./Ultimate.py --spec ../sv-benchmarks/c/properties/unreach-call.prp --file ../sv-benchmarks/c/loop-industry-pattern/mod3.c.v+sep-reducer.c --full-output --witness-type correctness_witness --validate ../results/automizer-verification-files/SV-COMP24_unreach-call/mod3.c.v+sep-reducer.yml/witness-2.1.yml --architecture 32bit -------------------------------------------------------------------------------- Checking for ERROR reachability Using default analysis Version 27b49876 Calling Ultimate with: /root/.sdkman/candidates/java/current/bin/java -Dosgi.configuration.area=/storage/repos/certificate-witnesses-artifact/referee/data/config -Xmx15G -Xms4m -jar /storage/repos/certificate-witnesses-artifact/referee/plugins/org.eclipse.equinox.launcher_1.5.800.v20200727-1323.jar -data @noDefault -ultimatedata /storage/repos/certificate-witnesses-artifact/referee/data -tc /storage/repos/certificate-witnesses-artifact/referee/config/RefereeReachWitnessValidation.xml -i ../sv-benchmarks/c/loop-industry-pattern/mod3.c.v+sep-reducer.c ../results/automizer-verification-files/SV-COMP24_unreach-call/mod3.c.v+sep-reducer.yml/witness-2.1.yml -s /storage/repos/certificate-witnesses-artifact/referee/config/svcomp-Reach-32bit-Referee_Default.epf --cacsl2boogietranslator.entry.function main --traceabstraction.positions.where.we.compute.the.hoare.annotation None --- Real Ultimate output --- This is Ultimate 0.2.4-tmp.dk.referee-eval-27b4987-m [2024-09-21 12:47:57,255 INFO L188 SettingsManager]: Resetting all preferences to default values... [2024-09-21 12:47:57,312 INFO L114 SettingsManager]: Loading settings from /storage/repos/certificate-witnesses-artifact/referee/config/svcomp-Reach-32bit-Referee_Default.epf [2024-09-21 12:47:57,317 WARN L101 SettingsManager]: Preference file contains the following unknown settings: [2024-09-21 12:47:57,319 WARN L103 SettingsManager]: * de.uni_freiburg.informatik.ultimate.core.Log level for class [2024-09-21 12:47:57,339 INFO L130 SettingsManager]: Preferences different from defaults after loading the file: [2024-09-21 12:47:57,339 INFO L151 SettingsManager]: Preferences of UltimateCore differ from their defaults: [2024-09-21 12:47:57,340 INFO L153 SettingsManager]: * Log level for class=de.uni_freiburg.informatik.ultimate.lib.smtlibutils.quantifier.QuantifierPusher=ERROR; [2024-09-21 12:47:57,340 INFO L151 SettingsManager]: Preferences of Boogie Preprocessor differ from their defaults: [2024-09-21 12:47:57,341 INFO L153 SettingsManager]: * Use memory slicer=true [2024-09-21 12:47:57,342 INFO L151 SettingsManager]: Preferences of Boogie Procedure Inliner differ from their defaults: [2024-09-21 12:47:57,342 INFO L153 SettingsManager]: * Ignore calls to procedures called more than once=ONLY_FOR_SEQUENTIAL_PROGRAMS [2024-09-21 12:47:57,342 INFO L151 SettingsManager]: Preferences of BlockEncodingV2 differ from their defaults: [2024-09-21 12:47:57,344 INFO L153 SettingsManager]: * Create parallel compositions if possible=false [2024-09-21 12:47:57,344 INFO L153 SettingsManager]: * Use SBE=true [2024-09-21 12:47:57,345 INFO L151 SettingsManager]: Preferences of CACSL2BoogieTranslator differ from their defaults: [2024-09-21 12:47:57,345 INFO L153 SettingsManager]: * Pointer base address is valid at dereference=IGNORE [2024-09-21 12:47:57,345 INFO L153 SettingsManager]: * sizeof long=4 [2024-09-21 12:47:57,345 INFO L153 SettingsManager]: * Overapproximate operations on floating types=true [2024-09-21 12:47:57,346 INFO L153 SettingsManager]: * sizeof POINTER=4 [2024-09-21 12:47:57,346 INFO L153 SettingsManager]: * Check division by zero=IGNORE [2024-09-21 12:47:57,349 INFO L153 SettingsManager]: * Pointer to allocated memory at dereference=IGNORE [2024-09-21 12:47:57,349 INFO L153 SettingsManager]: * If two pointers are subtracted or compared they have the same base address=IGNORE [2024-09-21 12:47:57,349 INFO L153 SettingsManager]: * Check array bounds for arrays that are off heap=IGNORE [2024-09-21 12:47:57,350 INFO L153 SettingsManager]: * Allow undefined functions=false [2024-09-21 12:47:57,350 INFO L153 SettingsManager]: * sizeof long double=12 [2024-09-21 12:47:57,350 INFO L153 SettingsManager]: * Check if freed pointer was valid=false [2024-09-21 12:47:57,350 INFO L153 SettingsManager]: * Use constant arrays=true [2024-09-21 12:47:57,350 INFO L151 SettingsManager]: Preferences of RCFGBuilder differ from their defaults: [2024-09-21 12:47:57,351 INFO L153 SettingsManager]: * Size of a code block=SequenceOfStatements [2024-09-21 12:47:57,351 INFO L153 SettingsManager]: * Future-live optimization=false [2024-09-21 12:47:57,351 INFO L153 SettingsManager]: * Only consider context switches at boundaries of atomic blocks=true [2024-09-21 12:47:57,351 INFO L153 SettingsManager]: * SMT solver=External_DefaultMode [2024-09-21 12:47:57,351 INFO L153 SettingsManager]: * Command for external solver=z3 SMTLIB2_COMPLIANT=true -memory:2024 -smt2 -in -t:4000 [2024-09-21 12:47:57,352 INFO L151 SettingsManager]: Preferences of TraceAbstraction differ from their defaults: [2024-09-21 12:47:57,352 INFO L153 SettingsManager]: * Compute Interpolants along a Counterexample=FPandBP [2024-09-21 12:47:57,352 INFO L153 SettingsManager]: * Positions where we compute the Hoare Annotation=LoopHeads [2024-09-21 12:47:57,352 INFO L153 SettingsManager]: * Trace refinement strategy=CAMEL [2024-09-21 12:47:57,353 INFO L153 SettingsManager]: * Command for external solver=z3 SMTLIB2_COMPLIANT=true -memory:2024 -smt2 -in [2024-09-21 12:47:57,353 INFO L153 SettingsManager]: * Apply one-shot large block encoding in concurrent analysis=false [2024-09-21 12:47:57,354 INFO L153 SettingsManager]: * Automaton type used in concurrency analysis=PETRI_NET [2024-09-21 12:47:57,354 INFO L153 SettingsManager]: * Order on configurations for Petri net unfoldings=DBO [2024-09-21 12:47:57,354 INFO L153 SettingsManager]: * SMT solver=External_ModelsAndUnsatCoreMode [2024-09-21 12:47:57,355 INFO L153 SettingsManager]: * Looper check in Petri net analysis=SEMANTIC WARNING: An illegal reflective access operation has occurred WARNING: Illegal reflective access by com.sun.xml.bind.v2.runtime.reflect.opt.Injector$1 (file:/storage/repos/certificate-witnesses-artifact/referee/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$1 WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations WARNING: All illegal access operations will be denied in a future release Applying setting for plugin de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator: Entry function -> main Applying setting for plugin de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction: Positions where we compute the Hoare Annotation -> None [2024-09-21 12:47:57,578 INFO L75 nceAwareModelManager]: Repository-Root is: /tmp [2024-09-21 12:47:57,603 INFO L261 ainManager$Toolchain]: [Toolchain 1]: Applicable parser(s) successfully (re)initialized [2024-09-21 12:47:57,606 INFO L217 ainManager$Toolchain]: [Toolchain 1]: Toolchain selected. [2024-09-21 12:47:57,607 INFO L270 PluginConnector]: Initializing Witness Parser... [2024-09-21 12:47:57,607 INFO L274 PluginConnector]: Witness Parser initialized [2024-09-21 12:47:57,608 INFO L431 ainManager$Toolchain]: [Toolchain 1]: Parsing single file: /storage/repos/certificate-witnesses-artifact/referee/../results/automizer-verification-files/SV-COMP24_unreach-call/mod3.c.v+sep-reducer.yml/witness-2.1.yml [2024-09-21 12:47:57,684 INFO L270 PluginConnector]: Initializing CDTParser... [2024-09-21 12:47:57,685 INFO L274 PluginConnector]: CDTParser initialized [2024-09-21 12:47:57,685 INFO L431 ainManager$Toolchain]: [Toolchain 1]: Parsing single file: /storage/repos/certificate-witnesses-artifact/referee/../sv-benchmarks/c/loop-industry-pattern/mod3.c.v+sep-reducer.c [2024-09-21 12:47:58,888 INFO L533 CDTParser]: Created temporary CDT project at NULL [2024-09-21 12:47:59,052 INFO L384 CDTParser]: Found 1 translation units. [2024-09-21 12:47:59,053 INFO L180 CDTParser]: Scanning /storage/repos/certificate-witnesses-artifact/sv-benchmarks/c/loop-industry-pattern/mod3.c.v+sep-reducer.c [2024-09-21 12:47:59,060 INFO L427 CDTParser]: About to delete temporary CDT project at /storage/repos/certificate-witnesses-artifact/referee/data/b68bd0d90/dbb1c620306446e7b99cf4c170cbe2eb/FLAG6546cbf64 [2024-09-21 12:47:59,455 INFO L435 CDTParser]: Successfully deleted /storage/repos/certificate-witnesses-artifact/referee/data/b68bd0d90/dbb1c620306446e7b99cf4c170cbe2eb [2024-09-21 12:47:59,455 INFO L299 ainManager$Toolchain]: ####################### [Toolchain 1] ####################### [2024-09-21 12:47:59,456 INFO L133 ToolchainWalker]: Walking toolchain with 4 elements. [2024-09-21 12:47:59,457 INFO L112 PluginConnector]: ------------------------CACSL2BoogieTranslator---------------------------- [2024-09-21 12:47:59,457 INFO L270 PluginConnector]: Initializing CACSL2BoogieTranslator... [2024-09-21 12:47:59,463 INFO L274 PluginConnector]: CACSL2BoogieTranslator initialized [2024-09-21 12:47:59,464 INFO L184 PluginConnector]: Executing the observer ACSLObjectContainerObserver from plugin CACSL2BoogieTranslator for "witness-2.1.yml de.uni_freiburg.informatik.ultimate.witnessparser CORRECTNESS_WITNESS 21.09 12:47:57" (1/2) ... [2024-09-21 12:47:59,464 INFO L204 PluginConnector]: Invalid model from CACSL2BoogieTranslator for observer de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator.ACSLObjectContainerObserver@f52c0f8 and model type witness-2.1.yml de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator CORRECTNESS_WITNESS 21.09 12:47:59, skipping insertion in model container [2024-09-21 12:47:59,465 INFO L184 PluginConnector]: Executing the observer CACSL2BoogieTranslatorObserver from plugin CACSL2BoogieTranslator for "witness-2.1.yml de.uni_freiburg.informatik.ultimate.witnessparser CORRECTNESS_WITNESS 21.09 12:47:57" (1/2) ... [2024-09-21 12:47:59,465 INFO L204 PluginConnector]: Invalid model from CACSL2BoogieTranslator for observer de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator.CACSL2BoogieTranslatorObserver@2c3801a1 and model type witness-2.1.yml de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator CORRECTNESS_WITNESS 21.09 12:47:59, skipping insertion in model container [2024-09-21 12:47:59,466 INFO L184 PluginConnector]: Executing the observer ACSLObjectContainerObserver from plugin CACSL2BoogieTranslator for "CDTParser AST 21.09 12:47:59" (2/2) ... [2024-09-21 12:47:59,466 INFO L204 PluginConnector]: Invalid model from CACSL2BoogieTranslator for observer de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator.ACSLObjectContainerObserver@f52c0f8 and model type de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.09 12:47:59, skipping insertion in model container [2024-09-21 12:47:59,466 INFO L184 PluginConnector]: Executing the observer CACSL2BoogieTranslatorObserver from plugin CACSL2BoogieTranslator for "CDTParser AST 21.09 12:47:59" (2/2) ... [2024-09-21 12:47:59,471 INFO L93 nessWitnessExtractor]: Found the following entries in the witness: [2024-09-21 12:47:59,472 INFO L1541 ArrayList]: Location invariant before [L36-L112] ((main__x % 3) < 1) [2024-09-21 12:47:59,472 INFO L1541 ArrayList]: Location invariant before [L24-L141] ((main__x % 3) < 1) [2024-09-21 12:47:59,472 INFO L1541 ArrayList]: Location invariant before [L42-L42] ((main__x % 3) < 1) [2024-09-21 12:47:59,486 INFO L175 MainTranslator]: Built tables and reachable declarations [2024-09-21 12:47:59,629 WARN L248 ndardFunctionHandler]: Function reach_error is already implemented but we override the implementation for the call at /storage/repos/certificate-witnesses-artifact/sv-benchmarks/c/loop-industry-pattern/mod3.c.v+sep-reducer.c[2057,2070] [2024-09-21 12:47:59,640 INFO L210 PostProcessor]: Analyzing one entry point: main [2024-09-21 12:47:59,649 INFO L200 MainTranslator]: Completed pre-run Start Parsing Local [2024-09-21 12:47:59,688 WARN L248 ndardFunctionHandler]: Function reach_error is already implemented but we override the implementation for the call at /storage/repos/certificate-witnesses-artifact/sv-benchmarks/c/loop-industry-pattern/mod3.c.v+sep-reducer.c[2057,2070] Start Parsing Local Start Parsing Local [2024-09-21 12:47:59,694 INFO L210 PostProcessor]: Analyzing one entry point: main [2024-09-21 12:47:59,710 INFO L204 MainTranslator]: Completed translation [2024-09-21 12:47:59,710 INFO L201 PluginConnector]: Adding new model de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.09 12:47:59 WrapperNode [2024-09-21 12:47:59,710 INFO L131 PluginConnector]: ------------------------ END CACSL2BoogieTranslator---------------------------- [2024-09-21 12:47:59,711 INFO L112 PluginConnector]: ------------------------Boogie Preprocessor---------------------------- [2024-09-21 12:47:59,711 INFO L270 PluginConnector]: Initializing Boogie Preprocessor... [2024-09-21 12:47:59,711 INFO L274 PluginConnector]: Boogie Preprocessor initialized [2024-09-21 12:47:59,720 INFO L184 PluginConnector]: Executing the observer EnsureBoogieModelObserver from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.09 12:47:59" (1/1) ... [2024-09-21 12:47:59,721 INFO L184 PluginConnector]: Executing the observer TypeChecker from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.09 12:47:59" (1/1) ... [2024-09-21 12:47:59,725 INFO L184 PluginConnector]: Executing the observer MemorySlicer from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.09 12:47:59" (1/1) ... [2024-09-21 12:47:59,759 INFO L175 MemorySlicer]: Split 2 memory accesses to 1 slices as follows [2]. 100 percent of accesses are in the largest equivalence class. The 2 initializations are split as follows [2]. The 0 writes are split as follows [0]. [2024-09-21 12:47:59,759 INFO L184 PluginConnector]: Executing the observer ConstExpander from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.09 12:47:59" (1/1) ... [2024-09-21 12:47:59,759 INFO L184 PluginConnector]: Executing the observer StructExpander from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.09 12:47:59" (1/1) ... [2024-09-21 12:47:59,762 INFO L184 PluginConnector]: Executing the observer UnstructureCode from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.09 12:47:59" (1/1) ... [2024-09-21 12:47:59,768 INFO L184 PluginConnector]: Executing the observer FunctionInliner from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.09 12:47:59" (1/1) ... [2024-09-21 12:47:59,769 INFO L184 PluginConnector]: Executing the observer LTLStepAnnotator from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.09 12:47:59" (1/1) ... [2024-09-21 12:47:59,773 INFO L184 PluginConnector]: Executing the observer BoogieSymbolTableConstructor from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.09 12:47:59" (1/1) ... [2024-09-21 12:47:59,784 INFO L131 PluginConnector]: ------------------------ END Boogie Preprocessor---------------------------- [2024-09-21 12:47:59,784 INFO L112 PluginConnector]: ------------------------RCFGBuilder---------------------------- [2024-09-21 12:47:59,784 INFO L270 PluginConnector]: Initializing RCFGBuilder... [2024-09-21 12:47:59,784 INFO L274 PluginConnector]: RCFGBuilder initialized [2024-09-21 12:47:59,785 INFO L184 PluginConnector]: Executing the observer RCFGBuilderObserver from plugin RCFGBuilder for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.09 12:47:59" (1/1) ... [2024-09-21 12:47:59,794 INFO L173 SolverBuilder]: Constructing external solver with command: z3 SMTLIB2_COMPLIANT=true -memory:2024 -smt2 -in -t:4000 [2024-09-21 12:47:59,800 INFO L189 MonitoredProcess]: No working directory specified, using /storage/repos/certificate-witnesses-artifact/referee/z3 [2024-09-21 12:47:59,812 INFO L229 MonitoredProcess]: Starting monitored process 1 with /storage/repos/certificate-witnesses-artifact/referee/z3 SMTLIB2_COMPLIANT=true -memory:2024 -smt2 -in -t:4000 (exit command is (exit), workingDir is null) [2024-09-21 12:47:59,813 INFO L327 MonitoredProcess]: [MP /storage/repos/certificate-witnesses-artifact/referee/z3 SMTLIB2_COMPLIANT=true -memory:2024 -smt2 -in -t:4000 (1)] Waiting until timeout for monitored process [2024-09-21 12:47:59,846 INFO L138 BoogieDeclarations]: Found implementation of procedure ULTIMATE.init [2024-09-21 12:47:59,846 INFO L138 BoogieDeclarations]: Found implementation of procedure ULTIMATE.start [2024-09-21 12:47:59,847 INFO L138 BoogieDeclarations]: Found implementation of procedure reach_error [2024-09-21 12:47:59,847 INFO L138 BoogieDeclarations]: Found implementation of procedure main [2024-09-21 12:47:59,847 INFO L130 BoogieDeclarations]: Found specification of procedure abort [2024-09-21 12:47:59,848 INFO L130 BoogieDeclarations]: Found specification of procedure __assert_fail [2024-09-21 12:47:59,848 INFO L130 BoogieDeclarations]: Found specification of procedure reach_error [2024-09-21 12:47:59,848 INFO L130 BoogieDeclarations]: Found specification of procedure #Ultimate.allocInit [2024-09-21 12:47:59,848 INFO L130 BoogieDeclarations]: Found specification of procedure __VERIFIER_nondet_int [2024-09-21 12:47:59,848 INFO L130 BoogieDeclarations]: Found specification of procedure __VERIFIER_assert [2024-09-21 12:47:59,848 INFO L130 BoogieDeclarations]: Found specification of procedure main [2024-09-21 12:47:59,848 INFO L130 BoogieDeclarations]: Found specification of procedure ULTIMATE.init [2024-09-21 12:47:59,848 INFO L130 BoogieDeclarations]: Found specification of procedure write~init~int#0 [2024-09-21 12:47:59,848 INFO L130 BoogieDeclarations]: Found specification of procedure ULTIMATE.start [2024-09-21 12:47:59,848 INFO L130 BoogieDeclarations]: Found specification of procedure write~int#0 [2024-09-21 12:47:59,848 INFO L130 BoogieDeclarations]: Found specification of procedure read~int#0 [2024-09-21 12:47:59,848 INFO L130 BoogieDeclarations]: Found specification of procedure ULTIMATE.dealloc [2024-09-21 12:47:59,912 INFO L242 CfgBuilder]: Building ICFG [2024-09-21 12:47:59,913 INFO L268 CfgBuilder]: Building CFG for each procedure with an implementation [2024-09-21 12:48:00,072 INFO L291 CfgBuilder]: Performing block encoding [2024-09-21 12:48:00,107 INFO L313 CfgBuilder]: Using the 1 location(s) as analysis (start of procedure ULTIMATE.start) [2024-09-21 12:48:00,108 INFO L318 CfgBuilder]: Removed 0 assume(true) statements. [2024-09-21 12:48:00,108 INFO L201 PluginConnector]: Adding new model de.uni_freiburg.informatik.ultimate.plugins.generator.rcfgbuilder CFG 21.09 12:48:00 BoogieIcfgContainer [2024-09-21 12:48:00,108 INFO L131 PluginConnector]: ------------------------ END RCFGBuilder---------------------------- [2024-09-21 12:48:00,108 INFO L112 PluginConnector]: ------------------------Referee---------------------------- [2024-09-21 12:48:00,108 INFO L270 PluginConnector]: Initializing Referee... [2024-09-21 12:48:00,109 INFO L274 PluginConnector]: Referee initialized [2024-09-21 12:48:00,109 INFO L184 PluginConnector]: Executing the observer RefereeObserver from plugin Referee for "witness-2.1.yml de.uni_freiburg.informatik.ultimate.witnessparser CORRECTNESS_WITNESS 21.09 12:47:57" (1/4) ... [2024-09-21 12:48:00,110 INFO L204 PluginConnector]: Invalid model from Referee for observer de.uni_freiburg.informatik.ultimate.plugins.generator.referee.RefereeObserver@5dea9e7a and model type witness-2.1.yml de.uni_freiburg.informatik.ultimate.plugins.generator.referee CORRECTNESS_WITNESS 21.09 12:48:00, skipping insertion in model container [2024-09-21 12:48:00,110 INFO L184 PluginConnector]: Executing the observer RefereeObserver from plugin Referee for "CDTParser AST 21.09 12:47:59" (2/4) ... [2024-09-21 12:48:00,110 INFO L204 PluginConnector]: Invalid model from Referee for observer de.uni_freiburg.informatik.ultimate.plugins.generator.referee.RefereeObserver@5dea9e7a and model type de.uni_freiburg.informatik.ultimate.plugins.generator.referee AST 21.09 12:48:00, skipping insertion in model container [2024-09-21 12:48:00,110 INFO L184 PluginConnector]: Executing the observer RefereeObserver from plugin Referee for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.09 12:47:59" (3/4) ... [2024-09-21 12:48:00,110 INFO L204 PluginConnector]: Invalid model from Referee for observer de.uni_freiburg.informatik.ultimate.plugins.generator.referee.RefereeObserver@5dea9e7a and model type de.uni_freiburg.informatik.ultimate.plugins.generator.referee AST 21.09 12:48:00, skipping insertion in model container [2024-09-21 12:48:00,110 INFO L184 PluginConnector]: Executing the observer RefereeObserver from plugin Referee for "de.uni_freiburg.informatik.ultimate.plugins.generator.rcfgbuilder CFG 21.09 12:48:00" (4/4) ... [2024-09-21 12:48:00,112 INFO L79 RefereeObserver]: Analyzing ICFG mod3.c.v+sep-reducer.c [2024-09-21 12:48:00,115 INFO L113 InvariantChecker]: Found 0 loops. [2024-09-21 12:48:00,116 INFO L373 InvariantChecker]: Will check inductivity from ENTRY $Ultimate##0 to ERROR_LOC mainErr2ASSERT_VIOLATIONWITNESS_INVARIANT. Corresponding subgraph has 26 edges. [2024-09-21 12:48:00,116 INFO L373 InvariantChecker]: Will check inductivity from ENTRY $Ultimate##0 to ERROR_LOC mainErr3ASSERT_VIOLATIONERROR_FUNCTION. Corresponding subgraph has 29 edges. [2024-09-21 12:48:00,116 INFO L373 InvariantChecker]: Will check inductivity from ENTRY $Ultimate##0 to ERROR_LOC mainErr0ASSERT_VIOLATIONWITNESS_INVARIANT. Corresponding subgraph has 26 edges. [2024-09-21 12:48:00,116 INFO L373 InvariantChecker]: Will check inductivity from ENTRY $Ultimate##0 to ERROR_LOC mainErr1ASSERT_VIOLATIONWITNESS_INVARIANT. Corresponding subgraph has 26 edges. [2024-09-21 12:48:00,116 INFO L131 InvariantChecker]: Will check 4 loop-free subgraphs from procedure entry to error location [2024-09-21 12:48:00,171 INFO L314 BlockEncoder]: Initial Icfg 20 locations, 26 edges [2024-09-21 12:48:00,174 INFO L264 BlockEncoder]: Using Maximize final states [2024-09-21 12:48:00,175 INFO L271 BlockEncoder]: Using Minimize states even if more edges are added than removed.=true [2024-09-21 12:48:00,175 INFO L277 BlockEncoder]: Using Minimize states using LBE with the strategy=MULTI [2024-09-21 12:48:00,177 INFO L172 BlockEncoder]: Using Apply optimizations until nothing changes=true [2024-09-21 12:48:00,179 INFO L71 MaximizeFinalStates]: 0 new accepting states [2024-09-21 12:48:00,271 INFO L101 BaseMinimizeStates]: Removed 62 edges and 16 locations by large block encoding [2024-09-21 12:48:00,272 INFO L71 MaximizeFinalStates]: 0 new accepting states [2024-09-21 12:48:00,272 INFO L101 BaseMinimizeStates]: Removed 0 edges and 0 locations by large block encoding [2024-09-21 12:48:00,272 INFO L238 BlockEncoder]: Using Create parallel compositions if possible [2024-09-21 12:48:00,273 INFO L68 ParallelComposer]: Creating parallel compositions [2024-09-21 12:48:00,289 INFO L314 BlockEncoder]: Encoded RCFG 4 locations, 7 edges [2024-09-21 12:48:00,300 INFO L314 BlockEncoder]: Initial Icfg 23 locations, 29 edges [2024-09-21 12:48:00,303 INFO L264 BlockEncoder]: Using Maximize final states [2024-09-21 12:48:00,303 INFO L271 BlockEncoder]: Using Minimize states even if more edges are added than removed.=true [2024-09-21 12:48:00,304 INFO L277 BlockEncoder]: Using Minimize states using LBE with the strategy=MULTI [2024-09-21 12:48:00,304 INFO L172 BlockEncoder]: Using Apply optimizations until nothing changes=true [2024-09-21 12:48:00,304 INFO L71 MaximizeFinalStates]: 0 new accepting states [2024-09-21 12:48:00,355 INFO L101 BaseMinimizeStates]: Removed 67 edges and 19 locations by large block encoding [2024-09-21 12:48:00,356 INFO L71 MaximizeFinalStates]: 0 new accepting states [2024-09-21 12:48:00,356 INFO L101 BaseMinimizeStates]: Removed 0 edges and 0 locations by large block encoding [2024-09-21 12:48:00,356 INFO L238 BlockEncoder]: Using Create parallel compositions if possible [2024-09-21 12:48:00,356 INFO L68 ParallelComposer]: Creating parallel compositions [2024-09-21 12:48:00,368 INFO L314 BlockEncoder]: Encoded RCFG 4 locations, 6 edges [2024-09-21 12:48:00,380 INFO L314 BlockEncoder]: Initial Icfg 20 locations, 26 edges [2024-09-21 12:48:00,380 INFO L264 BlockEncoder]: Using Maximize final states [2024-09-21 12:48:00,380 INFO L271 BlockEncoder]: Using Minimize states even if more edges are added than removed.=true [2024-09-21 12:48:00,380 INFO L277 BlockEncoder]: Using Minimize states using LBE with the strategy=MULTI [2024-09-21 12:48:00,380 INFO L172 BlockEncoder]: Using Apply optimizations until nothing changes=true [2024-09-21 12:48:00,380 INFO L71 MaximizeFinalStates]: 0 new accepting states [2024-09-21 12:48:00,444 INFO L101 BaseMinimizeStates]: Removed 65 edges and 16 locations by large block encoding [2024-09-21 12:48:00,444 INFO L71 MaximizeFinalStates]: 0 new accepting states [2024-09-21 12:48:00,445 INFO L101 BaseMinimizeStates]: Removed 0 edges and 0 locations by large block encoding [2024-09-21 12:48:00,445 INFO L238 BlockEncoder]: Using Create parallel compositions if possible [2024-09-21 12:48:00,445 INFO L68 ParallelComposer]: Creating parallel compositions [2024-09-21 12:48:00,460 INFO L314 BlockEncoder]: Encoded RCFG 4 locations, 8 edges [2024-09-21 12:48:00,461 FATAL L? ?]: The Plugin de.uni_freiburg.informatik.ultimate.plugins.generator.referee has thrown an exception: java.lang.AssertionError: Either subgraph not acyclic or there is a bug at de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction.AcyclicSubgraphMerger.(AcyclicSubgraphMerger.java:169) at de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction.InvariantChecker.(InvariantChecker.java:145) at de.uni_freiburg.informatik.ultimate.plugins.generator.referee.RefereeStarter.(RefereeStarter.java:56) at de.uni_freiburg.informatik.ultimate.plugins.generator.referee.RefereeObserver.finish(RefereeObserver.java:80) at de.uni_freiburg.informatik.ultimate.core.coreplugin.PluginConnector.runObserver(PluginConnector.java:167) at de.uni_freiburg.informatik.ultimate.core.coreplugin.PluginConnector.runTool(PluginConnector.java:150) at de.uni_freiburg.informatik.ultimate.core.coreplugin.PluginConnector.run(PluginConnector.java:127) at de.uni_freiburg.informatik.ultimate.core.coreplugin.ToolchainWalker.executePluginConnector(ToolchainWalker.java:233) at de.uni_freiburg.informatik.ultimate.core.coreplugin.ToolchainWalker.processPlugin(ToolchainWalker.java:227) at de.uni_freiburg.informatik.ultimate.core.coreplugin.ToolchainWalker.walkUnprotected(ToolchainWalker.java:144) at de.uni_freiburg.informatik.ultimate.core.coreplugin.ToolchainWalker.walk(ToolchainWalker.java:106) at de.uni_freiburg.informatik.ultimate.core.coreplugin.ToolchainManager$Toolchain.processToolchain(ToolchainManager.java:319) at de.uni_freiburg.informatik.ultimate.core.coreplugin.toolchain.DefaultToolchainJob.run(DefaultToolchainJob.java:145) at org.eclipse.core.internal.jobs.Worker.run(Worker.java:63) [2024-09-21 12:48:00,466 INFO L158 Benchmark]: Toolchain (without parser) took 1009.41ms. Allocated memory is still 167.8MB. Free memory was 96.3MB in the beginning and 50.8MB in the end (delta: 45.5MB). Peak memory consumption was 44.4MB. Max. memory is 16.1GB. [2024-09-21 12:48:00,466 INFO L158 Benchmark]: Witness Parser took 0.17ms. Allocated memory is still 167.8MB. Free memory is still 123.8MB. There was no memory consumed. Max. memory is 16.1GB. [2024-09-21 12:48:00,466 INFO L158 Benchmark]: CDTParser took 0.11ms. Allocated memory is still 167.8MB. Free memory is still 141.9MB. There was no memory consumed. Max. memory is 16.1GB. [2024-09-21 12:48:00,467 INFO L158 Benchmark]: CACSL2BoogieTranslator took 253.47ms. Allocated memory is still 167.8MB. Free memory was 96.1MB in the beginning and 82.1MB in the end (delta: 14.1MB). Peak memory consumption was 14.7MB. Max. memory is 16.1GB. [2024-09-21 12:48:00,469 INFO L158 Benchmark]: Boogie Preprocessor took 72.95ms. Allocated memory is still 167.8MB. Free memory was 82.1MB in the beginning and 139.3MB in the end (delta: -57.3MB). Peak memory consumption was 4.6MB. Max. memory is 16.1GB. [2024-09-21 12:48:00,470 INFO L158 Benchmark]: RCFGBuilder took 323.70ms. Allocated memory is still 167.8MB. Free memory was 139.3MB in the beginning and 124.4MB in the end (delta: 14.9MB). Peak memory consumption was 12.6MB. Max. memory is 16.1GB. [2024-09-21 12:48:00,470 INFO L158 Benchmark]: Referee took 356.29ms. Allocated memory is still 167.8MB. Free memory was 124.4MB in the beginning and 50.8MB in the end (delta: 73.6MB). Peak memory consumption was 73.4MB. Max. memory is 16.1GB. [2024-09-21 12:48:00,472 INFO L338 ainManager$Toolchain]: ####################### End [Toolchain 1] ####################### --- Results --- * Results from de.uni_freiburg.informatik.ultimate.plugins.generator.referee: - ExceptionOrErrorResult: AssertionError: Either subgraph not acyclic or there is a bug de.uni_freiburg.informatik.ultimate.plugins.generator.referee: AssertionError: Either subgraph not acyclic or there is a bug: de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction.AcyclicSubgraphMerger.(AcyclicSubgraphMerger.java:169) * Results from de.uni_freiburg.informatik.ultimate.core: - StatisticsResult: Toolchain Benchmarks Benchmark results are: * Witness Parser took 0.17ms. Allocated memory is still 167.8MB. Free memory is still 123.8MB. There was no memory consumed. Max. memory is 16.1GB. * CDTParser took 0.11ms. Allocated memory is still 167.8MB. Free memory is still 141.9MB. There was no memory consumed. Max. memory is 16.1GB. * CACSL2BoogieTranslator took 253.47ms. Allocated memory is still 167.8MB. Free memory was 96.1MB in the beginning and 82.1MB in the end (delta: 14.1MB). Peak memory consumption was 14.7MB. Max. memory is 16.1GB. * Boogie Preprocessor took 72.95ms. Allocated memory is still 167.8MB. Free memory was 82.1MB in the beginning and 139.3MB in the end (delta: -57.3MB). Peak memory consumption was 4.6MB. Max. memory is 16.1GB. * RCFGBuilder took 323.70ms. Allocated memory is still 167.8MB. Free memory was 139.3MB in the beginning and 124.4MB in the end (delta: 14.9MB). Peak memory consumption was 12.6MB. Max. memory is 16.1GB. * Referee took 356.29ms. Allocated memory is still 167.8MB. Free memory was 124.4MB in the beginning and 50.8MB in the end (delta: 73.6MB). Peak memory consumption was 73.4MB. Max. memory is 16.1GB. RESULT: Ultimate could not prove your program: Toolchain returned no result. [2024-09-21 12:48:00,499 INFO L552 MonitoredProcess]: [MP /storage/repos/certificate-witnesses-artifact/referee/z3 SMTLIB2_COMPLIANT=true -memory:2024 -smt2 -in -t:4000 (1)] Ended with exit code 0 Received shutdown request... --- End real Ultimate output --- Execution finished normally Using bit-precise analysis Retrying with bit-precise analysis ### Bit-precise run ### Calling Ultimate with: /root/.sdkman/candidates/java/current/bin/java -Dosgi.configuration.area=/storage/repos/certificate-witnesses-artifact/referee/data/config -Xmx15G -Xms4m -jar /storage/repos/certificate-witnesses-artifact/referee/plugins/org.eclipse.equinox.launcher_1.5.800.v20200727-1323.jar -data @noDefault -ultimatedata /storage/repos/certificate-witnesses-artifact/referee/data -tc /storage/repos/certificate-witnesses-artifact/referee/config/RefereeReachWitnessValidation.xml -i ../sv-benchmarks/c/loop-industry-pattern/mod3.c.v+sep-reducer.c ../results/automizer-verification-files/SV-COMP24_unreach-call/mod3.c.v+sep-reducer.yml/witness-2.1.yml -s /storage/repos/certificate-witnesses-artifact/referee/config/svcomp-Reach-32bit-Referee_Bitvector.epf --cacsl2boogietranslator.entry.function main --traceabstraction.positions.where.we.compute.the.hoare.annotation None --- Real Ultimate output --- This is Ultimate 0.2.4-tmp.dk.referee-eval-27b4987-m [2024-09-21 12:48:02,572 INFO L188 SettingsManager]: Resetting all preferences to default values... [2024-09-21 12:48:02,636 INFO L114 SettingsManager]: Loading settings from /storage/repos/certificate-witnesses-artifact/referee/config/svcomp-Reach-32bit-Referee_Bitvector.epf [2024-09-21 12:48:02,640 WARN L101 SettingsManager]: Preference file contains the following unknown settings: [2024-09-21 12:48:02,640 WARN L103 SettingsManager]: * de.uni_freiburg.informatik.ultimate.core.Log level for class [2024-09-21 12:48:02,655 INFO L130 SettingsManager]: Preferences different from defaults after loading the file: [2024-09-21 12:48:02,656 INFO L151 SettingsManager]: Preferences of UltimateCore differ from their defaults: [2024-09-21 12:48:02,656 INFO L153 SettingsManager]: * Log level for class=de.uni_freiburg.informatik.ultimate.lib.smtlibutils.quantifier.QuantifierPusher=ERROR; [2024-09-21 12:48:02,657 INFO L151 SettingsManager]: Preferences of Boogie Preprocessor differ from their defaults: [2024-09-21 12:48:02,658 INFO L153 SettingsManager]: * Use memory slicer=true [2024-09-21 12:48:02,658 INFO L151 SettingsManager]: Preferences of Boogie Procedure Inliner differ from their defaults: [2024-09-21 12:48:02,658 INFO L153 SettingsManager]: * Ignore calls to procedures called more than once=ONLY_FOR_SEQUENTIAL_PROGRAMS [2024-09-21 12:48:02,659 INFO L151 SettingsManager]: Preferences of BlockEncodingV2 differ from their defaults: [2024-09-21 12:48:02,661 INFO L153 SettingsManager]: * Create parallel compositions if possible=false [2024-09-21 12:48:02,662 INFO L153 SettingsManager]: * Use SBE=true [2024-09-21 12:48:02,662 INFO L151 SettingsManager]: Preferences of CACSL2BoogieTranslator differ from their defaults: [2024-09-21 12:48:02,662 INFO L153 SettingsManager]: * Pointer base address is valid at dereference=IGNORE [2024-09-21 12:48:02,662 INFO L153 SettingsManager]: * sizeof long=4 [2024-09-21 12:48:02,663 INFO L153 SettingsManager]: * sizeof POINTER=4 [2024-09-21 12:48:02,663 INFO L153 SettingsManager]: * Check division by zero=IGNORE [2024-09-21 12:48:02,663 INFO L153 SettingsManager]: * Pointer to allocated memory at dereference=IGNORE [2024-09-21 12:48:02,663 INFO L153 SettingsManager]: * If two pointers are subtracted or compared they have the same base address=IGNORE [2024-09-21 12:48:02,663 INFO L153 SettingsManager]: * Check array bounds for arrays that are off heap=IGNORE [2024-09-21 12:48:02,664 INFO L153 SettingsManager]: * Adapt memory model on pointer casts if necessary=true [2024-09-21 12:48:02,664 INFO L153 SettingsManager]: * Use bitvectors instead of ints=true [2024-09-21 12:48:02,664 INFO L153 SettingsManager]: * Allow undefined functions=false [2024-09-21 12:48:02,664 INFO L153 SettingsManager]: * Memory model=HoenickeLindenmann_4ByteResolution [2024-09-21 12:48:02,664 INFO L153 SettingsManager]: * sizeof long double=12 [2024-09-21 12:48:02,665 INFO L153 SettingsManager]: * Check if freed pointer was valid=false [2024-09-21 12:48:02,665 INFO L153 SettingsManager]: * Use constant arrays=true [2024-09-21 12:48:02,665 INFO L151 SettingsManager]: Preferences of RCFGBuilder differ from their defaults: [2024-09-21 12:48:02,665 INFO L153 SettingsManager]: * Size of a code block=SequenceOfStatements [2024-09-21 12:48:02,665 INFO L153 SettingsManager]: * Future-live optimization=false [2024-09-21 12:48:02,665 INFO L153 SettingsManager]: * Only consider context switches at boundaries of atomic blocks=true [2024-09-21 12:48:02,666 INFO L153 SettingsManager]: * SMT solver=External_DefaultMode [2024-09-21 12:48:02,666 INFO L153 SettingsManager]: * Command for external solver=z3 SMTLIB2_COMPLIANT=true -memory:2024 -smt2 -in -t:4000 [2024-09-21 12:48:02,666 INFO L151 SettingsManager]: Preferences of TraceAbstraction differ from their defaults: [2024-09-21 12:48:02,666 INFO L153 SettingsManager]: * Compute Interpolants along a Counterexample=FPandBP [2024-09-21 12:48:02,666 INFO L153 SettingsManager]: * Positions where we compute the Hoare Annotation=LoopHeads [2024-09-21 12:48:02,666 INFO L153 SettingsManager]: * Trace refinement strategy=WOLF [2024-09-21 12:48:02,666 INFO L153 SettingsManager]: * Command for external solver=cvc4 --incremental --print-success --lang smt [2024-09-21 12:48:02,668 INFO L153 SettingsManager]: * Apply one-shot large block encoding in concurrent analysis=false [2024-09-21 12:48:02,668 INFO L153 SettingsManager]: * Automaton type used in concurrency analysis=PETRI_NET [2024-09-21 12:48:02,668 INFO L153 SettingsManager]: * Order on configurations for Petri net unfoldings=DBO [2024-09-21 12:48:02,668 INFO L153 SettingsManager]: * SMT solver=External_ModelsAndUnsatCoreMode [2024-09-21 12:48:02,669 INFO L153 SettingsManager]: * Logic for external solver=AUFBV [2024-09-21 12:48:02,669 INFO L153 SettingsManager]: * Looper check in Petri net analysis=SEMANTIC WARNING: An illegal reflective access operation has occurred WARNING: Illegal reflective access by com.sun.xml.bind.v2.runtime.reflect.opt.Injector$1 (file:/storage/repos/certificate-witnesses-artifact/referee/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$1 WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations WARNING: All illegal access operations will be denied in a future release Applying setting for plugin de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator: Entry function -> main Applying setting for plugin de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction: Positions where we compute the Hoare Annotation -> None [2024-09-21 12:48:02,925 INFO L75 nceAwareModelManager]: Repository-Root is: /tmp [2024-09-21 12:48:02,945 INFO L261 ainManager$Toolchain]: [Toolchain 1]: Applicable parser(s) successfully (re)initialized [2024-09-21 12:48:02,947 INFO L217 ainManager$Toolchain]: [Toolchain 1]: Toolchain selected. [2024-09-21 12:48:02,949 INFO L270 PluginConnector]: Initializing Witness Parser... [2024-09-21 12:48:02,950 INFO L274 PluginConnector]: Witness Parser initialized [2024-09-21 12:48:02,952 INFO L431 ainManager$Toolchain]: [Toolchain 1]: Parsing single file: /storage/repos/certificate-witnesses-artifact/referee/../results/automizer-verification-files/SV-COMP24_unreach-call/mod3.c.v+sep-reducer.yml/witness-2.1.yml [2024-09-21 12:48:02,991 INFO L270 PluginConnector]: Initializing CDTParser... [2024-09-21 12:48:02,992 INFO L274 PluginConnector]: CDTParser initialized [2024-09-21 12:48:02,992 INFO L431 ainManager$Toolchain]: [Toolchain 1]: Parsing single file: /storage/repos/certificate-witnesses-artifact/referee/../sv-benchmarks/c/loop-industry-pattern/mod3.c.v+sep-reducer.c [2024-09-21 12:48:04,266 INFO L533 CDTParser]: Created temporary CDT project at NULL [2024-09-21 12:48:04,431 INFO L384 CDTParser]: Found 1 translation units. [2024-09-21 12:48:04,432 INFO L180 CDTParser]: Scanning /storage/repos/certificate-witnesses-artifact/sv-benchmarks/c/loop-industry-pattern/mod3.c.v+sep-reducer.c [2024-09-21 12:48:04,441 INFO L427 CDTParser]: About to delete temporary CDT project at /storage/repos/certificate-witnesses-artifact/referee/data/5aef3f7bb/b61fe25001ee4ad08df1668ad302b156/FLAG1be9c218b [2024-09-21 12:48:04,835 INFO L435 CDTParser]: Successfully deleted /storage/repos/certificate-witnesses-artifact/referee/data/5aef3f7bb/b61fe25001ee4ad08df1668ad302b156 [2024-09-21 12:48:04,836 INFO L299 ainManager$Toolchain]: ####################### [Toolchain 1] ####################### [2024-09-21 12:48:04,837 INFO L133 ToolchainWalker]: Walking toolchain with 4 elements. [2024-09-21 12:48:04,838 INFO L112 PluginConnector]: ------------------------CACSL2BoogieTranslator---------------------------- [2024-09-21 12:48:04,838 INFO L270 PluginConnector]: Initializing CACSL2BoogieTranslator... [2024-09-21 12:48:04,841 INFO L274 PluginConnector]: CACSL2BoogieTranslator initialized [2024-09-21 12:48:04,842 INFO L184 PluginConnector]: Executing the observer ACSLObjectContainerObserver from plugin CACSL2BoogieTranslator for "witness-2.1.yml de.uni_freiburg.informatik.ultimate.witnessparser CORRECTNESS_WITNESS 21.09 12:48:02" (1/2) ... [2024-09-21 12:48:04,843 INFO L204 PluginConnector]: Invalid model from CACSL2BoogieTranslator for observer de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator.ACSLObjectContainerObserver@44bcbc9c and model type witness-2.1.yml de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator CORRECTNESS_WITNESS 21.09 12:48:04, skipping insertion in model container [2024-09-21 12:48:04,843 INFO L184 PluginConnector]: Executing the observer CACSL2BoogieTranslatorObserver from plugin CACSL2BoogieTranslator for "witness-2.1.yml de.uni_freiburg.informatik.ultimate.witnessparser CORRECTNESS_WITNESS 21.09 12:48:02" (1/2) ... [2024-09-21 12:48:04,844 INFO L204 PluginConnector]: Invalid model from CACSL2BoogieTranslator for observer de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator.CACSL2BoogieTranslatorObserver@2cd450ff and model type witness-2.1.yml de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator CORRECTNESS_WITNESS 21.09 12:48:04, skipping insertion in model container [2024-09-21 12:48:04,847 INFO L184 PluginConnector]: Executing the observer ACSLObjectContainerObserver from plugin CACSL2BoogieTranslator for "CDTParser AST 21.09 12:48:04" (2/2) ... [2024-09-21 12:48:04,847 INFO L204 PluginConnector]: Invalid model from CACSL2BoogieTranslator for observer de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator.ACSLObjectContainerObserver@44bcbc9c and model type de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.09 12:48:04, skipping insertion in model container [2024-09-21 12:48:04,848 INFO L184 PluginConnector]: Executing the observer CACSL2BoogieTranslatorObserver from plugin CACSL2BoogieTranslator for "CDTParser AST 21.09 12:48:04" (2/2) ... [2024-09-21 12:48:04,853 INFO L93 nessWitnessExtractor]: Found the following entries in the witness: [2024-09-21 12:48:04,854 INFO L1541 ArrayList]: Location invariant before [L42-L42] ((main__x % 3) < 1) [2024-09-21 12:48:04,854 INFO L1541 ArrayList]: Location invariant before [L36-L112] ((main__x % 3) < 1) [2024-09-21 12:48:04,854 INFO L1541 ArrayList]: Location invariant before [L24-L141] ((main__x % 3) < 1) [2024-09-21 12:48:04,870 INFO L175 MainTranslator]: Built tables and reachable declarations [2024-09-21 12:48:05,005 WARN L248 ndardFunctionHandler]: Function reach_error is already implemented but we override the implementation for the call at /storage/repos/certificate-witnesses-artifact/sv-benchmarks/c/loop-industry-pattern/mod3.c.v+sep-reducer.c[2057,2070] [2024-09-21 12:48:05,019 INFO L210 PostProcessor]: Analyzing one entry point: main [2024-09-21 12:48:05,034 INFO L200 MainTranslator]: Completed pre-run Start Parsing Local [2024-09-21 12:48:05,070 WARN L248 ndardFunctionHandler]: Function reach_error is already implemented but we override the implementation for the call at /storage/repos/certificate-witnesses-artifact/sv-benchmarks/c/loop-industry-pattern/mod3.c.v+sep-reducer.c[2057,2070] Start Parsing Local Start Parsing Local [2024-09-21 12:48:05,073 INFO L210 PostProcessor]: Analyzing one entry point: main [2024-09-21 12:48:05,087 INFO L204 MainTranslator]: Completed translation [2024-09-21 12:48:05,087 INFO L201 PluginConnector]: Adding new model de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.09 12:48:05 WrapperNode [2024-09-21 12:48:05,087 INFO L131 PluginConnector]: ------------------------ END CACSL2BoogieTranslator---------------------------- [2024-09-21 12:48:05,088 INFO L112 PluginConnector]: ------------------------Boogie Preprocessor---------------------------- [2024-09-21 12:48:05,088 INFO L270 PluginConnector]: Initializing Boogie Preprocessor... [2024-09-21 12:48:05,088 INFO L274 PluginConnector]: Boogie Preprocessor initialized [2024-09-21 12:48:05,098 INFO L184 PluginConnector]: Executing the observer EnsureBoogieModelObserver from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.09 12:48:05" (1/1) ... [2024-09-21 12:48:05,098 INFO L184 PluginConnector]: Executing the observer TypeChecker from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.09 12:48:05" (1/1) ... [2024-09-21 12:48:05,106 INFO L184 PluginConnector]: Executing the observer MemorySlicer from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.09 12:48:05" (1/1) ... [2024-09-21 12:48:05,121 INFO L175 MemorySlicer]: Split 2 memory accesses to 1 slices as follows [2]. 100 percent of accesses are in the largest equivalence class. The 2 initializations are split as follows [2]. The 0 writes are split as follows [0]. [2024-09-21 12:48:05,122 INFO L184 PluginConnector]: Executing the observer ConstExpander from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.09 12:48:05" (1/1) ... [2024-09-21 12:48:05,122 INFO L184 PluginConnector]: Executing the observer StructExpander from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.09 12:48:05" (1/1) ... [2024-09-21 12:48:05,127 INFO L184 PluginConnector]: Executing the observer UnstructureCode from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.09 12:48:05" (1/1) ... [2024-09-21 12:48:05,129 INFO L184 PluginConnector]: Executing the observer FunctionInliner from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.09 12:48:05" (1/1) ... [2024-09-21 12:48:05,133 INFO L184 PluginConnector]: Executing the observer LTLStepAnnotator from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.09 12:48:05" (1/1) ... [2024-09-21 12:48:05,134 INFO L184 PluginConnector]: Executing the observer BoogieSymbolTableConstructor from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.09 12:48:05" (1/1) ... [2024-09-21 12:48:05,140 INFO L131 PluginConnector]: ------------------------ END Boogie Preprocessor---------------------------- [2024-09-21 12:48:05,141 INFO L112 PluginConnector]: ------------------------RCFGBuilder---------------------------- [2024-09-21 12:48:05,141 INFO L270 PluginConnector]: Initializing RCFGBuilder... [2024-09-21 12:48:05,141 INFO L274 PluginConnector]: RCFGBuilder initialized [2024-09-21 12:48:05,142 INFO L184 PluginConnector]: Executing the observer RCFGBuilderObserver from plugin RCFGBuilder for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.09 12:48:05" (1/1) ... [2024-09-21 12:48:05,146 INFO L173 SolverBuilder]: Constructing external solver with command: z3 SMTLIB2_COMPLIANT=true -memory:2024 -smt2 -in -t:4000 [2024-09-21 12:48:05,153 INFO L189 MonitoredProcess]: No working directory specified, using /storage/repos/certificate-witnesses-artifact/referee/z3 [2024-09-21 12:48:05,174 INFO L229 MonitoredProcess]: Starting monitored process 1 with /storage/repos/certificate-witnesses-artifact/referee/z3 SMTLIB2_COMPLIANT=true -memory:2024 -smt2 -in -t:4000 (exit command is (exit), workingDir is null) [2024-09-21 12:48:05,178 INFO L327 MonitoredProcess]: [MP /storage/repos/certificate-witnesses-artifact/referee/z3 SMTLIB2_COMPLIANT=true -memory:2024 -smt2 -in -t:4000 (1)] Waiting until timeout for monitored process [2024-09-21 12:48:05,222 INFO L138 BoogieDeclarations]: Found implementation of procedure ULTIMATE.init [2024-09-21 12:48:05,222 INFO L138 BoogieDeclarations]: Found implementation of procedure ULTIMATE.start [2024-09-21 12:48:05,222 INFO L138 BoogieDeclarations]: Found implementation of procedure reach_error [2024-09-21 12:48:05,222 INFO L138 BoogieDeclarations]: Found implementation of procedure main [2024-09-21 12:48:05,222 INFO L130 BoogieDeclarations]: Found specification of procedure abort [2024-09-21 12:48:05,222 INFO L130 BoogieDeclarations]: Found specification of procedure __assert_fail [2024-09-21 12:48:05,222 INFO L130 BoogieDeclarations]: Found specification of procedure reach_error [2024-09-21 12:48:05,222 INFO L130 BoogieDeclarations]: Found specification of procedure #Ultimate.allocInit [2024-09-21 12:48:05,222 INFO L130 BoogieDeclarations]: Found specification of procedure __VERIFIER_nondet_int [2024-09-21 12:48:05,222 INFO L130 BoogieDeclarations]: Found specification of procedure __VERIFIER_assert [2024-09-21 12:48:05,223 INFO L130 BoogieDeclarations]: Found specification of procedure main [2024-09-21 12:48:05,223 INFO L130 BoogieDeclarations]: Found specification of procedure ULTIMATE.init [2024-09-21 12:48:05,223 INFO L130 BoogieDeclarations]: Found specification of procedure write~init~intINTTYPE1#0 [2024-09-21 12:48:05,223 INFO L130 BoogieDeclarations]: Found specification of procedure ULTIMATE.start [2024-09-21 12:48:05,223 INFO L130 BoogieDeclarations]: Found specification of procedure write~intINTTYPE1#0 [2024-09-21 12:48:05,224 INFO L130 BoogieDeclarations]: Found specification of procedure read~intINTTYPE1#0 [2024-09-21 12:48:05,224 INFO L130 BoogieDeclarations]: Found specification of procedure ULTIMATE.dealloc [2024-09-21 12:48:05,289 INFO L242 CfgBuilder]: Building ICFG [2024-09-21 12:48:05,290 INFO L268 CfgBuilder]: Building CFG for each procedure with an implementation [2024-09-21 12:48:05,527 INFO L291 CfgBuilder]: Performing block encoding [2024-09-21 12:48:05,552 INFO L313 CfgBuilder]: Using the 1 location(s) as analysis (start of procedure ULTIMATE.start) [2024-09-21 12:48:05,552 INFO L318 CfgBuilder]: Removed 0 assume(true) statements. [2024-09-21 12:48:05,552 INFO L201 PluginConnector]: Adding new model de.uni_freiburg.informatik.ultimate.plugins.generator.rcfgbuilder CFG 21.09 12:48:05 BoogieIcfgContainer [2024-09-21 12:48:05,552 INFO L131 PluginConnector]: ------------------------ END RCFGBuilder---------------------------- [2024-09-21 12:48:05,553 INFO L112 PluginConnector]: ------------------------Referee---------------------------- [2024-09-21 12:48:05,553 INFO L270 PluginConnector]: Initializing Referee... [2024-09-21 12:48:05,554 INFO L274 PluginConnector]: Referee initialized [2024-09-21 12:48:05,554 INFO L184 PluginConnector]: Executing the observer RefereeObserver from plugin Referee for "witness-2.1.yml de.uni_freiburg.informatik.ultimate.witnessparser CORRECTNESS_WITNESS 21.09 12:48:02" (1/4) ... [2024-09-21 12:48:05,555 INFO L204 PluginConnector]: Invalid model from Referee for observer de.uni_freiburg.informatik.ultimate.plugins.generator.referee.RefereeObserver@5f71b2bc and model type witness-2.1.yml de.uni_freiburg.informatik.ultimate.plugins.generator.referee CORRECTNESS_WITNESS 21.09 12:48:05, skipping insertion in model container [2024-09-21 12:48:05,555 INFO L184 PluginConnector]: Executing the observer RefereeObserver from plugin Referee for "CDTParser AST 21.09 12:48:04" (2/4) ... [2024-09-21 12:48:05,555 INFO L204 PluginConnector]: Invalid model from Referee for observer de.uni_freiburg.informatik.ultimate.plugins.generator.referee.RefereeObserver@5f71b2bc and model type de.uni_freiburg.informatik.ultimate.plugins.generator.referee AST 21.09 12:48:05, skipping insertion in model container [2024-09-21 12:48:05,555 INFO L184 PluginConnector]: Executing the observer RefereeObserver from plugin Referee for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.09 12:48:05" (3/4) ... [2024-09-21 12:48:05,555 INFO L204 PluginConnector]: Invalid model from Referee for observer de.uni_freiburg.informatik.ultimate.plugins.generator.referee.RefereeObserver@5f71b2bc and model type de.uni_freiburg.informatik.ultimate.plugins.generator.referee AST 21.09 12:48:05, skipping insertion in model container [2024-09-21 12:48:05,555 INFO L184 PluginConnector]: Executing the observer RefereeObserver from plugin Referee for "de.uni_freiburg.informatik.ultimate.plugins.generator.rcfgbuilder CFG 21.09 12:48:05" (4/4) ... [2024-09-21 12:48:05,556 INFO L79 RefereeObserver]: Analyzing ICFG mod3.c.v+sep-reducer.c [2024-09-21 12:48:05,559 INFO L113 InvariantChecker]: Found 0 loops. [2024-09-21 12:48:05,560 INFO L373 InvariantChecker]: Will check inductivity from ENTRY $Ultimate##0 to ERROR_LOC mainErr2ASSERT_VIOLATIONWITNESS_INVARIANT. Corresponding subgraph has 26 edges. [2024-09-21 12:48:05,561 INFO L373 InvariantChecker]: Will check inductivity from ENTRY $Ultimate##0 to ERROR_LOC mainErr3ASSERT_VIOLATIONERROR_FUNCTION. Corresponding subgraph has 29 edges. [2024-09-21 12:48:05,561 INFO L373 InvariantChecker]: Will check inductivity from ENTRY $Ultimate##0 to ERROR_LOC mainErr0ASSERT_VIOLATIONWITNESS_INVARIANT. Corresponding subgraph has 26 edges. [2024-09-21 12:48:05,561 INFO L373 InvariantChecker]: Will check inductivity from ENTRY $Ultimate##0 to ERROR_LOC mainErr1ASSERT_VIOLATIONWITNESS_INVARIANT. Corresponding subgraph has 26 edges. [2024-09-21 12:48:05,561 INFO L131 InvariantChecker]: Will check 4 loop-free subgraphs from procedure entry to error location [2024-09-21 12:48:05,639 INFO L314 BlockEncoder]: Initial Icfg 20 locations, 26 edges [2024-09-21 12:48:05,640 INFO L264 BlockEncoder]: Using Maximize final states [2024-09-21 12:48:05,640 INFO L271 BlockEncoder]: Using Minimize states even if more edges are added than removed.=true [2024-09-21 12:48:05,641 INFO L277 BlockEncoder]: Using Minimize states using LBE with the strategy=MULTI [2024-09-21 12:48:05,643 INFO L172 BlockEncoder]: Using Apply optimizations until nothing changes=true [2024-09-21 12:48:05,644 INFO L71 MaximizeFinalStates]: 0 new accepting states [2024-09-21 12:48:05,734 INFO L101 BaseMinimizeStates]: Removed 62 edges and 16 locations by large block encoding [2024-09-21 12:48:05,735 INFO L71 MaximizeFinalStates]: 0 new accepting states [2024-09-21 12:48:05,735 INFO L101 BaseMinimizeStates]: Removed 0 edges and 0 locations by large block encoding [2024-09-21 12:48:05,736 INFO L238 BlockEncoder]: Using Create parallel compositions if possible [2024-09-21 12:48:05,736 INFO L68 ParallelComposer]: Creating parallel compositions [2024-09-21 12:48:05,755 INFO L314 BlockEncoder]: Encoded RCFG 4 locations, 7 edges [2024-09-21 12:48:05,768 INFO L314 BlockEncoder]: Initial Icfg 23 locations, 29 edges [2024-09-21 12:48:05,768 INFO L264 BlockEncoder]: Using Maximize final states [2024-09-21 12:48:05,769 INFO L271 BlockEncoder]: Using Minimize states even if more edges are added than removed.=true [2024-09-21 12:48:05,769 INFO L277 BlockEncoder]: Using Minimize states using LBE with the strategy=MULTI [2024-09-21 12:48:05,769 INFO L172 BlockEncoder]: Using Apply optimizations until nothing changes=true [2024-09-21 12:48:05,769 INFO L71 MaximizeFinalStates]: 0 new accepting states [2024-09-21 12:48:05,825 INFO L101 BaseMinimizeStates]: Removed 67 edges and 19 locations by large block encoding [2024-09-21 12:48:05,826 INFO L71 MaximizeFinalStates]: 0 new accepting states [2024-09-21 12:48:05,826 INFO L101 BaseMinimizeStates]: Removed 0 edges and 0 locations by large block encoding [2024-09-21 12:48:05,826 INFO L238 BlockEncoder]: Using Create parallel compositions if possible [2024-09-21 12:48:05,826 INFO L68 ParallelComposer]: Creating parallel compositions [2024-09-21 12:48:05,835 INFO L314 BlockEncoder]: Encoded RCFG 4 locations, 6 edges [2024-09-21 12:48:05,848 INFO L314 BlockEncoder]: Initial Icfg 20 locations, 26 edges [2024-09-21 12:48:05,848 INFO L264 BlockEncoder]: Using Maximize final states [2024-09-21 12:48:05,848 INFO L271 BlockEncoder]: Using Minimize states even if more edges are added than removed.=true [2024-09-21 12:48:05,848 INFO L277 BlockEncoder]: Using Minimize states using LBE with the strategy=MULTI [2024-09-21 12:48:05,848 INFO L172 BlockEncoder]: Using Apply optimizations until nothing changes=true [2024-09-21 12:48:05,848 INFO L71 MaximizeFinalStates]: 0 new accepting states [2024-09-21 12:48:05,894 INFO L101 BaseMinimizeStates]: Removed 65 edges and 16 locations by large block encoding [2024-09-21 12:48:05,894 INFO L71 MaximizeFinalStates]: 0 new accepting states [2024-09-21 12:48:05,894 INFO L101 BaseMinimizeStates]: Removed 0 edges and 0 locations by large block encoding [2024-09-21 12:48:05,895 INFO L238 BlockEncoder]: Using Create parallel compositions if possible [2024-09-21 12:48:05,895 INFO L68 ParallelComposer]: Creating parallel compositions [2024-09-21 12:48:05,904 INFO L314 BlockEncoder]: Encoded RCFG 4 locations, 8 edges [2024-09-21 12:48:05,905 FATAL L? ?]: The Plugin de.uni_freiburg.informatik.ultimate.plugins.generator.referee has thrown an exception: java.lang.AssertionError: Either subgraph not acyclic or there is a bug at de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction.AcyclicSubgraphMerger.(AcyclicSubgraphMerger.java:169) at de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction.InvariantChecker.(InvariantChecker.java:145) at de.uni_freiburg.informatik.ultimate.plugins.generator.referee.RefereeStarter.(RefereeStarter.java:56) at de.uni_freiburg.informatik.ultimate.plugins.generator.referee.RefereeObserver.finish(RefereeObserver.java:80) at de.uni_freiburg.informatik.ultimate.core.coreplugin.PluginConnector.runObserver(PluginConnector.java:167) at de.uni_freiburg.informatik.ultimate.core.coreplugin.PluginConnector.runTool(PluginConnector.java:150) at de.uni_freiburg.informatik.ultimate.core.coreplugin.PluginConnector.run(PluginConnector.java:127) at de.uni_freiburg.informatik.ultimate.core.coreplugin.ToolchainWalker.executePluginConnector(ToolchainWalker.java:233) at de.uni_freiburg.informatik.ultimate.core.coreplugin.ToolchainWalker.processPlugin(ToolchainWalker.java:227) at de.uni_freiburg.informatik.ultimate.core.coreplugin.ToolchainWalker.walkUnprotected(ToolchainWalker.java:144) at de.uni_freiburg.informatik.ultimate.core.coreplugin.ToolchainWalker.walk(ToolchainWalker.java:106) at de.uni_freiburg.informatik.ultimate.core.coreplugin.ToolchainManager$Toolchain.processToolchain(ToolchainManager.java:319) at de.uni_freiburg.informatik.ultimate.core.coreplugin.toolchain.DefaultToolchainJob.run(DefaultToolchainJob.java:145) at org.eclipse.core.internal.jobs.Worker.run(Worker.java:63) [2024-09-21 12:48:05,909 INFO L158 Benchmark]: Toolchain (without parser) took 1071.99ms. Allocated memory is still 96.5MB. Free memory was 75.2MB in the beginning and 37.1MB in the end (delta: 38.2MB). Peak memory consumption was 43.3MB. Max. memory is 16.1GB. [2024-09-21 12:48:05,910 INFO L158 Benchmark]: Witness Parser took 0.17ms. Allocated memory is still 67.1MB. Free memory is still 49.1MB. There was no memory consumed. Max. memory is 16.1GB. [2024-09-21 12:48:05,910 INFO L158 Benchmark]: CDTParser took 0.12ms. Allocated memory is still 67.1MB. Free memory is still 47.0MB. There was no memory consumed. Max. memory is 16.1GB. [2024-09-21 12:48:05,910 INFO L158 Benchmark]: CACSL2BoogieTranslator took 249.69ms. Allocated memory is still 96.5MB. Free memory was 74.8MB in the beginning and 60.7MB in the end (delta: 14.2MB). Peak memory consumption was 14.7MB. Max. memory is 16.1GB. [2024-09-21 12:48:05,911 INFO L158 Benchmark]: Boogie Preprocessor took 52.77ms. Allocated memory is still 96.5MB. Free memory was 60.7MB in the beginning and 58.3MB in the end (delta: 2.3MB). Peak memory consumption was 2.1MB. Max. memory is 16.1GB. [2024-09-21 12:48:05,911 INFO L158 Benchmark]: RCFGBuilder took 411.25ms. Allocated memory is still 96.5MB. Free memory was 58.3MB in the beginning and 42.8MB in the end (delta: 15.5MB). Peak memory consumption was 16.8MB. Max. memory is 16.1GB. [2024-09-21 12:48:05,912 INFO L158 Benchmark]: Referee took 355.27ms. Allocated memory is still 96.5MB. Free memory was 42.8MB in the beginning and 37.1MB in the end (delta: 5.7MB). Peak memory consumption was 9.7MB. Max. memory is 16.1GB. [2024-09-21 12:48:05,914 INFO L338 ainManager$Toolchain]: ####################### End [Toolchain 1] ####################### --- Results --- * Results from de.uni_freiburg.informatik.ultimate.plugins.generator.referee: - ExceptionOrErrorResult: AssertionError: Either subgraph not acyclic or there is a bug de.uni_freiburg.informatik.ultimate.plugins.generator.referee: AssertionError: Either subgraph not acyclic or there is a bug: de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction.AcyclicSubgraphMerger.(AcyclicSubgraphMerger.java:169) * Results from de.uni_freiburg.informatik.ultimate.core: - StatisticsResult: Toolchain Benchmarks Benchmark results are: * Witness Parser took 0.17ms. Allocated memory is still 67.1MB. Free memory is still 49.1MB. There was no memory consumed. Max. memory is 16.1GB. * CDTParser took 0.12ms. Allocated memory is still 67.1MB. Free memory is still 47.0MB. There was no memory consumed. Max. memory is 16.1GB. * CACSL2BoogieTranslator took 249.69ms. Allocated memory is still 96.5MB. Free memory was 74.8MB in the beginning and 60.7MB in the end (delta: 14.2MB). Peak memory consumption was 14.7MB. Max. memory is 16.1GB. * Boogie Preprocessor took 52.77ms. Allocated memory is still 96.5MB. Free memory was 60.7MB in the beginning and 58.3MB in the end (delta: 2.3MB). Peak memory consumption was 2.1MB. Max. memory is 16.1GB. * RCFGBuilder took 411.25ms. Allocated memory is still 96.5MB. Free memory was 58.3MB in the beginning and 42.8MB in the end (delta: 15.5MB). Peak memory consumption was 16.8MB. Max. memory is 16.1GB. * Referee took 355.27ms. Allocated memory is still 96.5MB. Free memory was 42.8MB in the beginning and 37.1MB in the end (delta: 5.7MB). Peak memory consumption was 9.7MB. Max. memory is 16.1GB. RESULT: Ultimate could not prove your program: Toolchain returned no result. [2024-09-21 12:48:05,944 INFO L552 MonitoredProcess]: [MP /storage/repos/certificate-witnesses-artifact/referee/z3 SMTLIB2_COMPLIANT=true -memory:2024 -smt2 -in -t:4000 (1)] Ended with exit code 0 Received shutdown request... --- End real Ultimate output --- Execution finished normally Writing output log to file Ultimate.log Result: ERROR: ExceptionOrErrorResult: AssertionError: Either subgraph not acyclic or there is a bug