C++/C#: Use unique to get a better join order

The previous changes made the optimizer choose a bad join order for the RHS of the antijoin in `addressOperandAllocationAndOffset`. Once again, `unique` to the rescue.

Author: Dave Bartolomeo

cpp/ql/src/semmle/code/cpp/ir/implementation/aliased_ssa/Operand.qll

@@ -289,7 +289,9 @@ class NonPhiMemoryOperand extends NonPhiOperand, MemoryOperand, NonPhiMemoryOper
 
   final override string toString() { result = tag.toString() }
 
-  final override Instruction getAnyDef() { hasDefinition(result, _) }
+  final override Instruction getAnyDef() {
+    result = unique(Instruction defInstr | hasDefinition(defInstr, _))
+  }
 
   final override Overlap getDefinitionOverlap() { hasDefinition(_, result) }
 

cpp/ql/src/semmle/code/cpp/ir/implementation/raw/Operand.qll

@@ -289,7 +289,9 @@ class NonPhiMemoryOperand extends NonPhiOperand, MemoryOperand, NonPhiMemoryOper
 
   final override string toString() { result = tag.toString() }
 
-  final override Instruction getAnyDef() { hasDefinition(result, _) }
+  final override Instruction getAnyDef() {
+    result = unique(Instruction defInstr | hasDefinition(defInstr, _))
+  }
 
   final override Overlap getDefinitionOverlap() { hasDefinition(_, result) }
 

cpp/ql/src/semmle/code/cpp/ir/implementation/unaliased_ssa/Operand.qll

@@ -289,7 +289,9 @@ class NonPhiMemoryOperand extends NonPhiOperand, MemoryOperand, NonPhiMemoryOper
 
   final override string toString() { result = tag.toString() }
 
-  final override Instruction getAnyDef() { hasDefinition(result, _) }
+  final override Instruction getAnyDef() {
+    result = unique(Instruction defInstr | hasDefinition(defInstr, _))
+  }
 
   final override Overlap getDefinitionOverlap() { hasDefinition(_, result) }
 

csharp/ql/src/semmle/code/csharp/ir/implementation/raw/Operand.qll

@@ -289,7 +289,9 @@ class NonPhiMemoryOperand extends NonPhiOperand, MemoryOperand, NonPhiMemoryOper
 
   final override string toString() { result = tag.toString() }
 
-  final override Instruction getAnyDef() { hasDefinition(result, _) }
+  final override Instruction getAnyDef() {
+    result = unique(Instruction defInstr | hasDefinition(defInstr, _))
+  }
 
   final override Overlap getDefinitionOverlap() { hasDefinition(_, result) }
 

csharp/ql/src/semmle/code/csharp/ir/implementation/unaliased_ssa/Operand.qll

@@ -289,7 +289,9 @@ class NonPhiMemoryOperand extends NonPhiOperand, MemoryOperand, NonPhiMemoryOper
 
   final override string toString() { result = tag.toString() }
 
-  final override Instruction getAnyDef() { hasDefinition(result, _) }
+  final override Instruction getAnyDef() {
+    result = unique(Instruction defInstr | hasDefinition(defInstr, _))
+  }
 
   final override Overlap getDefinitionOverlap() { hasDefinition(_, result) }