[SCCP] fix non-determinism (llvm#105758)

the visit order depended on hashing because we iterated over a
SmallPtrSet

(cherry picked from commit aec3ec0)

llvm/lib/Transforms/Utils/SCCPSolver.cpp

@@ -13,6 +13,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Transforms/Utils/SCCPSolver.h"
+#include "llvm/ADT/SetVector.h"
 #include "llvm/Analysis/ConstantFolding.h"
 #include "llvm/Analysis/InstructionSimplify.h"
 #include "llvm/Analysis/ValueLattice.h"
@@ -418,7 +419,7 @@ class SCCPInstVisitor : public InstVisitor<SCCPInstVisitor> {
 
   DenseMap<Function *, std::unique_ptr<PredicateInfo>> FnPredicateInfo;
 
-  DenseMap<Value *, SmallPtrSet<User *, 2>> AdditionalUsers;
+  DenseMap<Value *, SmallSetVector<User *, 2>> AdditionalUsers;
 
   LLVMContext &Ctx;