Why is LLVM AliasAnalysis unable to precisely decide alias relationships between pointers that are dereferenced twice?

I'm very confused by the LLVM AliasAnalysis implementation. Say I have this program:

int* key = malloc(4);
*key = 10;
*key = 11;

It gets transformed to IR code like this:

  %3 = call noalias i8* @malloc(i64 4) #2
  %4 = bitcast i8* %3 to i32*
  store i32* %4, i32** %2, align 8
  %5 = load i32*, i32** %2, align 8
  store i32 10, i32* %5, align 4
  %6 = load i32*, i32** %2, align 8
  store i32 11, i32* %6, align 4

Than I ask LLVM to print out the alias relationship between %5 and %6, by using the function static_cast<uint16_t>(AA_->getModRefInfo(FirstStore, MemoryLocation(SecondStorePointer))). It then shows that they may alias (as ModRefInfo::Mod) with each other. Why is LLVM unable to detect that they must alias each other? Is there any way I can fix it?