/usr/bin/java -Xmx8000000000 -Xss4m -jar ./plugins/org.eclipse.equinox.launcher_1.3.100.v20150511-1540.jar -data @noDefault -ultimatedata ./data -tc ../../../trunk/examples/toolchains/AutomizerC.xml --traceabstraction.trace.refinement.strategy FIXED_PREFERENCES --traceabstraction.compute.interpolants.along.a.counterexample Craig_NestedInterpolation --traceabstraction.smt.solver Internal_SMTInterpol --traceabstraction.compute.trace.for.counterexample.result false --rcfgbuilder.size.of.a.code.block SequenceOfStatements --traceabstraction.use.minimal.unsat.core.enumeration true --traceabstraction.additional.smt.options produce-proofs=true --traceabstraction.additional.smt.options produce-unsat-cores=true --traceabstraction.additional.smt.options enumeration-timeout=5000 --traceabstraction.additional.smt.options interpolation-heuristic=SMALLESTAMONGWIDE --traceabstraction.additional.smt.options tolerance=0.2 --traceabstraction.additional.smt.options log-additional-information=true --traceabstraction.additional.smt.options unknown-allowed=true -s ../../../trunk/examples/settings/default/automizer/svcomp-Reach-32bit-Automizer_Default.epf -i ../../../trunk/examples/svcomp/float-newlib/double_req_bl_0681b.c -------------------------------------------------------------------------------- This is Ultimate 0.1.25-adbd35c [2020-10-14 23:17:07,468 INFO L177 SettingsManager]: Resetting all preferences to default values... [2020-10-14 23:17:07,471 INFO L181 SettingsManager]: Resetting UltimateCore preferences to default values [2020-10-14 23:17:07,512 INFO L184 SettingsManager]: Ultimate Commandline Interface provides no preferences, ignoring... [2020-10-14 23:17:07,513 INFO L181 SettingsManager]: Resetting Boogie Preprocessor preferences to default values [2020-10-14 23:17:07,521 INFO L181 SettingsManager]: Resetting Boogie Procedure Inliner preferences to default values [2020-10-14 23:17:07,523 INFO L181 SettingsManager]: Resetting Abstract Interpretation preferences to default values [2020-10-14 23:17:07,527 INFO L181 SettingsManager]: Resetting LassoRanker preferences to default values [2020-10-14 23:17:07,529 INFO L181 SettingsManager]: Resetting Reaching Definitions preferences to default values [2020-10-14 23:17:07,533 INFO L181 SettingsManager]: Resetting SyntaxChecker preferences to default values [2020-10-14 23:17:07,534 INFO L181 SettingsManager]: Resetting Sifa preferences to default values [2020-10-14 23:17:07,535 INFO L184 SettingsManager]: Büchi Program Product provides no preferences, ignoring... [2020-10-14 23:17:07,535 INFO L181 SettingsManager]: Resetting LTL2Aut preferences to default values [2020-10-14 23:17:07,538 INFO L181 SettingsManager]: Resetting PEA to Boogie preferences to default values [2020-10-14 23:17:07,541 INFO L181 SettingsManager]: Resetting BlockEncodingV2 preferences to default values [2020-10-14 23:17:07,543 INFO L181 SettingsManager]: Resetting ChcToBoogie preferences to default values [2020-10-14 23:17:07,544 INFO L181 SettingsManager]: Resetting AutomataScriptInterpreter preferences to default values [2020-10-14 23:17:07,545 INFO L181 SettingsManager]: Resetting BuchiAutomizer preferences to default values [2020-10-14 23:17:07,547 INFO L181 SettingsManager]: Resetting CACSL2BoogieTranslator preferences to default values [2020-10-14 23:17:07,555 INFO L181 SettingsManager]: Resetting CodeCheck preferences to default values [2020-10-14 23:17:07,557 INFO L181 SettingsManager]: Resetting InvariantSynthesis preferences to default values [2020-10-14 23:17:07,558 INFO L181 SettingsManager]: Resetting RCFGBuilder preferences to default values [2020-10-14 23:17:07,559 INFO L181 SettingsManager]: Resetting Referee preferences to default values [2020-10-14 23:17:07,561 INFO L181 SettingsManager]: Resetting TraceAbstraction preferences to default values [2020-10-14 23:17:07,573 INFO L184 SettingsManager]: TraceAbstractionConcurrent provides no preferences, ignoring... [2020-10-14 23:17:07,578 INFO L184 SettingsManager]: TraceAbstractionWithAFAs provides no preferences, ignoring... [2020-10-14 23:17:07,579 INFO L181 SettingsManager]: Resetting TreeAutomizer preferences to default values [2020-10-14 23:17:07,580 INFO L181 SettingsManager]: Resetting IcfgToChc preferences to default values [2020-10-14 23:17:07,582 INFO L181 SettingsManager]: Resetting IcfgTransformer preferences to default values [2020-10-14 23:17:07,583 INFO L184 SettingsManager]: ReqToTest provides no preferences, ignoring... [2020-10-14 23:17:07,583 INFO L181 SettingsManager]: Resetting Boogie Printer preferences to default values [2020-10-14 23:17:07,584 INFO L181 SettingsManager]: Resetting ChcSmtPrinter preferences to default values [2020-10-14 23:17:07,584 INFO L181 SettingsManager]: Resetting ReqPrinter preferences to default values [2020-10-14 23:17:07,587 INFO L181 SettingsManager]: Resetting Witness Printer preferences to default values [2020-10-14 23:17:07,589 INFO L184 SettingsManager]: Boogie PL CUP Parser provides no preferences, ignoring... [2020-10-14 23:17:07,590 INFO L181 SettingsManager]: Resetting CDTParser preferences to default values [2020-10-14 23:17:07,590 INFO L184 SettingsManager]: AutomataScriptParser provides no preferences, ignoring... [2020-10-14 23:17:07,591 INFO L184 SettingsManager]: ReqParser provides no preferences, ignoring... [2020-10-14 23:17:07,591 INFO L181 SettingsManager]: Resetting SmtParser preferences to default values [2020-10-14 23:17:07,591 INFO L181 SettingsManager]: Resetting Witness Parser preferences to default values [2020-10-14 23:17:07,592 INFO L188 SettingsManager]: Finished resetting all preferences to default values... [2020-10-14 23:17:07,593 INFO L101 SettingsManager]: Beginning loading settings from /storage/repos/ultimate-2/releaseScripts/default/UAutomizer-linux/../../../trunk/examples/settings/default/automizer/svcomp-Reach-32bit-Automizer_Default.epf [2020-10-14 23:17:07,631 INFO L113 SettingsManager]: Loading preferences was successful [2020-10-14 23:17:07,631 INFO L115 SettingsManager]: Preferences different from defaults after loading the file: [2020-10-14 23:17:07,633 INFO L136 SettingsManager]: Preferences of BlockEncodingV2 differ from their defaults: [2020-10-14 23:17:07,633 INFO L138 SettingsManager]: * Create parallel compositions if possible=false [2020-10-14 23:17:07,634 INFO L138 SettingsManager]: * Use SBE=true [2020-10-14 23:17:07,634 INFO L136 SettingsManager]: Preferences of CACSL2BoogieTranslator differ from their defaults: [2020-10-14 23:17:07,634 INFO L138 SettingsManager]: * sizeof long=4 [2020-10-14 23:17:07,634 INFO L138 SettingsManager]: * Overapproximate operations on floating types=true [2020-10-14 23:17:07,634 INFO L138 SettingsManager]: * sizeof POINTER=4 [2020-10-14 23:17:07,635 INFO L138 SettingsManager]: * Check division by zero=IGNORE [2020-10-14 23:17:07,635 INFO L138 SettingsManager]: * Pointer to allocated memory at dereference=IGNORE [2020-10-14 23:17:07,636 INFO L138 SettingsManager]: * If two pointers are subtracted or compared they have the same base address=IGNORE [2020-10-14 23:17:07,636 INFO L138 SettingsManager]: * Check array bounds for arrays that are off heap=IGNORE [2020-10-14 23:17:07,636 INFO L138 SettingsManager]: * sizeof long double=12 [2020-10-14 23:17:07,637 INFO L138 SettingsManager]: * Check if freed pointer was valid=false [2020-10-14 23:17:07,637 INFO L138 SettingsManager]: * Use constant arrays=true [2020-10-14 23:17:07,637 INFO L138 SettingsManager]: * Pointer base address is valid at dereference=IGNORE [2020-10-14 23:17:07,637 INFO L136 SettingsManager]: Preferences of RCFGBuilder differ from their defaults: [2020-10-14 23:17:07,637 INFO L138 SettingsManager]: * Size of a code block=SequenceOfStatements [2020-10-14 23:17:07,637 INFO L138 SettingsManager]: * To the following directory=./dump/ [2020-10-14 23:17:07,638 INFO L138 SettingsManager]: * SMT solver=External_DefaultMode [2020-10-14 23:17:07,638 INFO L138 SettingsManager]: * Command for external solver=z3 SMTLIB2_COMPLIANT=true -memory:2024 -smt2 -in -t:2000 [2020-10-14 23:17:07,638 INFO L136 SettingsManager]: Preferences of TraceAbstraction differ from their defaults: [2020-10-14 23:17:07,639 INFO L138 SettingsManager]: * Compute Interpolants along a Counterexample=FPandBP [2020-10-14 23:17:07,639 INFO L138 SettingsManager]: * Positions where we compute the Hoare Annotation=LoopsAndPotentialCycles [2020-10-14 23:17:07,639 INFO L138 SettingsManager]: * Trace refinement strategy=CAMEL [2020-10-14 23:17:07,639 INFO L138 SettingsManager]: * Command for external solver=z3 SMTLIB2_COMPLIANT=true -memory:2024 -smt2 -in [2020-10-14 23:17:07,639 INFO L138 SettingsManager]: * Compute Hoare Annotation of negated interpolant automaton, abstraction and CFG=true [2020-10-14 23:17:07,639 INFO L138 SettingsManager]: * Trace refinement exception blacklist=NONE [2020-10-14 23:17:07,640 INFO L138 SettingsManager]: * SMT solver=External_ModelsAndUnsatCoreMode Applying setting for plugin de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction: Trace refinement strategy -> FIXED_PREFERENCES Applying setting for plugin de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction: Compute Interpolants along a Counterexample -> Craig_NestedInterpolation Applying setting for plugin de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction: SMT solver -> Internal_SMTInterpol Applying setting for plugin de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction: Compute trace for counterexample result -> false Applying setting for plugin de.uni_freiburg.informatik.ultimate.plugins.generator.rcfgbuilder: Size of a code block -> SequenceOfStatements Applying setting for plugin de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction: Use minimal unsat core enumeration -> true Applying setting for plugin de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction: Additional SMT options -> produce-proofs=true;produce-unsat-cores=true;enumeration-timeout=5000;interpolation-heuristic=SMALLESTAMONGWIDE;tolerance=0.2;log-additional-information=true;unknown-allowed=true; Applying setting for plugin de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction: Additional SMT options -> produce-proofs=true;produce-unsat-cores=true;enumeration-timeout=5000;interpolation-heuristic=SMALLESTAMONGWIDE;tolerance=0.2;log-additional-information=true;unknown-allowed=true; Applying setting for plugin de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction: Additional SMT options -> produce-proofs=true;produce-unsat-cores=true;enumeration-timeout=5000;interpolation-heuristic=SMALLESTAMONGWIDE;tolerance=0.2;log-additional-information=true;unknown-allowed=true; Applying setting for plugin de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction: Additional SMT options -> produce-proofs=true;produce-unsat-cores=true;enumeration-timeout=5000;interpolation-heuristic=SMALLESTAMONGWIDE;tolerance=0.2;log-additional-information=true;unknown-allowed=true; Applying setting for plugin de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction: Additional SMT options -> produce-proofs=true;produce-unsat-cores=true;enumeration-timeout=5000;interpolation-heuristic=SMALLESTAMONGWIDE;tolerance=0.2;log-additional-information=true;unknown-allowed=true; Applying setting for plugin de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction: Additional SMT options -> produce-proofs=true;produce-unsat-cores=true;enumeration-timeout=5000;interpolation-heuristic=SMALLESTAMONGWIDE;tolerance=0.2;log-additional-information=true;unknown-allowed=true; Applying setting for plugin de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction: Additional SMT options -> produce-proofs=true;produce-unsat-cores=true;enumeration-timeout=5000;interpolation-heuristic=SMALLESTAMONGWIDE;tolerance=0.2;log-additional-information=true;unknown-allowed=true; [2020-10-14 23:17:07,961 INFO L75 nceAwareModelManager]: Repository-Root is: /tmp [2020-10-14 23:17:07,973 INFO L258 ainManager$Toolchain]: [Toolchain 1]: Applicable parser(s) successfully (re)initialized [2020-10-14 23:17:07,976 INFO L214 ainManager$Toolchain]: [Toolchain 1]: Toolchain selected. [2020-10-14 23:17:07,978 INFO L271 PluginConnector]: Initializing CDTParser... [2020-10-14 23:17:07,978 INFO L275 PluginConnector]: CDTParser initialized [2020-10-14 23:17:07,979 INFO L429 ainManager$Toolchain]: [Toolchain 1]: Parsing single file: /storage/repos/ultimate-2/releaseScripts/default/UAutomizer-linux/../../../trunk/examples/svcomp/float-newlib/double_req_bl_0681b.c [2020-10-14 23:17:08,039 INFO L220 CDTParser]: Created temporary CDT project at /storage/repos/ultimate-2/releaseScripts/default/UAutomizer-linux/data/54cdd855c/ba7f10a1187446a1a3554e5d5194e94f/FLAGb9d850275 [2020-10-14 23:17:08,544 INFO L306 CDTParser]: Found 1 translation units. [2020-10-14 23:17:08,545 INFO L160 CDTParser]: Scanning /storage/repos/ultimate-2/trunk/examples/svcomp/float-newlib/double_req_bl_0681b.c [2020-10-14 23:17:08,564 INFO L349 CDTParser]: About to delete temporary CDT project at /storage/repos/ultimate-2/releaseScripts/default/UAutomizer-linux/data/54cdd855c/ba7f10a1187446a1a3554e5d5194e94f/FLAGb9d850275 [2020-10-14 23:17:08,879 INFO L357 CDTParser]: Successfully deleted /storage/repos/ultimate-2/releaseScripts/default/UAutomizer-linux/data/54cdd855c/ba7f10a1187446a1a3554e5d5194e94f [2020-10-14 23:17:08,887 INFO L296 ainManager$Toolchain]: ####################### [Toolchain 1] ####################### [2020-10-14 23:17:08,889 INFO L131 ToolchainWalker]: Walking toolchain with 4 elements. [2020-10-14 23:17:08,890 INFO L113 PluginConnector]: ------------------------CACSL2BoogieTranslator---------------------------- [2020-10-14 23:17:08,890 INFO L271 PluginConnector]: Initializing CACSL2BoogieTranslator... [2020-10-14 23:17:08,893 INFO L275 PluginConnector]: CACSL2BoogieTranslator initialized [2020-10-14 23:17:08,894 INFO L185 PluginConnector]: Executing the observer ACSLObjectContainerObserver from plugin CACSL2BoogieTranslator for "CDTParser AST 14.10 11:17:08" (1/1) ... [2020-10-14 23:17:08,897 INFO L205 PluginConnector]: Invalid model from CACSL2BoogieTranslator for observer de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator.ACSLObjectContainerObserver@609549d1 and model type de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 14.10 11:17:08, skipping insertion in model container [2020-10-14 23:17:08,898 INFO L185 PluginConnector]: Executing the observer CACSL2BoogieTranslatorObserver from plugin CACSL2BoogieTranslator for "CDTParser AST 14.10 11:17:08" (1/1) ... [2020-10-14 23:17:08,906 INFO L145 MainTranslator]: Starting translation in SV-COMP mode [2020-10-14 23:17:08,932 INFO L178 MainTranslator]: Built tables and reachable declarations [2020-10-14 23:17:09,276 INFO L206 PostProcessor]: Analyzing one entry point: main [2020-10-14 23:17:09,284 INFO L203 MainTranslator]: Completed pre-run [2020-10-14 23:17:09,379 INFO L206 PostProcessor]: Analyzing one entry point: main [2020-10-14 23:17:09,404 INFO L208 MainTranslator]: Completed translation [2020-10-14 23:17:09,404 INFO L202 PluginConnector]: Adding new model de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 14.10 11:17:09 WrapperNode [2020-10-14 23:17:09,405 INFO L132 PluginConnector]: ------------------------ END CACSL2BoogieTranslator---------------------------- [2020-10-14 23:17:09,405 INFO L113 PluginConnector]: ------------------------Boogie Preprocessor---------------------------- [2020-10-14 23:17:09,406 INFO L271 PluginConnector]: Initializing Boogie Preprocessor... [2020-10-14 23:17:09,406 INFO L275 PluginConnector]: Boogie Preprocessor initialized [2020-10-14 23:17:09,417 INFO L185 PluginConnector]: Executing the observer EnsureBoogieModelObserver from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 14.10 11:17:09" (1/1) ... [2020-10-14 23:17:09,417 INFO L185 PluginConnector]: Executing the observer TypeChecker from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 14.10 11:17:09" (1/1) ... [2020-10-14 23:17:09,433 INFO L185 PluginConnector]: Executing the observer ConstExpander from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 14.10 11:17:09" (1/1) ... [2020-10-14 23:17:09,433 INFO L185 PluginConnector]: Executing the observer StructExpander from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 14.10 11:17:09" (1/1) ... [2020-10-14 23:17:09,460 INFO L185 PluginConnector]: Executing the observer UnstructureCode from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 14.10 11:17:09" (1/1) ... [2020-10-14 23:17:09,472 INFO L185 PluginConnector]: Executing the observer FunctionInliner from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 14.10 11:17:09" (1/1) ... [2020-10-14 23:17:09,476 INFO L185 PluginConnector]: Executing the observer BoogieSymbolTableConstructor from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 14.10 11:17:09" (1/1) ... [2020-10-14 23:17:09,481 INFO L132 PluginConnector]: ------------------------ END Boogie Preprocessor---------------------------- [2020-10-14 23:17:09,482 INFO L113 PluginConnector]: ------------------------RCFGBuilder---------------------------- [2020-10-14 23:17:09,482 INFO L271 PluginConnector]: Initializing RCFGBuilder... [2020-10-14 23:17:09,482 INFO L275 PluginConnector]: RCFGBuilder initialized [2020-10-14 23:17:09,483 INFO L185 PluginConnector]: Executing the observer RCFGBuilderObserver from plugin RCFGBuilder for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 14.10 11:17:09" (1/1) ... No working directory specified, using /storage/repos/ultimate-2/releaseScripts/default/UAutomizer-linux/z3 Starting monitored process 1 with z3 SMTLIB2_COMPLIANT=true -memory:2024 -smt2 -in -t:2000 (exit command is (exit), workingDir is null) Waiting until toolchain timeout for monitored process 1 with z3 SMTLIB2_COMPLIANT=true -memory:2024 -smt2 -in -t:2000 [2020-10-14 23:17:09,549 INFO L138 BoogieDeclarations]: Found implementation of procedure ULTIMATE.init [2020-10-14 23:17:09,550 INFO L138 BoogieDeclarations]: Found implementation of procedure ULTIMATE.start [2020-10-14 23:17:09,550 INFO L138 BoogieDeclarations]: Found implementation of procedure fabs_double [2020-10-14 23:17:09,550 INFO L138 BoogieDeclarations]: Found implementation of procedure atan_double [2020-10-14 23:17:09,550 INFO L138 BoogieDeclarations]: Found implementation of procedure __ieee754_atan2 [2020-10-14 23:17:09,550 INFO L138 BoogieDeclarations]: Found implementation of procedure __signbit_double [2020-10-14 23:17:09,550 INFO L138 BoogieDeclarations]: Found implementation of procedure main [2020-10-14 23:17:09,551 INFO L130 BoogieDeclarations]: Found specification of procedure __VERIFIER_error [2020-10-14 23:17:09,552 INFO L130 BoogieDeclarations]: Found specification of procedure __VERIFIER_nondet_double [2020-10-14 23:17:09,552 INFO L130 BoogieDeclarations]: Found specification of procedure fabs_double [2020-10-14 23:17:09,552 INFO L130 BoogieDeclarations]: Found specification of procedure #Ultimate.allocOnStack [2020-10-14 23:17:09,552 INFO L130 BoogieDeclarations]: Found specification of procedure write~real [2020-10-14 23:17:09,552 INFO L130 BoogieDeclarations]: Found specification of procedure read~int [2020-10-14 23:17:09,552 INFO L130 BoogieDeclarations]: Found specification of procedure ULTIMATE.dealloc [2020-10-14 23:17:09,552 INFO L130 BoogieDeclarations]: Found specification of procedure write~int [2020-10-14 23:17:09,553 INFO L130 BoogieDeclarations]: Found specification of procedure read~real [2020-10-14 23:17:09,553 INFO L130 BoogieDeclarations]: Found specification of procedure atan_double [2020-10-14 23:17:09,554 INFO L130 BoogieDeclarations]: Found specification of procedure __ieee754_atan2 [2020-10-14 23:17:09,554 INFO L130 BoogieDeclarations]: Found specification of procedure __signbit_double [2020-10-14 23:17:09,554 INFO L130 BoogieDeclarations]: Found specification of procedure main [2020-10-14 23:17:09,555 INFO L130 BoogieDeclarations]: Found specification of procedure ULTIMATE.init [2020-10-14 23:17:09,555 INFO L130 BoogieDeclarations]: Found specification of procedure write~init~real [2020-10-14 23:17:09,555 INFO L130 BoogieDeclarations]: Found specification of procedure ULTIMATE.start [2020-10-14 23:17:10,332 INFO L290 CfgBuilder]: Using the 1 location(s) as analysis (start of procedure ULTIMATE.start) [2020-10-14 23:17:10,333 INFO L295 CfgBuilder]: Removed 18 assume(true) statements. [2020-10-14 23:17:10,338 INFO L202 PluginConnector]: Adding new model de.uni_freiburg.informatik.ultimate.plugins.generator.rcfgbuilder CFG 14.10 11:17:10 BoogieIcfgContainer [2020-10-14 23:17:10,339 INFO L132 PluginConnector]: ------------------------ END RCFGBuilder---------------------------- [2020-10-14 23:17:10,340 INFO L113 PluginConnector]: ------------------------TraceAbstraction---------------------------- [2020-10-14 23:17:10,340 INFO L271 PluginConnector]: Initializing TraceAbstraction... [2020-10-14 23:17:10,344 INFO L275 PluginConnector]: TraceAbstraction initialized [2020-10-14 23:17:10,344 INFO L185 PluginConnector]: Executing the observer TraceAbstractionObserver from plugin TraceAbstraction for "CDTParser AST 14.10 11:17:08" (1/3) ... [2020-10-14 23:17:10,345 INFO L205 PluginConnector]: Invalid model from TraceAbstraction for observer de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction.TraceAbstractionObserver@56d1ccc8 and model type de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction AST 14.10 11:17:10, skipping insertion in model container [2020-10-14 23:17:10,345 INFO L185 PluginConnector]: Executing the observer TraceAbstractionObserver from plugin TraceAbstraction for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 14.10 11:17:09" (2/3) ... [2020-10-14 23:17:10,346 INFO L205 PluginConnector]: Invalid model from TraceAbstraction for observer de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction.TraceAbstractionObserver@56d1ccc8 and model type de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction AST 14.10 11:17:10, skipping insertion in model container [2020-10-14 23:17:10,346 INFO L185 PluginConnector]: Executing the observer TraceAbstractionObserver from plugin TraceAbstraction for "de.uni_freiburg.informatik.ultimate.plugins.generator.rcfgbuilder CFG 14.10 11:17:10" (3/3) ... [2020-10-14 23:17:10,348 INFO L109 eAbstractionObserver]: Analyzing ICFG double_req_bl_0681b.c [2020-10-14 23:17:10,359 INFO L157 ceAbstractionStarter]: Automizer settings: Hoare:true NWA Interpolation:Craig_NestedInterpolation Determinization: PREDICATE_ABSTRACTION [2020-10-14 23:17:10,368 INFO L169 ceAbstractionStarter]: Appying trace abstraction to program that has 1 error locations. [2020-10-14 23:17:10,380 INFO L251 AbstractCegarLoop]: Starting to check reachability of 1 error locations. [2020-10-14 23:17:10,406 INFO L375 AbstractCegarLoop]: Interprodecural is true [2020-10-14 23:17:10,406 INFO L376 AbstractCegarLoop]: Hoare is true [2020-10-14 23:17:10,406 INFO L377 AbstractCegarLoop]: Compute interpolants for Craig_NestedInterpolation [2020-10-14 23:17:10,406 INFO L378 AbstractCegarLoop]: Backedges is STRAIGHT_LINE [2020-10-14 23:17:10,407 INFO L379 AbstractCegarLoop]: Determinization is PREDICATE_ABSTRACTION [2020-10-14 23:17:10,407 INFO L380 AbstractCegarLoop]: Difference is false [2020-10-14 23:17:10,407 INFO L381 AbstractCegarLoop]: Minimize is MINIMIZE_SEVPA [2020-10-14 23:17:10,407 INFO L385 AbstractCegarLoop]: ======== Iteration 0==of CEGAR loop == AllErrorsAtOnce======== [2020-10-14 23:17:10,437 INFO L276 IsEmpty]: Start isEmpty. Operand 110 states. [2020-10-14 23:17:10,442 INFO L282 IsEmpty]: Finished isEmpty. Found accepting run of length 20 [2020-10-14 23:17:10,443 INFO L414 BasicCegarLoop]: Found error trace [2020-10-14 23:17:10,444 INFO L422 BasicCegarLoop]: trace histogram [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1] [2020-10-14 23:17:10,444 INFO L427 AbstractCegarLoop]: === Iteration 1 === [mainErr0ASSERT_VIOLATIONERROR_FUNCTION]=== [2020-10-14 23:17:10,449 INFO L144 PredicateUnifier]: Initialized classic predicate unifier [2020-10-14 23:17:10,449 INFO L82 PathProgramCache]: Analyzing trace with hash -530639070, now seen corresponding path program 1 times [2020-10-14 23:17:10,457 INFO L163 FreeRefinementEngine]: Executing refinement strategy FIXED_PREFERENCES [2020-10-14 23:17:10,457 INFO L354 FreeRefinementEngine]: Using trace check IpTcStrategyModulePreferences [376075133] [2020-10-14 23:17:10,457 INFO L95 rtionOrderModulation]: Keeping assertion order NOT_INCREMENTALLY [2020-10-14 23:17:10,662 INFO L136 AnnotateAndAsserter]: Conjunction of SSA is unsat [2020-10-14 23:17:10,751 FATAL L256 erpolLogProxyWrapper]: Now shrinking... [2020-10-14 23:17:10,824 FATAL L256 erpolLogProxyWrapper]: Now shrinking... [2020-10-14 23:17:10,941 FATAL L256 erpolLogProxyWrapper]: Timeout: 5000 [2020-10-14 23:17:10,942 FATAL L256 erpolLogProxyWrapper]: Cardinality of Constraint set: 27 [2020-10-14 23:17:10,942 FATAL L256 erpolLogProxyWrapper]: Number of enumerated Muses: 2 [2020-10-14 23:17:10,943 FATAL L256 erpolLogProxyWrapper]: Time needed for enumeration: 262 [2020-10-14 23:17:10,946 FATAL L256 erpolLogProxyWrapper]: Heuristic: SMALLESTAMONGWIDE [2020-10-14 23:17:10,946 FATAL L256 erpolLogProxyWrapper]: Tolerance: 0.2 [2020-10-14 23:17:10,947 FATAL L256 erpolLogProxyWrapper]: Chosen Mus has size: 1 [2020-10-14 23:17:10,947 FATAL L256 erpolLogProxyWrapper]: Chosen Mus has depth: 16 [2020-10-14 23:17:10,947 FATAL L256 erpolLogProxyWrapper]: Chosen Mus has width: 1 [2020-10-14 23:17:10,947 FATAL L256 erpolLogProxyWrapper]: Time needed for Heuristics: 4 [2020-10-14 23:17:11,069 INFO L375 atingTraceCheckCraig]: Compute interpolants for subsequence at non-pending call position 0 [2020-10-14 23:17:11,074 INFO L136 AnnotateAndAsserter]: Conjunction of SSA is unsat [2020-10-14 23:17:11,076 FATAL L256 erpolLogProxyWrapper]: Now shrinking... [2020-10-14 23:17:11,098 FATAL L256 erpolLogProxyWrapper]: Timeout: 5000 [2020-10-14 23:17:11,099 FATAL L256 erpolLogProxyWrapper]: Cardinality of Constraint set: 8 [2020-10-14 23:17:11,099 FATAL L256 erpolLogProxyWrapper]: Number of enumerated Muses: 1 [2020-10-14 23:17:11,099 FATAL L256 erpolLogProxyWrapper]: Time needed for enumeration: 24 [2020-10-14 23:17:11,100 FATAL L256 erpolLogProxyWrapper]: Heuristic: SMALLESTAMONGWIDE [2020-10-14 23:17:11,100 FATAL L256 erpolLogProxyWrapper]: Tolerance: 0.2 [2020-10-14 23:17:11,100 FATAL L256 erpolLogProxyWrapper]: Chosen Mus has size: 1 [2020-10-14 23:17:11,100 FATAL L256 erpolLogProxyWrapper]: Chosen Mus has depth: 1 [2020-10-14 23:17:11,100 FATAL L256 erpolLogProxyWrapper]: Chosen Mus has width: 1 [2020-10-14 23:17:11,101 FATAL L256 erpolLogProxyWrapper]: Time needed for Heuristics: 1 [2020-10-14 23:17:11,128 INFO L375 atingTraceCheckCraig]: Compute interpolants for subsequence at non-pending call position 6 [2020-10-14 23:17:11,130 INFO L136 AnnotateAndAsserter]: Conjunction of SSA is unsat [2020-10-14 23:17:11,132 FATAL L256 erpolLogProxyWrapper]: Now shrinking... [2020-10-14 23:17:11,135 FATAL L256 erpolLogProxyWrapper]: Now shrinking... [2020-10-14 23:17:11,146 FATAL L256 erpolLogProxyWrapper]: Timeout: 5000 [2020-10-14 23:17:11,146 FATAL L256 erpolLogProxyWrapper]: Cardinality of Constraint set: 13 [2020-10-14 23:17:11,146 FATAL L256 erpolLogProxyWrapper]: Number of enumerated Muses: 2 [2020-10-14 23:17:11,147 FATAL L256 erpolLogProxyWrapper]: Time needed for enumeration: 14 [2020-10-14 23:17:11,147 FATAL L256 erpolLogProxyWrapper]: Heuristic: SMALLESTAMONGWIDE [2020-10-14 23:17:11,147 FATAL L256 erpolLogProxyWrapper]: Tolerance: 0.2 [2020-10-14 23:17:11,147 FATAL L256 erpolLogProxyWrapper]: Chosen Mus has size: 1 [2020-10-14 23:17:11,148 FATAL L256 erpolLogProxyWrapper]: Chosen Mus has depth: 3 [2020-10-14 23:17:11,148 FATAL L256 erpolLogProxyWrapper]: Chosen Mus has width: 1 [2020-10-14 23:17:11,148 FATAL L256 erpolLogProxyWrapper]: Time needed for Heuristics: 1 [2020-10-14 23:17:11,155 INFO L134 CoverageAnalysis]: Checked inductivity of 0 backedges. 0 proven. 0 refuted. 0 times theorem prover too weak. 0 trivial. 0 not checked. [2020-10-14 23:17:11,156 INFO L354 FreeRefinementEngine]: Using interpolant generator IpTcStrategyModulePreferences [376075133] [2020-10-14 23:17:11,158 INFO L220 FreeRefinementEngine]: Constructing automaton from 1 perfect and 0 imperfect interpolant sequences. [2020-10-14 23:17:11,159 INFO L233 FreeRefinementEngine]: Number of different interpolants: perfect sequences [4] imperfect sequences [] total 4 [2020-10-14 23:17:11,160 INFO L156 tionRefinementEngine]: Using interpolant automaton builder IpAbStrategyModuleStraightlineAll [2124918520] [2020-10-14 23:17:11,165 INFO L459 AbstractCegarLoop]: Interpolant automaton has 4 states [2020-10-14 23:17:11,165 INFO L143 FreeRefinementEngine]: Using predicate unifier PredicateUnifier provided by strategy FIXED_PREFERENCES [2020-10-14 23:17:11,180 INFO L142 InterpolantAutomaton]: Constructing interpolant automaton starting with 4 interpolants. [2020-10-14 23:17:11,181 INFO L144 InterpolantAutomaton]: CoverageRelationStatistics Valid=5, Invalid=7, Unknown=0, NotChecked=0, Total=12 [2020-10-14 23:17:11,183 INFO L87 Difference]: Start difference. First operand 110 states. Second operand 4 states. [2020-10-14 23:17:11,620 INFO L144 Difference]: Subtrahend was deterministic. Have not used determinization. [2020-10-14 23:17:11,620 INFO L93 Difference]: Finished difference Result 212 states and 335 transitions. [2020-10-14 23:17:11,621 INFO L141 InterpolantAutomaton]: Switched to read-only mode: deterministic interpolant automaton has 3 states. [2020-10-14 23:17:11,622 INFO L78 Accepts]: Start accepts. Automaton has 4 states. Word has length 19 [2020-10-14 23:17:11,623 INFO L84 Accepts]: Finished accepts. some prefix is accepted. [2020-10-14 23:17:11,636 INFO L225 Difference]: With dead ends: 212 [2020-10-14 23:17:11,636 INFO L226 Difference]: Without dead ends: 106 [2020-10-14 23:17:11,641 INFO L675 BasicCegarLoop]: 0 DeclaredPredicates, 9 GetRequests, 6 SyntacticMatches, 0 SemanticMatches, 3 ConstructedPredicates, 0 IntricatePredicates, 0 DeprecatedPredicates, 0 ImplicationChecksByTransitivity, 0.1s TimeCoverageRelationStatistics Valid=9, Invalid=11, Unknown=0, NotChecked=0, Total=20 [2020-10-14 23:17:11,664 INFO L82 GeneralOperation]: Start minimizeSevpa. Operand 106 states. [2020-10-14 23:17:11,700 INFO L88 GeneralOperation]: Finished minimizeSevpa. Reduced states from 106 to 106. [2020-10-14 23:17:11,701 INFO L82 GeneralOperation]: Start removeUnreachable. Operand 106 states. [2020-10-14 23:17:11,704 INFO L88 GeneralOperation]: Finished removeUnreachable. Reduced from 106 states to 106 states and 146 transitions. [2020-10-14 23:17:11,706 INFO L78 Accepts]: Start accepts. Automaton has 106 states and 146 transitions. Word has length 19 [2020-10-14 23:17:11,707 INFO L84 Accepts]: Finished accepts. word is rejected. [2020-10-14 23:17:11,707 INFO L479 AbstractCegarLoop]: Abstraction has 106 states and 146 transitions. [2020-10-14 23:17:11,707 INFO L480 AbstractCegarLoop]: Interpolant automaton has 4 states. [2020-10-14 23:17:11,708 INFO L276 IsEmpty]: Start isEmpty. Operand 106 states and 146 transitions. [2020-10-14 23:17:11,709 INFO L282 IsEmpty]: Finished isEmpty. Found accepting run of length 22 [2020-10-14 23:17:11,709 INFO L414 BasicCegarLoop]: Found error trace [2020-10-14 23:17:11,709 INFO L422 BasicCegarLoop]: trace histogram [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1] [2020-10-14 23:17:11,710 WARN L516 AbstractCegarLoop]: Destroyed unattended storables created during the last iteration: SelfDestructingSolverStorable0 [2020-10-14 23:17:11,710 INFO L427 AbstractCegarLoop]: === Iteration 2 === [mainErr0ASSERT_VIOLATIONERROR_FUNCTION]=== [2020-10-14 23:17:11,710 INFO L144 PredicateUnifier]: Initialized classic predicate unifier [2020-10-14 23:17:11,711 INFO L82 PathProgramCache]: Analyzing trace with hash 1749596857, now seen corresponding path program 1 times [2020-10-14 23:17:11,711 INFO L163 FreeRefinementEngine]: Executing refinement strategy FIXED_PREFERENCES [2020-10-14 23:17:11,711 INFO L354 FreeRefinementEngine]: Using trace check IpTcStrategyModulePreferences [714606139] [2020-10-14 23:17:11,711 INFO L95 rtionOrderModulation]: Keeping assertion order NOT_INCREMENTALLY [2020-10-14 23:17:11,772 INFO L136 AnnotateAndAsserter]: Conjunction of SSA is sat [2020-10-14 23:17:11,775 INFO L174 FreeRefinementEngine]: Strategy FIXED_PREFERENCES found a feasible trace [2020-10-14 23:17:11,775 INFO L520 BasicCegarLoop]: Counterexample might be feasible [2020-10-14 23:17:11,781 WARN L516 AbstractCegarLoop]: Destroyed unattended storables created during the last iteration: SelfDestructingSolverStorable1 [2020-10-14 23:17:11,801 INFO L202 PluginConnector]: Adding new model de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction CFG 14.10 11:17:11 BoogieIcfgContainer [2020-10-14 23:17:11,801 INFO L132 PluginConnector]: ------------------------ END TraceAbstraction---------------------------- [2020-10-14 23:17:11,804 INFO L168 Benchmark]: Toolchain (without parser) took 2914.49 ms. Allocated memory was 148.9 MB in the beginning and 231.7 MB in the end (delta: 82.8 MB). Free memory was 104.9 MB in the beginning and 112.3 MB in the end (delta: -7.4 MB). Peak memory consumption was 75.4 MB. Max. memory is 7.1 GB. [2020-10-14 23:17:11,806 INFO L168 Benchmark]: CDTParser took 0.18 ms. Allocated memory is still 148.9 MB. Free memory was 123.5 MB in the beginning and 123.0 MB in the end (delta: 419.8 kB). Peak memory consumption was 419.8 kB. Max. memory is 7.1 GB. [2020-10-14 23:17:11,810 INFO L168 Benchmark]: CACSL2BoogieTranslator took 515.43 ms. Allocated memory was 148.9 MB in the beginning and 204.5 MB in the end (delta: 55.6 MB). Free memory was 104.5 MB in the beginning and 176.6 MB in the end (delta: -72.2 MB). Peak memory consumption was 18.7 MB. Max. memory is 7.1 GB. [2020-10-14 23:17:11,811 INFO L168 Benchmark]: Boogie Preprocessor took 75.99 ms. Allocated memory is still 204.5 MB. Free memory was 176.6 MB in the beginning and 173.0 MB in the end (delta: 3.7 MB). Peak memory consumption was 3.7 MB. Max. memory is 7.1 GB. [2020-10-14 23:17:11,812 INFO L168 Benchmark]: RCFGBuilder took 857.09 ms. Allocated memory is still 204.5 MB. Free memory was 173.0 MB in the beginning and 126.9 MB in the end (delta: 46.1 MB). Peak memory consumption was 46.1 MB. Max. memory is 7.1 GB. [2020-10-14 23:17:11,814 INFO L168 Benchmark]: TraceAbstraction took 1461.33 ms. Allocated memory was 204.5 MB in the beginning and 231.7 MB in the end (delta: 27.3 MB). Free memory was 126.9 MB in the beginning and 112.3 MB in the end (delta: 14.6 MB). Peak memory consumption was 41.8 MB. Max. memory is 7.1 GB. [2020-10-14 23:17:11,825 INFO L336 ainManager$Toolchain]: ####################### End [Toolchain 1] ####################### --- Results --- * Results from de.uni_freiburg.informatik.ultimate.core: - StatisticsResult: Toolchain Benchmarks Benchmark results are: * CDTParser took 0.18 ms. Allocated memory is still 148.9 MB. Free memory was 123.5 MB in the beginning and 123.0 MB in the end (delta: 419.8 kB). Peak memory consumption was 419.8 kB. Max. memory is 7.1 GB. * CACSL2BoogieTranslator took 515.43 ms. Allocated memory was 148.9 MB in the beginning and 204.5 MB in the end (delta: 55.6 MB). Free memory was 104.5 MB in the beginning and 176.6 MB in the end (delta: -72.2 MB). Peak memory consumption was 18.7 MB. Max. memory is 7.1 GB. * Boogie Preprocessor took 75.99 ms. Allocated memory is still 204.5 MB. Free memory was 176.6 MB in the beginning and 173.0 MB in the end (delta: 3.7 MB). Peak memory consumption was 3.7 MB. Max. memory is 7.1 GB. * RCFGBuilder took 857.09 ms. Allocated memory is still 204.5 MB. Free memory was 173.0 MB in the beginning and 126.9 MB in the end (delta: 46.1 MB). Peak memory consumption was 46.1 MB. Max. memory is 7.1 GB. * TraceAbstraction took 1461.33 ms. Allocated memory was 204.5 MB in the beginning and 231.7 MB in the end (delta: 27.3 MB). Free memory was 126.9 MB in the beginning and 112.3 MB in the end (delta: 14.6 MB). Peak memory consumption was 41.8 MB. Max. memory is 7.1 GB. * Results from de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction: - UnprovableResult [Line: 268]: Unable to prove that call of __VERIFIER_error() unreachable Unable to prove that call of __VERIFIER_error() unreachable Reason: overapproximation of bitwiseOr at line 162, overapproximation of someUnaryDOUBLEoperation at line 264, overapproximation of bitwiseAnd at line 160, overapproximation of someBinaryArithmeticDOUBLEoperation at line 163, overapproximation of someBinaryDOUBLEComparisonOperation at line 267. Possible FailurePath: [L37-L42] static const double atanhi_atan[] = { 4.63647609000806093515e-01, 7.85398163397448278999e-01, 9.82793723247329054082e-01, 1.57079632679489655800e+00, }; [L44-L49] static const double atanlo_atan[] = { 2.26987774529616870924e-17, 3.06161699786838301793e-17, 1.39033110312309984516e-17, 6.12323399573676603587e-17, }; [L51-L58] static const double aT_atan[] = { 3.33333333333329318027e-01, -1.99999999998764832476e-01, 1.42857142725034663711e-01, -1.11111104054623557880e-01, 9.09088713343650656196e-02, -7.69187620504482999495e-02, 6.66107313738753120669e-02, -5.83357013379057348645e-02, 4.97687799461593236017e-02, -3.65315727442169155270e-02, 1.62858201153657823623e-02, }; [L60-L62] static const double one_atan = 1.0, pi_o_4 = 7.8539816339744827900E-01, pi_o_2 = 1.5707963267948965580E+00, pi = 3.1415926535897931160E+00, huge_atan = 1.0e300; [L139-L140] static const double tiny_atan2 = 1.0e-300, zero_atan2 = 0.0, pi_lo_atan2 = 1.2246467991473531772E-16; [L263] double x = 0.0; [L264] double y = -0.0; [L265] CALL, EXPR __ieee754_atan2(y, x) [L143] double z; [L144] __int32_t k, m, hx, hy, ix, iy; [L145] __uint32_t lx, ly; [L148] ieee_double_shape_type ew_u; [L149] ew_u.value = (x) [L150] EXPR ew_u.parts.msw [L150] (hx) = ew_u.parts.msw [L151] EXPR ew_u.parts.lsw [L151] (lx) = ew_u.parts.lsw [L153] ix = hx & 0x7fffffff [L155] ieee_double_shape_type ew_u; [L156] ew_u.value = (y) [L157] EXPR ew_u.parts.msw [L157] (hy) = ew_u.parts.msw [L158] EXPR ew_u.parts.lsw [L158] (ly) = ew_u.parts.lsw [L160] iy = hy & 0x7fffffff [L161-L162] COND TRUE ((ix | ((lx | -lx) >> 31)) > 0x7ff00000) || ((iy | ((ly | -ly) >> 31)) > 0x7ff00000) [L163] return x + y; [L265] RET, EXPR __ieee754_atan2(y, x) [L265] double res = __ieee754_atan2(y, x); [L267] EXPR res == -0.0 && __signbit_double(res) == 1 [L267] COND TRUE !(res == -0.0 && __signbit_double(res) == 1) [L268] __VERIFIER_error() - StatisticsResult: Ultimate Automizer benchmark data CFG has 7 procedures, 110 locations, 1 error locations. Started 1 CEGAR loops. VerificationResult: UNSAFE, OverallTime: 1.3s, OverallIterations: 2, TraceHistogramMax: 1, AutomataDifference: 0.4s, DeadEndRemovalTime: 0.0s, HoareAnnotationTime: 0.0s, InitialAbstractionConstructionTime: 0.0s, HoareTripleCheckerStatistics: 145 SDtfs, 10 SDslu, 134 SDs, 0 SdLazy, 145 SolverSat, 14 SolverUnsat, 0 SolverUnknown, 0 SolverNotchecked, 0.2s Time, PredicateUnifierStatistics: 0 DeclaredPredicates, 9 GetRequests, 6 SyntacticMatches, 0 SemanticMatches, 3 ConstructedPredicates, 0 IntricatePredicates, 0 DeprecatedPredicates, 0 ImplicationChecksByTransitivity, 0.1s Time, 0.0s BasicInterpolantAutomatonTime, BiggestAbstraction: size=110occurred in iteration=0, traceCheckStatistics: No data available, InterpolantConsolidationStatistics: No data available, PathInvariantsStatistics: No data available, 0/0 InterpolantCoveringCapability, TotalInterpolationStatistics: No data available, 0.0s DumpTime, AutomataMinimizationStatistics: 0.0s AutomataMinimizationTime, 1 MinimizatonAttempts, 0 StatesRemovedByMinimization, 0 NontrivialMinimizations, HoareAnnotationStatistics: No data available, RefinementEngineStatistics: TRACE_CHECK: 0.0s SsaConstructionTime, 0.1s SatisfiabilityAnalysisTime, 0.4s InterpolantComputationTime, 40 NumberOfCodeBlocks, 40 NumberOfCodeBlocksAsserted, 2 NumberOfCheckSat, 18 ConstructedInterpolants, 0 QuantifiedInterpolants, 1512 SizeOfPredicates, 0 NumberOfNonLiveVariables, 0 ConjunctsInSsa, 0 ConjunctsInUnsatCore, 1 InterpolantComputations, 1 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 Received shutdown request...