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From: "dhowells at redhat dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c/61812] gcc ICE incorrectly says "The bug is not reproducible, so it is likely a hardware or OS problem."
Date: Tue, 15 Jul 2014 17:42:00 -0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61812

--- Comment #5 from dhowells at redhat dot com <dhowells at redhat dot com> ---
(In reply to Andrew Pinski from comment #4)
> Also even though it might be a true gcc issue, it does not say it is a
> hardware issue, the message says likely. This could also mean a gc or a
> memory issue inside gcc. Except detecting that vs a memory issue is much
> harder.

It's a bug with the code on the redhat/ branch that generates this message. 
The problem is that when it detects an ICE, the gcc driver runs the cc1 binary
twice more and compares the output - but the output contains a userspace
pointer from within gcc itself, eg:

            (call (mem:QI (symbol_ref:SI ("abort") [flags 0x41] <function_decl 
             0x7f5784e05d00 abort>) [0 __builtin_abort S1 A8])


and this may legitimately differ due to the kernel mapping things in different
places during execve() and mmap().