Address pocl 7.x pyvkfft miscompilation

pocl/pocl#2069

Author: inducer

.test-conda-env-py3.yml

@@ -8,7 +8,8 @@ dependencies:
 - numpy
 - scipy
 - sympy
-- pocl
+# https://github.com/pocl/pocl/issues/2069
+- pocl<7
 - pocl-cuda
 - islpy
 - pyopencl

sumpy/test/test_fmm.py

@@ -146,6 +146,12 @@ def _test_sumpy_fmm(
 
     actx = actx_factory()
 
+    if fft_backend == "pyvkfft":
+        from pyopencl.characterize import get_pocl_version
+        if get_pocl_version(actx.queue.device.platform) >= (7,):
+            pytest.skip("pocl 7 and pyvkfft don't get along: "
+                        "https://github.com/pocl/pocl/issues/2069")
+
     nsources = 1000
     ntargets = 300
     dtype = np.float64