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Date: Mon, 4 Oct 2021 09:25:14 +0200 (CEST)
From: ibuclaw@gdcproject.org
To: Jeff Law <jeffreyalaw@gmail.com>,
 Jeff Law via Gcc-patches <gcc-patches@gcc.gnu.org>,
 =?UTF-8?Q?Lu=C3=ADs_Ferreira?= <contact@lsferreira.net>
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 <43f9005e-bc54-842b-b7c2-d3e899d8714f@gmail.com>
Subject: Re: [PATCH] libiberty: d-demangle: use switch instead of if-else
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> On 03/10/2021 23:55 Jeff Law via Gcc-patches <gcc-patches@gcc.gnu.org> wr=
ote:
>=20
> =20
> On 9/29/2021 7:08 PM, Lu=C3=ADs Ferreira wrote:
> > This patch allows the compiler to efficiently generate jump tables inst=
ead of
> > using if-else-if.
> >
> > Signed-off-by: Lu=C3=ADs Ferreira <contact@lsferreira.net>
> I'm not sure this is terribly useful.=C2=A0 Compilers have the ability to=
=20
> analyze the underlying code and make sensible decisions for how to=20
> implement either form.=C2=A0=C2=A0 So the right metric here is does this =
make the=20
> code cleaner/easier to understand.=C2=A0 With just 3 clauses it's hard (f=
or=20
> me) to make the case that it is considerably cleaner.
>=20

I'd be inclined to agree here.

FAOD, I put together a quick example of what difference this patch makes.  =
Other than freely reordering the conditions, the answer is nothing.

https://godbolt.org/z/nKjjv64zM

Iain.