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Re: [patch] h8300: Optimize addsi_h8300.
- From: <tm_gccmail at mail dot kloo dot net>
- To: Kazu Hirata <kazu at cs dot umass dot edu>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Tue, 21 Jan 2003 12:28:34 -0800 (PST)
- Subject: Re: [patch] h8300: Optimize addsi_h8300.
On Tue, 21 Jan 2003, Kazu Hirata wrote:
> Hi,
>
> Attached is a patch to optimize addsi_h8300.
>
> On H8/300, a constant can be added to a register at 8 bits at a time,
> so to add -32768 to a register in SImode, the following code is
> generated.
>
> add #0,r1l
> addx #128,r1h
> addx #255,r0l
> addx #255,r0h
>
BTW, does the H8/300 port do add-splitting early or late?
We noticed on the SH that if you do add-splitting early, it interferes
with CSE because the constants aren't exposed anymore...
Hopeflly this is done late?
Toshi