[PATCH] D150288: [SLP] Simplify `tryToVectorizeSequence()`

[Alexey Bataev via Phabricator via llvm-commits]

ABataev added inline comments.


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Comment at: llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp:14276
-    function_ref<bool(ArrayRef<T *>, bool)> TryToVectorizeHelper,
-    bool MaxVFOnly, BoUpSLP &R) {
   bool Changed = false;
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vporpo wrote:
> ABataev wrote:
> > ABataev wrote:
> > > vporpo wrote:
> > > > ABataev wrote:
> > > > > vporpo wrote:
> > > > > > ABataev wrote:
> > > > > > > Removal of this parameter causes regressions in the vectorization, better to restore it.
> > > > > > Do you have some examples where this is needed?
> > > > > No, I don't, just from my experience when I added this parameter. Testing showed regressions in LTO mode with it, IIRC.
> > > > Is this in SPEC?
> > > IIRC, test/Transforms/SLPVectorizer/slp-max-phi-size.ll is one of the tests
> > Yes
> OK, I will run SPEC lto to check. 
> 
> > IIRC, test/Transforms/SLPVectorizer/slp-max-phi-size.ll is one of the tests
> Doesn't slp-max-phi-size.ll look OK though? As far as I understand the purpose of this test is to make sure that we don't vectorize wider than specified by the `-slp-max-vf` option.
Probably. If I do remember correctly, it caused regresssions because of too early optimization of phi nodes and some other instructions.


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Comment at: llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp:14278-14280
+  MapVector<Type *, SmallVector<T *>> SeedsMap;
+  for (T *Seed : UnsortedSeeds)
+    SeedsMap[Seed->getType()].push_back(Seed);
----------------
vporpo wrote:
> ABataev wrote:
> > vporpo wrote:
> > > ABataev wrote:
> > > > vporpo wrote:
> > > > > ABataev wrote:
> > > > > > It increases memory consumption.
> > > > > The previous version was using a `Candidates` vector, this one is using a map, so the memory consumption should be fairly similar.
> > > > > Also this is not a global data structure, it is being freed right away, so memory consumption shouldn't matter much in this context.
> > > > It is not quite map, it is mapvector, which is vector + map
> > > OK, so if I use an std::map would you be fine with this?
> > DenseMap should be good here, yes, since the order of the types does not matter
> Hmm is iterating over a DenseMap deterministic though?
Yes, you cannot iterate through it, so here you need to use MapVector. 


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  https://reviews.llvm.org/D150288/new/

https://reviews.llvm.org/D150288