Hi!
The following testcase FAILs, because the UDR combiner is invoked incorrectly.
lower_omp_rec_clauses expects that when it sets
DECL_VALUE_EXPR/DECL_HAS_VALUE_EXPR_P
for both the placeholder and the var that everything will be properly
regimplified, but as the variable in question is a PARM_DECL rather than
VAR_DECL, lower_omp_regimplify_p doesn't say that it should be regimplified
and so it is not.
Bootstrapped/regtested on x86_64-linux and i686-linux, committed to trunk
so far.
2021-06-22 Jakub Jelinek <ja...@redhat.com>
PR middle-end/101167
* omp-low.c (lower_omp_regimplify_p): Regimplify also PARM_DECLs
and RESULT_DECLs that have DECL_HAS_VALUE_EXPR_P set.
* testsuite/libgomp.c-c++-common/task-reduction-15.c: New test.
--- gcc/omp-low.c.jj 2021-06-22 12:31:29.753251003 +0200
+++ gcc/omp-low.c 2021-06-22 19:24:11.955419382 +0200
@@ -13682,7 +13682,9 @@ lower_omp_regimplify_p (tree *tp, int *w
tree t = *tp;
/* Any variable with DECL_VALUE_EXPR needs to be regimplified. */
- if (VAR_P (t) && data == NULL && DECL_HAS_VALUE_EXPR_P (t))
+ if ((VAR_P (t) || TREE_CODE (t) == PARM_DECL || TREE_CODE (t) == RESULT_DECL)
+ && data == NULL
+ && DECL_HAS_VALUE_EXPR_P (t))
return t;
if (task_shared_vars
--- libgomp/testsuite/libgomp.c-c++-common/task-reduction-15.c.jj
2021-06-22 19:43:40.970141134 +0200
+++ libgomp/testsuite/libgomp.c-c++-common/task-reduction-15.c 2021-06-22
19:43:32.295252461 +0200
@@ -0,0 +1,61 @@
+/* PR middle-end/101167 */
+
+extern
+#ifdef __cplusplus
+"C"
+#endif
+void abort (void);
+
+struct S { int a, b, c[2]; };
+
+void
+init (struct S *x)
+{
+ x->a = 0;
+ x->b = 0;
+ x->c[0] = 0;
+ x->c[1] = 0;
+}
+
+void
+merge (struct S *x, struct S *y)
+{
+ x->a += y->a;
+ x->b += y->b;
+}
+
+#pragma omp declare reduction (+: struct S : merge (&omp_out, &omp_in))
initializer (init (&omp_priv))
+
+void
+foo (struct S x)
+{
+ #pragma omp taskgroup task_reduction (+: x)
+ {
+ #pragma omp task in_reduction (+: x)
+ {
+ x.a++;
+ x.b++;
+ }
+ #pragma omp task in_reduction (+: x)
+ {
+ x.a += 4;
+ x.b += 14;
+ }
+ #pragma omp task in_reduction (+: x)
+ {
+ x.a += 9;
+ x.b += 19;
+ }
+ }
+ if (x.a != 56 || x.b != 86)
+ abort ();
+}
+
+int
+main ()
+{
+ struct S x = { 42, 52 };
+ #pragma omp parallel master num_threads(3)
+ foo (x);
+ return 0;
+}
Jakub
