Stack overflow introduced in backend

[Martin Sjölund]

Sometime between r13263 and r13284 the backend started giving a stack overflow for model MSL 3.2.1 Modelica.Fluid.Examples.ControlledTankSystem.ControlledTanks.

[Willi Braun]

As far as I see it's caused by preOptModule "removeSimpleEquations".

[Jens Frenkel]

There is a cyclic binding in start values for

180: tank1.h_start:PARAM(min = -10000000000.0 max = 10000000000.0 start = Modelica.Fluid.Vessels.OpenTank.Medium.specificEnthalpy_pTX(tank1.p_start, tank1.T_start, {tank1.X_start[1]}) nominal = 1000000.0 ) = if tank1.use_T_start then Modelica.Fluid.Vessels.OpenTank.Medium.specificEnthalpy_pTX(tank1.p_start, tank1.T_start, {tank1.X_start[1]}) else 83680.0 .Modelica.Fluid.Examples.ControlledTankSystem.ControlledTanks, .Modelica.Fluid.Vessels.OpenTank, .Modelica.Fluid.Vessels.OpenTank.Medium.SpecificEnthalpy type: Real (min = -10000000000.0 max = 10000000000.0 start = Modelica.Fluid.Vessels.OpenTank.Medium.specificEnthalpy_pTX(tank1.p_start, tank1.T_start, {tank1.X_start[1]}) nominal = 1000000.0 )
181: tank1.T_start:PARAM(min = 1.0 max = 10000.0 start = system.T_start nominal = 300.0 ) = if tank1.use_T_start then system.T_start else Modelica.Fluid.Vessels.OpenTank.Medium.temperature_phX(tank1.p_start, tank1.h_start, {tank1.X_start[1]}) .Modelica.Fluid.Examples.ControlledTankSystem.ControlledTanks, .Modelica.Fluid.Vessels.OpenTank, .Modelica.Fluid.Vessels.OpenTank.Medium.Temperature type: Real (min = 1.0 max = 10000.0 start = system.T_start nominal = 300.0 )

This leads to a infinit loop.

[Jens Frenkel]

fixed in r13389