[PATCH] D78267: [InstCombine][SVE] Fix visitExtractElementInst for scalable type.

[Eli Friedman via Phabricator via llvm-commits]

efriedma added inline comments.


================
Comment at: llvm/lib/Analysis/VectorUtils.cpp:292
   if (ShuffleVectorInst *SVI = dyn_cast<ShuffleVectorInst>(V)) {
-    unsigned LHSWidth =
-        cast<VectorType>(SVI->getOperand(0)->getType())->getNumElements();
-    int InEl = SVI->getMaskValue(EltNo);
-    if (InEl < 0)
-      return UndefValue::get(VTy->getElementType());
-    if (InEl < (int)LHSWidth)
-      return findScalarElement(SVI->getOperand(0), InEl);
-    return findScalarElement(SVI->getOperand(1), InEl - LHSWidth);
+    // Make sure EltNo has valid record in shuffle mask if SVI is scalable type.
+    if (EltNo < SVI->getShuffleMask().size()) {
----------------
I think I'd prefer to avoid calling getMaskValue() and trying to compute LHSWidth for scalable vectors; it's not clear what it should mean.


================
Comment at: llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp:432
+                                  ->getElementCount()
+                                  .Min;
+
----------------
Same as above.


Repository:
  rG LLVM Github Monorepo

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https://reviews.llvm.org/D78267