[llvm] [SLP][REVEC] Make tryToReduce and related functions support vector instructions. (PR #102327)

[Alexey Bataev via llvm-commits]

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@@ -17710,8 +17710,25 @@ class HorizontalReduction {
                                          SameValuesCounter, TrackedToOrig);
         }
 
-        Value *ReducedSubTree =
-            emitReduction(VectorizedRoot, Builder, ReduxWidth, TTI);
+        Value *ReducedSubTree;
+        Type *ScalarTy = VL.front()->getType();
+        if (isa<FixedVectorType>(ScalarTy)) {
+          assert(SLPReVec && "FixedVectorType is not expected.");
+          unsigned ScalarTyNumElements = getNumElements(ScalarTy);
+          ReducedSubTree = PoisonValue::get(FixedVectorType::get(
+              VectorizedRoot->getType()->getScalarType(), ScalarTyNumElements));
+          for (unsigned I = 0; I != ScalarTyNumElements; ++I) {
+            // Do reduction for each lane.
+            SmallVector<int, 16> Mask =
+                createStrideMask(I, ScalarTyNumElements, VL.size());
+            Value *Lane = Builder.CreateShuffleVector(VectorizedRoot, Mask);
+            ReducedSubTree = Builder.CreateInsertElement(
+                ReducedSubTree, emitReduction(Lane, Builder, ReduxWidth, TTI),
+                I);
+          }
+        } else
+          ReducedSubTree =
+              emitReduction(VectorizedRoot, Builder, ReduxWidth, TTI);
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alexey-bataev wrote:

Enclose in braces

https://github.com/llvm/llvm-project/pull/102327