C++: Simplify. No need for the 'PhiInputNodeExt' class.

Author: MathiasVP

cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/DataFlowUtil.qll

@@ -2681,9 +2681,9 @@ class ContentSet instanceof Content {
 
 pragma[nomagic]
 private predicate guardControlsPhiInput(
-  IRGuardCondition g, boolean branch, Ssa::Definition def, IRBlock input, Ssa::PhiInputNodeExt phi
+  IRGuardCondition g, boolean branch, Ssa::Definition def, IRBlock input, Ssa::PhiNode phi
 ) {
-  phi.hasInputFromBlock(def, input) and
+  phi.hasInputFromBlock(def, _, _, _, input) and
   (
     g.controls(input, branch)
     or
@@ -2752,12 +2752,11 @@ module BarrierGuard<guardChecksSig/3 guardChecks> {
     )
     or
     exists(
-      IRGuardCondition g, boolean branch, Ssa::DefinitionExt def, IRBlock input,
-      Ssa::PhiInputNodeExt phi
+      IRGuardCondition g, boolean branch, Ssa::DefinitionExt def, IRBlock input, Ssa::PhiNode phi
     |
       guardChecks(g, def.getARead().asOperand().getDef().getConvertedResultExpression(), branch) and
       guardControlsPhiInput(g, branch, def, input, phi) and
-      result = TSsaPhiInputNode(phi.getPhi(), input)
+      result = TSsaPhiInputNode(phi, input)
     )
   }
 
@@ -2839,14 +2838,13 @@ module BarrierGuard<guardChecksSig/3 guardChecks> {
     )
     or
     exists(
-      IRGuardCondition g, boolean branch, Ssa::DefinitionExt def, IRBlock input,
-      Ssa::PhiInputNodeExt phi
+      IRGuardCondition g, boolean branch, Ssa::DefinitionExt def, IRBlock input, Ssa::PhiNode phi
     |
       guardChecks(g,
         def.getARead().asIndirectOperand(indirectionIndex).getDef().getConvertedResultExpression(),
         branch) and
       guardControlsPhiInput(g, branch, def, input, phi) and
-      result = TSsaPhiInputNode(phi.getPhi(), input)
+      result = TSsaPhiInputNode(phi, input)
     )
   }
 }
@@ -2881,12 +2879,11 @@ module InstructionBarrierGuard<instructionGuardChecksSig/3 instructionGuardCheck
     )
     or
     exists(
-      IRGuardCondition g, boolean branch, Ssa::DefinitionExt def, IRBlock input,
-      Ssa::PhiInputNodeExt phi
+      IRGuardCondition g, boolean branch, Ssa::DefinitionExt def, IRBlock input, Ssa::PhiNode phi
     |
       instructionGuardChecks(g, def.getARead().asOperand().getDef(), branch) and
       guardControlsPhiInput(g, branch, def, input, phi) and
-      result = TSsaPhiInputNode(phi.getPhi(), input)
+      result = TSsaPhiInputNode(phi, input)
     )
   }
 }

cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/SsaInternals.qll

@@ -1215,23 +1215,6 @@ class Phi extends TPhi, SsaDef {
 
 private module SsaImpl = SsaImplCommon::Make<Location, SsaInput>;
 
-/**
- * An static single assignment (SSA) definition that is used as an input to a
- * phi or phi-read node.
- */
-class PhiInputNodeExt extends SsaImpl::DefinitionExt {
-  PhiNode phi;
-
-  PhiInputNodeExt() { this = SsaCached::phiHasInputFromBlockExt(phi, _) }
-
-  /** Gets the phi or phi-read node that receives this node as input. */
-  PhiNode getPhi() { result = phi }
-
-  predicate hasInputFromBlock(DefinitionExt def, IRBlock input) {
-    SsaCached::lastRefRedefExt(def, _, _, _, input, this)
-  }
-}
-
 /**
  * An static single assignment (SSA) phi node.
  *