Re: [PATCH 1/2] allow target to check shrink-wrap-separate enabled or not

[Jeff Law <jeffreyalaw@gmail.com>]

On 6/20/23 03:40, Fei Gao wrote:
> gcc/ChangeLog:
> 
>          * shrink-wrap.cc (try_shrink_wrapping_separate):call
>            use_shrink_wrapping_separate.
>          (use_shrink_wrapping_separate): wrap the condition
>            check in use_shrink_wrapping_separate.
>          * shrink-wrap.h (use_shrink_wrapping_separate): add to extern
I'm still missing somethign here.

Why doesn't the RISC-V target simply disable separate shrink wrapping by 
indicating no components are eligible in the relevant cases.  ie, I do 
not think we need another knob here.

To be more concrete:

> /* Implement TARGET_SHRINK_WRAP_GET_SEPARATE_COMPONENTS.  */
>   
> static sbitmap
> riscv_get_separate_components (void)
> {       
>   HOST_WIDE_INT offset;
>   sbitmap components = sbitmap_alloc (FIRST_PSEUDO_REGISTER);
>   bitmap_clear (components);
>           
>   if (riscv_use_save_libcall (&cfun->machine->frame)
>       || cfun->machine->interrupt_handler_p
>       || !cfun->machine->frame.gp_sp_offset.is_constant ())
>     return components;
Don't we get the behavior we want if we change this code to return an 
zero'd sbitmap?

jeff