Clean up memoryview slice temporaries in parallel sections

Cython/Compiler/Nodes.py

@@ -7229,10 +7229,10 @@ class ParallelStatNode(StatNode, ParallelNode):
         if self.is_parallel:
             c = self.privatization_insertion_point
 
-            temps = code.funcstate.stop_collecting_temps()
+            self.temps = temps = code.funcstate.stop_collecting_temps()
             privates, firstprivates = [], []
             for temp, type in temps:
-                if type.is_pyobject:
+                if type.is_pyobject or type.is_memoryviewslice:
                     firstprivates.append(temp)
                 else:
                     privates.append(temp)
@@ -7250,6 +7250,16 @@ class ParallelStatNode(StatNode, ParallelNode):
 
                 c.put(" shared(%s)" % ', '.join(shared_vars))
 
+    def cleanup_slice_temps(self, code):
+        # Now clean up any memoryview slice temporaries
+        first = True
+        for temp, type in self.temps:
+            if type.is_memoryviewslice:
+                if first:
+                    first = False
+                    code.putln("/* Clean up any temporary slices */")
+                code.put_xdecref_memoryviewslice(temp, have_gil=False)
+
     def setup_parallel_control_flow_block(self, code):
         """
         Sets up a block that surrounds the parallel block to determine
@@ -7311,6 +7321,8 @@ class ParallelStatNode(StatNode, ParallelNode):
             end_code.put_release_ensured_gil()
             end_code.putln("#endif /* _OPENMP */")
 
+        self.cleanup_slice_temps(code)
+
     def trap_parallel_exit(self, code, should_flush=False):
         """
         Trap any kind of return inside a parallel construct. 'should_flush'

tests/run/memslice.pyx

@@ -6,7 +6,7 @@ from __future__ import unicode_literals
 
 cimport cython
 from cython cimport view
-from cython.parallel cimport prange
+from cython.parallel cimport prange, parallel
 
 import sys
 import re
@@ -1562,6 +1562,48 @@ def test_memslice_prange(arg):
             for k in range(src.shape[2]):
                 assert src[i, j, k] == dst[i, j, k], (src[i, j, k] == dst[i, j, k])
 
+@testcase
+def test_clean_temps_prange(int[:, :] buf):
+    """
+    Try to access a buffer out of bounds in a parallel section, and make sure any
+    temps used by the slicing processes are correctly counted.
+
+    >>> A = IntMockBuffer("A", range(100), (10, 10))
+    >>> test_clean_temps_prange(A)
+    acquired A
+    released A
+    """
+    cdef int i
+    try:
+        for i in prange(buf.shape[0], nogil=True):
+            buf[1:10, 20] = 0
+    except IndexError:
+        pass
+
+@testcase
+def test_clean_temps_parallel(int[:, :] buf):
+    """
+    Try to access a buffer out of bounds in a parallel section, and make sure any
+    temps used by the slicing processes are correctly counted.
+
+    >>> A = IntMockBuffer("A", range(100), (10, 10))
+    >>> test_clean_temps_parallel(A)
+    acquired A
+    released A
+    """
+    cdef int i
+    try:
+        with nogil, parallel():
+            try:
+                with gil: pass
+                for i in prange(buf.shape[0]):
+                    buf[1:10, 20] = 0
+            finally:
+                buf[1:10, 20] = 0
+    except IndexError:
+        pass
+
+
 # Test arrays in structs
 cdef struct ArrayStruct:
     int ints[10]