[NF] Evaluate functions with constant arguments.

- Implemented -d=nfEvalConstArgFuncs to turn on evaluation of functions
  with constant arguments (on by default). Evaluation failures are
  silently ignored, -d=failtrace can be used to display errors.
- Remove empty algorithms in SimplifyModel.

Belonging to [master]:
  - #2636
  - OpenModelica/OpenModelica-testsuite#1027

Author: perost

Compiler/NFFrontEnd/NFSimplifyExp.mo

@@ -49,6 +49,9 @@ import ComponentRef = NFComponentRef;
 import ExpandExp = NFExpandExp;
 import TypeCheck = NFTypeCheck;
 import Absyn;
+import ErrorExt;
+import Flags;
+import Debug;
 
 public
 
@@ -137,7 +140,7 @@ function simplifyCall
 protected
   Call call;
   list<Expression> args;
-  Boolean builtin;
+  Boolean builtin, is_pure;
 algorithm
   Expression.CALL(call = call) := callExp;
 
@@ -147,12 +150,19 @@ algorithm
         args := list(simplify(arg) for arg in call.arguments);
         call.arguments := args;
         builtin := Function.isBuiltin(call.fn);
+        is_pure := not Function.isImpure(call.fn);
 
         // Use Ceval for builtin pure functions with literal arguments.
-        if builtin and not Function.isImpure(call.fn) and List.all(args, Expression.isLiteral) then
-          callExp := Ceval.evalCall(call, EvalTarget.IGNORE_ERRORS());
+        if builtin then
+          if is_pure and List.all(args, Expression.isLiteral) then
+            callExp := Ceval.evalCall(call, EvalTarget.IGNORE_ERRORS());
+          else
+            callExp := simplifyBuiltinCall(Function.nameConsiderBuiltin(call.fn), args, call);
+          end if;
+        elseif Flags.isSet(Flags.NF_EVAL_CONST_ARG_FUNCS) and is_pure and List.all(args, Expression.isLiteral) then
+          callExp := simplifyCall2(call);
         else
-          callExp := simplifyBuiltinCall(Function.nameConsiderBuiltin(call.fn), args, call);
+          callExp := Expression.CALL(call);
         end if;
       then
         callExp;
@@ -168,6 +178,27 @@ algorithm
   end match;
 end simplifyCall;
 
+function simplifyCall2
+  input Call call;
+  output Expression outExp;
+algorithm
+  ErrorExt.setCheckpoint(getInstanceName());
+
+  try
+    outExp := Ceval.evalCall(call, EvalTarget.IGNORE_ERRORS());
+    ErrorExt.delCheckpoint(getInstanceName());
+  else
+    if Flags.isSet(Flags.FAILTRACE) then
+      ErrorExt.delCheckpoint(getInstanceName());
+      Debug.traceln("- " + getInstanceName() + " failed to evaluate " + Call.toString(call) + "\n");
+    else
+      ErrorExt.rollBack(getInstanceName());
+    end if;
+
+    outExp := Expression.CALL(call);
+  end try;
+end simplifyCall2;
+
 function simplifyBuiltinCall
   input Absyn.Path name;
   input list<Expression> args;

Compiler/NFFrontEnd/NFSimplifyModel.mo

@@ -61,8 +61,8 @@ algorithm
   flatModel.variables := list(simplifyVariable(v) for v in flatModel.variables);
   flatModel.equations := simplifyEquations(flatModel.equations);
   flatModel.initialEquations := simplifyEquations(flatModel.initialEquations);
-  flatModel.algorithms := list(simplifyAlgorithm(a) for a in flatModel.algorithms);
-  flatModel.initialAlgorithms := list(simplifyAlgorithm(a) for a in flatModel.initialAlgorithms);
+  flatModel.algorithms := simplifyAlgorithms(flatModel.algorithms);
+  flatModel.initialAlgorithms := simplifyAlgorithms(flatModel.initialAlgorithms);
 
   functions := FunctionTree.map(functions, simplifyFunction);
 
@@ -185,6 +185,21 @@ algorithm
   end match;
 end simplifyEquation;
 
+function simplifyAlgorithms
+  input list<Algorithm> algs;
+  output list<Algorithm> outAlgs = {};
+algorithm
+  for alg in algs loop
+    alg := simplifyAlgorithm(alg);
+
+    if not listEmpty(alg.statements) then
+      outAlgs := alg :: outAlgs;
+    end if;
+  end for;
+
+  outAlgs := listReverseInPlace(outAlgs);
+end simplifyAlgorithms;
+
 function simplifyAlgorithm
   input output Algorithm alg;
 algorithm

Compiler/Util/Flags.mo

@@ -532,7 +532,7 @@ constant DebugFlag DEBUG_DAEMODE = DEBUG_FLAG(178, "debugDAEmode", false,
   Util.gettext("Dump debug output for the DAEmode."));
 constant DebugFlag NF_SCALARIZE = DEBUG_FLAG(179, "nfScalarize", true,
   Util.gettext("Run scalarization in NF, default true."));
-constant DebugFlag NF_EVAL_CONST_ARG_FUNCS = DEBUG_FLAG(180, "nfEvalConstArgFuncs", false,
+constant DebugFlag NF_EVAL_CONST_ARG_FUNCS = DEBUG_FLAG(180, "nfEvalConstArgFuncs", true,
   Util.gettext("Evaluate all functions with constant arguments in the new frontend."));
 constant DebugFlag NF_EXPAND_OPERATIONS = DEBUG_FLAG(181, "nfExpandOperations", true,
   Util.gettext("Expand all unary/binary operations to scalar expressions in the new frontend."));