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Date: Fri, 30 Mar 2012 15:46:00 -0000
From: Jan Hubicka <hubicka@ucw.cz>
To: Richard Guenther <richard.guenther@gmail.com>
Cc: Jan Hubicka <hubicka@ucw.cz>, Richard Henderson <rth@redhat.com>,	Stephan Bergmann <sbergman@redhat.com>, gcc@gcc.gnu.org
Subject: Re: C++: Letting compiler know asm block can call function that	can throw?
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> 
> Motion across hardreg sets/uses are not restricted.  And I would not expect
> an optimizing compiler to do that (it's your own fault to use hardregs in
> complex C code).

Well, the syscall sequence is an example of somehting that should be inlined
into arbitrary code w/o potential risk of ICEs.  But I guess if things works in
practice (as they seem), we don't need to worry much at the moment.  Most of
code movement we do is very simple. I don't see how to convince GCC to move
memcpy or division into the middle of a basic block containing the libcall
sequence.... Even when the basic block can be broken up with
-fno-call-exceptions at the asm statement by an EH edge...

Honza
> 
> Richard.