Scop::makeScop: extract out halide2isl::makeParamContext

It is more convenient and more natural to iterate over
the parameters in the symbol table and these belong to halide2isl.

Author: Sven Verdoolaege

tc/core/halide2isl.cc

@@ -228,6 +228,16 @@ isl::space makeParamSpace(isl::ctx ctx, const SymbolTable& symbolTable) {
   return space;
 }
 
+isl::set makeParamContext(isl::ctx ctx, const SymbolTable& symbolTable) {
+  auto space = makeParamSpace(ctx, symbolTable);
+  auto context = isl::set::universe(space);
+  for (auto p : symbolTable.params) {
+    isl::aff a(isl::aff::param_on_domain_space(space, isl::id(ctx, p.name())));
+    context = context & (a >= 0);
+  }
+  return context;
+}
+
 isl::map extractAccess(
     isl::set domain,
     const IRNode* op,

tc/core/halide2isl.h

@@ -43,6 +43,10 @@ SymbolTable makeSymbolTable(const tc2halide::HalideComponents& components);
 /// Make the space of all parameter values from the symbol table
 isl::space makeParamSpace(isl::ctx ctx, const SymbolTable& symbolTable);
 
+/// Make the parameter set marking all parameters from the symbol table
+/// as non-negative.
+isl::set makeParamContext(isl::ctx ctx, const SymbolTable& symbolTable);
+
 /// Make a constant-valued affine function over a space.
 isl::aff makeIslAffFromInt(isl::space space, int64_t i);
 

tc/core/polyhedral/scop.cc

@@ -47,13 +47,8 @@ ScopUPtr Scop::makeScop(
 
   halide2isl::SymbolTable sym = halide2isl::makeSymbolTable(components);
 
-  isl::space paramSpace = halide2isl::makeParamSpace(ctx, sym);
-  auto globalParameterContext = isl::set::universe(paramSpace);
-  isl::local_space ls(globalParameterContext.get_space());
-  for (int i = 0; i < globalParameterContext.dim(isl::dim_type::param); ++i) {
-    globalParameterContext =
-        globalParameterContext & (isl::aff(ls, isl::dim_type::param, i) >= 0);
-  }
+  auto globalParameterContext = halide2isl::makeParamContext(ctx, sym);
+  isl::space paramSpace = globalParameterContext.get_space();
 
   ScopUPtr scop(new Scop());
   scop->globalParameterContext = globalParameterContext;