On Wed, May 04, 2022 at 01:10:03PM -0700, Linus Torvalds wrote: > On Wed, May 4, 2022 at 12:58 PM Stafford Horne <shorne@xxxxxxxxx> wrote: > > > > I have uploaded a diff I created here: > > https://gist.github.com/54334556f2907104cd12374872a0597c > > > > It shows the same output. > > In hex_to_bin itself it seems to only be a difference due to some > register allocation (r19 and r3 switched around). > > But then it gets inlined into hex2bin and there changes there seem to > be about instruction and basic block scheduling, so it's a lot harder > to see what's going on. > > And a lot of constant changes, which honestly look just like code code > moved around by 16 bytes and offsets changed due to that. > > So I doubt it's hex_to_bin() that is causing problems, I think it's > purely code movement. Which explains why adding a nop or a fake printk > fixes things. > > Some alignment assumption that got broken? This is what it looks like to me too. I will have to do a deep dive on what is going on with this particular build combination as I can't figure out what it is off the top of my head. This test is using a gcc 11 compiler, I tried with my gcc 12 toolchain and the issue cannot be reproduced. - musl gcc 11 - https://musl.cc/or1k-linux-musl-cross.tgz - openrisc gcc 12 - https://github.com/openrisc/or1k-gcc/releases/tag/or1k-12.0.1-20220210-20220304 But again the difference between the two compiler outputs is a lot of register allocation and offsets changes. Its not easy to see anything that stands out. I checked the change log for the openrisc specific changes from gcc 11 to gcc 12. Nothing seems to stand out, mcount profiler fix for PIC, a new large binary link flag. -Stafford
