[PATCH] D99205: Add jump-threading optimization for deterministic finite automata

[Alexey Zhikhartsev via Phabricator via llvm-commits]

alexey.zhikhar added a comment.
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In D99205#2792215 <https://reviews.llvm.org/D99205#2792215>, @alanphipps wrote:

> Thanks for all of the effort!  On our downstream Cortex-R5 compiler, I'm seeing a 20.4% speedup on Coremark with this patch, which is good, however, the older patch (https://reviews.llvm.org/D88307) gave me a 21.6% speedup. Any idea what could account for the difference there?

It would be very hard for us to explain the difference without having access to both the downstream compiler and the hardware but something that comes to mind is:

(1) were the two experiments performed on the same baseline compiler?
(2) 1% could be within noise and might be due to trivial changes in the generated code (change of alignment, change of branch addresses and branch target addresses, etc.)
(3) were both passes in the same place in the pipeline in both experiments?

>From the information provided, it is not possible to understand the root cause of the difference.


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https://reviews.llvm.org/D99205