On Wed, Aug 28, 2024 at 07:33:13AM -0500, Segher Boessenkool wrote: > On Wed, Aug 28, 2024 at 01:18:34PM +0200, Jason A. Donenfeld wrote: > > On Tue, Aug 27, 2024 at 05:53:30PM -0500, Segher Boessenkool wrote: > > > On Tue, Aug 27, 2024 at 11:08:19AM -0700, Eric Biggers wrote: > > > > > + for (i = 0; i < ARRAY_SIZE(params->reserved); i++) > > > > > + params->reserved[i] = 0; > > This is a loop. With -ftree-loop-distribute-patterns, the default at > -O2, this is optimised to > > memset(params->reserved, 0, ...); > > (which is perfectly fine, since memset is required to be there even > for freestanding environments, this is documented!) > > > > -fno-tree-loop-distribute-patterns . But, as always, read up on it, see > > > what it actually does (and how it avoids your problem, and mostly: learn > > > what the actual problem *was*!) > > > > This might help with various loops, but it doesn't help with the matter > > that this patch fixes, which is struct initialization. I just tried it > > with the arm64 patch to no avail. > > It very much *does* help. Try harder? Maybe you typoed? Scroll up and reread the original patch. You are confused. The loop is what fixes the matter. It's struct initialization that generates the memset.
