https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105342
--- Comment #5 from rguenther at suse dot de <rguenther at suse dot de> --- On Fri, 22 Apr 2022, 570070308 at qq dot com wrote: > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105342 > > --- Comment #4 from 。 <570070308 at qq dot com> --- > (In reply to Richard Biener from comment #1) > > Is it really important though? > > The doc says that "The asm statement allows you to include assembly > instructions directly within C code. This may help you to maximize performance > in time-sensitive code or to access assembly instructions that are not readily > available to C programs.", and I use extended-asm rather than writing a whole > function with assembly just for maximize performance. > > I try my best for not using "memory" clobber, but in some cases I have to use > it, for example, using the asm to operate a list structure like the `struct > list_head` in Linux. It is impossible to list all the list elements in the > Input/OutputOperands. Indeed. I think there's duplicate bugreports on the lack of a clobber specifying "memory reachable by pointer X", the clobber syntax is somewhat limited here.
