aboutsummaryrefslogtreecommitdiff
path: root/include
diff options
context:
space:
mode:
authorJakub Jelinek <jakub@redhat.com>2022-06-13 13:42:59 +0200
committerJakub Jelinek <jakub@redhat.com>2022-06-13 14:02:37 +0200
commit1158fe43407568f20415b16575ddbfff216bf8b6 (patch)
treef6d81a2caaae787317901639f42144396f359b40 /include
parent3b598848f6fdbf7e76eaf2beec1ce94fc3a14b9b (diff)
downloadgcc-1158fe43407568f20415b16575ddbfff216bf8b6.zip
gcc-1158fe43407568f20415b16575ddbfff216bf8b6.tar.gz
gcc-1158fe43407568f20415b16575ddbfff216bf8b6.tar.bz2
openmp: Conforming device numbers and omp_{initial,invalid}_device
OpenMP 5.2 changed once more what device numbers are allowed. In 5.1, valid device numbers were [0, omp_get_num_devices()]. 5.2 makes also -1 valid (calls it omp_initial_device), which is equivalent in behavior to omp_get_num_devices() number but has the advantage that it is a constant. And it also introduces omp_invalid_device which is also a constant with implementation defined value < -1. That value should act like sNaN, any time any device construct (GOMP_target*) or OpenMP runtime API routine is asked for such a device, the program is terminated. And if OMP_TARGET_OFFLOAD=mandatory, all non-conforming device numbers (which is all but [-1, omp_get_num_devices()] other than omp_invalid_device) must be treated like omp_invalid_device. For device constructs, we have a compatibility problem, we've historically used 2 magic negative values to mean something special. GOMP_DEVICE_ICV (-1) means device clause wasn't present, pick the omp_get_default_device () number GOMP_DEVICE_FALLBACK (-2) means the host device (this is used e.g. for #pragma omp target if (cond) where if cond is false, we pass -2 But 5.2 requires that omp_initial_device is -1 (there were discussions about it, advantage of -1 is that one can say iterate over the [-1, omp_get_num_devices()-1] range to get all devices starting with the host/initial one. And also, if user passes -2, unless it is omp_invalid_device, we need to treat it like non-conforming with OMP_TARGET_OFFLOAD=mandatory. So, the patch does on the compiler side some number remapping, user_device_num >= -2U ? user_device_num - 1 : user_device_num. This remapping is done at compile time if device clause has constant argument, otherwise at runtime, and means that for user -1 (omp_initial_device) we pass -2 to GOMP_* in the runtime library where it treats it like host fallback, while -2 is remapped to -3 (one of the non-conforming device numbers, for those it doesn't matter which one is which). omp_invalid_device is then -4. For the OpenMP device runtime APIs, no remapping is done. This patch doesn't deal with the initial default-device-var for OMP_TARGET_OFFLOAD=mandatory , the spec says that the inital ICV value for that should in that case depend on whether there are any offloading devices or not (if not, should be omp_invalid_device), but that means we can't determine the number of devices lazily (and let libraries have the possibility to register their offloading data etc.). 2022-06-13 Jakub Jelinek <jakub@redhat.com> gcc/ * omp-expand.cc (expand_omp_target): Remap user provided device clause arguments, -1 to -2 and -2 to -3, either at compile time if constant, or at runtime. include/ * gomp-constants.h (GOMP_DEVICE_INVALID): Define. libgomp/ * omp.h.in (omp_initial_device, omp_invalid_device): New enumerators. * omp_lib.f90.in (omp_initial_device, omp_invalid_device): New parameters. * omp_lib.h.in (omp_initial_device, omp_invalid_device): Likewise. * target.c (resolve_device): Add remapped argument, handle GOMP_DEVICE_ICV only if remapped is true (and clear remapped), for negative values, treat GOMP_DEVICE_FALLBACK as fallback only if remapped, otherwise treat omp_initial_device that way. For omp_invalid_device, always emit gomp_fatal, even when OMP_TARGET_OFFLOAD isn't mandatory. (GOMP_target, GOMP_target_ext, GOMP_target_data, GOMP_target_data_ext, GOMP_target_update, GOMP_target_update_ext, GOMP_target_enter_exit_data): Pass true as remapped argument to resolve_device. (omp_target_alloc, omp_target_free, omp_target_is_present, omp_target_memcpy_check, omp_target_associate_ptr, omp_target_disassociate_ptr, omp_get_mapped_ptr, omp_target_is_accessible): Pass false as remapped argument to resolve_device. Treat omp_initial_device the same as gomp_get_num_devices (). Don't bypass resolve_device calls if device_num is negative. (omp_pause_resource): Treat omp_initial_device the same as gomp_get_num_devices (). Call resolve_device. * icv-device.c (omp_set_default_device): Always set to device_num even when it is negative. * libgomp.texi: Document that Conforming device numbers, omp_initial_device and omp_invalid_device is implemented. * testsuite/libgomp.c/target-41.c (main): Add test with omp_initial_device. * testsuite/libgomp.c/target-45.c: New test. * testsuite/libgomp.c/target-46.c: New test. * testsuite/libgomp.c/target-47.c: New test. * testsuite/libgomp.c-c++-common/target-is-accessible-1.c (main): Add test with omp_initial_device. Use -5 instead of -1 for negative value test. * testsuite/libgomp.fortran/target-is-accessible-1.f90 (main): Likewise. Reorder stop numbers.
Diffstat (limited to 'include')
-rw-r--r--include/gomp-constants.h11
1 files changed, 11 insertions, 0 deletions
diff --git a/include/gomp-constants.h b/include/gomp-constants.h
index 701d33d..e4dd8ef 100644
--- a/include/gomp-constants.h
+++ b/include/gomp-constants.h
@@ -233,8 +233,19 @@ enum gomp_map_kind
#define GOMP_DEVICE_HSA 7
#define GOMP_DEVICE_GCN 8
+/* We have a compatibility issue. OpenMP 5.2 introduced
+ omp_initial_device with value of -1 which clashes with our
+ GOMP_DEVICE_ICV, so we need to remap user supplied device
+ ids, -1 (aka omp_initial_device) to GOMP_DEVICE_HOST_FALLBACK,
+ and -2 (one of many non-conforming device numbers, but with
+ OMP_TARGET_OFFLOAD=mandatory needs to be treated a
+ omp_invalid_device) to -3 (so that for dev_num >= -2U we can
+ subtract 1). -4 is then what we use for omp_invalid_device,
+ which unlike the other non-conforming device numbers results
+ in fatal error regardless of OMP_TARGET_OFFLOAD. */
#define GOMP_DEVICE_ICV -1
#define GOMP_DEVICE_HOST_FALLBACK -2
+#define GOMP_DEVICE_INVALID -4
/* GOMP_task/GOMP_taskloop* flags argument. */
#define GOMP_TASK_FLAG_UNTIED (1 << 0)