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[og13] OpenMP: Dimension ordering for array-shaping operator for C and C++

Message ID 20230714163340.3464603-1-julian@codesourcery.com
State New
Headers show
Series [og13] OpenMP: Dimension ordering for array-shaping operator for C and C++ | expand

Commit Message

Julian Brown July 14, 2023, 4:33 p.m. UTC 
This patch fixes a bug in non-contiguous 'target update' operations using
the new array-shaping operator for C and C++, processing the dimensions
of the array the wrong way round during the OpenMP lowering pass.
Fortran was also incorrectly using the wrong ordering but the second
reversal in omp-low.cc made it produce the correct result.

The C and C++ bug only affected array shapes where the dimension sizes
are different ([X][Y]) - several existing tests used the same value
for both/all dimensions ([X][X]), which masked the problem.  Only the
array dimensions (extents) are affected, not e.g. the indices, lengths
or strides for array sections.

This patch reverses the order used in both omp-low.cc and the Fortran
front-end, so the order should now be correct for all supported base
languages.

Tested with offloading to AMD GCN.  I will apply (to og13) shortly.

2023-07-14  Julian Brown  <julian@codesourcery.com>

gcc/fortran/
	* trans-openmp.cc (gfc_trans_omp_arrayshape_type): Reverse dimension
	ordering for created array type.

gcc/
	* omp-low.cc (lower_omp_target): Reverse iteration over array
	dimensions.

libgomp/
	* testsuite/libgomp.c-c++-common/array-shaping-14.c: New test.
---
 gcc/fortran/trans-openmp.cc                   |  2 +-
 gcc/omp-low.cc                                |  6 ++--
 .../libgomp.c-c++-common/array-shaping-14.c   | 34 +++++++++++++++++++
 3 files changed, 38 insertions(+), 4 deletions(-)
 create mode 100644 libgomp/testsuite/libgomp.c-c++-common/array-shaping-14.c
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Patch

diff --git a/gcc/fortran/trans-openmp.cc b/gcc/fortran/trans-openmp.cc
index 6cb5340687e..6b9a0430eba 100644
--- a/gcc/fortran/trans-openmp.cc
+++ b/gcc/fortran/trans-openmp.cc
@@ -4271,7 +4271,7 @@  gfc_trans_omp_arrayshape_type (tree type, vec<tree> *dims)
 {
   gcc_assert (dims->length () > 0);
 
-  for (int i = dims->length () - 1; i >= 0; i--)
+  for (unsigned i = 0; i < dims->length (); i++)
     {
       tree dim = fold_convert (sizetype, (*dims)[i]);
       /* We need the index of the last element, not the array size.  */
diff --git a/gcc/omp-low.cc b/gcc/omp-low.cc
index c7706a5921f..ab2e4145ab2 100644
--- a/gcc/omp-low.cc
+++ b/gcc/omp-low.cc
@@ -14290,7 +14290,7 @@  lower_omp_target (gimple_stmt_iterator *gsi_p, omp_context *ctx)
 		      dims++;
 		    }
 
-		int tdim = tdims.length () - 1;
+		unsigned tdim = 0;
 
 		vec<constructor_elt, va_gc> *vdim;
 		vec<constructor_elt, va_gc> *vindex;
@@ -14365,7 +14365,7 @@  lower_omp_target (gimple_stmt_iterator *gsi_p, omp_context *ctx)
 			    nc = nc2;
 			  }
 
-			if (tdim >= 0)
+			if (tdim < tdims.length ())
 			  {
 			    /* We have an array shape -- use that to find the
 			       total size of the data on the target to look up
@@ -14403,7 +14403,7 @@  lower_omp_target (gimple_stmt_iterator *gsi_p, omp_context *ctx)
 					"for array");
 			    dim = index = len = stride = error_mark_node;
 			  }
-			tdim--;
+			tdim++;
 
 			c = nc;
 		      }
diff --git a/libgomp/testsuite/libgomp.c-c++-common/array-shaping-14.c b/libgomp/testsuite/libgomp.c-c++-common/array-shaping-14.c
new file mode 100644
index 00000000000..4ca6f794f93
--- /dev/null
+++ b/libgomp/testsuite/libgomp.c-c++-common/array-shaping-14.c
@@ -0,0 +1,34 @@ 
+/* { dg-do run { target offload_device_nonshared_as } } */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <assert.h>
+
+typedef struct {
+  int *ptr;
+} S;
+
+int main(void)
+{
+  S q;
+  q.ptr = (int *) calloc (9 * 11, sizeof (int));
+
+#pragma omp target enter data map(to: q.ptr, q.ptr[0:9*11])
+
+#pragma omp target
+  for (int i = 0; i < 9*11; i++)
+    q.ptr[i] = i;
+
+#pragma omp target update from(([9][11]) q.ptr[3:3:2][1:4:3])
+
+  for (int j = 0; j < 9; j++)
+    for (int i = 0; i < 11; i++)
+      if (j >= 3 && j <= 7 && ((j - 3) % 2) == 0
+	  && i >= 1 && i <= 10 && ((i - 1) % 3) == 0)
+	assert (q.ptr[j * 11 + i] == j * 11 + i);
+      else
+	assert (q.ptr[j * 11 + i] == 0);
+
+#pragma omp target exit data map(release: q.ptr, q.ptr[0:9*11])
+  return 0;
+}