Defines lp.VectorizationFallback

loopy/__init__.py

@@ -150,7 +150,7 @@
 from loopy.frontend.fortran import (c_preprocess, parse_transformed_fortran,
         parse_fortran)
 
-from loopy.target import TargetBase, ASTBuilderBase
+from loopy.target import TargetBase, ASTBuilderBase, VectorizationFallback
 from loopy.target.c import (CFamilyTarget, CTarget, ExecutableCTarget,
                             generate_header, CWithGNULibcTarget,
                             ExecutableCWithGNULibcTarget)
@@ -298,7 +298,7 @@
 
         "LoopyError", "LoopyWarning",
 
-        "TargetBase",
+        "TargetBase", "VectorizationFallback",
         "CFamilyTarget", "CTarget", "ExecutableCTarget", "generate_header",
         "CWithGNULibcTarget", "ExecutableCWithGNULibcTarget",
         "CudaTarget", "OpenCLTarget",

loopy/target/__init__.py

@@ -10,6 +10,7 @@
 .. autoclass:: OpenCLTarget
 .. autoclass:: PyOpenCLTarget
 .. autoclass:: ISPCTarget
+.. autoclass:: VectorizationFallback
 
 References to Canonical Names
 -----------------------------
@@ -50,6 +51,7 @@
 from typing import (Any, Tuple, Generic, TypeVar, Sequence, ClassVar, Optional,
         TYPE_CHECKING, Type)
 import abc
+from enum import Enum, unique
 
 if TYPE_CHECKING:
     from loopy.typing import ExpressionT
@@ -60,12 +62,30 @@
 ASTType = TypeVar("ASTType")
 
 
+@unique
+class VectorizationFallback(Enum):
+    """
+    Directs :mod:`loopy`\'s code-generation pipeline how the code should be
+    generated if an instruction cannot be vectorized.
+
+    :attr UNROLL: Unrolls the instances the unvectorizable statement.
+    :attr UNROLL: Wraps the statement around a loop with an ``omp simd``
+        pragma-directive.
+    """
+    UNROLL = 0
+    OMP_SIMD = 1
+
+
 class TargetBase(abc.ABC):
     """Base class for all targets, i.e. different combinations of code that
     loopy can generate.
 
     Objects of this type must be picklable.
 
+    .. attribute:: vectorization_fallback
+
+        An instance of :class:`VectorizationFallback`.
+
     .. attribute:: allows_non_constant_indexing_for_vec_types
 
         An instance of :class:`bool` that is *True* only if the target
@@ -178,6 +198,10 @@ def is_executable(self) -> bool:
         translation units through :attr:`loopy.TranslationUnit.__call__`.
         """
 
+    @abc.abstractproperty
+    def vectorization_fallback(self):
+        pass
+
     @abc.abstractproperty
     def allows_non_constant_indexing_for_vec_types(self):
         pass

loopy/target/c/__init__.py

@@ -1375,6 +1375,11 @@ def allows_non_constant_indexing_for_vec_types(self):
     def broadcasts_scalar_assignment_to_vec_types(self):
         return False
 
+    @property
+    def vectorization_fallback(self):
+        from loopy.target import VectorizationFallback
+        return VectorizationFallback.UNROLL
+
 
 class CASTBuilder(CFamilyASTBuilder):
     def preamble_generators(self):

loopy/target/cuda.py

@@ -276,6 +276,11 @@ def allows_non_constant_indexing_for_vec_types(self):
     def broadcasts_scalar_assignment_to_vec_types(self):
         return True
 
+    @property
+    def vectorization_fallback(self):
+        from loopy.target import VectorizationFallback
+        return VectorizationFallback.UNROLL
+
 # }}}
 
 

loopy/target/ispc.py

@@ -210,6 +210,11 @@ def allows_non_constant_indexing_for_vec_types(self):
     def broadcasts_scalar_assignment_to_vec_types(self):
         return True
 
+    @property
+    def vectorization_fallback(self):
+        from loopy.target import VectorizationFallback
+        return VectorizationFallback.UNROLL
+
 
 class ISPCASTBuilder(CFamilyASTBuilder):
     # {{{ top-level codegen

loopy/target/opencl.py

@@ -606,6 +606,11 @@ def allows_non_constant_indexing_for_vec_types(self):
     def broadcasts_scalar_assignment_to_vec_types(self):
         return True
 
+    @property
+    def vectorization_fallback(self):
+        from loopy.target import VectorizationFallback
+        return VectorizationFallback.UNROLL
+
 # }}}