Merge pull request github#6347 from MathiasVP/import-gvn-to-prevent-ir-reevaluation

C++: Import 'GVN' in 'Overflow.qll' to prevent IR reevaluation.

Author: geoffw0

cpp/ql/src/semmle/code/cpp/security/Overflow.qll

@@ -5,6 +5,8 @@
 
 import cpp
 import semmle.code.cpp.controlflow.Dominance
+// `GlobalValueNumbering` is only imported to prevent IR re-evaluation.
+private import semmle.code.cpp.valuenumbering.GlobalValueNumbering
 import semmle.code.cpp.rangeanalysis.SimpleRangeAnalysis
 import semmle.code.cpp.rangeanalysis.RangeAnalysisUtils