Re: [PATCH] c++: Small initial fixes for zeroing of padding bits [PR117256]

2024-11-08 Thread Jason Merrill
On 11/8/24 4:29 AM, Jakub Jelinek wrote: Hi! https://eel.is/c++draft/dcl.init#general-6 says that even padding bits are supposed to be zeroed during zero-initialization. The following patch on top of the https://gcc.gnu.org/pipermail/gcc-patches/2024-October/665565.html patch attempts to impleme

Re: [PATCH] c++: Small initial fixes for zeroing of padding bits [PR117256]

2024-11-08 Thread Jakub Jelinek
On Fri, Nov 08, 2024 at 10:29:09AM +0100, Jakub Jelinek wrote: > I think we need far more than that, but am not sure where exactly > to implement that. > In particular, I think __builtin_bitcast should take it into account > during constant evaluation, if the padding bits in something are guarantee

[PATCH] c++: Small initial fixes for zeroing of padding bits [PR117256]

2024-11-08 Thread Jakub Jelinek
Hi! https://eel.is/c++draft/dcl.init#general-6 says that even padding bits are supposed to be zeroed during zero-initialization. The following patch on top of the https://gcc.gnu.org/pipermail/gcc-patches/2024-October/665565.html patch attempts to implement that, though only for the easy cases so