From: Paul Brook <paul@codesourcery.com>
To: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [4544] added tcg_temp_free() and improved the handling of constants
Date: Fri, 23 May 2008 19:03:35 +0100 [thread overview]
Message-ID: <200805231903.35923.paul@codesourcery.com> (raw)
In-Reply-To: <E1Jzb99-0007QE-J0@cvs.savannah.gnu.org>
> added tcg_temp_free() and improved the handling of constants
Should the return value of tcg_const_i32 et. al. be considered immutable, or
is it ok to use it as a temporary?
e.g.:
static TCGv do_frob(TCGv base, int addend)
{
TCGv tmp = tcg_const_i32(addend);
tcg_gen_helper_frob(tmp, tmp, base)
return tmp;
}
or should this be written as:
static TCGv do_frob(TCGv base, int addend)
{
TCGv tmp = tcg_temp_new(TCG_TYPE_I32);
tcg_gen_movi_i32(tmp, addend);
tcg_gen_helper_frob(tmp, tmp, base)
return tmp;
}
Currently it's fairly hard to enforce this restriction automatically, but we
need to decide whether it's a feature or a bug.
Paul
next prev parent reply other threads:[~2008-05-23 18:03 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-05-23 17:33 [Qemu-devel] [4544] added tcg_temp_free() and improved the handling of constants Fabrice Bellard
2008-05-23 18:03 ` Paul Brook [this message]
2008-05-23 18:27 ` Fabrice Bellard
2008-05-30 18:59 ` Blue Swirl
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