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Re: Scheduling problem - A more detailed explain

2007/10/11, Jim Wilson <>:
Thanks for you helpful hints !  And I am sorry for such a late reply.
I have figured out this problem yesterday :-).

> Do we know for sure that the scheduler is failing here?  Have you looked
> at -da RTL dumps to verify which pass is performing the incorrect
> optimization?

I use the method you mentioned above to find the problem, the
scheduling code that GCC used is correct, but there are some errors
with the order of my instrumentation INSN list. So...

> Currently, gcc only emits these pr reg group save/restores in the
> prologue and epilogue, and we have scheduling barriers after/before the
> prologue/epilogue, so it is possible that there is a latent problem here
> which has gone unnoticed simply because it is impossible to reproduce
> with unmodified FSF gcc sources.

Previously, I also doubt that it is a latent problem, however, I read
the code you mentioned and find it is correct with pr reg group
save/restore, and finally find it is due to my carelessness in the
instrumentation code; so, sorry for that :-).

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