From: Segher Boessenkool <segher@kernel.crashing.org>
To: Roger Sayle <roger@nextmovesoftware.com>
Cc: "'GCC Patches'" <gcc-patches@gcc.gnu.org>,
"'Tamar Christina'" <tnfchris@gcc.gnu.org>
Subject: Re: [PATCH] PR rtl-optimization/106594: Preserve zero_extend when cheap.
Date: Mon, 12 Sep 2022 13:09:16 -0500 [thread overview]
Message-ID: <20220912180916.GX25951@gate.crashing.org> (raw)
In-Reply-To: <20220912164747.GW25951@gate.crashing.org>
On Mon, Sep 12, 2022 at 11:47:47AM -0500, Segher Boessenkool wrote:
> On Mon, Sep 12, 2022 at 12:40:31AM +0100, Roger Sayle wrote:
> > * gcc/combine.cc (expand_compound_operation): Don't expand/transform
> > ZERO_EXTEND or SIGN_EXTEND on targets where rtx_cost claims they are
> > cheap. If gen_lowpart returns a SUBREG of something other than a
> > REG or a MEM, i.e. invalid RTL, return the original expression.
>
> This needs testing and analysis on all platforms.
Btw. This then needs to be of only the combine change. Importantly not
the simplify changes, which should be a separate patch anyway: they
should be an improvment always (otherwise they are not okay anyway!)
The i386 patches should be separate and probably can be committed first,
too? I haven't looked at those target things.
Other target will probably want changes as well?
Segher
prev parent reply other threads:[~2022-09-12 18:10 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-11 23:40 Roger Sayle
2022-09-12 10:31 ` Richard Sandiford
2022-09-12 14:16 ` Roger Sayle
2022-09-12 14:56 ` Richard Sandiford
2022-09-12 16:47 ` Segher Boessenkool
2022-09-12 18:09 ` Segher Boessenkool [this message]
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