Hi!
Both the C and C++ FEs weren't marking num_threads/schedule clause
expressions as read, so we could end up with false positive
-Wunused-but-set-{variable,parameter} warnings.
Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux,
committed to trunk. Will backport to 4.6 soon.
2011-12-15 Jakub Jelinek <ja...@redhat.com>
PR c/51360
* c-parser.c (c_parser_omp_clause_num_threads,
c_parser_omp_clause_schedule): Call mark_exp_read.
* semantics.c (finish_omp_clauses): For OMP_CLAUSE_NUM_THREADS_EXPR
and OMP_CLAUSE_SCHEDULE_CHUNK_EXPR call mark_rvalue_use.
* c-c++-common/gomp/pr51360.c: New test.
* g++.dg/gomp/pr51360.C: New test.
--- gcc/c-parser.c.jj 2011-12-01 11:45:06.000000000 +0100
+++ gcc/c-parser.c 2011-12-15 13:59:12.761892100 +0100
@@ -9011,6 +9011,7 @@ c_parser_omp_clause_num_threads (c_parse
{
location_t expr_loc = c_parser_peek_token (parser)->location;
tree c, t = c_parser_expression (parser).value;
+ mark_exp_read (t);
t = c_fully_fold (t, false, NULL);
c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
@@ -9218,6 +9219,7 @@ c_parser_omp_clause_schedule (c_parser *
here = c_parser_peek_token (parser)->location;
t = c_parser_expr_no_commas (parser, NULL).value;
+ mark_exp_read (t);
t = c_fully_fold (t, false, NULL);
if (OMP_CLAUSE_SCHEDULE_KIND (c) == OMP_CLAUSE_SCHEDULE_RUNTIME)
--- gcc/cp/semantics.c.jj 2011-12-15 08:06:54.000000000 +0100
+++ gcc/cp/semantics.c 2011-12-15 14:20:04.048888247 +0100
@@ -4087,6 +4087,8 @@ finish_omp_clauses (tree clauses)
error ("num_threads expression must be integral");
remove = true;
}
+ else
+ OMP_CLAUSE_NUM_THREADS_EXPR (c) = mark_rvalue_use (t);
break;
case OMP_CLAUSE_SCHEDULE:
@@ -4101,6 +4103,8 @@ finish_omp_clauses (tree clauses)
error ("schedule chunk size expression must be integral");
remove = true;
}
+ else
+ OMP_CLAUSE_SCHEDULE_CHUNK_EXPR (c) = mark_rvalue_use (t);
break;
case OMP_CLAUSE_NOWAIT:
--- gcc/testsuite/c-c++-common/gomp/pr51360.c.jj 2011-12-15
14:20:43.150577783 +0100
+++ gcc/testsuite/c-c++-common/gomp/pr51360.c 2011-12-15 14:14:56.000000000
+0100
@@ -0,0 +1,27 @@
+/* PR c/51360 */
+/* { dg-do compile } */
+/* { dg-options "-Wunused -W -fopenmp" } */
+
+void
+foo (int a, int b, int c, int d)
+{
+ int m, n, o, p, i;
+ m = 6;
+ n = 1;
+ o = 5;
+ p = 1;
+ a = 6;
+ b = 1;
+ c = 5;
+ d = 1;
+ #pragma omp parallel for num_threads (m) if (n) schedule (static, o)
+ for (i = 0; i < 10; i++)
+ ;
+ #pragma omp parallel for num_threads (a) if (b) schedule (static, c)
+ for (i = 0; i < 10; i++)
+ ;
+ #pragma omp task final (p)
+ ;
+ #pragma omp task final (d)
+ ;
+}
--- gcc/testsuite/g++.dg/gomp/pr51360.C.jj 2011-12-15 14:21:02.447810143
+0100
+++ gcc/testsuite/g++.dg/gomp/pr51360.C 2011-12-15 14:17:54.000000000 +0100
@@ -0,0 +1,34 @@
+// PR c/51360
+// { dg-do compile }
+// { dg-options "-Wunused -W -fopenmp" }
+
+template <typename T>
+void
+foo (T a, T b, T c, T d)
+{
+ T m, n, o, p, i;
+ m = 6;
+ n = 1;
+ o = 5;
+ p = 1;
+ a = 6;
+ b = 1;
+ c = 5;
+ d = 1;
+ #pragma omp parallel for num_threads (m) if (n) schedule (static, o)
+ for (i = 0; i < 10; i++)
+ ;
+ #pragma omp parallel for num_threads (a) if (b) schedule (static, c)
+ for (i = 0; i < 10; i++)
+ ;
+ #pragma omp task final (p)
+ ;
+ #pragma omp task final (d)
+ ;
+}
+
+void
+bar ()
+{
+ foo (0, 0, 0, 0);
+}
Jakub
