[PATCH] D81416: [LV][SLP] Interleave to expose ILP for small loops with scalar reductions.

Mon Jun 22 16:07:56 PDT 2020

xbolva00 added a subscriber: dmgreen.
xbolva00 added inline comments.

================
Comment at: llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:253
+    "interleave-small-loop-scalar-reduction", cl::init(false), cl::Hidden,
+    cl::desc("Enable interleaving for small loops with scalar reductions "
+             "to expose ILP."));
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bmahjour wrote:
> fhahn wrote:
> > xbolva00 wrote:
> > > Turn on by default? 
> > > 
> > > If you ran some benchmarks and no regressions, I see no reason why this should be off by default.
> > It would be good to at least give some details on the benchmarks run. Ideally they would include MultiSource & various version of SPEC on X86 and ideally also other platforms.
> The current measurements are done on IBM Power. It would be good if someone with access to other types of performance machines could help measure the impact of this change on other platforms. If not, can we leave the default enablement to a future patch?
> 
> In general, how are performance testing on multiple platforms performed by the community, prior to enabling a feature?
@dmgreen arm
@nikic x86?

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D81416/new/

https://reviews.llvm.org/D81416