On 10/11/2016 04:11 PM, Bernd Schmidt wrote:
Denys has submitted some patches to add more capabilities to the -falign-* options, but these still have some issues, and the original ideas seems to have been to allow for large alignments without over-aligning small functions. The following patch implements that idea by taking into account the function size as computed during shorten_branches: let's say we use "-falign-functions=128 -flimit-function-alignment", then a 15-byte function will be 16-byte aligned rather than 128-byte aligned. Bootstrapped and tested on x86_64-linux. Denys, does this solve your problem?
This is better than current behavior, but this is not what I want. 15-byte function does not need to be aligned to 16 bytes on a machine with 128-byte L1I cachelines. It needs to be aligned to 128 bytes if there are less than 15 bytes remaining; if there are MORE than 15 bytes remaining, why align at all? It's a waste of space.
