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>]

The following reply was made to PR toolchain/51094; it has been noted by GNATS.

From: matthew green <mrg%eterna.com.au@localhost>
To: Jim Bernard <jbernard%mines.edu@localhost>
Cc: toolchain-manager%NetBSD.org@localhost, gnats-admin%NetBSD.org@localhost,
    netbsd-bugs%NetBSD.org@localhost, gnats-bugs%NetBSD.org@localhost
Subject: re: toolchain/51094: repeatable file-system corruption: 7.99.2{7,8} i386/athlon gcc-5.3.0
Date: Fri, 29 Apr 2016 05:57:28 +1000

 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.