[PATCH] D149775: [AMDGPU] Reserve SGPR pair when long branches are present

[Valery Pykhtin via Phabricator via llvm-commits]

vpykhtin added a comment.

In D149775#4364811 <https://reviews.llvm.org/D149775#4364811>, @crobeck wrote:

> In D149775#4338257 <https://reviews.llvm.org/D149775#4338257>, @vpykhtin wrote:
>
>> What if we always reserve a register for long jumps?
>
> I think we still want the ability to not reserve them in cases where they might not actually be needed and would waste resources. The amdgpu-long-branch-factor initialized default has been reset higher so that we lean toward always reserving them now - if this value is 0 the long branch registers are never reserved. As this value grows the great chance the branch distance will fall within the threshold and the registers will be marked to be reserved.

Maybe we can reserve a register if the overall number of SGPRs is close to some threshold?


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