| Issue |
76633
|
| Summary |
[clang] `[[noreturn]]` can result in worse code gen
|
| Labels |
clang
|
| Assignees |
|
| Reporter |
philnik777
|
```c++
NORETURN void my_abort();
void call_abort() {
my_abort();
}
```
When `-DNORETURN=`, this results in
```
call_abort(): # @call_abort()
jmp my_abort()@PLT # TAILCALL
```
When `-DNORETURN=[[noreturn]]`, this results in
```
call_abort(): # @call_abort()
push rax
call my_abort()@PLT
```
([godbolt](https://godbolt.org/z/xfo5zWfM4)), which seems strictly worse than the above version. While this isn't significant performance-wise, a very similar pattern can be observed in libc++ for `__throw_` functions, which results in quite a bit of unnecessary code due to multiple layers of this.
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