• d-bugmail puremagic.com (45/45) Nov 05 2021 https://issues.dlang.org/show_bug.cgi?id=22484

d-bugmail puremagic.com writes:

https://issues.dlang.org/show_bug.cgi?id=22484

          Issue ID: 22484
           Summary: dmd generates wrong code for certain parameter/return
                    sizes
           Product: D
           Version: D2
          Hardware: x86_64
                OS: Linux
            Status: NEW
          Severity: major
          Priority: P1
         Component: dmd
          Assignee: nobody puremagic.com
          Reporter: stanislav.blinov gmail.com

The assert in `bug` below triggers with and without -O. Test is definitely not
minimal, but it's as far as I had the time to narrow it.

---

// Comment out the align to make the bug disappear
align(16)
struct Param
{
    uint x;
}

struct Result
{
    // Set num elements to 4 to make the bug disappear
    int[8] a;
}

void* actual; // global just for assert

// Comment out the `, int dummy=0` to make the bug disappear
auto bug(void* arg, Param param, uint u, void delegate() a, void delegate() b,
int dummy=0)
{
    assert(arg == actual);
    return Result.init;
}

// Actual codebase was betterC, but this should compile with and without
-betterC
extern(C) int main(int argc, char** argv)
{
    actual = argv[0];
    actual.bug(Param.init, 0, {}, {});
    return 0;
}

--