[Bug c/120361] New: Why does prefetch_write() not generate a PREFETCHW instruction?

[LYN_2019 at outlook dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120361

            Bug ID: 120361
           Summary: Why does prefetch_write() not generate a PREFETCHW
                    instruction?
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: LYN_2019 at outlook dot com
  Target Milestone: ---

https://godbolt.org/z/a8h8EoE7n

x86_64-linug-gnu-gcc(trunk)

```cpp
void prefetch_read(void const* i)
{
    __builtin_prefetch(i, static_cast<int>(false), 1);
}

void prefetch_write(void const* i)
{
    __builtin_prefetch(i, static_cast<int>(true), 1);
}
```

```asm

prefetch_read(void const*):
        prefetcht2      [rdi]
        ret
prefetch_write(void const*):
        prefetcht2      [rdi]
        ret
```

Why does prefetch_write() not generate a PREFETCHW instruction?

https://www.felixcloutier.com/x86/prefetchw
https://www.felixcloutier.com/x86/prefetchh