While I've not looked at the rest of the patch, this bit stood out:
+static bool
+is_oacc_parallel_reduction (tree var, omp_context *ctx)
+{
+ if (!is_oacc_parallel (ctx))
+ return false;
+
+ tree clauses = gimple_omp_target_clauses (ctx->stmt);
+
+ /* Don't install a local copy of the decl if it used
+ inside a acc parallel reduction. */
^^ comment is misleading -- this routine's not installing anything
+ if (is_oacc_parallel (ctx))
^^ already checked above.
+ for (tree c = clauses; c; c = OMP_CLAUSE_CHAIN (c))
+ if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_REDUCTION
+ && OMP_CLAUSE_DECL (c) == var)
+ return true;
+
+ return false;
+}
+
