On Fri, Feb 24, 2023 at 12:44:44PM +0100, Richard Biener wrote:
> --- a/gcc/vec.h
> +++ b/gcc/vec.h
> @@ -586,8 +586,8 @@ public:
> unsigned allocated (void) const { return m_vecpfx.m_alloc; }
> unsigned length (void) const { return m_vecpfx.m_num; }
> bool is_empty (void) const { return m_vecpfx.m_num == 0; }
> - T *address (void) { return m_vecdata; }
> - const T *address (void) const { return m_vecdata; }
> + T *address (void) { return reinterpret_cast <T *> (this + 1); }
> + const T *address (void) const { return reinterpret_cast <const T *> (this
> + 1); }
This is now too long.
> T *begin () { return address (); }
> const T *begin () const { return address (); }
> T *end () { return address () + length (); }
> @@ -631,8 +631,7 @@ public:
>
> /* FIXME - These fields should be private, but we need to cater to
> compilers that have stricter notions of PODness for types. */
> - vec_prefix m_vecpfx;
> - T m_vecdata[1];
> + alignas (T) vec_prefix m_vecpfx;
The comment needs adjustment and down't we need
alignas (T) alignas (vec_prefix) ?
> @@ -1588,7 +1587,7 @@ public:
>
> private:
> vec<T, va_heap, vl_embed> m_auto;
> - T m_data[MAX (N - 1, 1)];
> + alignas(T) unsigned char m_data[sizeof (T) * N];
> };
I still believe you don't need alignas(T) here (and space before (T) ).
Also, I think it needs to be MAX (N, 2) instead of N, because auto_vec
ctors use MAX (N, 2). We could also change all those to MAX (N, 1)
now, but it can't be N because m_data[sizeof (T) * 0] is invalid in
standard C.
Anyway, I wonder if you get the -Werror=stringop-overflow= errors during
bootstrap that I got with my version or not.
Jakub
