diff --git a/csharp/ql/lib/semmle/code/csharp/dataflow/internal/SsaImpl.qll b/csharp/ql/lib/semmle/code/csharp/dataflow/internal/SsaImpl.qll
index 00665d836e1d..ccc4b0f87fe4 100644
--- a/csharp/ql/lib/semmle/code/csharp/dataflow/internal/SsaImpl.qll
+++ b/csharp/ql/lib/semmle/code/csharp/dataflow/internal/SsaImpl.qll
@@ -1078,6 +1078,7 @@ class PhiReadNode extends DefinitionExt, Impl::PhiReadNode {
 private module DataFlowIntegrationInput implements Impl::DataFlowIntegrationInputSig {
   private import csharp as Cs
   private import semmle.code.csharp.controlflow.BasicBlocks
+  private import codeql.util.Boolean
 
   class Expr extends ControlFlow::Node {
     predicate hasCfgNode(ControlFlow::BasicBlock bb, int i) { this = bb.getNode(i) }
@@ -1114,6 +1115,58 @@ private module DataFlowIntegrationInput implements Impl::DataFlowIntegrationInpu
     }
   }
 
+  abstract class LogicalOperationGuard extends Guard {
+    abstract Guard getOperand(int i);
+
+    abstract predicate lift(string id, int i, boolean operandBranch, boolean branch);
+  }
+
+  private class NotGuard extends LogicalOperationGuard, LogicalNotExpr {
+    override Guard getOperand(int i) { i = 0 and result = this.getOperand() }
+
+    override predicate lift(string id, int i, boolean operandBranch, boolean branch) {
+      operandBranch instanceof Boolean and
+      id = operandBranch.toString() and
+      i = 0 and
+      branch = operandBranch.booleanNot()
+    }
+  }
+
+  abstract private class BinaryLogicalOperationGuard extends LogicalOperationGuard,
+    BinaryLogicalOperation
+  {
+    final override Guard getOperand(int i) {
+      i = 0 and result = this.getLeftOperand()
+      or
+      i = 1 and result = this.getRightOperand()
+    }
+
+    abstract predicate lift(Boolean branchLeft, Boolean branchRight, boolean branch);
+
+    final override predicate lift(string id, int i, boolean operandBranch, boolean branch) {
+      exists(Boolean branchLeft, Boolean branchRight |
+        this.lift(branchLeft, branchRight, branch) and
+        id = branchLeft + "," + branchRight
+      |
+        i = 0 and operandBranch = branchLeft
+        or
+        i = 1 and operandBranch = branchRight
+      )
+    }
+  }
+
+  private class AndGuard extends BinaryLogicalOperationGuard, LogicalAndExpr {
+    override predicate lift(Boolean branchLeft, Boolean branchRight, boolean branch) {
+      branch = branchLeft.booleanOr(branchRight) // yes, should not be `booleanAnd`
+    }
+  }
+
+  private class OrGuard extends BinaryLogicalOperationGuard, LogicalOrExpr {
+    override predicate lift(Boolean branchLeft, Boolean branchRight, boolean branch) {
+      branch = branchLeft.booleanAnd(branchRight) // yes, should not be `booleanOr`
+    }
+  }
+
   /** Holds if the guard `guard` controls block `bb` upon evaluating to `branch`. */
   predicate guardControlsBlock(Guard guard, ControlFlow::BasicBlock bb, boolean branch) {
     exists(ConditionBlock conditionBlock, ControlFlow::SuccessorTypes::ConditionalSuccessor s |
diff --git a/csharp/ql/test/library-tests/dataflow/barrier-guards/BarrierFlow.cs b/csharp/ql/test/library-tests/dataflow/barrier-guards/BarrierFlow.cs
index 3f3afed0a148..1fdc9b966671 100644
--- a/csharp/ql/test/library-tests/dataflow/barrier-guards/BarrierFlow.cs
+++ b/csharp/ql/test/library-tests/dataflow/barrier-guards/BarrierFlow.cs
@@ -80,4 +80,104 @@ void M6(bool b)
 
         Sink(x);
     }
+
+    void M7()
+    {
+        var x = Source(7);
+
+        if (x == "safe" && x == "safe")
+        {
+            Sink(x);
+        }
+        else
+        {
+            Sink(x);  // $ hasValueFlow=7
+        }
+
+        if (x != "safe" && x == "safe2")
+        {
+            Sink(x);
+        }
+        else
+        {
+            Sink(x);  // $ hasValueFlow=7
+        }
+
+        if (x == "safe" && x != "safe2")
+        {
+            Sink(x);
+        }
+        else
+        {
+            Sink(x);  // $ hasValueFlow=7
+        }
+
+        if (x != "safe1" && x != "safe2")
+        {
+            Sink(x);  // $ hasValueFlow=7
+        }
+        else
+        {
+            Sink(x);
+        }
+
+        if (!(x == "safe1") && x != "safe2")
+        {
+            Sink(x);  // $ hasValueFlow=7
+        }
+        else
+        {
+            Sink(x);
+        }
+    }
+
+    void M8()
+    {
+        var x = Source(8);
+
+        if (x == "safe1" || x == "safe2")
+        {
+            Sink(x);
+        }
+        else
+        {
+            Sink(x);  // $ hasValueFlow=8
+        }
+
+        if (x != "safe1" || x == "safe2")
+        {
+            Sink(x);  // $ hasValueFlow=8
+        }
+        else
+        {
+            Sink(x);
+        }
+
+        if (x == "safe1" || x != "safe2")
+        {
+            Sink(x);  // $ hasValueFlow=8
+        }
+        else
+        {
+            Sink(x);
+        }
+
+        if (x != "safe" || x != "safe")
+        {
+            Sink(x);  // $ hasValueFlow=8
+        }
+        else
+        {
+            Sink(x);
+        }
+
+        if (!(x == "safe") || x != "safe")
+        {
+            Sink(x);  // $ hasValueFlow=8
+        }
+        else
+        {
+            Sink(x);
+        }
+    }
 }
diff --git a/csharp/ql/test/library-tests/dataflow/barrier-guards/barrier-flow.expected b/csharp/ql/test/library-tests/dataflow/barrier-guards/barrier-flow.expected
index 4fb1c0c3df15..c6f74ce465ef 100644
--- a/csharp/ql/test/library-tests/dataflow/barrier-guards/barrier-flow.expected
+++ b/csharp/ql/test/library-tests/dataflow/barrier-guards/barrier-flow.expected
@@ -4,6 +4,18 @@ edges
 | BarrierFlow.cs:10:17:10:25 | call to method Source : Object | BarrierFlow.cs:10:13:10:13 | access to local variable x : Object | provenance |  |
 | BarrierFlow.cs:17:13:17:13 | access to local variable x : Object | BarrierFlow.cs:21:18:21:18 | access to local variable x | provenance |  |
 | BarrierFlow.cs:17:17:17:25 | call to method Source : Object | BarrierFlow.cs:17:13:17:13 | access to local variable x : Object | provenance |  |
+| BarrierFlow.cs:86:13:86:13 | access to local variable x : Object | BarrierFlow.cs:94:18:94:18 | access to local variable x | provenance |  |
+| BarrierFlow.cs:86:13:86:13 | access to local variable x : Object | BarrierFlow.cs:103:18:103:18 | access to local variable x | provenance |  |
+| BarrierFlow.cs:86:13:86:13 | access to local variable x : Object | BarrierFlow.cs:112:18:112:18 | access to local variable x | provenance |  |
+| BarrierFlow.cs:86:13:86:13 | access to local variable x : Object | BarrierFlow.cs:117:18:117:18 | access to local variable x | provenance |  |
+| BarrierFlow.cs:86:13:86:13 | access to local variable x : Object | BarrierFlow.cs:126:18:126:18 | access to local variable x | provenance |  |
+| BarrierFlow.cs:86:17:86:25 | call to method Source : Object | BarrierFlow.cs:86:13:86:13 | access to local variable x : Object | provenance |  |
+| BarrierFlow.cs:136:13:136:13 | access to local variable x : Object | BarrierFlow.cs:144:18:144:18 | access to local variable x | provenance |  |
+| BarrierFlow.cs:136:13:136:13 | access to local variable x : Object | BarrierFlow.cs:149:18:149:18 | access to local variable x | provenance |  |
+| BarrierFlow.cs:136:13:136:13 | access to local variable x : Object | BarrierFlow.cs:158:18:158:18 | access to local variable x | provenance |  |
+| BarrierFlow.cs:136:13:136:13 | access to local variable x : Object | BarrierFlow.cs:167:18:167:18 | access to local variable x | provenance |  |
+| BarrierFlow.cs:136:13:136:13 | access to local variable x : Object | BarrierFlow.cs:176:18:176:18 | access to local variable x | provenance |  |
+| BarrierFlow.cs:136:17:136:25 | call to method Source : Object | BarrierFlow.cs:136:13:136:13 | access to local variable x : Object | provenance |  |
 nodes
 | BarrierFlow.cs:10:13:10:13 | access to local variable x : Object | semmle.label | access to local variable x : Object |
 | BarrierFlow.cs:10:17:10:25 | call to method Source : Object | semmle.label | call to method Source : Object |
@@ -11,8 +23,32 @@ nodes
 | BarrierFlow.cs:17:13:17:13 | access to local variable x : Object | semmle.label | access to local variable x : Object |
 | BarrierFlow.cs:17:17:17:25 | call to method Source : Object | semmle.label | call to method Source : Object |
 | BarrierFlow.cs:21:18:21:18 | access to local variable x | semmle.label | access to local variable x |
+| BarrierFlow.cs:86:13:86:13 | access to local variable x : Object | semmle.label | access to local variable x : Object |
+| BarrierFlow.cs:86:17:86:25 | call to method Source : Object | semmle.label | call to method Source : Object |
+| BarrierFlow.cs:94:18:94:18 | access to local variable x | semmle.label | access to local variable x |
+| BarrierFlow.cs:103:18:103:18 | access to local variable x | semmle.label | access to local variable x |
+| BarrierFlow.cs:112:18:112:18 | access to local variable x | semmle.label | access to local variable x |
+| BarrierFlow.cs:117:18:117:18 | access to local variable x | semmle.label | access to local variable x |
+| BarrierFlow.cs:126:18:126:18 | access to local variable x | semmle.label | access to local variable x |
+| BarrierFlow.cs:136:13:136:13 | access to local variable x : Object | semmle.label | access to local variable x : Object |
+| BarrierFlow.cs:136:17:136:25 | call to method Source : Object | semmle.label | call to method Source : Object |
+| BarrierFlow.cs:144:18:144:18 | access to local variable x | semmle.label | access to local variable x |
+| BarrierFlow.cs:149:18:149:18 | access to local variable x | semmle.label | access to local variable x |
+| BarrierFlow.cs:158:18:158:18 | access to local variable x | semmle.label | access to local variable x |
+| BarrierFlow.cs:167:18:167:18 | access to local variable x | semmle.label | access to local variable x |
+| BarrierFlow.cs:176:18:176:18 | access to local variable x | semmle.label | access to local variable x |
 subpaths
 testFailures
 #select
 | BarrierFlow.cs:12:14:12:14 | access to local variable x | BarrierFlow.cs:10:17:10:25 | call to method Source : Object | BarrierFlow.cs:12:14:12:14 | access to local variable x | $@ | BarrierFlow.cs:10:17:10:25 | call to method Source : Object | call to method Source : Object |
 | BarrierFlow.cs:21:18:21:18 | access to local variable x | BarrierFlow.cs:17:17:17:25 | call to method Source : Object | BarrierFlow.cs:21:18:21:18 | access to local variable x | $@ | BarrierFlow.cs:17:17:17:25 | call to method Source : Object | call to method Source : Object |
+| BarrierFlow.cs:94:18:94:18 | access to local variable x | BarrierFlow.cs:86:17:86:25 | call to method Source : Object | BarrierFlow.cs:94:18:94:18 | access to local variable x | $@ | BarrierFlow.cs:86:17:86:25 | call to method Source : Object | call to method Source : Object |
+| BarrierFlow.cs:103:18:103:18 | access to local variable x | BarrierFlow.cs:86:17:86:25 | call to method Source : Object | BarrierFlow.cs:103:18:103:18 | access to local variable x | $@ | BarrierFlow.cs:86:17:86:25 | call to method Source : Object | call to method Source : Object |
+| BarrierFlow.cs:112:18:112:18 | access to local variable x | BarrierFlow.cs:86:17:86:25 | call to method Source : Object | BarrierFlow.cs:112:18:112:18 | access to local variable x | $@ | BarrierFlow.cs:86:17:86:25 | call to method Source : Object | call to method Source : Object |
+| BarrierFlow.cs:117:18:117:18 | access to local variable x | BarrierFlow.cs:86:17:86:25 | call to method Source : Object | BarrierFlow.cs:117:18:117:18 | access to local variable x | $@ | BarrierFlow.cs:86:17:86:25 | call to method Source : Object | call to method Source : Object |
+| BarrierFlow.cs:126:18:126:18 | access to local variable x | BarrierFlow.cs:86:17:86:25 | call to method Source : Object | BarrierFlow.cs:126:18:126:18 | access to local variable x | $@ | BarrierFlow.cs:86:17:86:25 | call to method Source : Object | call to method Source : Object |
+| BarrierFlow.cs:144:18:144:18 | access to local variable x | BarrierFlow.cs:136:17:136:25 | call to method Source : Object | BarrierFlow.cs:144:18:144:18 | access to local variable x | $@ | BarrierFlow.cs:136:17:136:25 | call to method Source : Object | call to method Source : Object |
+| BarrierFlow.cs:149:18:149:18 | access to local variable x | BarrierFlow.cs:136:17:136:25 | call to method Source : Object | BarrierFlow.cs:149:18:149:18 | access to local variable x | $@ | BarrierFlow.cs:136:17:136:25 | call to method Source : Object | call to method Source : Object |
+| BarrierFlow.cs:158:18:158:18 | access to local variable x | BarrierFlow.cs:136:17:136:25 | call to method Source : Object | BarrierFlow.cs:158:18:158:18 | access to local variable x | $@ | BarrierFlow.cs:136:17:136:25 | call to method Source : Object | call to method Source : Object |
+| BarrierFlow.cs:167:18:167:18 | access to local variable x | BarrierFlow.cs:136:17:136:25 | call to method Source : Object | BarrierFlow.cs:167:18:167:18 | access to local variable x | $@ | BarrierFlow.cs:136:17:136:25 | call to method Source : Object | call to method Source : Object |
+| BarrierFlow.cs:176:18:176:18 | access to local variable x | BarrierFlow.cs:136:17:136:25 | call to method Source : Object | BarrierFlow.cs:176:18:176:18 | access to local variable x | $@ | BarrierFlow.cs:136:17:136:25 | call to method Source : Object | call to method Source : Object |
diff --git a/ruby/ql/lib/codeql/ruby/dataflow/BarrierGuards.qll b/ruby/ql/lib/codeql/ruby/dataflow/BarrierGuards.qll
index 6b6c8d3b6815..d393e4e994a9 100644
--- a/ruby/ql/lib/codeql/ruby/dataflow/BarrierGuards.qll
+++ b/ruby/ql/lib/codeql/ruby/dataflow/BarrierGuards.qll
@@ -31,30 +31,6 @@ private predicate stringConstCompare(CfgNodes::AstCfgNode guard, CfgNode testedN
   )
   or
   stringConstCaseCompare(guard, testedNode, branch)
-  or
-  exists(CfgNodes::ExprNodes::BinaryOperationCfgNode g |
-    g = guard and
-    stringConstCompareOr(guard, branch) and
-    stringConstCompare(g.getLeftOperand(), testedNode, _)
-  )
-}
-
-/**
- * Holds if `guard` is an `or` expression whose operands are string comparison guards.
- * For example:
- *
- * ```rb
- * x == "foo" or x == "bar"
- * ```
- */
-private predicate stringConstCompareOr(
-  CfgNodes::ExprNodes::BinaryOperationCfgNode guard, boolean branch
-) {
-  guard.getExpr() instanceof LogicalOrExpr and
-  branch = true and
-  forall(CfgNode innerGuard | innerGuard = guard.getAnOperand() |
-    stringConstCompare(innerGuard, any(Ssa::Definition def).getARead(), branch)
-  )
 }
 
 /**
diff --git a/ruby/ql/lib/codeql/ruby/dataflow/internal/SsaImpl.qll b/ruby/ql/lib/codeql/ruby/dataflow/internal/SsaImpl.qll
index bc7a9cc0eb1b..375131493821 100644
--- a/ruby/ql/lib/codeql/ruby/dataflow/internal/SsaImpl.qll
+++ b/ruby/ql/lib/codeql/ruby/dataflow/internal/SsaImpl.qll
@@ -541,6 +541,7 @@ class ParameterExt extends TParameterExt {
 
 private module DataFlowIntegrationInput implements Impl::DataFlowIntegrationInputSig {
   private import codeql.ruby.controlflow.internal.Guards as Guards
+  private import codeql.util.Boolean
 
   class Parameter = ParameterExt;
 
@@ -560,6 +561,79 @@ private module DataFlowIntegrationInput implements Impl::DataFlowIntegrationInpu
     predicate hasCfgNode(SsaInput::BasicBlock bb, int i) { this = bb.getNode(i) }
   }
 
+  abstract class LogicalOperationGuard extends Guard {
+    abstract Guard getOperand(int i);
+
+    abstract predicate lift(string id, int i, boolean operandBranch, boolean branch);
+  }
+
+  private class NotGuard extends LogicalOperationGuard,
+    Cfg::CfgNodes::ExprNodes::UnaryOperationCfgNode
+  {
+    NotGuard() { this.getExpr() instanceof NotExpr }
+
+    override Guard getOperand(int i) { i = 0 and result = this.getOperand() }
+
+    override predicate lift(string id, int i, boolean operandBranch, boolean branch) {
+      operandBranch instanceof Boolean and
+      id = operandBranch.toString() and
+      i = 0 and
+      branch = operandBranch.booleanNot()
+    }
+  }
+
+  private class StmtSequenceGuard extends LogicalOperationGuard,
+    Cfg::CfgNodes::ExprNodes::StmtSequenceCfgNode
+  {
+    override Guard getOperand(int i) { i = 0 and result = this.getLastStmt() }
+
+    override predicate lift(string id, int i, boolean operandBranch, boolean branch) {
+      operandBranch instanceof Boolean and
+      id = operandBranch.toString() and
+      i = 0 and
+      branch = operandBranch
+    }
+  }
+
+  abstract private class BinaryLogicalOperationGuard extends LogicalOperationGuard,
+    Cfg::CfgNodes::ExprNodes::BinaryOperationCfgNode
+  {
+    final override Guard getOperand(int i) {
+      i = 0 and result = this.getLeftOperand()
+      or
+      i = 1 and result = this.getRightOperand()
+    }
+
+    abstract predicate lift(Boolean branchLeft, Boolean branchRight, boolean branch);
+
+    final override predicate lift(string id, int i, boolean operandBranch, boolean branch) {
+      exists(Boolean branchLeft, Boolean branchRight |
+        this.lift(branchLeft, branchRight, branch) and
+        id = branchLeft + "," + branchRight
+      |
+        i = 0 and operandBranch = branchLeft
+        or
+        i = 1 and operandBranch = branchRight
+      )
+    }
+  }
+
+  private class AndGuard extends BinaryLogicalOperationGuard {
+    AndGuard() { this.getExpr() instanceof LogicalAndExpr }
+
+    override predicate lift(Boolean branchLeft, Boolean branchRight, boolean branch) {
+      branch = branchLeft.booleanOr(branchRight) // yes, should not be `booleanAnd`
+    }
+  }
+
+  private class OrGuard extends BinaryLogicalOperationGuard {
+    OrGuard() { this.getExpr() instanceof LogicalOrExpr }
+
+    override predicate lift(Boolean branchLeft, Boolean branchRight, boolean branch) {
+      branch = branchLeft.booleanAnd(branchRight) // yes, should not be `booleanOr`
+    }
+  }
+
   /** Holds if the guard `guard` controls block `bb` upon evaluating to `branch`. */
   predicate guardControlsBlock(Guard guard, SsaInput::BasicBlock bb, boolean branch) {
     Guards::guardControlsBlock(guard, bb, branch)
diff --git a/ruby/ql/test/library-tests/dataflow/barrier-guards/barrier-flow.expected b/ruby/ql/test/library-tests/dataflow/barrier-guards/barrier-flow.expected
index 1bc62247a174..9cefcc5f7368 100644
--- a/ruby/ql/test/library-tests/dataflow/barrier-guards/barrier-flow.expected
+++ b/ruby/ql/test/library-tests/dataflow/barrier-guards/barrier-flow.expected
@@ -6,6 +6,18 @@ edges
 | barrier_flow.rb:8:9:8:17 | call to source | barrier_flow.rb:8:5:8:5 | x | provenance |  |
 | barrier_flow.rb:24:5:24:5 | x | barrier_flow.rb:26:10:26:10 | x | provenance |  |
 | barrier_flow.rb:24:9:24:17 | call to source | barrier_flow.rb:24:5:24:5 | x | provenance |  |
+| barrier_flow.rb:82:5:82:5 | x | barrier_flow.rb:87:14:87:14 | x | provenance |  |
+| barrier_flow.rb:82:5:82:5 | x | barrier_flow.rb:93:14:93:14 | x | provenance |  |
+| barrier_flow.rb:82:5:82:5 | x | barrier_flow.rb:99:14:99:14 | x | provenance |  |
+| barrier_flow.rb:82:5:82:5 | x | barrier_flow.rb:103:14:103:14 | x | provenance |  |
+| barrier_flow.rb:82:5:82:5 | x | barrier_flow.rb:109:14:109:14 | x | provenance |  |
+| barrier_flow.rb:82:9:82:18 | call to source | barrier_flow.rb:82:5:82:5 | x | provenance |  |
+| barrier_flow.rb:116:5:116:5 | x | barrier_flow.rb:121:14:121:14 | x | provenance |  |
+| barrier_flow.rb:116:5:116:5 | x | barrier_flow.rb:125:14:125:14 | x | provenance |  |
+| barrier_flow.rb:116:5:116:5 | x | barrier_flow.rb:131:14:131:14 | x | provenance |  |
+| barrier_flow.rb:116:5:116:5 | x | barrier_flow.rb:137:14:137:14 | x | provenance |  |
+| barrier_flow.rb:116:5:116:5 | x | barrier_flow.rb:143:14:143:14 | x | provenance |  |
+| barrier_flow.rb:116:9:116:18 | call to source | barrier_flow.rb:116:5:116:5 | x | provenance |  |
 nodes
 | barrier_flow.rb:2:5:2:5 | x | semmle.label | x |
 | barrier_flow.rb:2:9:2:17 | call to source | semmle.label | call to source |
@@ -16,9 +28,33 @@ nodes
 | barrier_flow.rb:24:5:24:5 | x | semmle.label | x |
 | barrier_flow.rb:24:9:24:17 | call to source | semmle.label | call to source |
 | barrier_flow.rb:26:10:26:10 | x | semmle.label | x |
+| barrier_flow.rb:82:5:82:5 | x | semmle.label | x |
+| barrier_flow.rb:82:9:82:18 | call to source | semmle.label | call to source |
+| barrier_flow.rb:87:14:87:14 | x | semmle.label | x |
+| barrier_flow.rb:93:14:93:14 | x | semmle.label | x |
+| barrier_flow.rb:99:14:99:14 | x | semmle.label | x |
+| barrier_flow.rb:103:14:103:14 | x | semmle.label | x |
+| barrier_flow.rb:109:14:109:14 | x | semmle.label | x |
+| barrier_flow.rb:116:5:116:5 | x | semmle.label | x |
+| barrier_flow.rb:116:9:116:18 | call to source | semmle.label | call to source |
+| barrier_flow.rb:121:14:121:14 | x | semmle.label | x |
+| barrier_flow.rb:125:14:125:14 | x | semmle.label | x |
+| barrier_flow.rb:131:14:131:14 | x | semmle.label | x |
+| barrier_flow.rb:137:14:137:14 | x | semmle.label | x |
+| barrier_flow.rb:143:14:143:14 | x | semmle.label | x |
 subpaths
 testFailures
 #select
 | barrier_flow.rb:4:10:4:10 | x | barrier_flow.rb:2:9:2:17 | call to source | barrier_flow.rb:4:10:4:10 | x | $@ | barrier_flow.rb:2:9:2:17 | call to source | call to source |
 | barrier_flow.rb:11:14:11:14 | x | barrier_flow.rb:8:9:8:17 | call to source | barrier_flow.rb:11:14:11:14 | x | $@ | barrier_flow.rb:8:9:8:17 | call to source | call to source |
 | barrier_flow.rb:26:10:26:10 | x | barrier_flow.rb:24:9:24:17 | call to source | barrier_flow.rb:26:10:26:10 | x | $@ | barrier_flow.rb:24:9:24:17 | call to source | call to source |
+| barrier_flow.rb:87:14:87:14 | x | barrier_flow.rb:82:9:82:18 | call to source | barrier_flow.rb:87:14:87:14 | x | $@ | barrier_flow.rb:82:9:82:18 | call to source | call to source |
+| barrier_flow.rb:93:14:93:14 | x | barrier_flow.rb:82:9:82:18 | call to source | barrier_flow.rb:93:14:93:14 | x | $@ | barrier_flow.rb:82:9:82:18 | call to source | call to source |
+| barrier_flow.rb:99:14:99:14 | x | barrier_flow.rb:82:9:82:18 | call to source | barrier_flow.rb:99:14:99:14 | x | $@ | barrier_flow.rb:82:9:82:18 | call to source | call to source |
+| barrier_flow.rb:103:14:103:14 | x | barrier_flow.rb:82:9:82:18 | call to source | barrier_flow.rb:103:14:103:14 | x | $@ | barrier_flow.rb:82:9:82:18 | call to source | call to source |
+| barrier_flow.rb:109:14:109:14 | x | barrier_flow.rb:82:9:82:18 | call to source | barrier_flow.rb:109:14:109:14 | x | $@ | barrier_flow.rb:82:9:82:18 | call to source | call to source |
+| barrier_flow.rb:121:14:121:14 | x | barrier_flow.rb:116:9:116:18 | call to source | barrier_flow.rb:121:14:121:14 | x | $@ | barrier_flow.rb:116:9:116:18 | call to source | call to source |
+| barrier_flow.rb:125:14:125:14 | x | barrier_flow.rb:116:9:116:18 | call to source | barrier_flow.rb:125:14:125:14 | x | $@ | barrier_flow.rb:116:9:116:18 | call to source | call to source |
+| barrier_flow.rb:131:14:131:14 | x | barrier_flow.rb:116:9:116:18 | call to source | barrier_flow.rb:131:14:131:14 | x | $@ | barrier_flow.rb:116:9:116:18 | call to source | call to source |
+| barrier_flow.rb:137:14:137:14 | x | barrier_flow.rb:116:9:116:18 | call to source | barrier_flow.rb:137:14:137:14 | x | $@ | barrier_flow.rb:116:9:116:18 | call to source | call to source |
+| barrier_flow.rb:143:14:143:14 | x | barrier_flow.rb:116:9:116:18 | call to source | barrier_flow.rb:143:14:143:14 | x | $@ | barrier_flow.rb:116:9:116:18 | call to source | call to source |
diff --git a/ruby/ql/test/library-tests/dataflow/barrier-guards/barrier-guards.expected b/ruby/ql/test/library-tests/dataflow/barrier-guards/barrier-guards.expected
index 21d697c86e93..4c1234683742 100644
--- a/ruby/ql/test/library-tests/dataflow/barrier-guards/barrier-guards.expected
+++ b/ruby/ql/test/library-tests/dataflow/barrier-guards/barrier-guards.expected
@@ -46,6 +46,25 @@ newStyleBarrierGuards
 | barrier_flow.rb:58:5:59:34 | [input] SSA phi read(x) |
 | barrier_flow.rb:68:10:71:11 | [input] SSA phi read(x) |
 | barrier_flow.rb:72:5:75:11 | [input] SSA phi read(x) |
+| barrier_flow.rb:84:24:84:24 | x |
+| barrier_flow.rb:84:24:84:34 | [input] SSA phi read(x) |
+| barrier_flow.rb:84:36:85:26 | [input] SSA phi read(x) |
+| barrier_flow.rb:85:14:85:14 | x |
+| barrier_flow.rb:91:14:91:14 | x |
+| barrier_flow.rb:96:24:96:24 | x |
+| barrier_flow.rb:97:14:97:14 | x |
+| barrier_flow.rb:105:14:105:14 | x |
+| barrier_flow.rb:111:14:111:14 | x |
+| barrier_flow.rb:118:8:118:19 | [input] SSA phi read(x) |
+| barrier_flow.rb:118:24:118:35 | [input] SSA phi read(x) |
+| barrier_flow.rb:119:14:119:14 | x |
+| barrier_flow.rb:124:23:124:23 | x |
+| barrier_flow.rb:127:14:127:14 | x |
+| barrier_flow.rb:133:14:133:14 | x |
+| barrier_flow.rb:136:23:136:23 | x |
+| barrier_flow.rb:139:14:139:14 | x |
+| barrier_flow.rb:142:29:142:29 | x |
+| barrier_flow.rb:145:14:145:14 | x |
 controls
 | barrier-guards.rb:3:4:3:15 | ... == ... | barrier-guards.rb:4:5:4:7 | foo | true |
 | barrier-guards.rb:3:4:3:15 | ... == ... | barrier-guards.rb:6:5:6:7 | foo | false |
@@ -367,3 +386,97 @@ controls
 | barrier_flow.rb:69:12:69:23 | ... != ... | barrier_flow.rb:70:13:70:18 | return | true |
 | barrier_flow.rb:73:12:73:23 | ... != ... | barrier_flow.rb:73:9:75:11 | if ... | false |
 | barrier_flow.rb:73:12:73:23 | ... != ... | barrier_flow.rb:74:13:74:18 | return | true |
+| barrier_flow.rb:84:8:84:18 | ... == ... | barrier_flow.rb:84:8:84:34 | [true] ... and ... | true |
+| barrier_flow.rb:84:8:84:18 | ... == ... | barrier_flow.rb:84:24:84:24 | x | true |
+| barrier_flow.rb:84:8:84:18 | ... == ... | barrier_flow.rb:85:9:85:14 | self | true |
+| barrier_flow.rb:84:8:84:34 | [false] ... and ... | barrier_flow.rb:87:9:87:14 | self | false |
+| barrier_flow.rb:84:8:84:34 | [true] ... and ... | barrier_flow.rb:85:9:85:14 | self | true |
+| barrier_flow.rb:84:24:84:34 | ... == ... | barrier_flow.rb:84:8:84:34 | [true] ... and ... | true |
+| barrier_flow.rb:84:24:84:34 | ... == ... | barrier_flow.rb:85:9:85:14 | self | true |
+| barrier_flow.rb:90:8:90:18 | ... != ... | barrier_flow.rb:90:8:90:35 | [true] ... and ... | true |
+| barrier_flow.rb:90:8:90:18 | ... != ... | barrier_flow.rb:90:24:90:24 | x | true |
+| barrier_flow.rb:90:8:90:18 | ... != ... | barrier_flow.rb:91:9:91:14 | self | true |
+| barrier_flow.rb:90:8:90:35 | [false] ... and ... | barrier_flow.rb:93:9:93:14 | self | false |
+| barrier_flow.rb:90:8:90:35 | [true] ... and ... | barrier_flow.rb:91:9:91:14 | self | true |
+| barrier_flow.rb:90:24:90:35 | ... == ... | barrier_flow.rb:90:8:90:35 | [true] ... and ... | true |
+| barrier_flow.rb:90:24:90:35 | ... == ... | barrier_flow.rb:91:9:91:14 | self | true |
+| barrier_flow.rb:96:8:96:18 | ... == ... | barrier_flow.rb:96:8:96:35 | [true] ... and ... | true |
+| barrier_flow.rb:96:8:96:18 | ... == ... | barrier_flow.rb:96:24:96:24 | x | true |
+| barrier_flow.rb:96:8:96:18 | ... == ... | barrier_flow.rb:97:9:97:14 | self | true |
+| barrier_flow.rb:96:8:96:35 | [false] ... and ... | barrier_flow.rb:99:9:99:14 | self | false |
+| barrier_flow.rb:96:8:96:35 | [true] ... and ... | barrier_flow.rb:97:9:97:14 | self | true |
+| barrier_flow.rb:96:24:96:35 | ... != ... | barrier_flow.rb:96:8:96:35 | [true] ... and ... | true |
+| barrier_flow.rb:96:24:96:35 | ... != ... | barrier_flow.rb:97:9:97:14 | self | true |
+| barrier_flow.rb:102:8:102:19 | ... != ... | barrier_flow.rb:102:8:102:36 | [true] ... and ... | true |
+| barrier_flow.rb:102:8:102:19 | ... != ... | barrier_flow.rb:102:25:102:25 | x | true |
+| barrier_flow.rb:102:8:102:19 | ... != ... | barrier_flow.rb:103:9:103:14 | self | true |
+| barrier_flow.rb:102:8:102:36 | [false] ... and ... | barrier_flow.rb:105:9:105:14 | self | false |
+| barrier_flow.rb:102:8:102:36 | [true] ... and ... | barrier_flow.rb:103:9:103:14 | self | true |
+| barrier_flow.rb:102:25:102:36 | ... != ... | barrier_flow.rb:102:8:102:36 | [true] ... and ... | true |
+| barrier_flow.rb:102:25:102:36 | ... != ... | barrier_flow.rb:103:9:103:14 | self | true |
+| barrier_flow.rb:108:8:108:25 | [true] not ... | barrier_flow.rb:108:8:108:42 | [true] ... and ... | true |
+| barrier_flow.rb:108:8:108:25 | [true] not ... | barrier_flow.rb:108:31:108:31 | x | true |
+| barrier_flow.rb:108:8:108:25 | [true] not ... | barrier_flow.rb:109:9:109:14 | self | true |
+| barrier_flow.rb:108:8:108:42 | [false] ... and ... | barrier_flow.rb:111:9:111:14 | self | false |
+| barrier_flow.rb:108:8:108:42 | [true] ... and ... | barrier_flow.rb:109:9:109:14 | self | true |
+| barrier_flow.rb:108:12:108:25 | [false] ( ... ) | barrier_flow.rb:108:8:108:25 | [true] not ... | false |
+| barrier_flow.rb:108:12:108:25 | [false] ( ... ) | barrier_flow.rb:108:8:108:42 | [true] ... and ... | false |
+| barrier_flow.rb:108:12:108:25 | [false] ( ... ) | barrier_flow.rb:108:31:108:31 | x | false |
+| barrier_flow.rb:108:12:108:25 | [false] ( ... ) | barrier_flow.rb:109:9:109:14 | self | false |
+| barrier_flow.rb:108:12:108:25 | [true] ( ... ) | barrier_flow.rb:108:8:108:25 | [false] not ... | true |
+| barrier_flow.rb:108:13:108:24 | ... == ... | barrier_flow.rb:108:8:108:25 | [false] not ... | true |
+| barrier_flow.rb:108:13:108:24 | ... == ... | barrier_flow.rb:108:8:108:25 | [true] not ... | false |
+| barrier_flow.rb:108:13:108:24 | ... == ... | barrier_flow.rb:108:8:108:42 | [true] ... and ... | false |
+| barrier_flow.rb:108:13:108:24 | ... == ... | barrier_flow.rb:108:12:108:25 | [false] ( ... ) | false |
+| barrier_flow.rb:108:13:108:24 | ... == ... | barrier_flow.rb:108:12:108:25 | [true] ( ... ) | true |
+| barrier_flow.rb:108:13:108:24 | ... == ... | barrier_flow.rb:108:31:108:31 | x | false |
+| barrier_flow.rb:108:13:108:24 | ... == ... | barrier_flow.rb:109:9:109:14 | self | false |
+| barrier_flow.rb:108:31:108:42 | ... != ... | barrier_flow.rb:108:8:108:42 | [true] ... and ... | true |
+| barrier_flow.rb:108:31:108:42 | ... != ... | barrier_flow.rb:109:9:109:14 | self | true |
+| barrier_flow.rb:118:8:118:19 | ... == ... | barrier_flow.rb:118:8:118:35 | [false] ... or ... | false |
+| barrier_flow.rb:118:8:118:19 | ... == ... | barrier_flow.rb:118:24:118:24 | x | false |
+| barrier_flow.rb:118:8:118:19 | ... == ... | barrier_flow.rb:121:9:121:14 | self | false |
+| barrier_flow.rb:118:8:118:35 | [false] ... or ... | barrier_flow.rb:121:9:121:14 | self | false |
+| barrier_flow.rb:118:8:118:35 | [true] ... or ... | barrier_flow.rb:119:9:119:14 | self | true |
+| barrier_flow.rb:118:24:118:35 | ... == ... | barrier_flow.rb:118:8:118:35 | [false] ... or ... | false |
+| barrier_flow.rb:118:24:118:35 | ... == ... | barrier_flow.rb:121:9:121:14 | self | false |
+| barrier_flow.rb:124:8:124:18 | ... != ... | barrier_flow.rb:124:8:124:34 | [false] ... or ... | false |
+| barrier_flow.rb:124:8:124:18 | ... != ... | barrier_flow.rb:124:23:124:23 | x | false |
+| barrier_flow.rb:124:8:124:18 | ... != ... | barrier_flow.rb:127:9:127:14 | self | false |
+| barrier_flow.rb:124:8:124:34 | [false] ... or ... | barrier_flow.rb:127:9:127:14 | self | false |
+| barrier_flow.rb:124:8:124:34 | [true] ... or ... | barrier_flow.rb:125:9:125:14 | self | true |
+| barrier_flow.rb:124:23:124:34 | ... == ... | barrier_flow.rb:124:8:124:34 | [false] ... or ... | false |
+| barrier_flow.rb:124:23:124:34 | ... == ... | barrier_flow.rb:127:9:127:14 | self | false |
+| barrier_flow.rb:130:8:130:18 | ... == ... | barrier_flow.rb:130:8:130:34 | [false] ... or ... | false |
+| barrier_flow.rb:130:8:130:18 | ... == ... | barrier_flow.rb:130:23:130:23 | x | false |
+| barrier_flow.rb:130:8:130:18 | ... == ... | barrier_flow.rb:133:9:133:14 | self | false |
+| barrier_flow.rb:130:8:130:34 | [false] ... or ... | barrier_flow.rb:133:9:133:14 | self | false |
+| barrier_flow.rb:130:8:130:34 | [true] ... or ... | barrier_flow.rb:131:9:131:14 | self | true |
+| barrier_flow.rb:130:23:130:34 | ... != ... | barrier_flow.rb:130:8:130:34 | [false] ... or ... | false |
+| barrier_flow.rb:130:23:130:34 | ... != ... | barrier_flow.rb:133:9:133:14 | self | false |
+| barrier_flow.rb:136:8:136:18 | ... != ... | barrier_flow.rb:136:8:136:33 | [false] ... or ... | false |
+| barrier_flow.rb:136:8:136:18 | ... != ... | barrier_flow.rb:136:23:136:23 | x | false |
+| barrier_flow.rb:136:8:136:18 | ... != ... | barrier_flow.rb:139:9:139:14 | self | false |
+| barrier_flow.rb:136:8:136:33 | [false] ... or ... | barrier_flow.rb:139:9:139:14 | self | false |
+| barrier_flow.rb:136:8:136:33 | [true] ... or ... | barrier_flow.rb:137:9:137:14 | self | true |
+| barrier_flow.rb:136:23:136:33 | ... != ... | barrier_flow.rb:136:8:136:33 | [false] ... or ... | false |
+| barrier_flow.rb:136:23:136:33 | ... != ... | barrier_flow.rb:139:9:139:14 | self | false |
+| barrier_flow.rb:142:8:142:24 | [false] not ... | barrier_flow.rb:142:8:142:39 | [false] ... or ... | false |
+| barrier_flow.rb:142:8:142:24 | [false] not ... | barrier_flow.rb:142:29:142:29 | x | false |
+| barrier_flow.rb:142:8:142:24 | [false] not ... | barrier_flow.rb:145:9:145:14 | self | false |
+| barrier_flow.rb:142:8:142:39 | [false] ... or ... | barrier_flow.rb:145:9:145:14 | self | false |
+| barrier_flow.rb:142:8:142:39 | [true] ... or ... | barrier_flow.rb:143:9:143:14 | self | true |
+| barrier_flow.rb:142:12:142:24 | [false] ( ... ) | barrier_flow.rb:142:8:142:24 | [true] not ... | false |
+| barrier_flow.rb:142:12:142:24 | [true] ( ... ) | barrier_flow.rb:142:8:142:24 | [false] not ... | true |
+| barrier_flow.rb:142:12:142:24 | [true] ( ... ) | barrier_flow.rb:142:8:142:39 | [false] ... or ... | true |
+| barrier_flow.rb:142:12:142:24 | [true] ( ... ) | barrier_flow.rb:142:29:142:29 | x | true |
+| barrier_flow.rb:142:12:142:24 | [true] ( ... ) | barrier_flow.rb:145:9:145:14 | self | true |
+| barrier_flow.rb:142:13:142:23 | ... == ... | barrier_flow.rb:142:8:142:24 | [false] not ... | true |
+| barrier_flow.rb:142:13:142:23 | ... == ... | barrier_flow.rb:142:8:142:24 | [true] not ... | false |
+| barrier_flow.rb:142:13:142:23 | ... == ... | barrier_flow.rb:142:8:142:39 | [false] ... or ... | true |
+| barrier_flow.rb:142:13:142:23 | ... == ... | barrier_flow.rb:142:12:142:24 | [false] ( ... ) | false |
+| barrier_flow.rb:142:13:142:23 | ... == ... | barrier_flow.rb:142:12:142:24 | [true] ( ... ) | true |
+| barrier_flow.rb:142:13:142:23 | ... == ... | barrier_flow.rb:142:29:142:29 | x | true |
+| barrier_flow.rb:142:13:142:23 | ... == ... | barrier_flow.rb:145:9:145:14 | self | true |
+| barrier_flow.rb:142:29:142:39 | ... != ... | barrier_flow.rb:142:8:142:39 | [false] ... or ... | false |
+| barrier_flow.rb:142:29:142:39 | ... != ... | barrier_flow.rb:145:9:145:14 | self | false |
diff --git a/ruby/ql/test/library-tests/dataflow/barrier-guards/barrier_flow.rb b/ruby/ql/test/library-tests/dataflow/barrier-guards/barrier_flow.rb
index d4c2d49eb362..567ceee07e40 100644
--- a/ruby/ql/test/library-tests/dataflow/barrier-guards/barrier_flow.rb
+++ b/ruby/ql/test/library-tests/dataflow/barrier-guards/barrier_flow.rb
@@ -77,3 +77,71 @@ def m9(b)
 
     sink x
 end
+
+def m10
+    x = source(10)
+
+    if x == "safe" and x == "safe" then # $ guarded
+        sink x # $ guarded
+    else
+        sink x # $ hasValueFlow=10
+    end
+
+    if x != "safe" and x == "safe2" then
+        sink x # $ guarded
+    else
+        sink x # $ hasValueFlow=10
+    end
+
+    if x == "safe" and x != "safe2" then # $ guarded
+        sink x # $ guarded
+    else
+        sink x # $ hasValueFlow=10
+    end
+
+    if x != "safe1" and x != "safe2" then
+        sink x # $ hasValueFlow=10
+    else
+        sink x # $ guarded
+    end
+
+    if not (x == "safe1") and x != "safe2" then
+        sink x # $ hasValueFlow=10
+    else
+        sink x # $ guarded
+    end
+end
+
+def m11
+    x = source(11)
+
+    if x == "safe1" or x == "safe2" then
+        sink x # $ guarded
+    else
+        sink x # $ hasValueFlow=11
+    end
+
+    if x != "safe" or x == "safe2" then # $ guarded
+        sink x # $ hasValueFlow=11
+    else
+        sink x # $ guarded
+    end
+
+    if x == "safe" or x != "safe2" then
+        sink x # $ hasValueFlow=11
+    else
+        sink x # $ guarded
+    end
+
+    if x != "safe" or x != "safe" then # $ guarded
+        sink x # $ hasValueFlow=11
+    else
+        sink x # $ guarded
+    end
+
+    if not (x == "safe") or x != "safe" then # $ guarded
+        sink x # $ hasValueFlow=11
+    else
+        sink x # $ guarded
+    end
+end
\ No newline at end of file
diff --git a/shared/ssa/codeql/ssa/Ssa.qll b/shared/ssa/codeql/ssa/Ssa.qll
index d3b1414dfcfc..ed278cae75d4 100644
--- a/shared/ssa/codeql/ssa/Ssa.qll
+++ b/shared/ssa/codeql/ssa/Ssa.qll
@@ -1220,6 +1220,139 @@ module Make<LocationSig Location, InputSig<Location> Input> {
 
       /** Holds if the `i`th node of basic block `bb` evaluates this guard. */
       predicate hasCfgNode(BasicBlock bb, int i);
+
+      /** Gets the location of this guard. */
+      Location getLocation();
+    }
+
+    /**
+     * A logical operation guard.
+     *
+     * Guards are automatically lifted to logical operations, as dictacted
+     * by the `lift` predicate. For example, logical conjunctions can be
+     * lifted as follows:
+     *
+     * ```csharp
+     * // Example 1
+     * if (x == "safe" && x == "safe")
+     * {
+     *     sink(x); // guarded
+     * }
+     * else
+     * {
+     *     sink(x); // unguarded
+     * }
+     *
+     * // Example 2
+     * if (x == "safe" && x != "safe2")
+     * {
+     *     sink(x); // guarded
+     * }
+     * else
+     * {
+     *     sink(x); // unguarded
+     * }
+     *
+     * // Example 3
+     * if (x != "safe" && x == "safe2")
+     * {
+     *     sink(x); // guarded
+     * }
+     * else
+     * {
+     *     sink(x); // unguarded
+     * }
+     *
+     * // Example 4
+     * if (x != "safe1" && x != "safe2")
+     * {
+     *     sink(x); // unguarded
+     * }
+     * else
+     * {
+     *     sink(x); // guarded
+     * }
+     * ```
+     *
+     * Examples 1--3 should normally be handled via the control-flow graph (CFG)
+     * implementation, but they are included for completeness.
+     *
+     * Example 4, which does not come for free just from the CFG, requires that
+     * logical conjunctions be modeled post-order in the CFG, as they will
+     * otherwise not dominate their `else` branch.
+     *
+     * Similarly, logical disjunctions can be lifted as follows:
+     *
+     * ```csharp
+     * // Example 1
+     * if (x == "safe1" || x == "safe2")
+     * {
+     *     sink(x); // guarded
+     * }
+     * else
+     * {
+     *     sink(x); // unguarded
+     * }
+     *
+     * // Example 2
+     * if (x == "safe" || x != "safe2")
+     * {
+     *     sink(x); // unguarded
+     * }
+     * else
+     * {
+     *     sink(x); // guarded
+     * }
+     *
+     * // Example 3
+     * if (x != "safe" || x == "safe2")
+     * {
+     *     sink(x); // unguarded
+     * }
+     * else
+     * {
+     *     sink(x); // guarded
+     * }
+     *
+     * // Example 4
+     * if (x != "safe" || x != "safe")
+     * {
+     *     sink(x); // unguarded
+     * }
+     * else
+     * {
+     *     sink(x); // guarded
+     * }
+     * ```
+     *
+     * Again, Examples 1--3 should normally be handled via the control-flow graph
+     * (CFG) implementation, while Example 4 requires that logical disjunctions be
+     * modeled post-order in the CFG.
+     */
+    class LogicalOperationGuard extends Guard {
+      /** Gets the `i`th operand of this logical operation. */
+      Guard getOperand(int i);
+
+      /**
+       * Holds if this logical operation guards `branch`, provided that the `i`th
+       * operand guards its `operandBranch`. The string `id` is used to encode
+       * the bit-pattern of the operands.
+       *
+       * Example: If this operand is a Boolean conjunction, then the following lift
+       * table should be used:
+       *
+       * | id            | i | operandBranch | branch |
+       * |---------------|---|---------------|--------|
+       * | "false,false" | 0 | false         | false  |
+       * | "false,false" | 1 | false         | false  |
+       * | "false,true"  | 0 | false         | true   |
+       * | "false,true"  | 1 | true          | true   |
+       * | "true,false"  | 0 | true          | true   |
+       * | "true,false"  | 1 | false         | true   |
+       * | "true,true"   | 0 | true          | true   |
+       * | "true,true"   | 1 | true          | true   |
+       */
+      predicate lift(string id, int i, boolean operandBranch, boolean branch);
     }
 
     /** Holds if `guard` controls block `bb` upon evaluating to `branch`. */
@@ -1681,6 +1814,26 @@ module Make<LocationSig Location, InputSig<Location> Input> {
         DfInput::Guard g, Definition def, boolean branch, State state
       ) {
         guardChecks(g, DfInput::getARead(def), branch, state)
+        or
+        exists(int last |
+          logicalOperationGuardChecksSsaDef(g, _, last, def, branch, state) and
+          last = strictcount(int i | exists(g.(DfInput::LogicalOperationGuard).getOperand(i))) - 1
+        )
+      }
+
+      pragma[nomagic]
+      private predicate logicalOperationGuardChecksSsaDef(
+        DfInput::LogicalOperationGuard op, string id, int i, Definition def, boolean branch,
+        State state
+      ) {
+        exists(boolean operandBranch |
+          op.lift(id, i, operandBranch, branch) and
+          guardChecksSsaDef(op.getOperand(i), def, operandBranch, state)
+        |
+          i = 0
+          or
+          logicalOperationGuardChecksSsaDef(op, id, i - 1, def, branch, state)
+        )
       }
 
       /** Gets a node that is safely guarded by the given guard check. */