[SLP]FIx PR81403: compiler crah because wrongly resized vector value.

The mask for the reshuffling/resizing might be calculated incorrectly,
fixed.

Author: alexey-bataev

llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp

@@ -10648,19 +10648,13 @@ Value *BoUpSLP::vectorizeOperand(TreeEntry *E, unsigned NodeIdx,
           // ... (use %2)
           // %shuffle = shuffle <2 x> %2, poison, <2 x> {2, 0}
           // br %block
-          SmallVector<int> UniqueIdxs(VF, PoisonMaskElem);
-          SmallSet<int, 4> UsedIdxs;
-          int Pos = 0;
-          for (int Idx : VE->ReuseShuffleIndices) {
-            if (Idx != static_cast<int>(VF) && Idx != PoisonMaskElem &&
-                UsedIdxs.insert(Idx).second)
-              UniqueIdxs[Idx] = Pos;
-            ++Pos;
+          SmallVector<int> Mask(VF, PoisonMaskElem);
+          for (auto [I, V] : enumerate(VL)) {
+            if (isa<PoisonValue>(V))
+              continue;
+            Mask[I] = VE->findLaneForValue(V);
           }
-          assert(VF >= UsedIdxs.size() && "Expected vectorization factor "
-                                          "less than original vector size.");
-          UniqueIdxs.append(VF - UsedIdxs.size(), PoisonMaskElem);
-          V = FinalShuffle(V, UniqueIdxs);
+          V = FinalShuffle(V, Mask);
         } else {
           assert(VF < cast<FixedVectorType>(V->getType())->getNumElements() &&
                  "Expected vectorization factor less "

llvm/test/Transforms/SLPVectorizer/SystemZ/reorder-same-node.ll

@@ -0,0 +1,67 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 4
+; RUN: opt -S --passes=slp-vectorizer -mtriple=s390x-unknown-linux -mcpu=z16 < %s | FileCheck %s
+
+define void @test() {
+; CHECK-LABEL: define void @test(
+; CHECK-SAME: ) #[[ATTR0:[0-9]+]] {
+; CHECK-NEXT:    [[TMP1:%.*]] = call i64 @llvm.vector.reduce.xor.v8i64(<8 x i64> zeroinitializer)
+; CHECK-NEXT:    store i64 [[TMP1]], ptr null, align 8
+; CHECK-NEXT:    ret void
+;
+  %1 = zext i8 0 to i32
+  %2 = lshr i32 0, %1
+  %3 = icmp ult i32 %2, 0
+  %4 = shl i32 0, %1
+  %5 = and i32 %4, 0
+  %narrow = select i1 %3, i32 0, i32 %5
+  %6 = zext i32 %narrow to i64
+  %7 = zext i8 0 to i32
+  %8 = lshr i32 0, %7
+  %9 = icmp ult i32 %8, 0
+  %10 = shl i32 0, %7
+  %11 = and i32 %10, 0
+  %narrow.1 = select i1 %9, i32 0, i32 %11
+  %12 = zext i32 %narrow.1 to i64
+  %13 = xor i64 %6, %12
+  %14 = zext i8 0 to i32
+  %15 = lshr i32 0, %14
+  %16 = icmp ult i32 %15, 0
+  %17 = shl i32 0, %14
+  %18 = and i32 %17, 0
+  %narrow.2 = select i1 %16, i32 0, i32 %18
+  %19 = zext i32 %narrow.2 to i64
+  %20 = xor i64 %13, %19
+  %21 = icmp ult i32 %8, 0
+  %22 = shl i32 0, %7
+  %23 = and i32 %22, 0
+  %narrow.3 = select i1 %21, i32 0, i32 %23
+  %24 = zext i32 %narrow.3 to i64
+  %25 = xor i64 %20, %24
+  %26 = icmp ult i32 %15, 0
+  %27 = shl i32 0, %14
+  %28 = and i32 %27, 0
+  %narrow.4 = select i1 %26, i32 0, i32 %28
+  %29 = zext i32 %narrow.4 to i64
+  %30 = xor i64 %25, %29
+  %31 = icmp ult i32 %8, 0
+  %32 = shl i32 0, %7
+  %33 = and i32 %32, 0
+  %narrow.5 = select i1 %31, i32 0, i32 %33
+  %34 = zext i32 %narrow.5 to i64
+  %35 = xor i64 %30, %34
+  %36 = icmp ult i32 %15, 0
+  %37 = shl i32 0, %14
+  %38 = and i32 %37, 0
+  %narrow.6 = select i1 %36, i32 0, i32 %38
+  %39 = zext i32 %narrow.6 to i64
+  %40 = xor i64 %35, %39
+  %41 = icmp ult i32 %8, 0
+  %42 = shl i32 0, %7
+  %43 = and i32 %42, 0
+  %narrow.7 = select i1 %41, i32 0, i32 %43
+  %44 = zext i32 %narrow.7 to i64
+  %45 = xor i64 %40, %44
+  store i64 %45, ptr null, align 8
+  ret void
+}
+