prefer AltOp instead of interchangeable instructions of MainOp

Author: HanKuanChen

llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp

@@ -1036,17 +1036,20 @@ static bool getInterchangeableInstruction(
 
 static bool isConvertible(Instruction *I, Instruction *MainOp,
                           Instruction *AltOp) {
-  if (!I->isBinaryOp())
-    return I->getOpcode() == MainOp->getOpcode() ||
-           I->getOpcode() == AltOp->getOpcode();
   assert(MainOp && "MainOp cannot be nullptr.");
+  if (I->getOpcode() == MainOp->getOpcode())
+    return true;
+  assert(AltOp && "AltOp cannot be nullptr.");
+  if (I->getOpcode() == AltOp->getOpcode())
+    return true;
+  if (!I->isBinaryOp())
+    return false;
   SmallVector<std::unique_ptr<InterchangeableInstruction>> Candidate(
       getInterchangeableInstruction(I));
   for (std::unique_ptr<InterchangeableInstruction> &C : Candidate)
     if (C->isSame(I) && C->isSame(MainOp))
       return true;
   Candidate = getInterchangeableInstruction(I);
-  assert(AltOp && "AltOp cannot be nullptr.");
   for (std::unique_ptr<InterchangeableInstruction> &C : Candidate)
     if (C->isSame(I) && C->isSame(AltOp))
       return true;
@@ -1056,10 +1059,12 @@ static bool isConvertible(Instruction *I, Instruction *MainOp,
 static std::pair<Instruction *, SmallVector<Value *>>
 convertTo(Instruction *I, Instruction *MainOp, Instruction *AltOp) {
   assert(isConvertible(I, MainOp, AltOp) && "Cannot convert the instruction.");
-  if (!I->isBinaryOp())
-    return std::make_pair(I->getOpcode() == MainOp->getOpcode() ? MainOp
-                                                                : AltOp,
-                          SmallVector<Value *>(I->operands()));
+  if (I->getOpcode() == MainOp->getOpcode())
+    return std::make_pair(MainOp, SmallVector<Value *>(I->operands()));
+  // Prefer AltOp instead of interchangeable instruction of MainOp.
+  if (I->getOpcode() == AltOp->getOpcode())
+    return std::make_pair(AltOp, SmallVector<Value *>(I->operands()));
+  assert(I->isBinaryOp() && "Cannot convert the instruction.");
   SmallVector<std::unique_ptr<InterchangeableInstruction>> Candidate(
       getInterchangeableInstruction(I));
   for (std::unique_ptr<InterchangeableInstruction> &C : Candidate)

llvm/test/Transforms/SLPVectorizer/AArch64/gather-with-minbith-user.ll

@@ -5,16 +5,7 @@ define void @h() {
 ; CHECK-LABEL: define void @h() {
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[ARRAYIDX2:%.*]] = getelementptr i8, ptr null, i64 16
-; CHECK-NEXT:    [[TMP0:%.*]] = call <8 x i1> @llvm.vector.insert.v8i1.v2i1(<8 x i1> <i1 false, i1 false, i1 false, i1 false, i1 poison, i1 poison, i1 false, i1 false>, <2 x i1> zeroinitializer, i64 4)
-; CHECK-NEXT:    [[TMP1:%.*]] = call <8 x i1> @llvm.vector.insert.v8i1.v2i1(<8 x i1> <i1 poison, i1 poison, i1 poison, i1 poison, i1 false, i1 false, i1 poison, i1 poison>, <2 x i1> zeroinitializer, i64 0)
-; CHECK-NEXT:    [[TMP2:%.*]] = call <8 x i1> @llvm.vector.insert.v8i1.v2i1(<8 x i1> [[TMP1]], <2 x i1> zeroinitializer, i64 2)
-; CHECK-NEXT:    [[TMP3:%.*]] = call <8 x i1> @llvm.vector.insert.v8i1.v2i1(<8 x i1> [[TMP2]], <2 x i1> zeroinitializer, i64 6)
-; CHECK-NEXT:    [[TMP4:%.*]] = sub <8 x i1> [[TMP0]], [[TMP3]]
-; CHECK-NEXT:    [[TMP5:%.*]] = add <8 x i1> [[TMP0]], [[TMP3]]
-; CHECK-NEXT:    [[TMP6:%.*]] = shufflevector <8 x i1> [[TMP4]], <8 x i1> [[TMP5]], <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 12, i32 13, i32 14, i32 15>
-; CHECK-NEXT:    [[TMP7:%.*]] = or <8 x i1> [[TMP6]], zeroinitializer
-; CHECK-NEXT:    [[TMP8:%.*]] = zext <8 x i1> [[TMP7]] to <8 x i16>
-; CHECK-NEXT:    store <8 x i16> [[TMP8]], ptr [[ARRAYIDX2]], align 2
+; CHECK-NEXT:    store <8 x i16> zeroinitializer, ptr [[ARRAYIDX2]], align 2
 ; CHECK-NEXT:    ret void
 ;
 entry: