[PATCH] Fix write-back value propagation for pre-indexed addressing modes

[Silviu Baranga]

> -----Original Message-----
> From: Hal Finkel [mailto:hfinkel at anl.gov]
> Sent: 25 April 2013 20:58
> To: Silviu Baranga
> Cc: llvm-commits at cs.uiuc.edu; Dmitry Antipov
> Subject: Re: [PATCH] Fix write-back value propagation for pre-indexed
> addressing modes


> I understand; we're kind of talking past each other at this point. In
> any case, looking at the ARM implementation, I disagree with Dmitry's
> interpretation of the problem. As I wrote the code in question, please
> feel free to commit your fix.

Sorry about that. The problem is reasonably complex and we both seem to
have strong divergent views about it.

> I would really like, however, if we had a test case for this. If you
> had code that the current implementation miscompiled, can you place an
> assert that triggers in the bad case (pre_dec + swap), and use bugpoint
> to reduce the test case?

I've only seen the pre_dec + swap failure in a user of the LLVM libraries,
and I cannot reproduce the failure with llc (I've really tried). Also, the
failure goes away with even small modifications of the test case.

I would actually like to include Dmitry's test case if he's OK with that
so at least the patch does gets a test case.

Thanks,
Silviu


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