diff --git a/cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/SsaInternals.qll b/cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/SsaInternals.qll
index 1ad6701cbf6..6d419e02543 100644
--- a/cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/SsaInternals.qll
+++ b/cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/SsaInternals.qll
@@ -1071,157 +1071,12 @@ module SsaCached {
   predicate variableWrite = SsaInput::variableWrite/4;
 }
 
-cached
-private newtype TSsaDef =
-  TDef(DefinitionExt def) or
-  TPhi(PhiNode phi)
+class GlobalDef extends DefinitionExt {
+  GlobalDefImpl impl;
 
-abstract private class SsaDef extends TSsaDef {
-  /** Gets a textual representation of this element. */
-  string toString() { none() }
+  GlobalDef() { impl = this.getImpl() }
 
-  /** Gets the underlying non-phi definition or use. */
-  DefinitionExt asDef() { none() }
-
-  /** Gets the underlying phi node. */
-  PhiNode asPhi() { none() }
-
-  /** Gets the location of this element. */
-  abstract Location getLocation();
-}
-
-abstract class Def extends SsaDef, TDef {
-  DefinitionExt def;
-
-  Def() { this = TDef(def) }
-
-  final override DefinitionExt asDef() { result = def }
-
-  /** Gets the source variable underlying this SSA definition. */
-  final SourceVariable getSourceVariable() { result = def.getSourceVariable() }
-
-  override string toString() { result = def.toString() }
-
-  /**
-   * Holds if this definition (or use) has index `index` in block `block`,
-   * and is a definition (or use) of the variable `sv`.
-   */
-  predicate hasIndexInBlock(IRBlock block, int index, SourceVariable sv) {
-    def.definesAt(sv, block, index, _)
-  }
-
-  /** Gets the value written by this definition, if any. */
-  Node0Impl getValue() { none() }
-
-  /**
-   * Holds if this definition is guaranteed to overwrite the entire
-   * destination's allocation.
-   */
-  abstract predicate isCertain();
-
-  /** Gets the address operand written to by this definition. */
-  Operand getAddressOperand() { none() }
-
-  /** Gets the address written to by this definition. */
-  final Instruction getAddress() { result = this.getAddressOperand().getDef() }
-
-  /** Gets the indirection index of this definition. */
-  abstract int getIndirectionIndex();
-
-  /**
-   * Gets the indirection level that this definition is writing to.
-   * For instance, `x = y` is a definition of `x` at indirection level 1 and
-   * `*x = y` is a definition of `x` at indirection level 2.
-   */
-  abstract int getIndirection();
-
-  /**
-   * Gets a definition that ultimately defines this SSA definition and is not
-   * itself a phi node.
-   */
-  Def getAnUltimateDefinition() { result.asDef() = def.getAnUltimateDefinition() }
-}
-
-private predicate isGlobal(DefinitionExt def, GlobalDefImpl global) {
-  exists(SourceVariable sv, IRBlock bb, int i |
-    def.definesAt(sv, bb, i, _) and
-    global.hasIndexInBlock(bb, i, sv)
-  )
-}
-
-private class NonGlobalDef extends Def {
-  NonGlobalDef() { not isGlobal(def, _) }
-
-  final override Location getLocation() { result = this.getImpl().getLocation() }
-
-  private DefImpl getImpl() {
-    exists(SourceVariable sv, IRBlock bb, int i |
-      this.hasIndexInBlock(bb, i, sv) and
-      result.hasIndexInBlock(bb, i, sv)
-    )
-  }
-
-  override Node0Impl getValue() { result = this.getImpl().getValue() }
-
-  override predicate isCertain() { this.getImpl().isCertain() }
-
-  override Operand getAddressOperand() { result = this.getImpl().getAddressOperand() }
-
-  override int getIndirectionIndex() { result = this.getImpl().getIndirectionIndex() }
-
-  override int getIndirection() { result = this.getImpl().getIndirection() }
-}
-
-class GlobalDef extends Def {
-  GlobalDefImpl global;
-
-  GlobalDef() { isGlobal(def, global) }
-
-  /** Gets a textual representation of this definition. */
-  override string toString() { result = global.toString() }
-
-  final override Location getLocation() { result = global.getLocation() }
-
-  /**
-   * Gets the type of this definition after specifiers have been deeply stripped
-   * and typedefs have been resolved.
-   */
-  DataFlowType getUnspecifiedType() { result = global.getUnspecifiedType() }
-
-  /**
-   * Gets the type of this definition, after typedefs have been resolved.
-   */
-  DataFlowType getUnderlyingType() { result = global.getUnderlyingType() }
-
-  /** Gets the `IRFunction` whose body is evaluated after this definition. */
-  IRFunction getIRFunction() { result = global.getIRFunction() }
-
-  /** Gets the global variable associated with this definition. */
-  GlobalLikeVariable getVariable() { result = global.getVariable() }
-
-  override predicate isCertain() { any() }
-
-  final override int getIndirectionIndex() { result = global.getIndirectionIndex() }
-
-  final override int getIndirection() { result = global.getIndirection() }
-}
-
-class Phi extends TPhi, SsaDef {
-  PhiNode phi;
-
-  Phi() { this = TPhi(phi) }
-
-  final override PhiNode asPhi() { result = phi }
-
-  final override Location getLocation() { result = phi.getBasicBlock().getLocation() }
-
-  override string toString() { result = phi.toString() }
-
-  SsaPhiInputNode getNode(IRBlock block) { result.getPhiNode() = phi and result.getBlock() = block }
-
-  predicate hasInputFromBlock(Definition inp, IRBlock bb) { inp = phiHasInputFromBlockExt(phi, bb) }
-
-  final Definition getAnInput() { this.hasInputFromBlock(result, _) }
+  GlobalLikeVariable getVariable() { result = impl.getVariable() }
 }
 
 private module SsaImpl = SsaImplCommon::Make<Location, SsaInput>;