C++: Cleanup.

Author: MathiasVP

cpp/ql/lib/semmle/code/cpp/controlflow/IRGuards.qll

@@ -763,11 +763,7 @@ private predicate compares_eq(
     compares_eq(test.(LogicalNotInstruction).getUnary(), left, right, k, areEqual, dual)
   )
   or
-  exists(CallInstruction call |
-    test = call and
-    call.getStaticCallTarget().hasName("__builtin_expect") and
-    compares_eq(call.getArgument(0).(ConvertInstruction).getUnary(), left, right, k, areEqual, value)
-  )
+  compares_eq(test.(BuiltinExpectCallInstruction).getCondition(), left, right, k, areEqual, value)
 }
 
 /**
@@ -838,12 +834,8 @@ private predicate unary_compares_eq(
     k = k1 + k2
   )
   or
-  exists(CallInstruction call, Instruction arg |
-    test = call and
-    call.getStaticCallTarget().hasName("__builtin_expect") and
-    arg = call.getArgument(0) and
-    unary_compares_eq(arg.(ConvertInstruction).getUnary(), op, k, areEqual, inNonZeroCase, value)
-  )
+  unary_compares_eq(test.(BuiltinExpectCallInstruction).getCondition(), op, k, areEqual,
+    inNonZeroCase, value)
 }
 
 /** Rearrange various simple comparisons into `left == right + k` form. */
@@ -926,6 +918,13 @@ private predicate unary_simple_comparison_eq(
 /** A call to the builtin operation `__builtin_expect`. */
 private class BuiltinExpectCallInstruction extends CallInstruction {
   BuiltinExpectCallInstruction() { this.getStaticCallTarget().hasName("__builtin_expect") }
+
+  /** Gets the condition of this call. */
+  Instruction getCondition() {
+    // The first parameter of `__builtin_expect` has type `long`. So we skip
+    // the conversion when inferring guards.
+    result = this.getArgument(0).(ConvertInstruction).getUnary()
+  }
 }
 
 /**
@@ -935,14 +934,10 @@ private class BuiltinExpectCallInstruction extends CallInstruction {
 private predicate builtin_expect_eq(
   CompareInstruction cmp, Operand left, Operand right, int k, boolean areEqual, AbstractValue value
 ) {
-  exists(
-    BuiltinExpectCallInstruction call, ConvertInstruction arg, Instruction const,
-    AbstractValue innerValue
-  |
+  exists(BuiltinExpectCallInstruction call, Instruction const, AbstractValue innerValue |
     int_value(const) = 0 and
     cmp.hasOperands(call.getAUse(), const.getAUse()) and
-    arg = call.getArgument(0) and
-    compares_eq(arg.getUnary(), left, right, k, areEqual, innerValue)
+    compares_eq(call.getCondition(), left, right, k, areEqual, innerValue)
   |
     cmp instanceof CompareNEInstruction and
     value = innerValue
@@ -970,14 +965,10 @@ private predicate unary_builtin_expect_eq(
   CompareInstruction cmp, Operand op, int k, boolean areEqual, boolean inNonZeroCase,
   AbstractValue value
 ) {
-  exists(
-    BuiltinExpectCallInstruction call, ConvertInstruction arg, Instruction const,
-    AbstractValue innerValue
-  |
+  exists(BuiltinExpectCallInstruction call, Instruction const, AbstractValue innerValue |
     int_value(const) = 0 and
     cmp.hasOperands(call.getAUse(), const.getAUse()) and
-    arg = call.getArgument(0) and
-    unary_compares_eq(arg.getUnary(), op, k, areEqual, inNonZeroCase, innerValue)
+    unary_compares_eq(call.getCondition(), op, k, areEqual, inNonZeroCase, innerValue)
   |
     cmp instanceof CompareNEInstruction and
     value = innerValue