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From: Richard Sandiford <richard.sandiford@arm.com>
To: =?utf-8?B?6ZKf5bGF5ZOy?= <juzhe.zhong@rivai.ai>
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Cc: gcc-patches <gcc-patches@gcc.gnu.org>,  rguenther <rguenther@suse.de>
Subject: Re: [PATCH V14] VECT: Add decrement IV iteration loop control by variable amount support
References: <20230524144801.73537-1-juzhe.zhong@rivai.ai>
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Date: Wed, 24 May 2023 21:05:01 +0100
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I'll look at the samples tomorrow, but just to address one thing:

=E9=92=9F=E5=B1=85=E5=93=B2 <juzhe.zhong@rivai.ai> writes:
>>> What gives the best code in these cases?  Is emitting a multiplication
>>> better?  Or is using a new IV better?
> Could you give me more detail information about "new refresh IV" approach.
> I'd like to try that.

By =E2=80=9Cusing a new IV=E2=80=9D I meant calling vect_set_loop_controls_=
directly
for every rgroup, not just the first.  So in the earlier example,
there would be one decrementing IV for x and one decrementing IV for y.

Thanks,
Richard