun(ptr noundef %x)
store ptr %call, ptr %p, align 1
%0 = load ptr, ptr %p, align 1
%1 = load i16, ptr %0, align 1
%cmp = icmp eq i16 %1, 42
%conv = zext i1 %cmp to i16
call void @llvm.lifetime.end.p0(i64 2, ptr %p)
call void @llvm.lifetime.end.p0(i64 2, ptr %x)
ret i16 %conv
}
declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture)
declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture)
```
Executing `opt -passes='attributor-light,function(dse)' repr.ll` produces an IR where the `store i16 42` is eliminated, but the store is not dead.
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