[llvm-dev] Inclusion of Polly and isl into core LLVM

[Alex Elsayed via llvm-dev]

On Mon, 15 Jan 2018 22:44:45 +0100, Tobias Grosser via llvm-dev wrote:

<snip>

>  * How stable/fast/… is Polly today
>    * We build all of AOSP with rather restrictive compile-time limits
>    * Bootstrapping time of clang is regressed by 6% (at most)
>    * Removal of scalar dependences is today very generic and must be
>      sped up in the future
>    * Polly still shows up at the top of the middle-end, but larger
>      compile time regressions are often due to increased code size (and
>      the LLVM backend)
>    * We see non-trivial speedups for hmmer, libquantum, and various
>      linear-algebra kernels (we use gemm-specific optimizations). The
>      first two require additional flags to be enabled.

On the topic of performance, this paper might be of interest:

Fast Polyhedral Abstract Domain
Gagandeep Singh, Markus Püschel, Martin Vechev
http://www.srl.inf.ethz.ch/papers/POPL17-Polyhedra.pdf

> Our experimental results demonstrate massive gains in both space and
> time: we show end-to-end speedups of two to five orders of magnitude
> compared to state-of-the-art  Polyhedra implementations as well as
> significant memory gains, on all larger benchmarks. In fact, in many
> cases our analysis terminates in seconds where prior code runs out of
> memory or times out after 4 hours.

They compared against PPL and ELISA.