[llvm] [SLP] Vectorize struct-returning intrinsics (PR #195521)

[Ryan Buchner via llvm-commits]

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@@ -328,23 +330,41 @@ static Type *getValueType(Value *V, bool LookThroughCmp = false) {
 static unsigned getNumElements(Type *Ty) {
   assert(!isa<ScalableVectorType>(Ty) &&
          "ScalableVectorType is not supported.");
-  if (auto *VecTy = dyn_cast<FixedVectorType>(Ty))
-    return VecTy->getNumElements();
+  if (isVectorizedTy(Ty))
+    return getVectorizedTypeVF(Ty).getFixedValue();
   return 1;
 }
 
 /// \returns the vector type of ScalarTy based on vectorization factor.
-static FixedVectorType *getWidenedType(Type *ScalarTy, unsigned VF) {
-  return FixedVectorType::get(ScalarTy->getScalarType(),
-                              VF * getNumElements(ScalarTy));
+static Type *getWidenedType(Type *ScalarTy, unsigned VF) {
+  if (VF == 1 && !isVectorizedTy(ScalarTy)) {
+    // Workaround for 1 x vector types: toVectorizedTy returns the type
+    // unchanged when EC is scalar, but BoUpSLP relies on widening to
+    // <1 x ScalarTy> (or struct of <1 x ElTy>) to keep the rest of the
+    // pipeline operating on vector types.
+    if (auto *StructTy = dyn_cast<StructType>(ScalarTy)) {
+      assert(isUnpackedStructLiteral(StructTy) &&
+             "expected unpacked struct literal");
+      assert(all_of(StructTy->elements(), VectorType::isValidElementType) &&
+             "expected all element types to be valid vector element types");
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bababuck wrote:

I had expected this code to fail in the `slp-revec` case, but it appears the failure is elsewhere.

https://github.com/llvm/llvm-project/pull/195521