On 12/3/24 2:02 PM, Maciej W. Rozycki wrote:
On Mon, 18 Nov 2024, Maciej W. Rozycki wrote:
As it happens these data races also apply to BWX Alpha systems, as I have
discovered in the course of this effort, although owing to how the Alpha
backend of GCC has implemented block copy and clear operations rather than
actual hardware limitations, for example GCC will happily produce code
such as:
ldbu $1,0($3)
stw $31,8($3)
stq $1,0($3)
to zero a 9-byte member at the byte offset of 1 of a quadword-aligned
struct, happily clobbering a 1-byte member at the beginning of said struct
if there is a concurrent or parallel write to that member in the middle of
the unprotected RMW sequence.
Ping for:
<https://inbox.sourceware.org/gcc-patches/alpine.deb.2.21.2411161629290.59...@angie.orcam.me.uk/>
<https://inbox.sourceware.org/gcc-patches/alpine.deb.2.21.2411161734280.59...@angie.orcam.me.uk/>
(this will presumably need tweaks similar to ones made to __builtin_memcpy
tests, to exclude for AVR targets and to mark as expensive)
<https://inbox.sourceware.org/gcc-patches/alpine.deb.2.21.2411162040420.59...@angie.orcam.me.uk/>
<https://inbox.sourceware.org/gcc-patches/alpine.deb.2.21.2411162102000.59...@angie.orcam.me.uk/>
These are OK. I know it's not a review of the complete set, but the
others require more time/brainpower than I've got right now.
jeff
