Improve flattening without scalarization (#8214)

- Flatten equations and algorithms with an empty prefix when not doing
  scalarization, to get rid of any remaining split indices.

OMCompiler/Compiler/NFFrontEnd/NFFlatten.mo

@@ -136,6 +136,8 @@ uniontype FlattenSettings
   end SETTINGS;
 end FlattenSettings;
 
+constant ComponentRef EMPTY_PREFIX = ComponentRef.EMPTY();
+
 function flatten
   input InstNode classInst;
   input String name;
@@ -164,7 +166,7 @@ algorithm
 
   deleted_vars := UnorderedSet.new(ComponentRef.hash, ComponentRef.isEqual);
 
-  (vars, sections) := flattenClass(InstNode.getClass(classInst), ComponentRef.EMPTY(),
+  (vars, sections) := flattenClass(InstNode.getClass(classInst), EMPTY_PREFIX,
     Visibility.PUBLIC, NONE(), {}, sections, deleted_vars, settings);
   vars := listReverseInPlace(vars);
 
@@ -736,10 +738,10 @@ algorithm
     case Sections.SECTIONS()
       algorithm
         for eqn in listReverse(sects.equations) loop
-          sections := Sections.prependEquation(vectorizeEquation(eqn, dimensions, prefix), sections);
+          sections := Sections.prependEquation(vectorizeEquation(eqn, dimensions, prefix, settings), sections);
         end for;
         for eqn in listReverse(sects.initialEquations) loop
-          sections := Sections.prependEquation(vectorizeEquation(eqn, dimensions, prefix), sections, true);
+          sections := Sections.prependEquation(vectorizeEquation(eqn, dimensions, prefix, settings), sections, true);
         end for;
         for alg in listReverse(sects.algorithms) loop
           sections := Sections.prependAlgorithm(vectorizeAlgorithm(alg, dimensions, prefix), sections);
@@ -752,12 +754,15 @@ algorithm
 end vectorizeArray;
 
 function vectorizeEquation
-  input Equation eqn;
+  input output Equation eqn;
   input list<Dimension> dimensions;
   input ComponentRef prefix;
-  output Equation veqn;
+  input FlattenSettings settings;
 algorithm
-  veqn := match eqn
+  // Flatten with an empty prefix to get rid of any split indices.
+  {eqn} := flattenEquation(eqn, EMPTY_PREFIX, {}, settings);
+
+  eqn := match eqn
     local
       InstNode iter;
       list<InstNode> iters;
@@ -775,31 +780,33 @@ algorithm
       algorithm
         (iters, ranges, subs) := makeIterators(prefix, dimensions);
         subs := listReverseInPlace(subs);
-        veqn := Equation.mapExp(eqn, function addIterator(prefix = prefix, subscripts = subs));
+        eqn := Equation.mapExp(eqn, function addIterator(prefix = prefix, subscripts = subs));
         src := Equation.source(eqn);
 
         iter :: iters := iters;
         range :: ranges := ranges;
-        veqn := Equation.FOR(iter, SOME(range), {veqn}, src);
+        eqn := Equation.FOR(iter, SOME(range), {eqn}, src);
 
         while not listEmpty(iters) loop
           iter :: iters := iters;
           range :: ranges := ranges;
-          veqn := Equation.FOR(iter, SOME(range), {veqn}, src);
+          eqn := Equation.FOR(iter, SOME(range), {eqn}, src);
         end while;
       then
-        veqn;
+        eqn;
 
   end match;
 end vectorizeEquation;
 
 function vectorizeAlgorithm
-  input Algorithm alg;
+  input output Algorithm alg;
   input list<Dimension> dimensions;
   input ComponentRef prefix;
-  output Algorithm valg;
 algorithm
-  valg := match alg
+  // Flatten with an empty prefix to get rid of any split indices.
+  alg.statements := flattenStatements(alg.statements, EMPTY_PREFIX);
+
+  alg := match alg
     local
       InstNode iter;
       list<InstNode> iters;
@@ -1200,6 +1207,7 @@ algorithm
     case Equation.FOR()
       algorithm
         if settings.arrayConnect then
+          eq.body := flattenEquations(eq.body, EMPTY_PREFIX, settings);
           eql := eq :: equations;
         elseif not settings.scalarize then
           eql := splitForLoop(eq, prefix, equations, settings);
@@ -1422,6 +1430,7 @@ protected
   Equation eq;
 algorithm
   Equation.FOR(iter, range, body, src) := forLoop;
+  body := flattenEquations(body, EMPTY_PREFIX, settings);
   (connects, non_connects) := splitForLoop2(body);
 
   if not listEmpty(connects) then

testsuite/flattening/modelica/scodeinst/ArrayConnect3.mo

@@ -56,24 +56,24 @@ end ArrayConnect3;
 //   Real[1000, 100] cells.l.f;
 //   Real[1000, 100] cells.l.e;
 // equation
-//   for $i1 in 1:999 loop
-//     for $i2 in 2:100 loop
-//       cells[$i1,$i2].l.e = cells[$i1,$i2 - 1].r.e;
+//   for $i1 in 2:1000 loop
+//     for $i2 in 1:99 loop
+//       cells[$i1,$i2].u.e = cells[$i1 - 1,$i2].d.e;
 //     end for;
 //   end for;
 //   for $i1 in 1:999 loop
 //     for $i2 in 1:99 loop
-//       cells[$i1,$i2].r.f + cells[$i1,$i2 + 1].l.f = 0.0;
+//       cells[$i1,$i2].d.f + cells[$i1 + 1,$i2].u.f = 0.0;
 //     end for;
 //   end for;
-//   for $i1 in 2:1000 loop
-//     for $i2 in 1:99 loop
-//       cells[$i1,$i2].u.e = cells[$i1 - 1,$i2].d.e;
+//   for $i1 in 1:999 loop
+//     for $i2 in 2:100 loop
+//       cells[$i1,$i2].l.e = cells[$i1,$i2 - 1].r.e;
 //     end for;
 //   end for;
 //   for $i1 in 1:999 loop
 //     for $i2 in 1:99 loop
-//       cells[$i1,$i2].d.f + cells[$i1 + 1,$i2].u.f = 0.0;
+//       cells[$i1,$i2].r.f + cells[$i1,$i2 + 1].l.f = 0.0;
 //     end for;
 //   end for;
 //   for $i1 in 1:1000 loop
@@ -83,13 +83,13 @@ end ArrayConnect3;
 //     cells[$i1,100].r.f + cells[$i1,1].l.f = 0.0;
 //   end for;
 //   for $i2 in 1:100 loop
-//     cells[1,$i2].u.e = S.p.e;
-//   end for;
-//   sum(cells[1,:].u.f) + S.p.f = 0.0;
-//   for $i2 in 1:100 loop
 //     cells[1000,$i2].d.e = S.n.e;
 //   end for;
 //   sum(cells[1000,:].d.f) + S.n.f = 0.0;
+//   for $i2 in 1:100 loop
+//     cells[1,$i2].u.e = S.p.e;
+//   end for;
+//   sum(cells[1,:].u.f) + S.p.f = 0.0;
 //   for $i1 in 1:999 loop
 //     cells[$i1,100].d.f = 0.0;
 //   end for;

testsuite/flattening/modelica/scodeinst/PrintRecordTypes1.mo

@@ -45,8 +45,8 @@ end PrintRecordTypes1;
 //   Real[100, 10] b.c.rb.y;
 // equation
 //   for i in 1:100 loop
-//     b[i].c[1].rb = R1(/*Real*/(i), 0.0);
 //     b[i].c[10] = R2(R1(1.0, 0.0), R1(/*Real*/(i), 1.0));
+//     b[i].c[1].rb = R1(/*Real*/(i), 0.0);
 //   end for;
 // end PrintRecordTypes1;
 // endResult