Re: [RFA] Improve initialization of objects when the initializer has trailing zeros.

[Takayuki 'January June' Suwa <jjsuwa_sys3175@yahoo.co.jp>]

On 2022/07/07 23:46, Jeff Law wrote:
> This is an update to a patch originally posted by Takayuki Suwa a few months ago.
> 
> When we initialize an array from a STRING_CST we perform the initialization in two steps.  The first step copies the STRING_CST to the destination.  The second step uses clear_storage to initialize storage in the array beyond TREE_STRING_LENGTH of the initializer.
> 
> Takayuki's patch added a special case when the STRING_CST itself was all zeros which would avoid the copy from the STRING_CST and instead do all the initialization via clear_storage which is clearly more runtime efficient.

Thank you for understanding what I mean...

> Richie had the suggestion that instead of special casing when the entire STRING_CST was NULs  to instead identify when the tail of the STRING_CST was NULs.   That's more general and handles Takayuki's case as well.

and offering good explanation.

> Bootstrapped and regression tested on x86_64-linux-gnu.  Given I rewrote Takayuki's patch I think it needs someone else to review rather than self-approving.

LGTM and of course it resolves the beginning of the first place (https://gcc.gnu.org/pipermail/gcc-patches/2022-May/595685.html).

> 
> OK for the trunk?
> 
> Jeff
>