Allow empty value list in propagateMetadata(Inst, ArrayOf...)

This will allow writing
  propagateMetadata(Inst, collectInterestingValues(...))
without concern about empty lists. In case of an empty list,
Inst is returned without any changes.

diff --git a/llvm/lib/Analysis/VectorUtils.cpp b/llvm/lib/Analysis/VectorUtils.cpp
index aeec439..f7c3929 100644 (file)
--- a/llvm/lib/Analysis/VectorUtils.cpp
+++ b/llvm/lib/Analysis/VectorUtils.cpp
@@ -708,6 +708,8 @@ MDNode *llvm::intersectAccessGroups(const Instruction *Inst1,
 
 /// \returns \p I after propagating metadata from \p VL.
 Instruction *llvm::propagateMetadata(Instruction *Inst, ArrayRef<Value *> VL) {
+  if (VL.empty())
+    return Inst;
   Instruction *I0 = cast<Instruction>(VL[0]);
   SmallVector<std::pair<unsigned, MDNode *>, 4> Metadata;
   I0->getAllMetadataOtherThanDebugLoc(Metadata);