[llvm] [SLP] NFC. Remove the useless check for alternate instruction. (PR #117116)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-vectorizers

Author: Han-Kuan Chen (HanKuanChen)

<details>
<summary>Changes</summary>

Only BinaryOperator and CastInst support alternate instruction. It always returns false for TreeEntry::isAltShuffle if an instruction is ExtractElementInst, ExtractValueInst, LoadInst, StoreInst or InsertElementInst.

---
Full diff: https://github.com/llvm/llvm-project/pull/117116.diff


1 Files Affected:

- (modified) llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp (+2-3) 


``````````diff
diff --git a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
index dc0dffd9fcbf81..1b900f256489ca 100644
--- a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -1003,7 +1003,7 @@ static InstructionsState getSameOpcode(ArrayRef<Value *> VL,
             AltPred == CurrentPred || AltPred == SwappedCurrentPred)
           continue;
       }
-    } else if (InstOpcode == Opcode || InstOpcode == AltOpcode) {
+    } else if (InstOpcode == Opcode) {
       if (auto *Gep = dyn_cast<GetElementPtrInst>(I)) {
         if (Gep->getNumOperands() != 2 ||
             Gep->getOperand(0)->getType() != IBase->getOperand(0)->getType())
@@ -5999,8 +5999,7 @@ void BoUpSLP::reorderTopToBottom() {
       if ((TE->State == TreeEntry::Vectorize ||
            TE->State == TreeEntry::StridedVectorize) &&
           isa<ExtractElementInst, ExtractValueInst, LoadInst, StoreInst,
-              InsertElementInst>(TE->getMainOp()) &&
-          !TE->isAltShuffle()) {
+              InsertElementInst>(TE->getMainOp())) {
         // Build correct orders for extract{element,value}, loads and
         // stores.
         reorderOrder(TE->ReorderIndices, Mask);

``````````

</details>


https://github.com/llvm/llvm-project/pull/117116