[gcc/devel/omp/gcc-12] Force '--param openacc-kernels=parloops' in 'libgomp.oacc-c-c++-common/abort-3.c'

[Thomas Schwinge <tschwinge@gcc.gnu.org>]

https://gcc.gnu.org/g:9dde5e1fd14eb336afe161c0b43c74b522e20f3e

commit 9dde5e1fd14eb336afe161c0b43c74b522e20f3e
Author: Thomas Schwinge <thomas@codesourcery.com>
Date:   Tue Jan 17 09:56:15 2023 +0100

    Force '--param openacc-kernels=parloops' in 'libgomp.oacc-c-c++-common/abort-3.c'
    
            libgomp/
            * testsuite/libgomp.oacc-c-c++-common/abort-3.c: Force
            '--param openacc-kernels=parloops'.

Diff:
---
 libgomp/ChangeLog.omp                              |  3 ++
 .../testsuite/libgomp.oacc-c-c++-common/abort-3.c  | 57 ++++++++++++++++++++++
 2 files changed, 60 insertions(+)

diff --git a/libgomp/ChangeLog.omp b/libgomp/ChangeLog.omp
index 23e93495b62..0f8fca4e71c 100644
--- a/libgomp/ChangeLog.omp
+++ b/libgomp/ChangeLog.omp
@@ -1,5 +1,8 @@
 2023-01-20  Thomas Schwinge  <thomas@codesourcery.com>
 
+	* testsuite/libgomp.oacc-c-c++-common/abort-3.c: Force
+	'--param openacc-kernels=parloops'.
+
 	* testsuite/libgomp.c/simd-math-1.c: Fix configuration.
 
 2023-01-19  Tobias Burnus  <tobias@codesourcery.com>
diff --git a/libgomp/testsuite/libgomp.oacc-c-c++-common/abort-3.c b/libgomp/testsuite/libgomp.oacc-c-c++-common/abort-3.c
index bca425e8473..3ba4ef76ade 100644
--- a/libgomp/testsuite/libgomp.oacc-c-c++-common/abort-3.c
+++ b/libgomp/testsuite/libgomp.oacc-c-c++-common/abort-3.c
@@ -1,4 +1,61 @@
 /* { dg-do run } */
+/* This test case is meant to 'abort' in device execution, which works as
+   expected with '--param openacc-kernels=parloops':
+
+   GCN:
+
+       GCN Kernel Aborted
+
+   nvptx:
+
+       libgomp: cuStreamSynchronize error: unspecified launch failure (perhaps abort was called)
+
+   ..., or:
+
+       libgomp: cuStreamSynchronize error: an illegal instruction was encountered
+
+   However, with '--param openacc-kernels=decompose', for '-O0', '-O1', this
+   does *not* 'abort' in device execution, but instead we run into whatever the
+   compiler generates for (implicit) host-side '__builtin_unreachable ()':
+
+       Segmentation fault (core dumped)
+
+   ..., or:
+
+       Illegal instruction (core dumped)
+
+   (This, unfortunately, still means "correct" execution of this test case...)
+
+   And, with '--param openacc-kernels=decompose', with '-O2' and higher, we
+   get things like the following:
+
+   GCN:
+
+       libgomp: Called kernel must be initialized
+
+   ..., potentially followed by:
+
+       libgomp: Duplicate node
+       WARNING: program timed out.
+
+   nvptx:
+
+       libgomp: cuModuleLoadData error: unspecified launch failure
+
+   ..., or:
+
+       libgomp: cuModuleLoadData error: an illegal instruction was encountered
+
+   That is, for nvptx, the code doesn't even load?
+
+   Worse, on one system, this process then shows 100 % CPU utilization, GPU
+   locks up; process un-SIGKILLable, system needs to be (forcefully) rebooted.
+
+   Until we understand what's happening (how the decomposed OpenACC 'kernels'
+   code is different from 'abort-1.c', for example), play it safe:
+
+   { dg-additional-options {--param openacc-kernels=parloops} }
+*/
 
 #include <stdio.h>
 #include <stdlib.h>