[llvm] [NFC] Add assertions for Src and Dst vec types in VecCombine folding (PR #134432)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-vectorizers

Author: None (calebwat)

<details>
<summary>Changes</summary>

SrcVecTy and DstVecTy are used without a null check, and originate from a dyn_cast. This patch adds an assertion that these values are non-null before they are used/dereferenced.

---
Full diff: https://github.com/llvm/llvm-project/pull/134432.diff


1 Files Affected:

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


``````````diff
diff --git a/llvm/lib/Transforms/Vectorize/VectorCombine.cpp b/llvm/lib/Transforms/Vectorize/VectorCombine.cpp
index 4bfe41a5ed00d..fc04266cac51b 100644
--- a/llvm/lib/Transforms/Vectorize/VectorCombine.cpp
+++ b/llvm/lib/Transforms/Vectorize/VectorCombine.cpp
@@ -2052,6 +2052,9 @@ bool VectorCombine::foldShuffleOfSelects(Instruction &I) {
 
   auto *SrcVecTy = dyn_cast<FixedVectorType>(T1->getType());
   auto *DstVecTy = dyn_cast<FixedVectorType>(I.getType());
+  assert(SrcVecTy && DstVecTy &&
+         "Expected shuffle/select vector types to be defined");
+
   auto SK = TargetTransformInfo::SK_PermuteTwoSrc;
   auto SelOp = Instruction::Select;
   InstructionCost OldCost = TTI.getCmpSelInstrCost(

``````````

</details>


https://github.com/llvm/llvm-project/pull/134432