[PATCH] D26083: [LV] Scalarize operands of predicated instructions

[Matthew Simpson via Phabricator via llvm-commits]

mssimpso added inline comments.


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Comment at: lib/Transforms/Vectorize/LoopVectorize.cpp:6688
+        else
+          ScalarCost += getScalarizationOverhead(ToVectorTy(J->getType(), VF),
+                                                 false, true, TTI);
----------------
gilr wrote:
> Is there scalarization overhead if canBeScalarized(J) is false due to isScalarAfterVectorization(J)?
> More generally, shouldn't this line be under a !isScalarAfterVectorization(J) condition? We may have bailed out e.g. due to J being on a different basic block but J itself may be scalar (meaning we've "smoothed" a scalar-vector-scalar sequence). Is that correct?
That's right Gil. We also should check that J is actually contained in the loop before adding in the extract overhead. I had already added this to my working copy after uploading the last revision. But I'll upload a new revision with this change and Michael's comment suggestions for clarity. Thanks!


https://reviews.llvm.org/D26083