--- Comment #2 from Mark Wielaard <mjw at redhat dot com> 2011-05-17 09:21:09 UTC ---
(In reply to comment #1)
> Mark, is there reason to suspect systemtap here, or is this a pure gcc
> "guality" regression?
A quick looks shows gcc doing partial inlining of foo. Some of the variables
might indeed not be available in the partial inlined version of foo that stap
probes. So it might actually reflect reality in this case of where the probe
gets placed. I think I just filed the testcase to do a deeper analysis of what
is going on.
--- Comment #4 from Mark Wielaard <mjw at redhat dot com> 2011-05-17 09:31:30 UTC ---
Looking at the debug_info shows some of these variables are available as
const_value at other addresses. It might just be that staps heuristic of
choosing the probe address doesn't match up with where gcc expects these
constant values to materialize. This is a very synthetic testcase though.