[PATCH] D123231: [StructurizeCFG] Improve basic block ordering

[Sameer Sahasrabuddhe via Phabricator via llvm-commits]

sameerds added a comment.

In D123231#3445997 <https://reviews.llvm.org/D123231#3445997>, @ruiling wrote:

>> which increases compilation time and register pressure.
>
> Have you looked at which part is responsible for the compilation time increase? Is is possible that we hit inefficiency in certain pass?
> The "register pressure" here specifically means SGPR usage, right?
>
> I don't think it is a good idea to move exist blocks into the loop especially when threads in a wave exit the loop in different iterations. Executing the exit block after loop should benefit for runtime performance.

We do know exactly why we need this patch, which is for the address sanitizer. Performance is not an issue when asan is ON. Then one safe way forward could be to hide this patch behind a new command-line option, which is turned on by default when asan is enabled. The new option will also allow us to separately investigate impact on important workloads before we make any call on enabling it by default with or without asan.


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https://reviews.llvm.org/D123231