/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=WIDESTAMONGSMALL --traceabstraction.additional.smt.options tolerance=0.4 --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 04:46:19,728 INFO L177 SettingsManager]: Resetting all preferences to default values... [2020-10-14 04:46:19,732 INFO L181 SettingsManager]: Resetting UltimateCore preferences to default values [2020-10-14 04:46:19,772 INFO L184 SettingsManager]: Ultimate Commandline Interface provides no preferences, ignoring... [2020-10-14 04:46:19,772 INFO L181 SettingsManager]: Resetting Boogie Preprocessor preferences to default values [2020-10-14 04:46:19,783 INFO L181 SettingsManager]: Resetting Boogie Procedure Inliner preferences to default values [2020-10-14 04:46:19,785 INFO L181 SettingsManager]: Resetting Abstract Interpretation preferences to default values [2020-10-14 04:46:19,788 INFO L181 SettingsManager]: Resetting LassoRanker preferences to default values [2020-10-14 04:46:19,790 INFO L181 SettingsManager]: Resetting Reaching Definitions preferences to default values [2020-10-14 04:46:19,794 INFO L181 SettingsManager]: Resetting SyntaxChecker preferences to default values [2020-10-14 04:46:19,794 INFO L181 SettingsManager]: Resetting Sifa preferences to default values [2020-10-14 04:46:19,795 INFO L184 SettingsManager]: Büchi Program Product provides no preferences, ignoring... [2020-10-14 04:46:19,795 INFO L181 SettingsManager]: Resetting LTL2Aut preferences to default values [2020-10-14 04:46:19,798 INFO L181 SettingsManager]: Resetting PEA to Boogie preferences to default values [2020-10-14 04:46:19,800 INFO L181 SettingsManager]: Resetting BlockEncodingV2 preferences to default values [2020-10-14 04:46:19,802 INFO L181 SettingsManager]: Resetting ChcToBoogie preferences to default values [2020-10-14 04:46:19,804 INFO L181 SettingsManager]: Resetting AutomataScriptInterpreter preferences to default values [2020-10-14 04:46:19,804 INFO L181 SettingsManager]: Resetting BuchiAutomizer preferences to default values [2020-10-14 04:46:19,806 INFO L181 SettingsManager]: Resetting CACSL2BoogieTranslator preferences to default values [2020-10-14 04:46:19,811 INFO L181 SettingsManager]: Resetting CodeCheck preferences to default values [2020-10-14 04:46:19,814 INFO L181 SettingsManager]: Resetting InvariantSynthesis preferences to default values [2020-10-14 04:46:19,814 INFO L181 SettingsManager]: Resetting RCFGBuilder preferences to default values [2020-10-14 04:46:19,815 INFO L181 SettingsManager]: Resetting Referee preferences to default values [2020-10-14 04:46:19,816 INFO L181 SettingsManager]: Resetting TraceAbstraction preferences to default values [2020-10-14 04:46:19,820 INFO L184 SettingsManager]: TraceAbstractionConcurrent provides no preferences, ignoring... [2020-10-14 04:46:19,820 INFO L184 SettingsManager]: TraceAbstractionWithAFAs provides no preferences, ignoring... [2020-10-14 04:46:19,820 INFO L181 SettingsManager]: Resetting TreeAutomizer preferences to default values [2020-10-14 04:46:19,823 INFO L181 SettingsManager]: Resetting IcfgToChc preferences to default values [2020-10-14 04:46:19,823 INFO L181 SettingsManager]: Resetting IcfgTransformer preferences to default values [2020-10-14 04:46:19,824 INFO L184 SettingsManager]: ReqToTest provides no preferences, ignoring... [2020-10-14 04:46:19,824 INFO L181 SettingsManager]: Resetting Boogie Printer preferences to default values [2020-10-14 04:46:19,825 INFO L181 SettingsManager]: Resetting ChcSmtPrinter preferences to default values [2020-10-14 04:46:19,825 INFO L181 SettingsManager]: Resetting ReqPrinter preferences to default values [2020-10-14 04:46:19,826 INFO L181 SettingsManager]: Resetting Witness Printer preferences to default values [2020-10-14 04:46:19,827 INFO L184 SettingsManager]: Boogie PL CUP Parser provides no preferences, ignoring... [2020-10-14 04:46:19,827 INFO L181 SettingsManager]: Resetting CDTParser preferences to default values [2020-10-14 04:46:19,828 INFO L184 SettingsManager]: AutomataScriptParser provides no preferences, ignoring... [2020-10-14 04:46:19,828 INFO L184 SettingsManager]: ReqParser provides no preferences, ignoring... [2020-10-14 04:46:19,828 INFO L181 SettingsManager]: Resetting SmtParser preferences to default values [2020-10-14 04:46:19,830 INFO L181 SettingsManager]: Resetting Witness Parser preferences to default values [2020-10-14 04:46:19,831 INFO L188 SettingsManager]: Finished resetting all preferences to default values... [2020-10-14 04:46:19,832 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 04:46:19,868 INFO L113 SettingsManager]: Loading preferences was successful [2020-10-14 04:46:19,868 INFO L115 SettingsManager]: Preferences different from defaults after loading the file: [2020-10-14 04:46:19,870 INFO L136 SettingsManager]: Preferences of BlockEncodingV2 differ from their defaults: [2020-10-14 04:46:19,870 INFO L138 SettingsManager]: * Create parallel compositions if possible=false [2020-10-14 04:46:19,871 INFO L138 SettingsManager]: * Use SBE=true [2020-10-14 04:46:19,871 INFO L136 SettingsManager]: Preferences of CACSL2BoogieTranslator differ from their defaults: [2020-10-14 04:46:19,871 INFO L138 SettingsManager]: * sizeof long=4 [2020-10-14 04:46:19,871 INFO L138 SettingsManager]: * Overapproximate operations on floating types=true [2020-10-14 04:46:19,871 INFO L138 SettingsManager]: * sizeof POINTER=4 [2020-10-14 04:46:19,872 INFO L138 SettingsManager]: * Check division by zero=IGNORE [2020-10-14 04:46:19,873 INFO L138 SettingsManager]: * Pointer to allocated memory at dereference=IGNORE [2020-10-14 04:46:19,873 INFO L138 SettingsManager]: * If two pointers are subtracted or compared they have the same base address=IGNORE [2020-10-14 04:46:19,873 INFO L138 SettingsManager]: * Check array bounds for arrays that are off heap=IGNORE [2020-10-14 04:46:19,874 INFO L138 SettingsManager]: * sizeof long double=12 [2020-10-14 04:46:19,874 INFO L138 SettingsManager]: * Check if freed pointer was valid=false [2020-10-14 04:46:19,874 INFO L138 SettingsManager]: * Use constant arrays=true [2020-10-14 04:46:19,874 INFO L138 SettingsManager]: * Pointer base address is valid at dereference=IGNORE [2020-10-14 04:46:19,874 INFO L136 SettingsManager]: Preferences of RCFGBuilder differ from their defaults: [2020-10-14 04:46:19,875 INFO L138 SettingsManager]: * Size of a code block=SequenceOfStatements [2020-10-14 04:46:19,875 INFO L138 SettingsManager]: * To the following directory=./dump/ [2020-10-14 04:46:19,875 INFO L138 SettingsManager]: * SMT solver=External_DefaultMode [2020-10-14 04:46:19,875 INFO L138 SettingsManager]: * Command for external solver=z3 SMTLIB2_COMPLIANT=true -memory:2024 -smt2 -in -t:2000 [2020-10-14 04:46:19,875 INFO L136 SettingsManager]: Preferences of TraceAbstraction differ from their defaults: [2020-10-14 04:46:19,876 INFO L138 SettingsManager]: * Compute Interpolants along a Counterexample=FPandBP [2020-10-14 04:46:19,876 INFO L138 SettingsManager]: * Positions where we compute the Hoare Annotation=LoopsAndPotentialCycles [2020-10-14 04:46:19,876 INFO L138 SettingsManager]: * Trace refinement strategy=CAMEL [2020-10-14 04:46:19,876 INFO L138 SettingsManager]: * Command for external solver=z3 SMTLIB2_COMPLIANT=true -memory:2024 -smt2 -in [2020-10-14 04:46:19,876 INFO L138 SettingsManager]: * Compute Hoare Annotation of negated interpolant automaton, abstraction and CFG=true [2020-10-14 04:46:19,877 INFO L138 SettingsManager]: * Trace refinement exception blacklist=NONE [2020-10-14 04:46:19,877 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=WIDESTAMONGSMALL;tolerance=0.4;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=WIDESTAMONGSMALL;tolerance=0.4;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=WIDESTAMONGSMALL;tolerance=0.4;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=WIDESTAMONGSMALL;tolerance=0.4;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=WIDESTAMONGSMALL;tolerance=0.4;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=WIDESTAMONGSMALL;tolerance=0.4;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=WIDESTAMONGSMALL;tolerance=0.4;log-additional-information=true;unknown-allowed=true; [2020-10-14 04:46:20,166 INFO L75 nceAwareModelManager]: Repository-Root is: /tmp [2020-10-14 04:46:20,178 INFO L258 ainManager$Toolchain]: [Toolchain 1]: Applicable parser(s) successfully (re)initialized [2020-10-14 04:46:20,181 INFO L214 ainManager$Toolchain]: [Toolchain 1]: Toolchain selected. [2020-10-14 04:46:20,182 INFO L271 PluginConnector]: Initializing CDTParser... [2020-10-14 04:46:20,183 INFO L275 PluginConnector]: CDTParser initialized [2020-10-14 04:46:20,183 INFO L429 ainManager$Toolchain]: [Toolchain 1]: Parsing single file: /storage/repos/ultimate-2/releaseScripts/default/UAutomizer-linux/../../../trunk/examples/svcomp/float-newlib/double_req_bl_0681b.c [2020-10-14 04:46:20,242 INFO L220 CDTParser]: Created temporary CDT project at /storage/repos/ultimate-2/releaseScripts/default/UAutomizer-linux/data/4d8d85a33/ccb7b1259bea4df7aae31bcd83d8271c/FLAG1fd90dcea [2020-10-14 04:46:20,666 INFO L306 CDTParser]: Found 1 translation units. [2020-10-14 04:46:20,667 INFO L160 CDTParser]: Scanning /storage/repos/ultimate-2/trunk/examples/svcomp/float-newlib/double_req_bl_0681b.c [2020-10-14 04:46:20,675 INFO L349 CDTParser]: About to delete temporary CDT project at /storage/repos/ultimate-2/releaseScripts/default/UAutomizer-linux/data/4d8d85a33/ccb7b1259bea4df7aae31bcd83d8271c/FLAG1fd90dcea [2020-10-14 04:46:21,082 INFO L357 CDTParser]: Successfully deleted /storage/repos/ultimate-2/releaseScripts/default/UAutomizer-linux/data/4d8d85a33/ccb7b1259bea4df7aae31bcd83d8271c [2020-10-14 04:46:21,091 INFO L296 ainManager$Toolchain]: ####################### [Toolchain 1] ####################### [2020-10-14 04:46:21,093 INFO L131 ToolchainWalker]: Walking toolchain with 4 elements. [2020-10-14 04:46:21,094 INFO L113 PluginConnector]: ------------------------CACSL2BoogieTranslator---------------------------- [2020-10-14 04:46:21,094 INFO L271 PluginConnector]: Initializing CACSL2BoogieTranslator... [2020-10-14 04:46:21,097 INFO L275 PluginConnector]: CACSL2BoogieTranslator initialized [2020-10-14 04:46:21,098 INFO L185 PluginConnector]: Executing the observer ACSLObjectContainerObserver from plugin CACSL2BoogieTranslator for "CDTParser AST 14.10 04:46:21" (1/1) ... [2020-10-14 04:46:21,101 INFO L205 PluginConnector]: Invalid model from CACSL2BoogieTranslator for observer de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator.ACSLObjectContainerObserver@5e4956b1 and model type de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 14.10 04:46:21, skipping insertion in model container [2020-10-14 04:46:21,101 INFO L185 PluginConnector]: Executing the observer CACSL2BoogieTranslatorObserver from plugin CACSL2BoogieTranslator for "CDTParser AST 14.10 04:46:21" (1/1) ... [2020-10-14 04:46:21,108 INFO L145 MainTranslator]: Starting translation in SV-COMP mode [2020-10-14 04:46:21,137 INFO L178 MainTranslator]: Built tables and reachable declarations [2020-10-14 04:46:21,477 INFO L206 PostProcessor]: Analyzing one entry point: main [2020-10-14 04:46:21,488 INFO L203 MainTranslator]: Completed pre-run [2020-10-14 04:46:21,545 INFO L206 PostProcessor]: Analyzing one entry point: main [2020-10-14 04:46:21,570 INFO L208 MainTranslator]: Completed translation [2020-10-14 04:46:21,570 INFO L202 PluginConnector]: Adding new model de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 14.10 04:46:21 WrapperNode [2020-10-14 04:46:21,570 INFO L132 PluginConnector]: ------------------------ END CACSL2BoogieTranslator---------------------------- [2020-10-14 04:46:21,571 INFO L113 PluginConnector]: ------------------------Boogie Preprocessor---------------------------- [2020-10-14 04:46:21,571 INFO L271 PluginConnector]: Initializing Boogie Preprocessor... [2020-10-14 04:46:21,571 INFO L275 PluginConnector]: Boogie Preprocessor initialized [2020-10-14 04:46:21,581 INFO L185 PluginConnector]: Executing the observer EnsureBoogieModelObserver from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 14.10 04:46:21" (1/1) ... [2020-10-14 04:46:21,581 INFO L185 PluginConnector]: Executing the observer TypeChecker from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 14.10 04:46:21" (1/1) ... [2020-10-14 04:46:21,601 INFO L185 PluginConnector]: Executing the observer ConstExpander from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 14.10 04:46:21" (1/1) ... [2020-10-14 04:46:21,602 INFO L185 PluginConnector]: Executing the observer StructExpander from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 14.10 04:46:21" (1/1) ... [2020-10-14 04:46:21,652 INFO L185 PluginConnector]: Executing the observer UnstructureCode from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 14.10 04:46:21" (1/1) ... [2020-10-14 04:46:21,668 INFO L185 PluginConnector]: Executing the observer FunctionInliner from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 14.10 04:46:21" (1/1) ... [2020-10-14 04:46:21,676 INFO L185 PluginConnector]: Executing the observer BoogieSymbolTableConstructor from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 14.10 04:46:21" (1/1) ... [2020-10-14 04:46:21,682 INFO L132 PluginConnector]: ------------------------ END Boogie Preprocessor---------------------------- [2020-10-14 04:46:21,682 INFO L113 PluginConnector]: ------------------------RCFGBuilder---------------------------- [2020-10-14 04:46:21,682 INFO L271 PluginConnector]: Initializing RCFGBuilder... [2020-10-14 04:46:21,682 INFO L275 PluginConnector]: RCFGBuilder initialized [2020-10-14 04:46:21,683 INFO L185 PluginConnector]: Executing the observer RCFGBuilderObserver from plugin RCFGBuilder for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 14.10 04:46:21" (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 04:46:21,742 INFO L138 BoogieDeclarations]: Found implementation of procedure ULTIMATE.init [2020-10-14 04:46:21,743 INFO L138 BoogieDeclarations]: Found implementation of procedure ULTIMATE.start [2020-10-14 04:46:21,743 INFO L138 BoogieDeclarations]: Found implementation of procedure fabs_double [2020-10-14 04:46:21,743 INFO L138 BoogieDeclarations]: Found implementation of procedure atan_double [2020-10-14 04:46:21,743 INFO L138 BoogieDeclarations]: Found implementation of procedure __ieee754_atan2 [2020-10-14 04:46:21,743 INFO L138 BoogieDeclarations]: Found implementation of procedure __signbit_double [2020-10-14 04:46:21,743 INFO L138 BoogieDeclarations]: Found implementation of procedure main [2020-10-14 04:46:21,744 INFO L130 BoogieDeclarations]: Found specification of procedure __VERIFIER_error [2020-10-14 04:46:21,745 INFO L130 BoogieDeclarations]: Found specification of procedure __VERIFIER_nondet_double [2020-10-14 04:46:21,745 INFO L130 BoogieDeclarations]: Found specification of procedure fabs_double [2020-10-14 04:46:21,745 INFO L130 BoogieDeclarations]: Found specification of procedure #Ultimate.allocOnStack [2020-10-14 04:46:21,745 INFO L130 BoogieDeclarations]: Found specification of procedure write~real [2020-10-14 04:46:21,745 INFO L130 BoogieDeclarations]: Found specification of procedure read~int [2020-10-14 04:46:21,745 INFO L130 BoogieDeclarations]: Found specification of procedure ULTIMATE.dealloc [2020-10-14 04:46:21,745 INFO L130 BoogieDeclarations]: Found specification of procedure write~int [2020-10-14 04:46:21,746 INFO L130 BoogieDeclarations]: Found specification of procedure read~real [2020-10-14 04:46:21,746 INFO L130 BoogieDeclarations]: Found specification of procedure atan_double [2020-10-14 04:46:21,747 INFO L130 BoogieDeclarations]: Found specification of procedure __ieee754_atan2 [2020-10-14 04:46:21,747 INFO L130 BoogieDeclarations]: Found specification of procedure __signbit_double [2020-10-14 04:46:21,747 INFO L130 BoogieDeclarations]: Found specification of procedure main [2020-10-14 04:46:21,747 INFO L130 BoogieDeclarations]: Found specification of procedure ULTIMATE.init [2020-10-14 04:46:21,747 INFO L130 BoogieDeclarations]: Found specification of procedure write~init~real [2020-10-14 04:46:21,748 INFO L130 BoogieDeclarations]: Found specification of procedure ULTIMATE.start [2020-10-14 04:46:22,458 INFO L290 CfgBuilder]: Using the 1 location(s) as analysis (start of procedure ULTIMATE.start) [2020-10-14 04:46:22,459 INFO L295 CfgBuilder]: Removed 18 assume(true) statements. [2020-10-14 04:46:22,468 INFO L202 PluginConnector]: Adding new model de.uni_freiburg.informatik.ultimate.plugins.generator.rcfgbuilder CFG 14.10 04:46:22 BoogieIcfgContainer [2020-10-14 04:46:22,469 INFO L132 PluginConnector]: ------------------------ END RCFGBuilder---------------------------- [2020-10-14 04:46:22,471 INFO L113 PluginConnector]: ------------------------TraceAbstraction---------------------------- [2020-10-14 04:46:22,471 INFO L271 PluginConnector]: Initializing TraceAbstraction... [2020-10-14 04:46:22,474 INFO L275 PluginConnector]: TraceAbstraction initialized [2020-10-14 04:46:22,475 INFO L185 PluginConnector]: Executing the observer TraceAbstractionObserver from plugin TraceAbstraction for "CDTParser AST 14.10 04:46:21" (1/3) ... [2020-10-14 04:46:22,476 INFO L205 PluginConnector]: Invalid model from TraceAbstraction for observer de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction.TraceAbstractionObserver@2bb084e1 and model type de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction AST 14.10 04:46:22, skipping insertion in model container [2020-10-14 04:46:22,476 INFO L185 PluginConnector]: Executing the observer TraceAbstractionObserver from plugin TraceAbstraction for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 14.10 04:46:21" (2/3) ... [2020-10-14 04:46:22,476 INFO L205 PluginConnector]: Invalid model from TraceAbstraction for observer de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction.TraceAbstractionObserver@2bb084e1 and model type de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction AST 14.10 04:46:22, skipping insertion in model container [2020-10-14 04:46:22,477 INFO L185 PluginConnector]: Executing the observer TraceAbstractionObserver from plugin TraceAbstraction for "de.uni_freiburg.informatik.ultimate.plugins.generator.rcfgbuilder CFG 14.10 04:46:22" (3/3) ... [2020-10-14 04:46:22,479 INFO L109 eAbstractionObserver]: Analyzing ICFG double_req_bl_0681b.c [2020-10-14 04:46:22,490 INFO L157 ceAbstractionStarter]: Automizer settings: Hoare:true NWA Interpolation:Craig_NestedInterpolation Determinization: PREDICATE_ABSTRACTION [2020-10-14 04:46:22,497 INFO L169 ceAbstractionStarter]: Appying trace abstraction to program that has 1 error locations. [2020-10-14 04:46:22,507 INFO L251 AbstractCegarLoop]: Starting to check reachability of 1 error locations. [2020-10-14 04:46:22,525 INFO L375 AbstractCegarLoop]: Interprodecural is true [2020-10-14 04:46:22,526 INFO L376 AbstractCegarLoop]: Hoare is true [2020-10-14 04:46:22,526 INFO L377 AbstractCegarLoop]: Compute interpolants for Craig_NestedInterpolation [2020-10-14 04:46:22,526 INFO L378 AbstractCegarLoop]: Backedges is STRAIGHT_LINE [2020-10-14 04:46:22,526 INFO L379 AbstractCegarLoop]: Determinization is PREDICATE_ABSTRACTION [2020-10-14 04:46:22,526 INFO L380 AbstractCegarLoop]: Difference is false [2020-10-14 04:46:22,527 INFO L381 AbstractCegarLoop]: Minimize is MINIMIZE_SEVPA [2020-10-14 04:46:22,527 INFO L385 AbstractCegarLoop]: ======== Iteration 0==of CEGAR loop == AllErrorsAtOnce======== [2020-10-14 04:46:22,545 INFO L276 IsEmpty]: Start isEmpty. Operand 110 states. [2020-10-14 04:46:22,552 INFO L282 IsEmpty]: Finished isEmpty. Found accepting run of length 20 [2020-10-14 04:46:22,552 INFO L414 BasicCegarLoop]: Found error trace [2020-10-14 04:46:22,553 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 04:46:22,553 INFO L427 AbstractCegarLoop]: === Iteration 1 === [mainErr0ASSERT_VIOLATIONERROR_FUNCTION]=== [2020-10-14 04:46:22,557 INFO L144 PredicateUnifier]: Initialized classic predicate unifier [2020-10-14 04:46:22,558 INFO L82 PathProgramCache]: Analyzing trace with hash -530639070, now seen corresponding path program 1 times [2020-10-14 04:46:22,564 INFO L163 FreeRefinementEngine]: Executing refinement strategy FIXED_PREFERENCES [2020-10-14 04:46:22,565 INFO L354 FreeRefinementEngine]: Using trace check IpTcStrategyModulePreferences [1032287646] [2020-10-14 04:46:22,565 INFO L95 rtionOrderModulation]: Keeping assertion order NOT_INCREMENTALLY [2020-10-14 04:46:22,698 INFO L136 AnnotateAndAsserter]: Conjunction of SSA is unsat [2020-10-14 04:46:22,738 FATAL L256 erpolLogProxyWrapper]: Now shrinking... [2020-10-14 04:46:22,814 FATAL L256 erpolLogProxyWrapper]: Now shrinking... [2020-10-14 04:46:23,001 FATAL L256 erpolLogProxyWrapper]: Timeout: 5000 [2020-10-14 04:46:23,002 FATAL L256 erpolLogProxyWrapper]: Cardinality of Constraint set: 27 [2020-10-14 04:46:23,002 FATAL L256 erpolLogProxyWrapper]: Number of enumerated Muses: 2 [2020-10-14 04:46:23,004 FATAL L256 erpolLogProxyWrapper]: Time needed for enumeration: 299 [2020-10-14 04:46:23,007 FATAL L256 erpolLogProxyWrapper]: Heuristic: WIDESTAMONGSMALL [2020-10-14 04:46:23,008 FATAL L256 erpolLogProxyWrapper]: Tolerance: 0.4 [2020-10-14 04:46:23,008 FATAL L256 erpolLogProxyWrapper]: Chosen Mus has size: 1 [2020-10-14 04:46:23,008 FATAL L256 erpolLogProxyWrapper]: Chosen Mus has depth: 16 [2020-10-14 04:46:23,008 FATAL L256 erpolLogProxyWrapper]: Chosen Mus has width: 1 [2020-10-14 04:46:23,009 FATAL L256 erpolLogProxyWrapper]: Time needed for Heuristics: 4 [2020-10-14 04:46:23,162 INFO L375 atingTraceCheckCraig]: Compute interpolants for subsequence at non-pending call position 0 [2020-10-14 04:46:23,167 INFO L136 AnnotateAndAsserter]: Conjunction of SSA is unsat [2020-10-14 04:46:23,169 FATAL L256 erpolLogProxyWrapper]: Now shrinking... [2020-10-14 04:46:23,188 FATAL L256 erpolLogProxyWrapper]: Timeout: 5000 [2020-10-14 04:46:23,188 FATAL L256 erpolLogProxyWrapper]: Cardinality of Constraint set: 8 [2020-10-14 04:46:23,188 FATAL L256 erpolLogProxyWrapper]: Number of enumerated Muses: 1 [2020-10-14 04:46:23,189 FATAL L256 erpolLogProxyWrapper]: Time needed for enumeration: 20 [2020-10-14 04:46:23,189 FATAL L256 erpolLogProxyWrapper]: Heuristic: WIDESTAMONGSMALL [2020-10-14 04:46:23,189 FATAL L256 erpolLogProxyWrapper]: Tolerance: 0.4 [2020-10-14 04:46:23,189 FATAL L256 erpolLogProxyWrapper]: Chosen Mus has size: 1 [2020-10-14 04:46:23,190 FATAL L256 erpolLogProxyWrapper]: Chosen Mus has depth: 1 [2020-10-14 04:46:23,190 FATAL L256 erpolLogProxyWrapper]: Chosen Mus has width: 1 [2020-10-14 04:46:23,190 FATAL L256 erpolLogProxyWrapper]: Time needed for Heuristics: 1 [2020-10-14 04:46:23,216 INFO L375 atingTraceCheckCraig]: Compute interpolants for subsequence at non-pending call position 6 [2020-10-14 04:46:23,219 INFO L136 AnnotateAndAsserter]: Conjunction of SSA is unsat [2020-10-14 04:46:23,220 FATAL L256 erpolLogProxyWrapper]: Now shrinking... [2020-10-14 04:46:23,222 FATAL L256 erpolLogProxyWrapper]: Now shrinking... [2020-10-14 04:46:23,230 FATAL L256 erpolLogProxyWrapper]: Timeout: 5000 [2020-10-14 04:46:23,231 FATAL L256 erpolLogProxyWrapper]: Cardinality of Constraint set: 13 [2020-10-14 04:46:23,231 FATAL L256 erpolLogProxyWrapper]: Number of enumerated Muses: 2 [2020-10-14 04:46:23,231 FATAL L256 erpolLogProxyWrapper]: Time needed for enumeration: 11 [2020-10-14 04:46:23,232 FATAL L256 erpolLogProxyWrapper]: Heuristic: WIDESTAMONGSMALL [2020-10-14 04:46:23,232 FATAL L256 erpolLogProxyWrapper]: Tolerance: 0.4 [2020-10-14 04:46:23,232 FATAL L256 erpolLogProxyWrapper]: Chosen Mus has size: 1 [2020-10-14 04:46:23,232 FATAL L256 erpolLogProxyWrapper]: Chosen Mus has depth: 3 [2020-10-14 04:46:23,232 FATAL L256 erpolLogProxyWrapper]: Chosen Mus has width: 1 [2020-10-14 04:46:23,233 FATAL L256 erpolLogProxyWrapper]: Time needed for Heuristics: 1 [2020-10-14 04:46:23,239 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 04:46:23,240 INFO L354 FreeRefinementEngine]: Using interpolant generator IpTcStrategyModulePreferences [1032287646] [2020-10-14 04:46:23,242 INFO L220 FreeRefinementEngine]: Constructing automaton from 1 perfect and 0 imperfect interpolant sequences. [2020-10-14 04:46:23,242 INFO L233 FreeRefinementEngine]: Number of different interpolants: perfect sequences [4] imperfect sequences [] total 4 [2020-10-14 04:46:23,243 INFO L156 tionRefinementEngine]: Using interpolant automaton builder IpAbStrategyModuleStraightlineAll [334314881] [2020-10-14 04:46:23,248 INFO L459 AbstractCegarLoop]: Interpolant automaton has 4 states [2020-10-14 04:46:23,248 INFO L143 FreeRefinementEngine]: Using predicate unifier PredicateUnifier provided by strategy FIXED_PREFERENCES [2020-10-14 04:46:23,262 INFO L142 InterpolantAutomaton]: Constructing interpolant automaton starting with 4 interpolants. [2020-10-14 04:46:23,263 INFO L144 InterpolantAutomaton]: CoverageRelationStatistics Valid=5, Invalid=7, Unknown=0, NotChecked=0, Total=12 [2020-10-14 04:46:23,265 INFO L87 Difference]: Start difference. First operand 110 states. Second operand 4 states. [2020-10-14 04:46:23,648 INFO L144 Difference]: Subtrahend was deterministic. Have not used determinization. [2020-10-14 04:46:23,649 INFO L93 Difference]: Finished difference Result 212 states and 335 transitions. [2020-10-14 04:46:23,649 INFO L141 InterpolantAutomaton]: Switched to read-only mode: deterministic interpolant automaton has 3 states. [2020-10-14 04:46:23,651 INFO L78 Accepts]: Start accepts. Automaton has 4 states. Word has length 19 [2020-10-14 04:46:23,651 INFO L84 Accepts]: Finished accepts. some prefix is accepted. [2020-10-14 04:46:23,662 INFO L225 Difference]: With dead ends: 212 [2020-10-14 04:46:23,662 INFO L226 Difference]: Without dead ends: 106 [2020-10-14 04:46:23,667 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 04:46:23,689 INFO L82 GeneralOperation]: Start minimizeSevpa. Operand 106 states. [2020-10-14 04:46:23,723 INFO L88 GeneralOperation]: Finished minimizeSevpa. Reduced states from 106 to 106. [2020-10-14 04:46:23,725 INFO L82 GeneralOperation]: Start removeUnreachable. Operand 106 states. [2020-10-14 04:46:23,727 INFO L88 GeneralOperation]: Finished removeUnreachable. Reduced from 106 states to 106 states and 146 transitions. [2020-10-14 04:46:23,729 INFO L78 Accepts]: Start accepts. Automaton has 106 states and 146 transitions. Word has length 19 [2020-10-14 04:46:23,729 INFO L84 Accepts]: Finished accepts. word is rejected. [2020-10-14 04:46:23,729 INFO L479 AbstractCegarLoop]: Abstraction has 106 states and 146 transitions. [2020-10-14 04:46:23,730 INFO L480 AbstractCegarLoop]: Interpolant automaton has 4 states. [2020-10-14 04:46:23,730 INFO L276 IsEmpty]: Start isEmpty. Operand 106 states and 146 transitions. [2020-10-14 04:46:23,731 INFO L282 IsEmpty]: Finished isEmpty. Found accepting run of length 22 [2020-10-14 04:46:23,731 INFO L414 BasicCegarLoop]: Found error trace [2020-10-14 04:46:23,731 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 04:46:23,732 WARN L516 AbstractCegarLoop]: Destroyed unattended storables created during the last iteration: SelfDestructingSolverStorable0 [2020-10-14 04:46:23,732 INFO L427 AbstractCegarLoop]: === Iteration 2 === [mainErr0ASSERT_VIOLATIONERROR_FUNCTION]=== [2020-10-14 04:46:23,732 INFO L144 PredicateUnifier]: Initialized classic predicate unifier [2020-10-14 04:46:23,732 INFO L82 PathProgramCache]: Analyzing trace with hash 1749596857, now seen corresponding path program 1 times [2020-10-14 04:46:23,733 INFO L163 FreeRefinementEngine]: Executing refinement strategy FIXED_PREFERENCES [2020-10-14 04:46:23,733 INFO L354 FreeRefinementEngine]: Using trace check IpTcStrategyModulePreferences [1823875284] [2020-10-14 04:46:23,733 INFO L95 rtionOrderModulation]: Keeping assertion order NOT_INCREMENTALLY [2020-10-14 04:46:23,779 INFO L136 AnnotateAndAsserter]: Conjunction of SSA is sat [2020-10-14 04:46:23,782 INFO L174 FreeRefinementEngine]: Strategy FIXED_PREFERENCES found a feasible trace [2020-10-14 04:46:23,782 INFO L520 BasicCegarLoop]: Counterexample might be feasible [2020-10-14 04:46:23,788 WARN L516 AbstractCegarLoop]: Destroyed unattended storables created during the last iteration: SelfDestructingSolverStorable1 [2020-10-14 04:46:23,806 INFO L202 PluginConnector]: Adding new model de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction CFG 14.10 04:46:23 BoogieIcfgContainer [2020-10-14 04:46:23,806 INFO L132 PluginConnector]: ------------------------ END TraceAbstraction---------------------------- [2020-10-14 04:46:23,809 INFO L168 Benchmark]: Toolchain (without parser) took 2715.44 ms. Allocated memory was 147.3 MB in the beginning and 234.9 MB in the end (delta: 87.6 MB). Free memory was 102.4 MB in the beginning and 121.9 MB in the end (delta: -19.5 MB). Peak memory consumption was 68.0 MB. Max. memory is 7.1 GB. [2020-10-14 04:46:23,810 INFO L168 Benchmark]: CDTParser took 0.17 ms. Allocated memory is still 147.3 MB. Free memory was 120.6 MB in the beginning and 120.2 MB in the end (delta: 419.6 kB). Peak memory consumption was 419.6 kB. Max. memory is 7.1 GB. [2020-10-14 04:46:23,811 INFO L168 Benchmark]: CACSL2BoogieTranslator took 477.20 ms. Allocated memory was 147.3 MB in the beginning and 203.4 MB in the end (delta: 56.1 MB). Free memory was 102.0 MB in the beginning and 176.8 MB in the end (delta: -74.9 MB). Peak memory consumption was 21.3 MB. Max. memory is 7.1 GB. [2020-10-14 04:46:23,811 INFO L168 Benchmark]: Boogie Preprocessor took 110.69 ms. Allocated memory is still 203.4 MB. Free memory was 176.8 MB in the beginning and 173.7 MB in the end (delta: 3.1 MB). Peak memory consumption was 3.1 MB. Max. memory is 7.1 GB. [2020-10-14 04:46:23,812 INFO L168 Benchmark]: RCFGBuilder took 786.67 ms. Allocated memory is still 203.4 MB. Free memory was 173.7 MB in the beginning and 128.5 MB in the end (delta: 45.2 MB). Peak memory consumption was 45.2 MB. Max. memory is 7.1 GB. [2020-10-14 04:46:23,813 INFO L168 Benchmark]: TraceAbstraction took 1335.56 ms. Allocated memory was 203.4 MB in the beginning and 234.9 MB in the end (delta: 31.5 MB). Free memory was 127.6 MB in the beginning and 121.9 MB in the end (delta: 5.7 MB). Peak memory consumption was 37.1 MB. Max. memory is 7.1 GB. [2020-10-14 04:46:23,817 INFO L336 ainManager$Toolchain]: ####################### End [Toolchain 1] ####################### --- Results --- * Results from de.uni_freiburg.informatik.ultimate.core: - StatisticsResult: Toolchain Benchmarks Benchmark results are: * CDTParser took 0.17 ms. Allocated memory is still 147.3 MB. Free memory was 120.6 MB in the beginning and 120.2 MB in the end (delta: 419.6 kB). Peak memory consumption was 419.6 kB. Max. memory is 7.1 GB. * CACSL2BoogieTranslator took 477.20 ms. Allocated memory was 147.3 MB in the beginning and 203.4 MB in the end (delta: 56.1 MB). Free memory was 102.0 MB in the beginning and 176.8 MB in the end (delta: -74.9 MB). Peak memory consumption was 21.3 MB. Max. memory is 7.1 GB. * Boogie Preprocessor took 110.69 ms. Allocated memory is still 203.4 MB. Free memory was 176.8 MB in the beginning and 173.7 MB in the end (delta: 3.1 MB). Peak memory consumption was 3.1 MB. Max. memory is 7.1 GB. * RCFGBuilder took 786.67 ms. Allocated memory is still 203.4 MB. Free memory was 173.7 MB in the beginning and 128.5 MB in the end (delta: 45.2 MB). Peak memory consumption was 45.2 MB. Max. memory is 7.1 GB. * TraceAbstraction took 1335.56 ms. Allocated memory was 203.4 MB in the beginning and 234.9 MB in the end (delta: 31.5 MB). Free memory was 127.6 MB in the beginning and 121.9 MB in the end (delta: 5.7 MB). Peak memory consumption was 37.1 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: 1.2s, 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, 0.5s 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...