[PATCH] [AArch64] FPLoadBalancing: move ownership of the chain to its current accumulator register

[James Molloy]

Hi Arnaud,

LGTM, please commit.

Cheers,

James


On 29 August 2014 10:48, Arnaud A. de Grandmaison <
arnaud.degrandmaison at arm.com> wrote:

> While experimenting with the PBQP allocator on aarch64, it triggered a bug
>
> in AArch64A57FPLoadBalancing.cpp, where an accumulator chain could be
>
> reference from different accumulator registers at the same time.
>
>
>
> The attached patch fixes it.
>
>
>
> Coming up with a simple testcase is not easy, as this highly depends on
>
> what the register allocator is doing: this issue showed up while working
>
> with the PBQP allocator, which produced a different allocation scheme.
>
> A testcase would need to come up with chain starting in D[0-7], then
>
> Moving it to D[8-15], followed by a call to a function whose regmask
>
> clobbers the starting accumulator in D[0-7], then another use of the chain.
>
>
>
> I also fixed some formatting and added some invariant checks while there.
>
>
>
> Cheers,
>
> --
>
> Arnaud A. de Grandmaison
>
>
>
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>
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