Repost on commits list: Predication bug in AggressiveAntiDepBreaker?

[Rafael Espíndola]

Can you include a testcase in the patch?

On 31 July 2013 05:35, Verena Beckham <verena at codeplay.com> wrote:
> Hi,
>
> I wondered whether the AggressiveAntiDepBreaker can properly handle
> predicated instructions.
>
> At the end of PrescanInstruction the "DefIndices" array is updated with
> the destination register without checking whether the instruction is
> predicated. That shortens the live range: Later on, in HandleLastUse we
> check whether the register IsLive, which considers only "KillIndices"
> and "DefIndices", and therefore returns False for the interval between
> the predicated instruction and any non-predicated read before it. So
> that read is considered the last use.
> In my example this leads to a register not being fully renamed everywhere.
>
> I don't think a predicated write should count as a define.
>
> The attached patch fixes this test case.
>
> I'm afraid I'm working on a custom target and am not sufficiently familiar
> with other predicated architectures to write a test case that I can post.
> Maybe someone who has worked on predication can think of a test?
>
> --
> Verena Beckham
>
> Vice President Engineering
>
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