Repost on commits list: Predication bug in AggressiveAntiDepBreaker?

[Verena Beckham]

As explained in the email: no I cannot, unfortunately.

  Verena


On 31/07/2013 15:43, Rafael Espíndola wrote:
> 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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