[Bug bootstrap/43170] gcc 4.5 20100218 bootstrap compare fails on os x 10.6

[rwild at gcc dot gnu dot org]

------- Comment #12 from rwild at gcc dot gnu dot org  2010-02-28 18:14 -------
Thanks.  You are right that the chance for a non-parallelism-related failure
was low, but comparison failures can be due to the phase of the moon literally.

Anyway, here's how I usually debug parallel build failures: rebuild until you
have both a successful and failed build, moving prior build trees away like:
  for i in 1 2 3 4; do
    mv build build-$i && mkdir build && cd build &&
    ../gcc/configure ... && make -jN
  done

That way one can compare the trees afterward without spurious path name diffs.

Compare the contents of build-$i/stage-{1,2,3}-$host/libgomp with that of a bad
build and in between the three stages.  Esp. the libgomp/.deps subdirs and the
config.log and config.status files.  Chances are you will find suspect issues
even when looking only at those of the different stages of a single build.

If that all doesn't lead anywhere, then posting the output from a failed build
would be a good idea.  Sorry I can't help better.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43170