The attached patch fixes a bug I found in the C++ front end's handling
of OpenACC data clauses. The problem here is that the C++ front end
wraps the array bounds expressions in NON_LVALUE_EXPR tree nodes, and
the code here (which appears to have been copied from similar code in
the C front end) was failing to strip those before checking to see if
they were INTEGER_CST nodes, etc.
Sadly, I have no test case for this because it was only triggering an
error in conjunction with some other OpenACC patches that are not yet on
trunk, and the tree dumps don't show anything useful. I confirmed that
the problem exists on trunk without those other patches by examining
things in the debugger. This is the example I was using for my
hand-testing:
void f (float a[16][16], float b[16][16], float c[16][16])
{
int i, j, k;
#pragma acc kernels copyin(a[0:16][0:16], b[0:16][0:16])
copyout(c[0:16][0:16])
{
for (i = 0; i < 16; i++) {
for (j = 0; j < 16; j++) {
float t = 0;
for (k = 0; k < 16; k++)
t += a[i][k] * b[k][j];
c[i][j] = t;
}
}
}
}
Is this patch OK to commit now, or in Stage 1?
-Sandra
commit 3d2cda1e758a54111af04e80ea3dbaa27b3387e7
Author: Sandra Loosemore <san...@codesourcery.com>
Date: Wed Mar 25 21:29:17 2020 -0700
Bug fix for processing OpenACC data clauses in C++.
The C++ front end wraps the values in OpenACC data clause array range
specifications in NON_LVALUE_EXPR tree nodes. The existing code was
failing to strip these before checking for constant values.
2020-03-25 Sandra Loosemore <san...@codesourcery.com>
gcc/cp/
* semantics.c (handle_omp_array_sections_1): Call STRIP_NOPS
on length and low_bound to unwrap NON_LVALUE_EXPRs.
(handle_omp_array_sections): Likewise.
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 34ccb9f..8945939 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2020-03-25 Sandra Loosemore <san...@codesourcery.com>
+
+ * semantics.c (handle_omp_array_sections_1): Call STRIP_NOPS
+ on length and low_bound to unwrap NON_LVALUE_EXPRs.
+ (handle_omp_array_sections): Likewise.
+
2020-03-25 Patrick Palka <ppa...@redhat.com>
PR c++/94265
diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c
index 2721a55..2efc077 100644
--- a/gcc/cp/semantics.c
+++ b/gcc/cp/semantics.c
@@ -4861,6 +4861,10 @@ handle_omp_array_sections_1 (tree c, tree t, vec<tree> &types,
length = mark_rvalue_use (length);
/* We need to reduce to real constant-values for checks below. */
if (length)
+ STRIP_NOPS (length);
+ if (low_bound)
+ STRIP_NOPS (low_bound);
+ if (length)
length = fold_simple (length);
if (low_bound)
low_bound = fold_simple (low_bound);
@@ -5160,6 +5164,11 @@ handle_omp_array_sections (tree c, enum c_omp_region_type ort)
tree low_bound = TREE_PURPOSE (t);
tree length = TREE_VALUE (t);
+ if (length)
+ STRIP_NOPS (length);
+ if (low_bound)
+ STRIP_NOPS (low_bound);
+
i--;
if (low_bound
&& TREE_CODE (low_bound) == INTEGER_CST
