re: toolchain/51094: repeatable file-system corruption: 7.99.2{7,8} i386/athlon gcc-5.3.0

[matthew green <mrg%eterna.com.au@localhost>]

i have commited a hack to amd64 kernel builds to use this option
for ufs_lookup.c only.  if you update it should work without any
special options.  (i was running a kernel with everything built
-fno-tree-vrp -Wno-error=maybe-uninitialized to avoid the issues
you mentioned, but they don't apply to the problem source.)

ideally, someone should do something like this:

remove this hack and instead apply it directly inside ufs_lookup.c
itself.  there are only a relatively small number of functions so
it shouldn't be too hard to binary search.  you can use (i believe)
__attribute__((__optimize__("no-tree-vrp"))) on each function to
turn it off just here, and then test against a known failing case.


.mrg.