compiler: refine nested parallel support with decl check

Author: mloubout

devito/passes/iet/parpragma.py

@@ -346,10 +346,18 @@ def _make_parregion(self, partree, parrays):
     def _make_guard(self, parregion):
         return parregion
 
+    def _support_uindices(self, uindices):
+        if not uindices:
+            # No secondary indices, so we can apply nested parallelism
+            return True
+        else:
+            # Compiler supports nested parallelism with multiple indices
+            # such as for(int i = 0, j=1; ...)
+            return self._support_nested_parallelism(self.compiler)
+
     def _make_nested_partree(self, partree):
         # Apply heuristic
-        if self.nhyperthreads <= self.nested or \
-           not self._support_nested_parallelism(self.compiler):
+        if self.nhyperthreads <= self.nested:
             return partree
 
         # Note: there might be multiple sub-trees amenable to nested parallelism,
@@ -371,7 +379,8 @@ def _make_nested_partree(self, partree):
             # within a block)
             candidates = []
             for i in inner:
-                if self.key(i) and any((j.dim.root is i.dim.root) for j in outer):
+                if self.key(i) and any((j.dim.root is i.dim.root) for j in outer) and \
+                   self._support_uindices(i.uindices):
                     candidates.append(i)
                 elif candidates:
                     # If there's at least one candidate but `i` doesn't honor the

tests/test_caching.py

@@ -5,7 +5,6 @@
 import pytest
 from sympy import Expr
 
-from conftest import skipif
 from devito import (
     ConditionalDimension, Constant, DefaultDimension, Dimension, Eq, Function, Grid,
     Operator, SparseFunction, SparseTimeFunction, SubDimension, TensorFunction,
@@ -468,7 +467,6 @@ def test_grid_dtypes(self):
 
         assert hash(grid0) != hash(grid1)
 
-    @skipif('nointel')
     def test_special_symbols(self):
         """
         This test checks the singletonization, through the caching infrastructure,

tests/test_dle.py

@@ -1238,7 +1238,6 @@ def test_parallel_prec_inject(self):
 
 class TestNestedParallelism:
 
-    @skipif('nointel')
     def test_basic(self):
         grid = Grid(shape=(3, 3, 3))
 
@@ -1251,7 +1250,6 @@ def test_basic(self):
                                                   'par-dynamic-work': 0}))
 
         # Does it compile? Honoring the OpenMP specification isn't trivial
-        print(op)
         assert op.cfunction
 
         # Does it produce the right result
@@ -1271,7 +1269,6 @@ def test_basic(self):
         assert iterations[2].pragmas[0].ccode.value ==\
             'omp parallel for schedule(dynamic,1) num_threads(nthreads_nested)'
 
-    @skipif('nointel')
     def test_collapsing(self):
         grid = Grid(shape=(3, 3, 3))
 
@@ -1280,7 +1277,6 @@ def test_collapsing(self):
 
         op = Operator(Eq(u.forward, u + f + 1),
                       opt=('blocking', 'openmp', {'par-nested': 0,
-                                                  'cire-rotate': True,
                                                   'par-collapse-ncores': 1,
                                                   'par-collapse-work': 0,
                                                   'par-dynamic-work': 0}))
@@ -1374,7 +1370,6 @@ def test_multiple_subnests_v1(self):
         assert trees[-1][3].pragmas[0].ccode.value ==\
             'omp parallel for schedule(dynamic,1) num_threads(nthreads_nested)'
 
-    @skipif('nointel')
     @pytest.mark.parametrize('blocklevels', [1, 2])
     def test_nested_cache_blocking_structure_subdims(self, blocklevels):
         """
@@ -1438,7 +1433,6 @@ def test_nested_cache_blocking_structure_subdims(self, blocklevels):
             ('omp parallel for collapse(2) schedule(dynamic,1) '
              'num_threads(nthreads_nested)')
 
-    @skipif('nointel')
     @pytest.mark.parametrize('exprs,collapsed,scheduling', [
         (['Eq(u.forward, u.dx)'], '2', 'static'),
         (['Eq(u.forward, u.dy)'], '2', 'static'),
@@ -1471,7 +1465,6 @@ def test_collapsing_w_wo_halo(self, exprs, collapsed, scheduling):
         assert iterations[1].pragmas[0].ccode.value ==\
             "".join([ompfor_string, scheduling_string])
 
-    @skipif('device')
     def test_nested_parallelism_support(self):
         grid = Grid(shape=(10, 10, 10))
 
@@ -1484,7 +1477,9 @@ def test_nested_parallelism_support(self):
         v1.data_with_halo[:] = 1.
 
         eqn = Eq(v.forward, (v.dx * (1 + 2*f) * f).dx)
-        op = Operator(eqn, opt=('advanced', {'openmp': True, 'par-nested': 0}))
+        op = Operator(eqn, opt=('advanced', {'openmp': True,
+                                             'par-collapse-ncores': 1,
+                                             'par-nested': 0}))
 
         bns, _ = assert_blocking(op, {'x0_blk0'})
         trees = retrieve_iteration_tree(bns['x0_blk0'])
@@ -1496,7 +1491,7 @@ def test_nested_parallelism_support(self):
         if isinstance(configuration['compiler'], (IntelCompiler, OneapiCompiler)):
             # Supports nested parallelism
             assert trees[0][2].pragmas[0].ccode.value == \
-                '#pragma omp parallel for collapse(2) schedule(dynamic,1)'\
+                'omp parallel for collapse(2) schedule(dynamic,1)'\
                 ' num_threads(nthreads_nested)'
             assert trees[1][2].pragmas[0].ccode.value == \
                 trees[0][2].pragmas[0].ccode.value