Hi!
On the following testcase, we warn with -Wunused-value twice, once
in the FEs and later on cgraphunit again with slightly different
wording.
The following patch fixes that by registering a warning suppression in the
FEs when we warn and not warning in cgraphunit anymore if that happened.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2022-12-22 Jakub Jelinek <ja...@redhat.com>
PR c/108079
gcc/
* cgraphunit.cc (check_global_declaration): Don't warn for unused
variables which have OPT_Wunused_variable warning suppressed.
gcc/c/
* c-decl.cc (pop_scope): Suppress OPT_Wunused_variable warning
after diagnosing it.
gcc/cp/
* decl.cc (poplevel): Suppress OPT_Wunused_variable warning
after diagnosing it.
gcc/testsuite/
* c-c++-common/Wunused-var-18.c: New test.
--- gcc/cgraphunit.cc.jj 2022-10-18 10:38:48.000000000 +0200
+++ gcc/cgraphunit.cc 2022-12-21 15:14:34.687939477 +0100
@@ -1122,6 +1122,7 @@ check_global_declaration (symtab_node *s
&& (TREE_CODE (decl) != FUNCTION_DECL
|| (!DECL_STATIC_CONSTRUCTOR (decl)
&& !DECL_STATIC_DESTRUCTOR (decl)))
+ && (! VAR_P (decl) || !warning_suppressed_p (decl, OPT_Wunused_variable))
/* Otherwise, ask the language. */
&& lang_hooks.decls.warn_unused_global (decl))
warning_at (DECL_SOURCE_LOCATION (decl),
--- gcc/c/c-decl.cc.jj 2022-12-19 11:08:31.500766238 +0100
+++ gcc/c/c-decl.cc 2022-12-21 14:52:40.251919370 +0100
@@ -1310,7 +1310,10 @@ pop_scope (void)
&& scope != external_scope)
{
if (!TREE_USED (p))
- warning (OPT_Wunused_variable, "unused variable %q+D", p);
+ {
+ warning (OPT_Wunused_variable, "unused variable %q+D", p);
+ suppress_warning (p, OPT_Wunused_variable);
+ }
else if (DECL_CONTEXT (p) == current_function_decl)
warning_at (DECL_SOURCE_LOCATION (p),
OPT_Wunused_but_set_variable,
--- gcc/cp/decl.cc.jj 2022-12-21 09:03:45.437566855 +0100
+++ gcc/cp/decl.cc 2022-12-21 14:51:07.043265263 +0100
@@ -693,6 +693,7 @@ poplevel (int keep, int reverse, int fun
else
warning_at (DECL_SOURCE_LOCATION (decl),
OPT_Wunused_variable, "unused variable %qD",
decl);
+ suppress_warning (decl, OPT_Wunused_variable);
}
else if (DECL_CONTEXT (decl) == current_function_decl
// For -Wunused-but-set-variable leave references alone.
--- gcc/testsuite/c-c++-common/Wunused-var-18.c.jj 2022-12-21
15:28:03.112273963 +0100
+++ gcc/testsuite/c-c++-common/Wunused-var-18.c 2022-12-21 15:27:05.246107581
+0100
@@ -0,0 +1,10 @@
+/* PR c/108079 */
+/* { dg-do compile } */
+/* { dg-options "-Wunused-variable" } */
+
+int
+main ()
+{
+ static int x; /* { dg-warning "unused variable 'x'" } */
+ /* { dg-bogus "'x' defined but not used" "" { target *-*-* }
.-1 } */
+}
Jakub
