/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/float_req_bl_0490a.c -------------------------------------------------------------------------------- This is Ultimate 0.1.25-adbd35c [2020-10-14 04:47:38,828 INFO L177 SettingsManager]: Resetting all preferences to default values... [2020-10-14 04:47:38,831 INFO L181 SettingsManager]: Resetting UltimateCore preferences to default values [2020-10-14 04:47:38,855 INFO L184 SettingsManager]: Ultimate Commandline Interface provides no preferences, ignoring... [2020-10-14 04:47:38,855 INFO L181 SettingsManager]: Resetting Boogie Preprocessor preferences to default values [2020-10-14 04:47:38,857 INFO L181 SettingsManager]: Resetting Boogie Procedure Inliner preferences to default values [2020-10-14 04:47:38,858 INFO L181 SettingsManager]: Resetting Abstract Interpretation preferences to default values [2020-10-14 04:47:38,860 INFO L181 SettingsManager]: Resetting LassoRanker preferences to default values [2020-10-14 04:47:38,862 INFO L181 SettingsManager]: Resetting Reaching Definitions preferences to default values [2020-10-14 04:47:38,863 INFO L181 SettingsManager]: Resetting SyntaxChecker preferences to default values [2020-10-14 04:47:38,864 INFO L181 SettingsManager]: Resetting Sifa preferences to default values [2020-10-14 04:47:38,865 INFO L184 SettingsManager]: Büchi Program Product provides no preferences, ignoring... [2020-10-14 04:47:38,866 INFO L181 SettingsManager]: Resetting LTL2Aut preferences to default values [2020-10-14 04:47:38,867 INFO L181 SettingsManager]: Resetting PEA to Boogie preferences to default values [2020-10-14 04:47:38,868 INFO L181 SettingsManager]: Resetting BlockEncodingV2 preferences to default values [2020-10-14 04:47:38,869 INFO L181 SettingsManager]: Resetting ChcToBoogie preferences to default values [2020-10-14 04:47:38,873 INFO L181 SettingsManager]: Resetting AutomataScriptInterpreter preferences to default values [2020-10-14 04:47:38,874 INFO L181 SettingsManager]: Resetting BuchiAutomizer preferences to default values [2020-10-14 04:47:38,875 INFO L181 SettingsManager]: Resetting CACSL2BoogieTranslator preferences to default values [2020-10-14 04:47:38,877 INFO L181 SettingsManager]: Resetting CodeCheck preferences to default values [2020-10-14 04:47:38,879 INFO L181 SettingsManager]: Resetting InvariantSynthesis preferences to default values [2020-10-14 04:47:38,880 INFO L181 SettingsManager]: Resetting RCFGBuilder preferences to default values [2020-10-14 04:47:38,881 INFO L181 SettingsManager]: Resetting Referee preferences to default values [2020-10-14 04:47:38,882 INFO L181 SettingsManager]: Resetting TraceAbstraction preferences to default values [2020-10-14 04:47:38,884 INFO L184 SettingsManager]: TraceAbstractionConcurrent provides no preferences, ignoring... [2020-10-14 04:47:38,885 INFO L184 SettingsManager]: TraceAbstractionWithAFAs provides no preferences, ignoring... [2020-10-14 04:47:38,885 INFO L181 SettingsManager]: Resetting TreeAutomizer preferences to default values [2020-10-14 04:47:38,886 INFO L181 SettingsManager]: Resetting IcfgToChc preferences to default values [2020-10-14 04:47:38,886 INFO L181 SettingsManager]: Resetting IcfgTransformer preferences to default values [2020-10-14 04:47:38,887 INFO L184 SettingsManager]: ReqToTest provides no preferences, ignoring... [2020-10-14 04:47:38,888 INFO L181 SettingsManager]: Resetting Boogie Printer preferences to default values [2020-10-14 04:47:38,889 INFO L181 SettingsManager]: Resetting ChcSmtPrinter preferences to default values [2020-10-14 04:47:38,890 INFO L181 SettingsManager]: Resetting ReqPrinter preferences to default values [2020-10-14 04:47:38,890 INFO L181 SettingsManager]: Resetting Witness Printer preferences to default values [2020-10-14 04:47:38,891 INFO L184 SettingsManager]: Boogie PL CUP Parser provides no preferences, ignoring... [2020-10-14 04:47:38,892 INFO L181 SettingsManager]: Resetting CDTParser preferences to default values [2020-10-14 04:47:38,892 INFO L184 SettingsManager]: AutomataScriptParser provides no preferences, ignoring... [2020-10-14 04:47:38,892 INFO L184 SettingsManager]: ReqParser provides no preferences, ignoring... [2020-10-14 04:47:38,893 INFO L181 SettingsManager]: Resetting SmtParser preferences to default values [2020-10-14 04:47:38,894 INFO L181 SettingsManager]: Resetting Witness Parser preferences to default values [2020-10-14 04:47:38,894 INFO L188 SettingsManager]: Finished resetting all preferences to default values... [2020-10-14 04:47:38,895 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 04:47:38,919 INFO L113 SettingsManager]: Loading preferences was successful [2020-10-14 04:47:38,919 INFO L115 SettingsManager]: Preferences different from defaults after loading the file: [2020-10-14 04:47:38,920 INFO L136 SettingsManager]: Preferences of BlockEncodingV2 differ from their defaults: [2020-10-14 04:47:38,920 INFO L138 SettingsManager]: * Create parallel compositions if possible=false [2020-10-14 04:47:38,921 INFO L138 SettingsManager]: * Use SBE=true [2020-10-14 04:47:38,921 INFO L136 SettingsManager]: Preferences of CACSL2BoogieTranslator differ from their defaults: [2020-10-14 04:47:38,921 INFO L138 SettingsManager]: * sizeof long=4 [2020-10-14 04:47:38,921 INFO L138 SettingsManager]: * Overapproximate operations on floating types=true [2020-10-14 04:47:38,922 INFO L138 SettingsManager]: * sizeof POINTER=4 [2020-10-14 04:47:38,922 INFO L138 SettingsManager]: * Check division by zero=IGNORE [2020-10-14 04:47:38,922 INFO L138 SettingsManager]: * Pointer to allocated memory at dereference=IGNORE [2020-10-14 04:47:38,922 INFO L138 SettingsManager]: * If two pointers are subtracted or compared they have the same base address=IGNORE [2020-10-14 04:47:38,922 INFO L138 SettingsManager]: * Check array bounds for arrays that are off heap=IGNORE [2020-10-14 04:47:38,923 INFO L138 SettingsManager]: * sizeof long double=12 [2020-10-14 04:47:38,923 INFO L138 SettingsManager]: * Check if freed pointer was valid=false [2020-10-14 04:47:38,923 INFO L138 SettingsManager]: * Use constant arrays=true [2020-10-14 04:47:38,923 INFO L138 SettingsManager]: * Pointer base address is valid at dereference=IGNORE [2020-10-14 04:47:38,923 INFO L136 SettingsManager]: Preferences of RCFGBuilder differ from their defaults: [2020-10-14 04:47:38,924 INFO L138 SettingsManager]: * Size of a code block=SequenceOfStatements [2020-10-14 04:47:38,924 INFO L138 SettingsManager]: * To the following directory=./dump/ [2020-10-14 04:47:38,924 INFO L138 SettingsManager]: * SMT solver=External_DefaultMode [2020-10-14 04:47:38,924 INFO L138 SettingsManager]: * Command for external solver=z3 SMTLIB2_COMPLIANT=true -memory:2024 -smt2 -in -t:2000 [2020-10-14 04:47:38,925 INFO L136 SettingsManager]: Preferences of TraceAbstraction differ from their defaults: [2020-10-14 04:47:38,925 INFO L138 SettingsManager]: * Compute Interpolants along a Counterexample=FPandBP [2020-10-14 04:47:38,925 INFO L138 SettingsManager]: * Positions where we compute the Hoare Annotation=LoopsAndPotentialCycles [2020-10-14 04:47:38,925 INFO L138 SettingsManager]: * Trace refinement strategy=CAMEL [2020-10-14 04:47:38,926 INFO L138 SettingsManager]: * Command for external solver=z3 SMTLIB2_COMPLIANT=true -memory:2024 -smt2 -in [2020-10-14 04:47:38,926 INFO L138 SettingsManager]: * Compute Hoare Annotation of negated interpolant automaton, abstraction and CFG=true [2020-10-14 04:47:38,926 INFO L138 SettingsManager]: * Trace refinement exception blacklist=NONE [2020-10-14 04:47:38,926 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 04:47:39,270 INFO L75 nceAwareModelManager]: Repository-Root is: /tmp [2020-10-14 04:47:39,291 INFO L258 ainManager$Toolchain]: [Toolchain 1]: Applicable parser(s) successfully (re)initialized [2020-10-14 04:47:39,297 INFO L214 ainManager$Toolchain]: [Toolchain 1]: Toolchain selected. [2020-10-14 04:47:39,299 INFO L271 PluginConnector]: Initializing CDTParser... [2020-10-14 04:47:39,300 INFO L275 PluginConnector]: CDTParser initialized [2020-10-14 04:47:39,301 INFO L429 ainManager$Toolchain]: [Toolchain 1]: Parsing single file: /storage/repos/ultimate-2/releaseScripts/default/UAutomizer-linux/../../../trunk/examples/svcomp/float-newlib/float_req_bl_0490a.c [2020-10-14 04:47:39,353 INFO L220 CDTParser]: Created temporary CDT project at /storage/repos/ultimate-2/releaseScripts/default/UAutomizer-linux/data/b8d326c5f/f62b55fa0563468291d7421dfb3c6442/FLAGd05f4d444 [2020-10-14 04:47:39,794 INFO L306 CDTParser]: Found 1 translation units. [2020-10-14 04:47:39,794 INFO L160 CDTParser]: Scanning /storage/repos/ultimate-2/trunk/examples/svcomp/float-newlib/float_req_bl_0490a.c [2020-10-14 04:47:39,803 INFO L349 CDTParser]: About to delete temporary CDT project at /storage/repos/ultimate-2/releaseScripts/default/UAutomizer-linux/data/b8d326c5f/f62b55fa0563468291d7421dfb3c6442/FLAGd05f4d444 [2020-10-14 04:47:40,203 INFO L357 CDTParser]: Successfully deleted /storage/repos/ultimate-2/releaseScripts/default/UAutomizer-linux/data/b8d326c5f/f62b55fa0563468291d7421dfb3c6442 [2020-10-14 04:47:40,212 INFO L296 ainManager$Toolchain]: ####################### [Toolchain 1] ####################### [2020-10-14 04:47:40,214 INFO L131 ToolchainWalker]: Walking toolchain with 4 elements. [2020-10-14 04:47:40,215 INFO L113 PluginConnector]: ------------------------CACSL2BoogieTranslator---------------------------- [2020-10-14 04:47:40,215 INFO L271 PluginConnector]: Initializing CACSL2BoogieTranslator... [2020-10-14 04:47:40,218 INFO L275 PluginConnector]: CACSL2BoogieTranslator initialized [2020-10-14 04:47:40,219 INFO L185 PluginConnector]: Executing the observer ACSLObjectContainerObserver from plugin CACSL2BoogieTranslator for "CDTParser AST 14.10 04:47:40" (1/1) ... [2020-10-14 04:47:40,222 INFO L205 PluginConnector]: Invalid model from CACSL2BoogieTranslator for observer de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator.ACSLObjectContainerObserver@2d1565d0 and model type de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 14.10 04:47:40, skipping insertion in model container [2020-10-14 04:47:40,222 INFO L185 PluginConnector]: Executing the observer CACSL2BoogieTranslatorObserver from plugin CACSL2BoogieTranslator for "CDTParser AST 14.10 04:47:40" (1/1) ... [2020-10-14 04:47:40,230 INFO L145 MainTranslator]: Starting translation in SV-COMP mode [2020-10-14 04:47:40,264 INFO L178 MainTranslator]: Built tables and reachable declarations [2020-10-14 04:47:40,475 INFO L206 PostProcessor]: Analyzing one entry point: main [2020-10-14 04:47:40,480 INFO L203 MainTranslator]: Completed pre-run [2020-10-14 04:47:40,618 INFO L206 PostProcessor]: Analyzing one entry point: main [2020-10-14 04:47:40,641 INFO L208 MainTranslator]: Completed translation [2020-10-14 04:47:40,641 INFO L202 PluginConnector]: Adding new model de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 14.10 04:47:40 WrapperNode [2020-10-14 04:47:40,641 INFO L132 PluginConnector]: ------------------------ END CACSL2BoogieTranslator---------------------------- [2020-10-14 04:47:40,642 INFO L113 PluginConnector]: ------------------------Boogie Preprocessor---------------------------- [2020-10-14 04:47:40,642 INFO L271 PluginConnector]: Initializing Boogie Preprocessor... [2020-10-14 04:47:40,642 INFO L275 PluginConnector]: Boogie Preprocessor initialized [2020-10-14 04:47:40,653 INFO L185 PluginConnector]: Executing the observer EnsureBoogieModelObserver from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 14.10 04:47:40" (1/1) ... [2020-10-14 04:47:40,653 INFO L185 PluginConnector]: Executing the observer TypeChecker from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 14.10 04:47:40" (1/1) ... [2020-10-14 04:47:40,667 INFO L185 PluginConnector]: Executing the observer ConstExpander from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 14.10 04:47:40" (1/1) ... [2020-10-14 04:47:40,668 INFO L185 PluginConnector]: Executing the observer StructExpander from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 14.10 04:47:40" (1/1) ... [2020-10-14 04:47:40,685 INFO L185 PluginConnector]: Executing the observer UnstructureCode from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 14.10 04:47:40" (1/1) ... [2020-10-14 04:47:40,694 INFO L185 PluginConnector]: Executing the observer FunctionInliner from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 14.10 04:47:40" (1/1) ... [2020-10-14 04:47:40,696 INFO L185 PluginConnector]: Executing the observer BoogieSymbolTableConstructor from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 14.10 04:47:40" (1/1) ... [2020-10-14 04:47:40,701 INFO L132 PluginConnector]: ------------------------ END Boogie Preprocessor---------------------------- [2020-10-14 04:47:40,701 INFO L113 PluginConnector]: ------------------------RCFGBuilder---------------------------- [2020-10-14 04:47:40,702 INFO L271 PluginConnector]: Initializing RCFGBuilder... [2020-10-14 04:47:40,702 INFO L275 PluginConnector]: RCFGBuilder initialized [2020-10-14 04:47:40,703 INFO L185 PluginConnector]: Executing the observer RCFGBuilderObserver from plugin RCFGBuilder for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 14.10 04:47:40" (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 04:47:40,765 INFO L138 BoogieDeclarations]: Found implementation of procedure ULTIMATE.init [2020-10-14 04:47:40,765 INFO L138 BoogieDeclarations]: Found implementation of procedure ULTIMATE.start [2020-10-14 04:47:40,765 INFO L138 BoogieDeclarations]: Found implementation of procedure isnan_float [2020-10-14 04:47:40,765 INFO L138 BoogieDeclarations]: Found implementation of procedure __ieee754_sqrtf [2020-10-14 04:47:40,765 INFO L138 BoogieDeclarations]: Found implementation of procedure __ieee754_acosf [2020-10-14 04:47:40,765 INFO L138 BoogieDeclarations]: Found implementation of procedure main [2020-10-14 04:47:40,766 INFO L130 BoogieDeclarations]: Found specification of procedure __VERIFIER_error [2020-10-14 04:47:40,766 INFO L130 BoogieDeclarations]: Found specification of procedure __VERIFIER_nondet_float [2020-10-14 04:47:40,766 INFO L130 BoogieDeclarations]: Found specification of procedure isnan_float [2020-10-14 04:47:40,766 INFO L130 BoogieDeclarations]: Found specification of procedure __ieee754_sqrtf [2020-10-14 04:47:40,766 INFO L130 BoogieDeclarations]: Found specification of procedure #Ultimate.allocOnStack [2020-10-14 04:47:40,766 INFO L130 BoogieDeclarations]: Found specification of procedure write~real [2020-10-14 04:47:40,767 INFO L130 BoogieDeclarations]: Found specification of procedure read~int [2020-10-14 04:47:40,767 INFO L130 BoogieDeclarations]: Found specification of procedure ULTIMATE.dealloc [2020-10-14 04:47:40,767 INFO L130 BoogieDeclarations]: Found specification of procedure write~int [2020-10-14 04:47:40,767 INFO L130 BoogieDeclarations]: Found specification of procedure read~real [2020-10-14 04:47:40,767 INFO L130 BoogieDeclarations]: Found specification of procedure __ieee754_acosf [2020-10-14 04:47:40,767 INFO L130 BoogieDeclarations]: Found specification of procedure main [2020-10-14 04:47:40,767 INFO L130 BoogieDeclarations]: Found specification of procedure ULTIMATE.init [2020-10-14 04:47:40,768 INFO L130 BoogieDeclarations]: Found specification of procedure ULTIMATE.start [2020-10-14 04:47:41,242 INFO L290 CfgBuilder]: Using the 1 location(s) as analysis (start of procedure ULTIMATE.start) [2020-10-14 04:47:41,243 INFO L295 CfgBuilder]: Removed 12 assume(true) statements. [2020-10-14 04:47:41,247 INFO L202 PluginConnector]: Adding new model de.uni_freiburg.informatik.ultimate.plugins.generator.rcfgbuilder CFG 14.10 04:47:41 BoogieIcfgContainer [2020-10-14 04:47:41,248 INFO L132 PluginConnector]: ------------------------ END RCFGBuilder---------------------------- [2020-10-14 04:47:41,249 INFO L113 PluginConnector]: ------------------------TraceAbstraction---------------------------- [2020-10-14 04:47:41,249 INFO L271 PluginConnector]: Initializing TraceAbstraction... [2020-10-14 04:47:41,252 INFO L275 PluginConnector]: TraceAbstraction initialized [2020-10-14 04:47:41,253 INFO L185 PluginConnector]: Executing the observer TraceAbstractionObserver from plugin TraceAbstraction for "CDTParser AST 14.10 04:47:40" (1/3) ... [2020-10-14 04:47:41,254 INFO L205 PluginConnector]: Invalid model from TraceAbstraction for observer de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction.TraceAbstractionObserver@2e7ae69d and model type de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction AST 14.10 04:47:41, skipping insertion in model container [2020-10-14 04:47:41,254 INFO L185 PluginConnector]: Executing the observer TraceAbstractionObserver from plugin TraceAbstraction for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 14.10 04:47:40" (2/3) ... [2020-10-14 04:47:41,254 INFO L205 PluginConnector]: Invalid model from TraceAbstraction for observer de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction.TraceAbstractionObserver@2e7ae69d and model type de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction AST 14.10 04:47:41, skipping insertion in model container [2020-10-14 04:47:41,255 INFO L185 PluginConnector]: Executing the observer TraceAbstractionObserver from plugin TraceAbstraction for "de.uni_freiburg.informatik.ultimate.plugins.generator.rcfgbuilder CFG 14.10 04:47:41" (3/3) ... [2020-10-14 04:47:41,257 INFO L109 eAbstractionObserver]: Analyzing ICFG float_req_bl_0490a.c [2020-10-14 04:47:41,267 INFO L157 ceAbstractionStarter]: Automizer settings: Hoare:true NWA Interpolation:Craig_NestedInterpolation Determinization: PREDICATE_ABSTRACTION [2020-10-14 04:47:41,274 INFO L169 ceAbstractionStarter]: Appying trace abstraction to program that has 1 error locations. [2020-10-14 04:47:41,285 INFO L251 AbstractCegarLoop]: Starting to check reachability of 1 error locations. [2020-10-14 04:47:41,308 INFO L375 AbstractCegarLoop]: Interprodecural is true [2020-10-14 04:47:41,309 INFO L376 AbstractCegarLoop]: Hoare is true [2020-10-14 04:47:41,309 INFO L377 AbstractCegarLoop]: Compute interpolants for Craig_NestedInterpolation [2020-10-14 04:47:41,309 INFO L378 AbstractCegarLoop]: Backedges is STRAIGHT_LINE [2020-10-14 04:47:41,310 INFO L379 AbstractCegarLoop]: Determinization is PREDICATE_ABSTRACTION [2020-10-14 04:47:41,310 INFO L380 AbstractCegarLoop]: Difference is false [2020-10-14 04:47:41,311 INFO L381 AbstractCegarLoop]: Minimize is MINIMIZE_SEVPA [2020-10-14 04:47:41,311 INFO L385 AbstractCegarLoop]: ======== Iteration 0==of CEGAR loop == AllErrorsAtOnce======== [2020-10-14 04:47:41,332 INFO L276 IsEmpty]: Start isEmpty. Operand 67 states. [2020-10-14 04:47:41,339 INFO L282 IsEmpty]: Finished isEmpty. Found accepting run of length 23 [2020-10-14 04:47:41,339 INFO L414 BasicCegarLoop]: Found error trace [2020-10-14 04:47:41,340 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, 1] [2020-10-14 04:47:41,341 INFO L427 AbstractCegarLoop]: === Iteration 1 === [mainErr0ASSERT_VIOLATIONERROR_FUNCTION]=== [2020-10-14 04:47:41,345 INFO L144 PredicateUnifier]: Initialized classic predicate unifier [2020-10-14 04:47:41,346 INFO L82 PathProgramCache]: Analyzing trace with hash -652363391, now seen corresponding path program 1 times [2020-10-14 04:47:41,353 INFO L163 FreeRefinementEngine]: Executing refinement strategy FIXED_PREFERENCES [2020-10-14 04:47:41,354 INFO L354 FreeRefinementEngine]: Using trace check IpTcStrategyModulePreferences [814185750] [2020-10-14 04:47:41,354 INFO L95 rtionOrderModulation]: Keeping assertion order NOT_INCREMENTALLY [2020-10-14 04:47:41,497 INFO L136 AnnotateAndAsserter]: Conjunction of SSA is unsat [2020-10-14 04:47:41,539 FATAL L256 erpolLogProxyWrapper]: Now shrinking... [2020-10-14 04:47:41,664 FATAL L256 erpolLogProxyWrapper]: Timeout: 5000 [2020-10-14 04:47:41,665 FATAL L256 erpolLogProxyWrapper]: Cardinality of Constraint set: 32 [2020-10-14 04:47:41,665 FATAL L256 erpolLogProxyWrapper]: Number of enumerated Muses: 1 [2020-10-14 04:47:41,666 FATAL L256 erpolLogProxyWrapper]: Time needed for enumeration: 163 [2020-10-14 04:47:41,668 FATAL L256 erpolLogProxyWrapper]: Heuristic: WIDESTAMONGSMALL [2020-10-14 04:47:41,669 FATAL L256 erpolLogProxyWrapper]: Tolerance: 0.4 [2020-10-14 04:47:41,669 FATAL L256 erpolLogProxyWrapper]: Chosen Mus has size: 1 [2020-10-14 04:47:41,669 FATAL L256 erpolLogProxyWrapper]: Chosen Mus has depth: 16 [2020-10-14 04:47:41,669 FATAL L256 erpolLogProxyWrapper]: Chosen Mus has width: 1 [2020-10-14 04:47:41,670 FATAL L256 erpolLogProxyWrapper]: Time needed for Heuristics: 3 [2020-10-14 04:47:41,792 INFO L375 atingTraceCheckCraig]: Compute interpolants for subsequence at non-pending call position 0 [2020-10-14 04:47:41,799 INFO L136 AnnotateAndAsserter]: Conjunction of SSA is unsat [2020-10-14 04:47:41,803 FATAL L256 erpolLogProxyWrapper]: Now shrinking... [2020-10-14 04:47:41,815 FATAL L256 erpolLogProxyWrapper]: Timeout: 5000 [2020-10-14 04:47:41,816 FATAL L256 erpolLogProxyWrapper]: Cardinality of Constraint set: 8 [2020-10-14 04:47:41,816 FATAL L256 erpolLogProxyWrapper]: Number of enumerated Muses: 1 [2020-10-14 04:47:41,816 FATAL L256 erpolLogProxyWrapper]: Time needed for enumeration: 15 [2020-10-14 04:47:41,816 FATAL L256 erpolLogProxyWrapper]: Heuristic: WIDESTAMONGSMALL [2020-10-14 04:47:41,817 FATAL L256 erpolLogProxyWrapper]: Tolerance: 0.4 [2020-10-14 04:47:41,817 FATAL L256 erpolLogProxyWrapper]: Chosen Mus has size: 1 [2020-10-14 04:47:41,817 FATAL L256 erpolLogProxyWrapper]: Chosen Mus has depth: 1 [2020-10-14 04:47:41,817 FATAL L256 erpolLogProxyWrapper]: Chosen Mus has width: 1 [2020-10-14 04:47:41,818 FATAL L256 erpolLogProxyWrapper]: Time needed for Heuristics: 1 [2020-10-14 04:47:41,842 INFO L375 atingTraceCheckCraig]: Compute interpolants for subsequence at non-pending call position 6 [2020-10-14 04:47:41,845 INFO L136 AnnotateAndAsserter]: Conjunction of SSA is unsat [2020-10-14 04:47:41,848 FATAL L256 erpolLogProxyWrapper]: Now shrinking... [2020-10-14 04:47:41,855 FATAL L256 erpolLogProxyWrapper]: Timeout: 5000 [2020-10-14 04:47:41,856 FATAL L256 erpolLogProxyWrapper]: Cardinality of Constraint set: 12 [2020-10-14 04:47:41,856 FATAL L256 erpolLogProxyWrapper]: Number of enumerated Muses: 1 [2020-10-14 04:47:41,856 FATAL L256 erpolLogProxyWrapper]: Time needed for enumeration: 9 [2020-10-14 04:47:41,857 FATAL L256 erpolLogProxyWrapper]: Heuristic: WIDESTAMONGSMALL [2020-10-14 04:47:41,857 FATAL L256 erpolLogProxyWrapper]: Tolerance: 0.4 [2020-10-14 04:47:41,857 FATAL L256 erpolLogProxyWrapper]: Chosen Mus has size: 1 [2020-10-14 04:47:41,857 FATAL L256 erpolLogProxyWrapper]: Chosen Mus has depth: 3 [2020-10-14 04:47:41,858 FATAL L256 erpolLogProxyWrapper]: Chosen Mus has width: 1 [2020-10-14 04:47:41,858 FATAL L256 erpolLogProxyWrapper]: Time needed for Heuristics: 1 [2020-10-14 04:47:41,866 INFO L375 atingTraceCheckCraig]: Compute interpolants for subsequence at non-pending call position 15 [2020-10-14 04:47:41,870 INFO L136 AnnotateAndAsserter]: Conjunction of SSA is unsat [2020-10-14 04:47:41,878 FATAL L256 erpolLogProxyWrapper]: Now shrinking... [2020-10-14 04:47:41,889 FATAL L256 erpolLogProxyWrapper]: Timeout: 5000 [2020-10-14 04:47:41,889 FATAL L256 erpolLogProxyWrapper]: Cardinality of Constraint set: 8 [2020-10-14 04:47:41,890 FATAL L256 erpolLogProxyWrapper]: Number of enumerated Muses: 1 [2020-10-14 04:47:41,890 FATAL L256 erpolLogProxyWrapper]: Time needed for enumeration: 16 [2020-10-14 04:47:41,890 FATAL L256 erpolLogProxyWrapper]: Heuristic: WIDESTAMONGSMALL [2020-10-14 04:47:41,891 FATAL L256 erpolLogProxyWrapper]: Tolerance: 0.4 [2020-10-14 04:47:41,893 FATAL L256 erpolLogProxyWrapper]: Chosen Mus has size: 1 [2020-10-14 04:47:41,893 FATAL L256 erpolLogProxyWrapper]: Chosen Mus has depth: 5 [2020-10-14 04:47:41,894 FATAL L256 erpolLogProxyWrapper]: Chosen Mus has width: 1 [2020-10-14 04:47:41,894 FATAL L256 erpolLogProxyWrapper]: Time needed for Heuristics: 3 [2020-10-14 04:47:41,911 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 04:47:41,912 INFO L354 FreeRefinementEngine]: Using interpolant generator IpTcStrategyModulePreferences [814185750] [2020-10-14 04:47:41,915 INFO L220 FreeRefinementEngine]: Constructing automaton from 1 perfect and 0 imperfect interpolant sequences. [2020-10-14 04:47:41,916 INFO L233 FreeRefinementEngine]: Number of different interpolants: perfect sequences [4] imperfect sequences [] total 4 [2020-10-14 04:47:41,917 INFO L156 tionRefinementEngine]: Using interpolant automaton builder IpAbStrategyModuleStraightlineAll [1034006059] [2020-10-14 04:47:41,924 INFO L459 AbstractCegarLoop]: Interpolant automaton has 4 states [2020-10-14 04:47:41,925 INFO L143 FreeRefinementEngine]: Using predicate unifier PredicateUnifier provided by strategy FIXED_PREFERENCES [2020-10-14 04:47:41,939 INFO L142 InterpolantAutomaton]: Constructing interpolant automaton starting with 4 interpolants. [2020-10-14 04:47:41,941 INFO L144 InterpolantAutomaton]: CoverageRelationStatistics Valid=5, Invalid=7, Unknown=0, NotChecked=0, Total=12 [2020-10-14 04:47:41,943 INFO L87 Difference]: Start difference. First operand 67 states. Second operand 4 states. [2020-10-14 04:47:42,427 INFO L144 Difference]: Subtrahend was deterministic. Have not used determinization. [2020-10-14 04:47:42,427 INFO L93 Difference]: Finished difference Result 126 states and 188 transitions. [2020-10-14 04:47:42,428 INFO L141 InterpolantAutomaton]: Switched to read-only mode: deterministic interpolant automaton has 4 states. [2020-10-14 04:47:42,429 INFO L78 Accepts]: Start accepts. Automaton has 4 states. Word has length 22 [2020-10-14 04:47:42,430 INFO L84 Accepts]: Finished accepts. some prefix is accepted. [2020-10-14 04:47:42,441 INFO L225 Difference]: With dead ends: 126 [2020-10-14 04:47:42,441 INFO L226 Difference]: Without dead ends: 63 [2020-10-14 04:47:42,445 INFO L675 BasicCegarLoop]: 0 DeclaredPredicates, 11 GetRequests, 8 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 04:47:42,463 INFO L82 GeneralOperation]: Start minimizeSevpa. Operand 63 states. [2020-10-14 04:47:42,494 INFO L88 GeneralOperation]: Finished minimizeSevpa. Reduced states from 63 to 63. [2020-10-14 04:47:42,495 INFO L82 GeneralOperation]: Start removeUnreachable. Operand 63 states. [2020-10-14 04:47:42,497 INFO L88 GeneralOperation]: Finished removeUnreachable. Reduced from 63 states to 63 states and 80 transitions. [2020-10-14 04:47:42,499 INFO L78 Accepts]: Start accepts. Automaton has 63 states and 80 transitions. Word has length 22 [2020-10-14 04:47:42,499 INFO L84 Accepts]: Finished accepts. word is rejected. [2020-10-14 04:47:42,499 INFO L479 AbstractCegarLoop]: Abstraction has 63 states and 80 transitions. [2020-10-14 04:47:42,500 INFO L480 AbstractCegarLoop]: Interpolant automaton has 4 states. [2020-10-14 04:47:42,500 INFO L276 IsEmpty]: Start isEmpty. Operand 63 states and 80 transitions. [2020-10-14 04:47:42,502 INFO L282 IsEmpty]: Finished isEmpty. Found accepting run of length 24 [2020-10-14 04:47:42,502 INFO L414 BasicCegarLoop]: Found error trace [2020-10-14 04:47:42,502 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, 1, 1] [2020-10-14 04:47:42,503 WARN L516 AbstractCegarLoop]: Destroyed unattended storables created during the last iteration: SelfDestructingSolverStorable0 [2020-10-14 04:47:42,503 INFO L427 AbstractCegarLoop]: === Iteration 2 === [mainErr0ASSERT_VIOLATIONERROR_FUNCTION]=== [2020-10-14 04:47:42,503 INFO L144 PredicateUnifier]: Initialized classic predicate unifier [2020-10-14 04:47:42,504 INFO L82 PathProgramCache]: Analyzing trace with hash -1965902596, now seen corresponding path program 1 times [2020-10-14 04:47:42,504 INFO L163 FreeRefinementEngine]: Executing refinement strategy FIXED_PREFERENCES [2020-10-14 04:47:42,504 INFO L354 FreeRefinementEngine]: Using trace check IpTcStrategyModulePreferences [1179793791] [2020-10-14 04:47:42,504 INFO L95 rtionOrderModulation]: Keeping assertion order NOT_INCREMENTALLY [2020-10-14 04:47:42,545 INFO L136 AnnotateAndAsserter]: Conjunction of SSA is sat [2020-10-14 04:47:42,553 INFO L174 FreeRefinementEngine]: Strategy FIXED_PREFERENCES found a feasible trace [2020-10-14 04:47:42,553 INFO L520 BasicCegarLoop]: Counterexample might be feasible [2020-10-14 04:47:42,560 WARN L516 AbstractCegarLoop]: Destroyed unattended storables created during the last iteration: SelfDestructingSolverStorable1 [2020-10-14 04:47:42,582 INFO L202 PluginConnector]: Adding new model de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction CFG 14.10 04:47:42 BoogieIcfgContainer [2020-10-14 04:47:42,583 INFO L132 PluginConnector]: ------------------------ END TraceAbstraction---------------------------- [2020-10-14 04:47:42,586 INFO L168 Benchmark]: Toolchain (without parser) took 2371.25 ms. Allocated memory was 146.8 MB in the beginning and 235.4 MB in the end (delta: 88.6 MB). Free memory was 102.5 MB in the beginning and 156.6 MB in the end (delta: -54.2 MB). Peak memory consumption was 34.4 MB. Max. memory is 7.1 GB. [2020-10-14 04:47:42,588 INFO L168 Benchmark]: CDTParser took 0.23 ms. Allocated memory is still 146.8 MB. Free memory was 121.4 MB in the beginning and 120.9 MB in the end (delta: 419.7 kB). Peak memory consumption was 419.7 kB. Max. memory is 7.1 GB. [2020-10-14 04:47:42,590 INFO L168 Benchmark]: CACSL2BoogieTranslator took 426.98 ms. Allocated memory was 146.8 MB in the beginning and 202.9 MB in the end (delta: 56.1 MB). Free memory was 102.1 MB in the beginning and 178.3 MB in the end (delta: -76.3 MB). Peak memory consumption was 20.2 MB. Max. memory is 7.1 GB. [2020-10-14 04:47:42,590 INFO L168 Benchmark]: Boogie Preprocessor took 58.98 ms. Allocated memory is still 202.9 MB. Free memory was 178.3 MB in the beginning and 175.5 MB in the end (delta: 2.9 MB). Peak memory consumption was 2.9 MB. Max. memory is 7.1 GB. [2020-10-14 04:47:42,592 INFO L168 Benchmark]: RCFGBuilder took 546.48 ms. Allocated memory is still 202.9 MB. Free memory was 175.5 MB in the beginning and 146.5 MB in the end (delta: 29.0 MB). Peak memory consumption was 29.0 MB. Max. memory is 7.1 GB. [2020-10-14 04:47:42,593 INFO L168 Benchmark]: TraceAbstraction took 1333.92 ms. Allocated memory was 202.9 MB in the beginning and 235.4 MB in the end (delta: 32.5 MB). Free memory was 145.5 MB in the beginning and 156.6 MB in the end (delta: -11.1 MB). Peak memory consumption was 21.4 MB. Max. memory is 7.1 GB. [2020-10-14 04:47:42,603 INFO L336 ainManager$Toolchain]: ####################### End [Toolchain 1] ####################### --- Results --- * Results from de.uni_freiburg.informatik.ultimate.core: - StatisticsResult: Toolchain Benchmarks Benchmark results are: * CDTParser took 0.23 ms. Allocated memory is still 146.8 MB. Free memory was 121.4 MB in the beginning and 120.9 MB in the end (delta: 419.7 kB). Peak memory consumption was 419.7 kB. Max. memory is 7.1 GB. * CACSL2BoogieTranslator took 426.98 ms. Allocated memory was 146.8 MB in the beginning and 202.9 MB in the end (delta: 56.1 MB). Free memory was 102.1 MB in the beginning and 178.3 MB in the end (delta: -76.3 MB). Peak memory consumption was 20.2 MB. Max. memory is 7.1 GB. * Boogie Preprocessor took 58.98 ms. Allocated memory is still 202.9 MB. Free memory was 178.3 MB in the beginning and 175.5 MB in the end (delta: 2.9 MB). Peak memory consumption was 2.9 MB. Max. memory is 7.1 GB. * RCFGBuilder took 546.48 ms. Allocated memory is still 202.9 MB. Free memory was 175.5 MB in the beginning and 146.5 MB in the end (delta: 29.0 MB). Peak memory consumption was 29.0 MB. Max. memory is 7.1 GB. * TraceAbstraction took 1333.92 ms. Allocated memory was 202.9 MB in the beginning and 235.4 MB in the end (delta: 32.5 MB). Free memory was 145.5 MB in the beginning and 156.6 MB in the end (delta: -11.1 MB). Peak memory consumption was 21.4 MB. Max. memory is 7.1 GB. * Results from de.uni_freiburg.informatik.ultimate.plugins.generator.traceabstraction: - UnprovableResult [Line: 173]: Unable to prove that call of __VERIFIER_error() unreachable Unable to prove that call of __VERIFIER_error() unreachable Reason: overapproximation of someBinaryFLOATComparisonOperation at line 13, overapproximation of someUnaryDOUBLEoperation at line 87, overapproximation of bitwiseAnd at line 101, overapproximation of someBinaryArithmeticFLOAToperation at line 168. Possible FailurePath: [L15] static const float one_sqrt = 1.0, tiny_sqrt = 1.0e-30; [L84-L91] static const float one_acos = 1.0000000000e+00, pi = 3.1415925026e+00, pio2_hi_acos = 1.5707962513e+00, pio2_lo_acos = 7.5497894159e-08, pS0_acos = 1.6666667163e-01, pS1_acos = -3.2556581497e-01, pS2_acos = 2.0121252537e-01, pS3_acos = -4.0055535734e-02, pS4_acos = 7.9153501429e-04, pS5_acos = 3.4793309169e-05, qS1_acos = -2.4033949375e+00, qS2_acos = 2.0209457874e+00, qS3_acos = -6.8828397989e-01, qS4_acos = 7.7038154006e-02; [L168] float x = 1.0f / 0.0f; [L169] CALL, EXPR __ieee754_acosf(x) [L94] float z, p, q, r, w, s, c, df; [L95] __int32_t hx, ix; [L97] ieee_float_shape_type gf_u; [L98] gf_u.value = (x) [L99] EXPR gf_u.word [L99] (hx) = gf_u.word [L101] ix = hx & 0x7fffffff [L102] COND TRUE ix == 0x3f800000 [L103] COND TRUE hx > 0 [L104] return 0.0; [L169] RET, EXPR __ieee754_acosf(x) [L169] float res = __ieee754_acosf(x); [L172] CALL, EXPR isnan_float(res) [L13] return x != x; [L172] RET, EXPR isnan_float(res) [L172] COND TRUE !isnan_float(res) [L173] __VERIFIER_error() - StatisticsResult: Ultimate Automizer benchmark data CFG has 6 procedures, 67 locations, 1 error locations. Started 1 CEGAR loops. VerificationResult: UNSAFE, OverallTime: 1.2s, OverallIterations: 2, TraceHistogramMax: 1, AutomataDifference: 0.5s, DeadEndRemovalTime: 0.0s, HoareAnnotationTime: 0.0s, InitialAbstractionConstructionTime: 0.0s, HoareTripleCheckerStatistics: 74 SDtfs, 69 SDslu, 5 SDs, 0 SdLazy, 83 SolverSat, 18 SolverUnsat, 0 SolverUnknown, 0 SolverNotchecked, 0.2s Time, PredicateUnifierStatistics: 0 DeclaredPredicates, 11 GetRequests, 8 SyntacticMatches, 0 SemanticMatches, 3 ConstructedPredicates, 0 IntricatePredicates, 0 DeprecatedPredicates, 0 ImplicationChecksByTransitivity, 0.1s Time, 0.0s BasicInterpolantAutomatonTime, BiggestAbstraction: size=67occurred 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, 0.0s SatisfiabilityAnalysisTime, 0.4s InterpolantComputationTime, 45 NumberOfCodeBlocks, 45 NumberOfCodeBlocksAsserted, 2 NumberOfCheckSat, 21 ConstructedInterpolants, 0 QuantifiedInterpolants, 1890 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...