https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66240
--- Comment #4 from Denis Vlasenko <vda.linux at googlemail dot com> --- Created attachment 38293 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=38293&action=edit Proposed patch This patch implements -falign-functions=N[,M] for now, with the eye for easy extension to other -falign options. I tested that with -falign-functions=N (tried 8, 15, 16, 17...) the alignment directives are the same before and after the patch: -falign-functions=8 generates ".p2align 3,,7" before and after. -falign-functions=17 generates ".p2align 5,,16" before and after. I tested that -falign-functions=N,N (two equal paramenters) works exactly like -falign-functions=N. Patch drops currently performed forced alignment to 8 if requested alignment is higher than 8: before the patch, -falign-functions=9 was generating .p2align 4,,8 .p2align 3 which means "Align to 16 if the skip is 8 bytes or less; else align to 8". After the patch, "p2align 3" is not emitted. I drop that because I ultimately want to do something like -falign-functions=64,8 - IOW, I want to align functions by 64 bytes, but only if that entails a skip of less than 8 bytes - otherwise I want **no alignment at all**. The forced ".p2align 3" interferes with that intention. This is an RFC-patch, IOW: I don't insist on removal of ".p2align 3" generation. I imagine that it should be retained for compat, and yet another option should be added to suppress it if desired (how about "-mno-8byte-code-subalign"? Argh...)
