[SLP]Fix PR89635: do not try to vectorize single-gather alternate node.

No need to try to vectorize single gather/buildvector with alternate
opcode graph, it is not profitable. In other cases, need to use last
instruction for inserting the vectorized code.

Author: alexey-bataev

llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp

@@ -9640,6 +9640,7 @@ bool BoUpSLP::isTreeTinyAndNotFullyVectorizable(bool ForReduction) const {
   bool IsAllowedSingleBVNode =
       VectorizableTree.size() > 1 ||
       (VectorizableTree.size() == 1 && VectorizableTree.front()->getOpcode() &&
+       !VectorizableTree.front()->isAltShuffle() &&
        VectorizableTree.front()->getOpcode() != Instruction::PHI &&
        VectorizableTree.front()->getOpcode() != Instruction::GetElementPtr &&
        allSameBlock(VectorizableTree.front()->Scalars));
@@ -11032,7 +11033,10 @@ Instruction &BoUpSLP::getLastInstructionInBundle(const TreeEntry *E) {
                         isUsedOutsideBlock(V);
                }) ||
         (E->State == TreeEntry::NeedToGather && E->Idx == 0 &&
-         all_of(E->Scalars, IsaPred<ExtractElementInst, UndefValue>)))
+         all_of(E->Scalars, [](Value *V) {
+           return isa<ExtractElementInst, UndefValue>(V) ||
+                  areAllOperandsNonInsts(V);
+         })))
       Res.second = FindLastInst();
     else
       Res.second = FindFirstInst();

llvm/test/Transforms/SLPVectorizer/X86/alternate-opcode-sindle-bv.ll

@@ -0,0 +1,25 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 4
+; RUN: opt -S --passes=slp-vectorizer -mtriple=x86_64-unknown-linux-gnu < %s | FileCheck %s
+
+define <2 x i32> @test(i32 %arg) {
+; CHECK-LABEL: define <2 x i32> @test(
+; CHECK-SAME: i32 [[ARG:%.*]]) {
+; CHECK-NEXT:  bb:
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[ARG]], 0
+; CHECK-NEXT:    [[MUL:%.*]] = mul i32 0, 1
+; CHECK-NEXT:    [[MUL1:%.*]] = mul i32 [[OR]], [[MUL]]
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ugt i32 0, [[MUL1]]
+; CHECK-NEXT:    [[TMP0:%.*]] = insertelement <2 x i32> poison, i32 [[OR]], i32 0
+; CHECK-NEXT:    [[TMP1:%.*]] = insertelement <2 x i32> [[TMP0]], i32 [[MUL]], i32 1
+; CHECK-NEXT:    ret <2 x i32> [[TMP1]]
+;
+bb:
+  %or = or i32 %arg, 0
+  %mul = mul i32 0, 1
+  %mul1 = mul i32 %or, %mul
+  %cmp = icmp ugt i32 0, %mul1
+  %0 = insertelement <2 x i32> poison, i32 %or, i32 0
+  %1 = insertelement <2 x i32> %0, i32 %mul, i32 1
+  ret <2 x i32> %1
+}
+