Expression.isConst failed

[Vitalij Ruge]

In the example
OpenModelica/testsuite/simulation/modelica/others/Bug3885.mos we can find wrong check for expr

expr := min(-(if false then 0.0 else -1.0), min(100000.0, min(if Modelica.Fluid.Types.PortFlowDirection.Bidirectional == Modelica.Fluid.Types.PortFlowDirection.Leaving then 0.0 else 9.999999999999999e+59, min(100000.0, min(100000.0, min(100000.0, 100000.0)))))); 
 Expression.isConst(expr);// false
 ExpressionSimplify.simplify(expr); // 1

(I will mark this issue as critical because it's a base function)

[Vitalij Ruge]

for example:
In
​https://github.com/OpenModelica/OMCompiler/pull/2338/files#diff-7c8afefc8241e5b85e5424595841fdd4R218

the guard failed with isConst

[Martin Sjölund]

It seems any expression containing builtin calls is considered not constant.

[Martin Sjölund]

I think it's possibly correct to always simplify the expression in this case; simplify catches more things such as an if-condition that can select a constant-expression branch.

I will update isConst though: ​https://github.com/OpenModelica/OMCompiler/pull/2340

[Martin Sjölund]

It seems this fails due to the ExpressionSolve+CSE doing something bad: it moves the sinh calculation to a separate (initial) equation, but this call should never be executed...

[Martin Sjölund]

Closing this. But we still have a problem with the CSE modules, etc executing code that never should be executed...