./Ultimate.py --spec ../../sv-benchmarks/c/properties/no-overflow.prp --file ../../sv-benchmarks/c/Juliet_Test/CWE190_Integer_Overflow__int_rand_square_01_bad.i --full-output --architecture 64bit -------------------------------------------------------------------------------- Checking for overflows Using default analysis Version 8393723b Calling Ultimate with: /usr/lib/jvm/java-11-openjdk-amd64/bin/java -Dosgi.configuration.area=/tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_2654dc4e-57d6-40fb-8b49-624868eeec46/bin/utaipan-I9t0OCRTmS/data/config -Xmx15G -Xms4m -jar /tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_2654dc4e-57d6-40fb-8b49-624868eeec46/bin/utaipan-I9t0OCRTmS/plugins/org.eclipse.equinox.launcher_1.5.800.v20200727-1323.jar -data @noDefault -ultimatedata /tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_2654dc4e-57d6-40fb-8b49-624868eeec46/bin/utaipan-I9t0OCRTmS/data -tc /tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_2654dc4e-57d6-40fb-8b49-624868eeec46/bin/utaipan-I9t0OCRTmS/config/TaipanReach.xml -i ../../sv-benchmarks/c/Juliet_Test/CWE190_Integer_Overflow__int_rand_square_01_bad.i -s /tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_2654dc4e-57d6-40fb-8b49-624868eeec46/bin/utaipan-I9t0OCRTmS/config/svcomp-Overflow-64bit-Taipan_Default.epf --cacsl2boogietranslator.entry.function main --witnessprinter.witness.directory /tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_2654dc4e-57d6-40fb-8b49-624868eeec46/bin/utaipan-I9t0OCRTmS --witnessprinter.witness.filename witness.graphml --witnessprinter.write.witness.besides.input.file false --witnessprinter.graph.data.specification CHECK( init(main()), LTL(G ! overflow) ) --witnessprinter.graph.data.producer Taipan --witnessprinter.graph.data.architecture 64bit --witnessprinter.graph.data.programhash 88c4c4aad9bad1e1394be24cdd0636d4bd415e869a1d9111dae50b45937d171e --- Real Ultimate output --- [0.001s][warning][os,container] Duplicate cpuset controllers detected. Picking /sys/fs/cgroup/cpuset, skipping /sys/fs/cgroup/cpuset. This is Ultimate 0.2.2-dev-8393723 [2022-11-19 07:33:48,632 INFO L177 SettingsManager]: Resetting all preferences to default values... [2022-11-19 07:33:48,634 INFO L181 SettingsManager]: Resetting UltimateCore preferences to default values [2022-11-19 07:33:48,674 INFO L184 SettingsManager]: Ultimate Commandline Interface provides no preferences, ignoring... [2022-11-19 07:33:48,674 INFO L181 SettingsManager]: Resetting Boogie Preprocessor preferences to default values [2022-11-19 07:33:48,676 INFO L181 SettingsManager]: Resetting Boogie Procedure Inliner preferences to default values [2022-11-19 07:33:48,677 INFO L181 SettingsManager]: Resetting Abstract Interpretation preferences to default values [2022-11-19 07:33:48,679 INFO L181 SettingsManager]: Resetting LassoRanker preferences to default values [2022-11-19 07:33:48,681 INFO L181 SettingsManager]: Resetting Reaching Definitions preferences to default values [2022-11-19 07:33:48,682 INFO L181 SettingsManager]: Resetting SyntaxChecker preferences to default values [2022-11-19 07:33:48,689 INFO L181 SettingsManager]: Resetting Sifa preferences to default values [2022-11-19 07:33:48,693 INFO L184 SettingsManager]: Büchi Program Product provides no preferences, ignoring... [2022-11-19 07:33:48,693 INFO L181 SettingsManager]: Resetting LTL2Aut preferences to default values [2022-11-19 07:33:48,696 INFO L181 SettingsManager]: Resetting PEA to Boogie preferences to default values [2022-11-19 07:33:48,697 INFO L181 SettingsManager]: Resetting BlockEncodingV2 preferences to default values [2022-11-19 07:33:48,698 INFO L181 SettingsManager]: Resetting ChcToBoogie preferences to default values [2022-11-19 07:33:48,699 INFO L181 SettingsManager]: Resetting AutomataScriptInterpreter preferences to default values [2022-11-19 07:33:48,699 INFO L181 SettingsManager]: Resetting BuchiAutomizer preferences to default values [2022-11-19 07:33:48,701 INFO L181 SettingsManager]: Resetting CACSL2BoogieTranslator preferences to default values [2022-11-19 07:33:48,703 INFO L181 SettingsManager]: Resetting CodeCheck preferences to default values [2022-11-19 07:33:48,707 INFO L181 SettingsManager]: Resetting InvariantSynthesis preferences to default values [2022-11-19 07:33:48,708 INFO L181 SettingsManager]: Resetting RCFGBuilder preferences to default values [2022-11-19 07:33:48,709 INFO L181 SettingsManager]: Resetting Referee preferences to default values [2022-11-19 07:33:48,710 INFO L181 SettingsManager]: Resetting TraceAbstraction preferences to default values [2022-11-19 07:33:48,713 INFO L184 SettingsManager]: TraceAbstractionConcurrent provides no preferences, ignoring... [2022-11-19 07:33:48,713 INFO L184 SettingsManager]: TraceAbstractionWithAFAs provides no preferences, ignoring... [2022-11-19 07:33:48,714 INFO L181 SettingsManager]: Resetting TreeAutomizer preferences to default values [2022-11-19 07:33:48,714 INFO L181 SettingsManager]: Resetting IcfgToChc preferences to default values [2022-11-19 07:33:48,715 INFO L181 SettingsManager]: Resetting IcfgTransformer preferences to default values [2022-11-19 07:33:48,716 INFO L184 SettingsManager]: ReqToTest provides no preferences, ignoring... [2022-11-19 07:33:48,716 INFO L181 SettingsManager]: Resetting Boogie Printer preferences to default values [2022-11-19 07:33:48,717 INFO L181 SettingsManager]: Resetting ChcSmtPrinter preferences to default values [2022-11-19 07:33:48,718 INFO L181 SettingsManager]: Resetting ReqPrinter preferences to default values [2022-11-19 07:33:48,718 INFO L181 SettingsManager]: Resetting Witness Printer preferences to default values [2022-11-19 07:33:48,719 INFO L184 SettingsManager]: Boogie PL CUP Parser provides no preferences, ignoring... [2022-11-19 07:33:48,720 INFO L181 SettingsManager]: Resetting CDTParser preferences to default values [2022-11-19 07:33:48,720 INFO L184 SettingsManager]: AutomataScriptParser provides no preferences, ignoring... [2022-11-19 07:33:48,721 INFO L184 SettingsManager]: ReqParser provides no preferences, ignoring... [2022-11-19 07:33:48,721 INFO L181 SettingsManager]: Resetting SmtParser preferences to default values [2022-11-19 07:33:48,722 INFO L181 SettingsManager]: Resetting Witness Parser preferences to default values [2022-11-19 07:33:48,723 INFO L188 SettingsManager]: Finished resetting all preferences to default values... [2022-11-19 07:33:48,725 INFO L101 SettingsManager]: Beginning loading settings from /tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_2654dc4e-57d6-40fb-8b49-624868eeec46/bin/utaipan-I9t0OCRTmS/config/svcomp-Overflow-64bit-Taipan_Default.epf [2022-11-19 07:33:48,758 INFO L113 SettingsManager]: Loading preferences was successful [2022-11-19 07:33:48,758 INFO L115 SettingsManager]: Preferences different from defaults after loading the file: [2022-11-19 07:33:48,759 INFO L136 SettingsManager]: Preferences of UltimateCore differ from their defaults: [2022-11-19 07:33:48,759 INFO L138 SettingsManager]: * Log level for class=de.uni_freiburg.informatik.ultimate.lib.smtlibutils.quantifier.QuantifierPusher=ERROR; [2022-11-19 07:33:48,760 INFO L136 SettingsManager]: Preferences of Boogie Procedure Inliner differ from their defaults: [2022-11-19 07:33:48,761 INFO L138 SettingsManager]: * Ignore calls to procedures called more than once=ONLY_FOR_SEQUENTIAL_PROGRAMS [2022-11-19 07:33:48,761 INFO L138 SettingsManager]: * User list type=DISABLED [2022-11-19 07:33:48,761 INFO L136 SettingsManager]: Preferences of Abstract Interpretation differ from their defaults: [2022-11-19 07:33:48,761 INFO L138 SettingsManager]: * Explicit value domain=true [2022-11-19 07:33:48,762 INFO L138 SettingsManager]: * Abstract domain for RCFG-of-the-future=PoormanAbstractDomain [2022-11-19 07:33:48,763 INFO L138 SettingsManager]: * Octagon Domain=false [2022-11-19 07:33:48,763 INFO L138 SettingsManager]: * Abstract domain=CompoundDomain [2022-11-19 07:33:48,763 INFO L138 SettingsManager]: * Check feasibility of abstract posts with an SMT solver=true [2022-11-19 07:33:48,764 INFO L138 SettingsManager]: * Use the RCFG-of-the-future interface=true [2022-11-19 07:33:48,764 INFO L138 SettingsManager]: * Interval Domain=false [2022-11-19 07:33:48,764 INFO L136 SettingsManager]: Preferences of Sifa differ from their defaults: [2022-11-19 07:33:48,764 INFO L138 SettingsManager]: * Call Summarizer=TopInputCallSummarizer [2022-11-19 07:33:48,765 INFO L138 SettingsManager]: * Simplification Technique=POLY_PAC [2022-11-19 07:33:48,766 INFO L136 SettingsManager]: Preferences of CACSL2BoogieTranslator differ from their defaults: [2022-11-19 07:33:48,766 INFO L138 SettingsManager]: * Check unreachability of error function in SV-COMP mode=false [2022-11-19 07:33:48,766 INFO L138 SettingsManager]: * Overapproximate operations on floating types=true [2022-11-19 07:33:48,766 INFO L138 SettingsManager]: * Check division by zero=IGNORE [2022-11-19 07:33:48,767 INFO L138 SettingsManager]: * Pointer to allocated memory at dereference=IGNORE [2022-11-19 07:33:48,769 INFO L138 SettingsManager]: * If two pointers are subtracted or compared they have the same base address=IGNORE [2022-11-19 07:33:48,769 INFO L138 SettingsManager]: * Check array bounds for arrays that are off heap=IGNORE [2022-11-19 07:33:48,769 INFO L138 SettingsManager]: * Check absence of signed integer overflows=true [2022-11-19 07:33:48,769 INFO L138 SettingsManager]: * Check if freed pointer was valid=false [2022-11-19 07:33:48,770 INFO L138 SettingsManager]: * Use constant arrays=true [2022-11-19 07:33:48,770 INFO L138 SettingsManager]: * Pointer base address is valid at dereference=IGNORE [2022-11-19 07:33:48,770 INFO L136 SettingsManager]: Preferences of RCFGBuilder differ from their defaults: [2022-11-19 07:33:48,770 INFO L138 SettingsManager]: * SMT solver=External_DefaultMode [2022-11-19 07:33:48,771 INFO L138 SettingsManager]: * Command for external solver=z3 SMTLIB2_COMPLIANT=true -memory:2024 -smt2 -in -t:2000 [2022-11-19 07:33:48,771 INFO L136 SettingsManager]: Preferences of TraceAbstraction differ from their defaults: [2022-11-19 07:33:48,771 INFO L138 SettingsManager]: * Abstract interpretation Mode=USE_PREDICATES [2022-11-19 07:33:48,772 INFO L138 SettingsManager]: * Compute Interpolants along a Counterexample=FPandBP [2022-11-19 07:33:48,772 INFO L138 SettingsManager]: * Positions where we compute the Hoare Annotation=LoopsAndPotentialCycles [2022-11-19 07:33:48,772 INFO L138 SettingsManager]: * Trace refinement strategy=SIFA_TAIPAN [2022-11-19 07:33:48,772 INFO L138 SettingsManager]: * Command for external solver=z3 SMTLIB2_COMPLIANT=true -memory:2024 -smt2 -in [2022-11-19 07:33:48,773 INFO L138 SettingsManager]: * Compute Hoare Annotation of negated interpolant automaton, abstraction and CFG=true [2022-11-19 07:33:48,773 INFO L138 SettingsManager]: * Trace refinement exception blacklist=NONE [2022-11-19 07:33:48,773 INFO L138 SettingsManager]: * SMT solver=External_ModelsAndUnsatCoreMode WARNING: An illegal reflective access operation has occurred WARNING: Illegal reflective access by com.sun.xml.bind.v2.runtime.reflect.opt.Injector$1 (file:/tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_2654dc4e-57d6-40fb-8b49-624868eeec46/bin/utaipan-I9t0OCRTmS/plugins/com.sun.xml.bind_2.2.0.v201505121915.jar) to method java.lang.ClassLoader.defineClass(java.lang.String,byte[],int,int) WARNING: Please consider reporting this to the maintainers of com.sun.xml.bind.v2.runtime.reflect.opt.Injector$1 WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations WARNING: All illegal access operations will be denied in a future release Applying setting for plugin de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator: Entry function -> main Applying setting for plugin de.uni_freiburg.informatik.ultimate.witnessprinter: Witness directory -> /tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_2654dc4e-57d6-40fb-8b49-624868eeec46/bin/utaipan-I9t0OCRTmS Applying setting for plugin de.uni_freiburg.informatik.ultimate.witnessprinter: Witness filename -> witness.graphml Applying setting for plugin de.uni_freiburg.informatik.ultimate.witnessprinter: Write witness besides input file -> false Applying setting for plugin de.uni_freiburg.informatik.ultimate.witnessprinter: Graph data specification -> CHECK( init(main()), LTL(G ! overflow) ) Applying setting for plugin de.uni_freiburg.informatik.ultimate.witnessprinter: Graph data producer -> Taipan Applying setting for plugin de.uni_freiburg.informatik.ultimate.witnessprinter: Graph data architecture -> 64bit Applying setting for plugin de.uni_freiburg.informatik.ultimate.witnessprinter: Graph data programhash -> 88c4c4aad9bad1e1394be24cdd0636d4bd415e869a1d9111dae50b45937d171e [2022-11-19 07:33:49,076 INFO L75 nceAwareModelManager]: Repository-Root is: /tmp [2022-11-19 07:33:49,108 INFO L261 ainManager$Toolchain]: [Toolchain 1]: Applicable parser(s) successfully (re)initialized [2022-11-19 07:33:49,111 INFO L217 ainManager$Toolchain]: [Toolchain 1]: Toolchain selected. [2022-11-19 07:33:49,112 INFO L271 PluginConnector]: Initializing CDTParser... [2022-11-19 07:33:49,113 INFO L275 PluginConnector]: CDTParser initialized [2022-11-19 07:33:49,114 INFO L432 ainManager$Toolchain]: [Toolchain 1]: Parsing single file: /tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_2654dc4e-57d6-40fb-8b49-624868eeec46/bin/utaipan-I9t0OCRTmS/../../sv-benchmarks/c/Juliet_Test/CWE190_Integer_Overflow__int_rand_square_01_bad.i [2022-11-19 07:33:49,186 INFO L220 CDTParser]: Created temporary CDT project at /tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_2654dc4e-57d6-40fb-8b49-624868eeec46/bin/utaipan-I9t0OCRTmS/data/990ed0c31/80e1e67af8574b55a9b2020ecb69e6c6/FLAGb84ba00d2 [2022-11-19 07:33:49,916 INFO L306 CDTParser]: Found 1 translation units. [2022-11-19 07:33:49,920 INFO L160 CDTParser]: Scanning /tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_2654dc4e-57d6-40fb-8b49-624868eeec46/sv-benchmarks/c/Juliet_Test/CWE190_Integer_Overflow__int_rand_square_01_bad.i [2022-11-19 07:33:49,957 INFO L349 CDTParser]: About to delete temporary CDT project at /tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_2654dc4e-57d6-40fb-8b49-624868eeec46/bin/utaipan-I9t0OCRTmS/data/990ed0c31/80e1e67af8574b55a9b2020ecb69e6c6/FLAGb84ba00d2 [2022-11-19 07:33:50,053 INFO L357 CDTParser]: Successfully deleted /tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_2654dc4e-57d6-40fb-8b49-624868eeec46/bin/utaipan-I9t0OCRTmS/data/990ed0c31/80e1e67af8574b55a9b2020ecb69e6c6 [2022-11-19 07:33:50,056 INFO L299 ainManager$Toolchain]: ####################### [Toolchain 1] ####################### [2022-11-19 07:33:50,058 INFO L131 ToolchainWalker]: Walking toolchain with 6 elements. [2022-11-19 07:33:50,061 INFO L113 PluginConnector]: ------------------------CACSL2BoogieTranslator---------------------------- [2022-11-19 07:33:50,061 INFO L271 PluginConnector]: Initializing CACSL2BoogieTranslator... [2022-11-19 07:33:50,065 INFO L275 PluginConnector]: CACSL2BoogieTranslator initialized [2022-11-19 07:33:50,066 INFO L185 PluginConnector]: Executing the observer ACSLObjectContainerObserver from plugin CACSL2BoogieTranslator for "CDTParser AST 19.11 07:33:50" (1/1) ... [2022-11-19 07:33:50,067 INFO L205 PluginConnector]: Invalid model from CACSL2BoogieTranslator for observer de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator.ACSLObjectContainerObserver@b97de21 and model type de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 19.11 07:33:50, skipping insertion in model container [2022-11-19 07:33:50,067 INFO L185 PluginConnector]: Executing the observer CACSL2BoogieTranslatorObserver from plugin CACSL2BoogieTranslator for "CDTParser AST 19.11 07:33:50" (1/1) ... [2022-11-19 07:33:50,074 INFO L145 MainTranslator]: Starting translation in SV-COMP mode [2022-11-19 07:33:50,158 INFO L178 MainTranslator]: Built tables and reachable declarations [2022-11-19 07:33:50,610 WARN L611 FunctionHandler]: implicit declaration of function __builtin_bswap16 [2022-11-19 07:33:51,512 INFO L210 PostProcessor]: Analyzing one entry point: main [2022-11-19 07:33:51,520 INFO L203 MainTranslator]: Completed pre-run [2022-11-19 07:33:51,538 WARN L611 FunctionHandler]: implicit declaration of function __builtin_bswap16 [2022-11-19 07:33:51,606 INFO L210 PostProcessor]: Analyzing one entry point: main [2022-11-19 07:33:51,853 INFO L208 MainTranslator]: Completed translation [2022-11-19 07:33:51,854 INFO L202 PluginConnector]: Adding new model de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 19.11 07:33:51 WrapperNode [2022-11-19 07:33:51,854 INFO L132 PluginConnector]: ------------------------ END CACSL2BoogieTranslator---------------------------- [2022-11-19 07:33:51,855 INFO L113 PluginConnector]: ------------------------Boogie Procedure Inliner---------------------------- [2022-11-19 07:33:51,855 INFO L271 PluginConnector]: Initializing Boogie Procedure Inliner... [2022-11-19 07:33:51,855 INFO L275 PluginConnector]: Boogie Procedure Inliner initialized [2022-11-19 07:33:51,864 INFO L185 PluginConnector]: Executing the observer TypeChecker from plugin Boogie Procedure Inliner for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 19.11 07:33:51" (1/1) ... [2022-11-19 07:33:51,892 INFO L185 PluginConnector]: Executing the observer Inliner from plugin Boogie Procedure Inliner for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 19.11 07:33:51" (1/1) ... [2022-11-19 07:33:51,918 INFO L138 Inliner]: procedures = 937, calls = 54, calls flagged for inlining = 4, calls inlined = 4, statements flattened = 54 [2022-11-19 07:33:51,919 INFO L132 PluginConnector]: ------------------------ END Boogie Procedure Inliner---------------------------- [2022-11-19 07:33:51,920 INFO L113 PluginConnector]: ------------------------Boogie Preprocessor---------------------------- [2022-11-19 07:33:51,920 INFO L271 PluginConnector]: Initializing Boogie Preprocessor... [2022-11-19 07:33:51,920 INFO L275 PluginConnector]: Boogie Preprocessor initialized [2022-11-19 07:33:51,929 INFO L185 PluginConnector]: Executing the observer EnsureBoogieModelObserver from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 19.11 07:33:51" (1/1) ... [2022-11-19 07:33:51,930 INFO L185 PluginConnector]: Executing the observer TypeChecker from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 19.11 07:33:51" (1/1) ... [2022-11-19 07:33:51,933 INFO L185 PluginConnector]: Executing the observer ConstExpander from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 19.11 07:33:51" (1/1) ... [2022-11-19 07:33:51,933 INFO L185 PluginConnector]: Executing the observer StructExpander from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 19.11 07:33:51" (1/1) ... [2022-11-19 07:33:51,938 INFO L185 PluginConnector]: Executing the observer UnstructureCode from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 19.11 07:33:51" (1/1) ... [2022-11-19 07:33:51,940 INFO L185 PluginConnector]: Executing the observer FunctionInliner from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 19.11 07:33:51" (1/1) ... [2022-11-19 07:33:51,942 INFO L185 PluginConnector]: Executing the observer LTLStepAnnotator from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 19.11 07:33:51" (1/1) ... [2022-11-19 07:33:51,943 INFO L185 PluginConnector]: Executing the observer BoogieSymbolTableConstructor from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 19.11 07:33:51" (1/1) ... [2022-11-19 07:33:51,945 INFO L132 PluginConnector]: ------------------------ END Boogie Preprocessor---------------------------- [2022-11-19 07:33:51,946 INFO L113 PluginConnector]: ------------------------RCFGBuilder---------------------------- [2022-11-19 07:33:51,946 INFO L271 PluginConnector]: Initializing RCFGBuilder... [2022-11-19 07:33:51,946 INFO L275 PluginConnector]: RCFGBuilder initialized [2022-11-19 07:33:51,947 INFO L185 PluginConnector]: Executing the observer RCFGBuilderObserver from plugin RCFGBuilder for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 19.11 07:33:51" (1/1) ... [2022-11-19 07:33:51,960 INFO L173 SolverBuilder]: Constructing external solver with command: z3 SMTLIB2_COMPLIANT=true -memory:2024 -smt2 -in -t:2000 [2022-11-19 07:33:51,972 INFO L189 MonitoredProcess]: No working directory specified, using /tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_2654dc4e-57d6-40fb-8b49-624868eeec46/bin/utaipan-I9t0OCRTmS/z3 [2022-11-19 07:33:51,985 INFO L229 MonitoredProcess]: Starting monitored process 1 with /tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_2654dc4e-57d6-40fb-8b49-624868eeec46/bin/utaipan-I9t0OCRTmS/z3 SMTLIB2_COMPLIANT=true -memory:2024 -smt2 -in -t:2000 (exit command is (exit), workingDir is null) [2022-11-19 07:33:52,000 INFO L327 MonitoredProcess]: [MP /tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_2654dc4e-57d6-40fb-8b49-624868eeec46/bin/utaipan-I9t0OCRTmS/z3 SMTLIB2_COMPLIANT=true -memory:2024 -smt2 -in -t:2000 (1)] Waiting until timeout for monitored process [2022-11-19 07:33:52,039 INFO L130 BoogieDeclarations]: Found specification of procedure #Ultimate.allocInit [2022-11-19 07:33:52,039 INFO L130 BoogieDeclarations]: Found specification of procedure ULTIMATE.start [2022-11-19 07:33:52,039 INFO L138 BoogieDeclarations]: Found implementation of procedure ULTIMATE.start [2022-11-19 07:33:52,039 INFO L130 BoogieDeclarations]: Found specification of procedure time [2022-11-19 07:33:52,040 INFO L130 BoogieDeclarations]: Found specification of procedure printLine [2022-11-19 07:33:52,040 INFO L138 BoogieDeclarations]: Found implementation of procedure printLine [2022-11-19 07:33:52,040 INFO L130 BoogieDeclarations]: Found specification of procedure write~init~int [2022-11-19 07:33:52,207 INFO L235 CfgBuilder]: Building ICFG [2022-11-19 07:33:52,209 INFO L261 CfgBuilder]: Building CFG for each procedure with an implementation [2022-11-19 07:33:52,448 INFO L276 CfgBuilder]: Performing block encoding [2022-11-19 07:33:52,549 INFO L295 CfgBuilder]: Using the 1 location(s) as analysis (start of procedure ULTIMATE.start) [2022-11-19 07:33:52,560 INFO L300 CfgBuilder]: Removed 0 assume(true) statements. [2022-11-19 07:33:52,562 INFO L202 PluginConnector]: Adding new model de.uni_freiburg.informatik.ultimate.plugins.generator.rcfgbuilder CFG 19.11 07:33:52 BoogieIcfgContainer [2022-11-19 07:33:52,563 INFO L132 PluginConnector]: ------------------------ END RCFGBuilder---------------------------- [2022-11-19 07:33:52,565 INFO L113 PluginConnector]: ------------------------TraceAbstraction---------------------------- [2022-11-19 07:33:52,566 INFO L271 PluginConnector]: Initializing TraceAbstraction... [2022-11-19 07:33:52,569 INFO L275 PluginConnector]: TraceAbstraction initialized [2022-11-19 07:33:52,570 INFO L185 PluginConnector]: Executing the observer TraceAbstractionObserver from plugin TraceAbstraction for "CDTParser AST 19.11 07:33:50" (1/3) ... [2022-11-19 07:33:52,571 INFO L205 PluginConnector]: Invalid model from TraceAbstraction for observer de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction.TraceAbstractionObserver@38e34223 and model type de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction AST 19.11 07:33:52, skipping insertion in model container [2022-11-19 07:33:52,572 INFO L185 PluginConnector]: Executing the observer TraceAbstractionObserver from plugin TraceAbstraction for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 19.11 07:33:51" (2/3) ... [2022-11-19 07:33:52,572 INFO L205 PluginConnector]: Invalid model from TraceAbstraction for observer de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction.TraceAbstractionObserver@38e34223 and model type de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction AST 19.11 07:33:52, skipping insertion in model container [2022-11-19 07:33:52,572 INFO L185 PluginConnector]: Executing the observer TraceAbstractionObserver from plugin TraceAbstraction for "de.uni_freiburg.informatik.ultimate.plugins.generator.rcfgbuilder CFG 19.11 07:33:52" (3/3) ... [2022-11-19 07:33:52,574 INFO L112 eAbstractionObserver]: Analyzing ICFG CWE190_Integer_Overflow__int_rand_square_01_bad.i [2022-11-19 07:33:52,592 INFO L203 ceAbstractionStarter]: Automizer settings: Hoare:true NWA Interpolation:FPandBP Determinization: PREDICATE_ABSTRACTION [2022-11-19 07:33:52,593 INFO L162 ceAbstractionStarter]: Applying trace abstraction to program that has 2 error locations. [2022-11-19 07:33:52,649 INFO L356 AbstractCegarLoop]: ======== Iteration 0 == of CEGAR loop == AllErrorsAtOnce ======== [2022-11-19 07:33:52,657 INFO L357 AbstractCegarLoop]: Settings: SEPARATE_VIOLATION_CHECK=true, mInterprocedural=true, mMaxIterations=1000000, mWatchIteration=1000000, mArtifact=RCFG, mInterpolation=FPandBP, mInterpolantAutomaton=STRAIGHT_LINE, mDumpAutomata=false, mAutomataFormat=ATS_NUMERATE, mDumpPath=., mDeterminiation=PREDICATE_ABSTRACTION, mMinimize=MINIMIZE_SEVPA, mHoare=true, mAutomataTypeConcurrency=FINITE_AUTOMATA, mHoareTripleChecks=INCREMENTAL, mHoareAnnotationPositions=LoopsAndPotentialCycles, mDumpOnlyReuseAutomata=false, mLimitTraceHistogram=0, mErrorLocTimeLimit=0, mLimitPathProgramCount=0, mCollectInterpolantStatistics=true, mHeuristicEmptinessCheck=false, mHeuristicEmptinessCheckAStarHeuristic=ZERO, mHeuristicEmptinessCheckAStarHeuristicRandomSeed=1337, mHeuristicEmptinessCheckSmtFeatureScoringMethod=DAGSIZE, mSMTFeatureExtraction=false, mSMTFeatureExtractionDumpPath=., mOverrideInterpolantAutomaton=false, mMcrInterpolantMethod=WP, mPorIndependenceSettings=[Lde.uni_freiburg.informatik.ultimate.lib.tracecheckerutils.partialorder.independence.IndependenceSettings;@6f41ca8e, mLbeIndependenceSettings=[IndependenceType=SEMANTIC, AbstractionType=NONE, UseConditional=false, UseSemiCommutativity=true, Solver=Z3, SolverTimeout=1000ms] [2022-11-19 07:33:52,658 INFO L358 AbstractCegarLoop]: Starting to check reachability of 2 error locations. [2022-11-19 07:33:52,663 INFO L276 IsEmpty]: Start isEmpty. Operand has 12 states, 6 states have (on average 1.3333333333333333) internal successors, (8), 8 states have internal predecessors, (8), 2 states have call successors, (2), 1 states have call predecessors, (2), 1 states have return successors, (2), 2 states have call predecessors, (2), 2 states have call successors, (2) [2022-11-19 07:33:52,670 INFO L282 IsEmpty]: Finished isEmpty. Found accepting run of length 7 [2022-11-19 07:33:52,671 INFO L187 NwaCegarLoop]: Found error trace [2022-11-19 07:33:52,671 INFO L195 NwaCegarLoop]: trace histogram [1, 1, 1, 1, 1, 1] [2022-11-19 07:33:52,673 INFO L420 AbstractCegarLoop]: === Iteration 1 === Targeting ULTIMATE.startErr0ASSERT_VIOLATIONINTEGER_OVERFLOW === [ULTIMATE.startErr0ASSERT_VIOLATIONINTEGER_OVERFLOW, ULTIMATE.startErr1ASSERT_VIOLATIONINTEGER_OVERFLOW] === [2022-11-19 07:33:52,680 INFO L144 PredicateUnifier]: Initialized classic predicate unifier [2022-11-19 07:33:52,681 INFO L85 PathProgramCache]: Analyzing trace with hash 2064490869, now seen corresponding path program 1 times [2022-11-19 07:33:52,692 INFO L118 FreeRefinementEngine]: Executing refinement strategy SIFA_TAIPAN [2022-11-19 07:33:52,694 INFO L333 FreeRefinementEngine]: Using trace check IpTcStrategyModuleSmtInterpolCraig [1131797152] [2022-11-19 07:33:52,694 INFO L95 rtionOrderModulation]: Keeping assertion order NOT_INCREMENTALLY [2022-11-19 07:33:52,695 INFO L127 SolverBuilder]: Constructing new instance of SMTInterpol with explicit timeout -1 ms and remaining time -1 ms [2022-11-19 07:33:52,901 ERROR L245 FreeRefinementEngine]: Caught known exception: Unsupported non-linear arithmetic [2022-11-19 07:33:52,904 INFO L333 FreeRefinementEngine]: Using trace check IpTcStrategyModuleZ3 [967528100] [2022-11-19 07:33:52,904 INFO L95 rtionOrderModulation]: Keeping assertion order NOT_INCREMENTALLY [2022-11-19 07:33:52,905 INFO L173 SolverBuilder]: Constructing external solver with command: z3 -smt2 -in SMTLIB2_COMPLIANT=true [2022-11-19 07:33:52,905 INFO L189 MonitoredProcess]: No working directory specified, using /tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_2654dc4e-57d6-40fb-8b49-624868eeec46/bin/utaipan-I9t0OCRTmS/z3 [2022-11-19 07:33:52,909 INFO L229 MonitoredProcess]: Starting monitored process 2 with /tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_2654dc4e-57d6-40fb-8b49-624868eeec46/bin/utaipan-I9t0OCRTmS/z3 -smt2 -in SMTLIB2_COMPLIANT=true (exit command is (exit), workingDir is null) [2022-11-19 07:33:52,937 INFO L327 MonitoredProcess]: [MP /tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_2654dc4e-57d6-40fb-8b49-624868eeec46/bin/utaipan-I9t0OCRTmS/z3 -smt2 -in SMTLIB2_COMPLIANT=true (2)] Waiting until timeout for monitored process [2022-11-19 07:33:53,039 INFO L136 AnnotateAndAsserter]: Conjunction of SSA is sat [2022-11-19 07:33:53,039 INFO L356 TraceCheck]: Trace is feasible, we will do another trace check, this time with branch encoders. [2022-11-19 07:33:53,068 INFO L136 AnnotateAndAsserter]: Conjunction of SSA is sat [2022-11-19 07:33:53,104 INFO L130 FreeRefinementEngine]: Strategy SIFA_TAIPAN found a feasible trace [2022-11-19 07:33:53,108 INFO L359 BasicCegarLoop]: Counterexample is feasible [2022-11-19 07:33:53,109 INFO L805 garLoopResultBuilder]: Registering result UNSAFE for location ULTIMATE.startErr0ASSERT_VIOLATIONINTEGER_OVERFLOW (1 of 2 remaining) [2022-11-19 07:33:53,113 INFO L805 garLoopResultBuilder]: Registering result UNKNOWN for location ULTIMATE.startErr1ASSERT_VIOLATIONINTEGER_OVERFLOW (0 of 2 remaining) [2022-11-19 07:33:53,125 INFO L552 MonitoredProcess]: [MP /tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_2654dc4e-57d6-40fb-8b49-624868eeec46/bin/utaipan-I9t0OCRTmS/z3 -smt2 -in SMTLIB2_COMPLIANT=true (2)] Ended with exit code 0 [2022-11-19 07:33:53,319 WARN L477 AbstractCegarLoop]: Destroyed unattended storables created during the last iteration: 2 /tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_2654dc4e-57d6-40fb-8b49-624868eeec46/bin/utaipan-I9t0OCRTmS/z3 -smt2 -in SMTLIB2_COMPLIANT=true,SelfDestructingSolverStorable0 [2022-11-19 07:33:53,323 INFO L444 BasicCegarLoop]: Path program histogram: [1] [2022-11-19 07:33:53,327 INFO L178 ceAbstractionStarter]: Computing trace abstraction results [2022-11-19 07:33:53,365 INFO L202 PluginConnector]: Adding new model de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction CFG 19.11 07:33:53 BoogieIcfgContainer [2022-11-19 07:33:53,365 INFO L132 PluginConnector]: ------------------------ END TraceAbstraction---------------------------- [2022-11-19 07:33:53,366 INFO L113 PluginConnector]: ------------------------Witness Printer---------------------------- [2022-11-19 07:33:53,366 INFO L271 PluginConnector]: Initializing Witness Printer... [2022-11-19 07:33:53,366 INFO L275 PluginConnector]: Witness Printer initialized [2022-11-19 07:33:53,367 INFO L185 PluginConnector]: Executing the observer RCFGCatcher from plugin Witness Printer for "de.uni_freiburg.informatik.ultimate.plugins.generator.rcfgbuilder CFG 19.11 07:33:52" (3/4) ... [2022-11-19 07:33:53,370 INFO L140 WitnessPrinter]: No result that supports witness generation found [2022-11-19 07:33:53,370 INFO L132 PluginConnector]: ------------------------ END Witness Printer---------------------------- [2022-11-19 07:33:53,372 INFO L158 Benchmark]: Toolchain (without parser) took 3313.66ms. Allocated memory was 142.6MB in the beginning and 176.2MB in the end (delta: 33.6MB). Free memory was 108.6MB in the beginning and 132.5MB in the end (delta: -23.8MB). Peak memory consumption was 8.8MB. Max. memory is 16.1GB. [2022-11-19 07:33:53,373 INFO L158 Benchmark]: CDTParser took 0.28ms. Allocated memory is still 92.3MB. Free memory is still 49.3MB. There was no memory consumed. Max. memory is 16.1GB. [2022-11-19 07:33:53,375 INFO L158 Benchmark]: CACSL2BoogieTranslator took 1793.81ms. Allocated memory is still 142.6MB. Free memory was 108.2MB in the beginning and 94.6MB in the end (delta: 13.7MB). Peak memory consumption was 57.2MB. Max. memory is 16.1GB. [2022-11-19 07:33:53,376 INFO L158 Benchmark]: Boogie Procedure Inliner took 64.14ms. Allocated memory is still 142.6MB. Free memory was 94.6MB in the beginning and 90.7MB in the end (delta: 3.9MB). Peak memory consumption was 4.2MB. Max. memory is 16.1GB. [2022-11-19 07:33:53,382 INFO L158 Benchmark]: Boogie Preprocessor took 25.77ms. Allocated memory is still 142.6MB. Free memory was 90.7MB in the beginning and 88.6MB in the end (delta: 2.1MB). Peak memory consumption was 2.1MB. Max. memory is 16.1GB. [2022-11-19 07:33:53,383 INFO L158 Benchmark]: RCFGBuilder took 616.73ms. Allocated memory is still 142.6MB. Free memory was 88.6MB in the beginning and 70.6MB in the end (delta: 18.0MB). Peak memory consumption was 18.9MB. Max. memory is 16.1GB. [2022-11-19 07:33:53,385 INFO L158 Benchmark]: TraceAbstraction took 800.00ms. Allocated memory was 142.6MB in the beginning and 176.2MB in the end (delta: 33.6MB). Free memory was 69.8MB in the beginning and 133.3MB in the end (delta: -63.5MB). There was no memory consumed. Max. memory is 16.1GB. [2022-11-19 07:33:53,386 INFO L158 Benchmark]: Witness Printer took 4.58ms. Allocated memory is still 176.2MB. Free memory was 133.3MB in the beginning and 132.5MB in the end (delta: 815.8kB). There was no memory consumed. Max. memory is 16.1GB. [2022-11-19 07:33:53,394 INFO L339 ainManager$Toolchain]: ####################### End [Toolchain 1] ####################### --- Results --- * Results from de.uni_freiburg.informatik.ultimate.core: - StatisticsResult: Toolchain Benchmarks Benchmark results are: * CDTParser took 0.28ms. Allocated memory is still 92.3MB. Free memory is still 49.3MB. There was no memory consumed. Max. memory is 16.1GB. * CACSL2BoogieTranslator took 1793.81ms. Allocated memory is still 142.6MB. Free memory was 108.2MB in the beginning and 94.6MB in the end (delta: 13.7MB). Peak memory consumption was 57.2MB. Max. memory is 16.1GB. * Boogie Procedure Inliner took 64.14ms. Allocated memory is still 142.6MB. Free memory was 94.6MB in the beginning and 90.7MB in the end (delta: 3.9MB). Peak memory consumption was 4.2MB. Max. memory is 16.1GB. * Boogie Preprocessor took 25.77ms. Allocated memory is still 142.6MB. Free memory was 90.7MB in the beginning and 88.6MB in the end (delta: 2.1MB). Peak memory consumption was 2.1MB. Max. memory is 16.1GB. * RCFGBuilder took 616.73ms. Allocated memory is still 142.6MB. Free memory was 88.6MB in the beginning and 70.6MB in the end (delta: 18.0MB). Peak memory consumption was 18.9MB. Max. memory is 16.1GB. * TraceAbstraction took 800.00ms. Allocated memory was 142.6MB in the beginning and 176.2MB in the end (delta: 33.6MB). Free memory was 69.8MB in the beginning and 133.3MB in the end (delta: -63.5MB). There was no memory consumed. Max. memory is 16.1GB. * Witness Printer took 4.58ms. Allocated memory is still 176.2MB. Free memory was 133.3MB in the beginning and 132.5MB in the end (delta: 815.8kB). There was no memory consumed. Max. memory is 16.1GB. * Results from de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction: - StatisticsResult: ErrorAutomatonStatistics NumberErrorTraces: 0, NumberStatementsAllTraces: 0, NumberRelevantStatements: 0, 0.0s ErrorAutomatonConstructionTimeTotal, 0.0s FaulLocalizationTime, NumberStatementsFirstTrace: -1, TraceLengthAvg: 0, 0.0s ErrorAutomatonConstructionTimeAvg, 0.0s ErrorAutomatonDifferenceTimeAvg, 0.0s ErrorAutomatonDifferenceTimeTotal, NumberOfNoEnhancement: 0, NumberOfFiniteEnhancement: 0, NumberOfInfiniteEnhancement: 0 - UnprovableResult [Line: 1838]: Unable to prove that integer overflow can never occur Unable to prove that integer overflow can never occur Reason: overapproximation of bitwiseXor at line 1836, overapproximation of bitwiseAnd at line 1836. Possible FailurePath: [L1525] int globalTrue = 1; [L1547] char** globalArgv = ((void *)0); [L1526] int globalFalse = 0; [L1523] const int GLOBAL_CONST_FALSE = 0; [L1524] const int GLOBAL_CONST_FIVE = 5; [L1546] int globalArgc = 0; [L1522] const int GLOBAL_CONST_TRUE = 1; [L1527] int globalFive = 5; [L1845] CALL printLine("Calling bad()...") VAL [GLOBAL_CONST_FALSE=0, GLOBAL_CONST_FIVE=5, GLOBAL_CONST_TRUE=1, globalArgc=0, globalArgv={0:0}, globalFalse=0, globalFive=5, globalTrue=1, line={2:0}] [L1414] COND TRUE line != ((void *)0) [L1845] RET printLine("Calling bad()...") VAL [\old(argc)=13, argc=13, argv={14:12}, argv={14:12}, GLOBAL_CONST_FALSE=0, GLOBAL_CONST_FIVE=5, GLOBAL_CONST_TRUE=1, globalArgc=0, globalArgv={0:0}, globalFalse=0, globalFive=5, globalTrue=1] [L1846] CALL CWE190_Integer_Overflow__int_rand_square_01_bad() [L1834] int data; [L1835] data = 0 [L1836] EXPR rand() & 1 ? (((unsigned)rand()<<30) ^ ((unsigned)rand()<<15) ^ rand()) : -(((unsigned)rand()<<30) ^ ((unsigned)rand()<<15) ^ rand()) - 1 [L1836] EXPR rand() & 1 ? (((unsigned)rand()<<30) ^ ((unsigned)rand()<<15) ^ rand()) : -(((unsigned)rand()<<30) ^ ((unsigned)rand()<<15) ^ rand()) - 1 [L1836] data = ((int)(rand() & 1 ? (((unsigned)rand()<<30) ^ ((unsigned)rand()<<15) ^ rand()) : -(((unsigned)rand()<<30) ^ ((unsigned)rand()<<15) ^ rand()) - 1)) [L1838] data * data VAL [data=-2147483648, GLOBAL_CONST_FALSE=0, GLOBAL_CONST_FIVE=5, GLOBAL_CONST_TRUE=1, globalArgc=0, globalArgv={0:0}, globalFalse=0, globalFive=5, globalTrue=1] - UnprovableResult [Line: 1838]: Unable to prove that integer overflow can never occur Unable to prove that integer overflow can never occur Reason: Not analyzed. - StatisticsResult: Ultimate Automizer benchmark data CFG has 2 procedures, 12 locations, 2 error locations. Started 1 CEGAR loops. OverallTime: 0.7s, OverallIterations: 1, TraceHistogramMax: 1, PathProgramHistogramMax: 1, EmptinessCheckTime: 0.0s, AutomataDifference: 0.0s, DeadEndRemovalTime: 0.0s, HoareAnnotationTime: 0.0s, InitialAbstractionConstructionTime: 0.0s, HoareTripleCheckerStatistics: , PredicateUnifierStatistics: No data available, 0.0s BasicInterpolantAutomatonTime, BiggestAbstraction: size=12occurred in iteration=0, InterpolantAutomatonStates: 0, traceCheckStatistics: No data available, InterpolantConsolidationStatistics: No data available, PathInvariantsStatistics: No data available, 0/0 InterpolantCoveringCapability, TotalInterpolationStatistics: No data available, 0.0s DumpTime, AutomataMinimizationStatistics: No data available, HoareAnnotationStatistics: No data available, RefinementEngineStatistics: TRACE_CHECK: 0.0s SsaConstructionTime, 0.1s SatisfiabilityAnalysisTime, 0.0s InterpolantComputationTime, 6 NumberOfCodeBlocks, 6 NumberOfCodeBlocksAsserted, 1 NumberOfCheckSat, 0 ConstructedInterpolants, 0 QuantifiedInterpolants, 0 SizeOfPredicates, 0 NumberOfNonLiveVariables, 0 ConjunctsInSsa, 0 ConjunctsInUnsatCore, 0 InterpolantComputations, 0 PerfectInterpolantSequences, 0/0 InterpolantCoveringCapability, INVARIANT_SYNTHESIS: No data available, INTERPOLANT_CONSOLIDATION: No data available, ABSTRACT_INTERPRETATION: No data available, PDR: No data available, ACCELERATED_INTERPOLATION: No data available, SIFA: No data available, ReuseStatistics: No data available RESULT: Ultimate could not prove your program: unable to determine feasibility of some traces [2022-11-19 07:33:53,427 INFO L540 MonitoredProcess]: [MP /tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_2654dc4e-57d6-40fb-8b49-624868eeec46/bin/utaipan-I9t0OCRTmS/z3 SMTLIB2_COMPLIANT=true -memory:2024 -smt2 -in -t:2000 (1)] Forceful destruction successful, exit code 0 Received shutdown request... --- End real Ultimate output --- Execution finished normally Using bit-precise analysis No suitable file found in config dir /tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_2654dc4e-57d6-40fb-8b49-624868eeec46/bin/utaipan-I9t0OCRTmS/config using search string *Overflow*64bit*_Bitvector*.epf No suitable settings file found using Overflow*64bit*_Bitvector ERROR: UNSUPPORTED PROPERTY Writing output log to file Ultimate.log Result: UNKNOWN: Overapproximated counterexample