[PATCH] D122126: [LoopVectorize] Don't interleave when the number of runtime checks exceeds the threshold

[Dave Green via Phabricator via llvm-commits]

dmgreen accepted this revision.
dmgreen added a comment.
This revision is now accepted and ready to land.

> 1. `Requirements`  can not be accessed in `selectInterleaveCount`, so additional parameters need to be added to selectInterleaveCount. Do you think it is necessary?<br>

Yeah - it might need to pass Requirements.getNumRuntimePointerChecks() through to selectInterleaveCount. I think it's OK as you have it right now, but Florian (or anyone else) can complain if they disagree.

> 2. I'm not sure if I need to keep `SelectedVF.Width.getKnownMinValue() > 1`, but if it is not necessary, we could remove it in a separate patch.

I was just hoping that if it got to that block then it would prevent the interleaving. It looks like it doesn't work like that though.

LGTM. Perhaps wait a day or two in case anyone else has comments.



================
Comment at: llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:7673-7674
   // Check if it is profitable to vectorize with runtime checks.
-  unsigned NumRuntimePointerChecks = Requirements.getNumRuntimePointerChecks();
-  if (SelectedVF.Width.getKnownMinValue() > 1 && NumRuntimePointerChecks) {
-    bool PragmaThresholdReached =
-        NumRuntimePointerChecks > PragmaVectorizeMemoryCheckThreshold;
-    bool ThresholdReached =
-        NumRuntimePointerChecks > VectorizerParams::RuntimeMemoryCheckThreshold;
-    if ((ThresholdReached && !Hints.allowReordering()) ||
-        PragmaThresholdReached) {
+  if (SelectedVF.Width.getKnownMinValue() > 1) {
+    if (hasTooManyRuntimeChecks()) {
       ORE->emit([&]() {
----------------
Maybe just use a single if now: `if (SelectedVF.Width.getKnownMinValue() > 1 && hasTooManyRuntimeChecks()) {`


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https://reviews.llvm.org/D122126