[LLVMdev] FreeBSD tester failure

Dimitry Andric dimitry at andric.com
Thu Sep 9 15:26:40 PDT 2010


On 2010-09-09 23:44, Jakob Stoklund Olesen wrote:
> The clang-i686-freebsd-selfhost-rel buildbot is failing APIntTest.i33_Count on the first run, but the stage 2 test is passing.
>
> It looks like it could be a miscompilation by the system gcc.

Yes, unfortunately on FreeBSD the first stage should be compiled using
"-O2 -fno-strict-aliasing" instead of the default optimization flags, or
this particular test will always fail.  Stage 2 (which is compiled by
stage 1 clang) has no problems with it, and does not require
-fno-strict-aliasing.

This is some obscure gcc 4.2.1 problem, but it is extremely hard to find
out whether it really is an aliasing issue, or plainly a bug.  It is
most likely the latter, since compiling with e.g. gcc 4.5 and -O3 did
not give such failures, the last time I tried it (about two months ago,
approximately).


> We should upgrade the system gcc on that machine, or stop testing the stage 1 llvm.
>
> The tester is not useful as is. It is failing constantly.
>
> Who owns this machine? Can the system be upgraded?

FreeBSD's gcc will probably never be upgraded past 4.2.1, because that
was the last GPLv2 version.  This is one of the main reasons for getting
clang in the tree... ;)



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