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Date: Wed, 14 Nov 2018 18:01:00 -0000
From: Alexander Monakov <amonakov@ispras.ru>
To: Segher Boessenkool <segher@kernel.crashing.org>
cc: Jakub Jelinek <jakub@redhat.com>, Martin Sebor <msebor@gmail.com>,     Gcc Patch List <gcc-patches@gcc.gnu.org>
Subject: Re: [PATCH] diagnose unsupported uses of hardware register variables (PR 88000)
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On Wed, 14 Nov 2018, Segher Boessenkool wrote:
> Yeah, using local register vars to access global registers only works
> by accident.  It does work currently though, and people apparently use
> it, so we shouldn't break it :-/

In the proposed approach (copying from/to pseudos just before/after the
asm) we can emulate historic behavior by making uninitialized pseudos
take values of the corresponding hardregs. If we decide that doing that
just for must-uninit pseudos is enough, it's a simple extension to the
existing init-regs pass.  Does this sound reasonable?

Alexander