https://gcc.gnu.org/g:e25ce4d65f69cefd36f625ebabf13c0b41638954
commit e25ce4d65f69cefd36f625ebabf13c0b41638954
Author: Nathan Sidwell <nat...@acm.org>
Date: Mon Apr 14 16:38:55 2025 +0000
Default compute dimensions (compile time)
This patch was previously combined with an unrelated change and testcases
that was upstreamed separately ("Add '-Wopenacc-parallelism'",
22cff118f7526bec195ed6e41452980820fdf3a8).
gcc/ChangeLog
* doc/invoke.texi (fopenacc-dim): Document syntax for using
runtime value from environment variable.
* omp-offload.cc (oacc_parse_default_dims): Implement it.
libgomp/ChangeLog
* testsuite/libgomp.oacc-c-c++-common/loop-default-compile.c: New.
Co-Authored-By: Tom de Vries <tdevr...@suse.de>
Co-Authored-By: Thomas Schwinge <tho...@codesourcery.com>
Co-Authored-By: Julian Brown <jul...@codesourcery.com>
Diff:
---
gcc/doc/invoke.texi | 6 +++++-
gcc/omp-offload.cc | 25 ++++++++++++++--------
.../loop-default-compile.c | 13 +++++++++++
3 files changed, 34 insertions(+), 10 deletions(-)
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 617a3d8ae182..f55f7896d20a 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -5249,7 +5249,11 @@ have support for @option{-pthread}.
Specify default compute dimensions for parallel offload regions that do
not explicitly specify them. The @var{geom} value is a triple of
@samp{:}-separated sizes, in order @var{gang}, @var{worker}, and @var{vector}.
-A size can be omitted, to use a target-specific default value.
+If a size is to be deferred until execution @samp{-} can be used;
+alternatively a size can be omitted to use a target-specific default value.
+When deferring to runtime, the environment variable @env{GOMP_OPENACC_DIM}
+can be set. It has the same format as the option value, except that
+@samp{-} is not permitted.
@opindex fopenmp
@cindex OpenMP parallel
diff --git a/gcc/omp-offload.cc b/gcc/omp-offload.cc
index de9b06314a9e..536bfb7889ce 100644
--- a/gcc/omp-offload.cc
+++ b/gcc/omp-offload.cc
@@ -875,8 +875,9 @@ oacc_get_min_dim (int dim)
}
/* Parse the default dimension parameter. This is a set of
- :-separated optional compute dimensions. Each specified dimension
- is a positive integer. When device type support is added, it is
+ :-separated optional compute dimensions. Each dimension is either
+ a positive integer, or '-' for a dynamic value computed at
+ runtime. When device type support is added, it is
planned to be a comma separated list of such compute dimensions,
with all but the first prefixed by the colon-terminated device
type. */
@@ -911,14 +912,20 @@ oacc_parse_default_dims (const char *dims)
if (*pos != ':')
{
- long val;
- const char *eptr;
+ long val = 0;
- errno = 0;
- val = strtol (pos, CONST_CAST (char **, &eptr), 10);
- if (errno || val <= 0 || (int) val != val)
- goto malformed;
- pos = eptr;
+ if (*pos == '-')
+ pos++;
+ else
+ {
+ const char *eptr;
+
+ errno = 0;
+ val = strtol (pos, CONST_CAST (char **, &eptr), 10);
+ if (errno || val <= 0 || (int) val != val)
+ goto malformed;
+ pos = eptr;
+ }
oacc_default_dims[ix] = (int) val;
}
}
diff --git a/libgomp/testsuite/libgomp.oacc-c-c++-common/loop-default-compile.c
b/libgomp/testsuite/libgomp.oacc-c-c++-common/loop-default-compile.c
new file mode 100644
index 000000000000..6c479e4eb258
--- /dev/null
+++ b/libgomp/testsuite/libgomp.oacc-c-c++-common/loop-default-compile.c
@@ -0,0 +1,13 @@
+/* { dg-additional-options "-fopenacc-dim=16:16" } */
+/* This code uses nvptx inline assembly guarded with acc_on_device, which is
+ not optimized away at -O0, and then confuses the target assembler.
+ { dg-skip-if "" { *-*-* } { "-O0" } { "" } } */
+/* { dg-set-target-env-var "GOMP_OPENACC_DIM" "8:8" } */
+
+#include "loop-default.h"
+
+int main ()
+{
+ /* Environment should be ignored. */
+ return test_1 (16, 16, 32);
+}
