Hi!
The PR13358 r0-92909 change changed the diagnostics on long long
in C++ (either with -std=c++98 or -Wlong-long), but unlike the
C FE we unfortunately warn even in the
__extension__ long long a;
etc. cases. The C FE in that case in
disable_extension_diagnostics saves and clears not just
pedantic flag but also warn_long_long (and several others), while
C++ FE only temporarily disables pedantic.
The following patch makes it behave like the C FE in this regard,
though (__extension__ 1LL) still doesn't work because of the
separate lexing (and I must say I have no idea how to fix that).
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
Or do you prefer a solution closer to the C FE, cp_parser_extension_opt
saving the values into a bitfield and have another function to restore
the state (or use RAII)?
2025-07-29 Jakub Jelinek <ja...@redhat.com>
PR c++/121133
* parser.cc (cp_parser_unary_expression): Adjust
cp_parser_extension_opt caller and restore warn_long_long.
(cp_parser_declaration): Likewise.
(cp_parser_block_declaration): Likewise.
(cp_parser_member_declaration): Likewise.
(cp_parser_extension_opt): Add SAVED_LONG_LONG argument,
save previous warn_long_long state into it and clear it
for __extension__.
* g++.dg/warn/pr121133-1.C: New test.
* g++.dg/warn/pr121133-2.C: New test.
* g++.dg/warn/pr121133-3.C: New test.
* g++.dg/warn/pr121133-4.C: New test.
--- gcc/cp/parser.cc.jj 2025-07-27 23:31:09.730006891 +0200
+++ gcc/cp/parser.cc 2025-07-28 14:15:05.450578933 +0200
@@ -2921,7 +2921,7 @@ static size_t cp_parser_skip_std_attribu
static size_t cp_parser_skip_attributes_opt
(cp_parser *, size_t);
static bool cp_parser_extension_opt
- (cp_parser *, int *);
+ (cp_parser *, int *, int *);
static void cp_parser_label_declaration
(cp_parser *);
@@ -9504,11 +9504,12 @@ cp_parser_unary_expression (cp_parser *p
case RID_EXTENSION:
{
/* The saved value of the PEDANTIC flag. */
- int saved_pedantic;
+ int saved_pedantic, saved_long_long;
tree expr;
/* Save away the PEDANTIC flag. */
- cp_parser_extension_opt (parser, &saved_pedantic);
+ cp_parser_extension_opt (parser, &saved_pedantic,
+ &saved_long_long);
/* Also suppress -Wconditionally-supported. */
diagnostic_push_diagnostics (global_dc, input_location);
diagnostic_classify_diagnostic
@@ -9519,6 +9520,7 @@ cp_parser_unary_expression (cp_parser *p
/* Restore the PEDANTIC flag. */
diagnostic_pop_diagnostics (global_dc, input_location);
pedantic = saved_pedantic;
+ warn_long_long = saved_long_long;
return expr;
}
@@ -16047,15 +16049,16 @@ cp_parser_declaration_seq_opt (cp_parser
static void
cp_parser_declaration (cp_parser* parser, tree prefix_attrs)
{
- int saved_pedantic;
+ int saved_pedantic, saved_long_long;
/* Check for the `__extension__' keyword. */
- if (cp_parser_extension_opt (parser, &saved_pedantic))
+ if (cp_parser_extension_opt (parser, &saved_pedantic, &saved_long_long))
{
/* Parse the qualified declaration. */
cp_parser_declaration (parser, prefix_attrs);
/* Restore the PEDANTIC flag. */
pedantic = saved_pedantic;
+ warn_long_long = saved_long_long;
return;
}
@@ -16323,15 +16326,16 @@ static void
cp_parser_block_declaration (cp_parser *parser,
bool statement_p)
{
- int saved_pedantic;
+ int saved_pedantic, saved_long_long;
/* Check for the `__extension__' keyword. */
- if (cp_parser_extension_opt (parser, &saved_pedantic))
+ if (cp_parser_extension_opt (parser, &saved_pedantic, &saved_long_long))
{
/* Parse the qualified declaration. */
cp_parser_block_declaration (parser, statement_p);
/* Restore the PEDANTIC flag. */
pedantic = saved_pedantic;
+ warn_long_long = saved_long_long;
return;
}
@@ -28869,16 +28873,17 @@ cp_parser_member_declaration (cp_parser*
cp_token *token = NULL;
cp_token *decl_spec_token_start = NULL;
cp_token *initializer_token_start = NULL;
- int saved_pedantic;
+ int saved_pedantic, saved_long_long;
bool saved_colon_corrects_to_scope_p = parser->colon_corrects_to_scope_p;
/* Check for the `__extension__' keyword. */
- if (cp_parser_extension_opt (parser, &saved_pedantic))
+ if (cp_parser_extension_opt (parser, &saved_pedantic, &saved_long_long))
{
/* Recurse. */
cp_parser_member_declaration (parser);
/* Restore the old value of the PEDANTIC flag. */
pedantic = saved_pedantic;
+ warn_long_long = saved_long_long;
return;
}
@@ -32020,13 +32025,16 @@ cp_parser_skip_attributes_opt (cp_parser
present, and FALSE otherwise. *SAVED_PEDANTIC is set to the
current value of the PEDANTIC flag, regardless of whether or not
the `__extension__' keyword is present. The caller is responsible
- for restoring the value of the PEDANTIC flag. */
+ for restoring the value of the PEDANTIC flag. Similarly *SAVED_LONG_LONG
+ for warn_long_long flag. */
static bool
-cp_parser_extension_opt (cp_parser* parser, int* saved_pedantic)
+cp_parser_extension_opt (cp_parser *parser, int *saved_pedantic,
+ int *saved_long_long)
{
/* Save the old value of the PEDANTIC flag. */
*saved_pedantic = pedantic;
+ *saved_long_long = warn_long_long;
if (cp_lexer_next_token_is_keyword (parser->lexer, RID_EXTENSION))
{
@@ -32035,6 +32043,8 @@ cp_parser_extension_opt (cp_parser* pars
/* We're not being pedantic while the `__extension__' keyword is
in effect. */
pedantic = 0;
+ /* And we don't want -Wlong-long warning. */
+ warn_long_long = 0;
return true;
}
--- gcc/testsuite/g++.dg/warn/pr121133-1.C.jj 2025-07-28 14:35:06.847066122
+0200
+++ gcc/testsuite/g++.dg/warn/pr121133-1.C 2025-07-28 15:07:31.648968490
+0200
@@ -0,0 +1,16 @@
+// PR c++/121133
+// { dg-do compile }
+// { dg-options "-std=c++98 -Wno-long-long -pedantic-errors" }
+
+__extension__ typedef long long L;
+__extension__ long long a;
+struct S {
+ __extension__ long long b;
+};
+
+void
+foo ()
+{
+ __extension__ long long c;
+ c = c + (__extension__ (long long) 1);
+}
--- gcc/testsuite/g++.dg/warn/pr121133-2.C.jj 2025-07-28 14:35:36.996677078
+0200
+++ gcc/testsuite/g++.dg/warn/pr121133-2.C 2025-07-28 14:36:43.821814791
+0200
@@ -0,0 +1,5 @@
+// PR c++/121133
+// { dg-do compile }
+// { dg-options "-std=c++98 -pedantic-errors" }
+
+#include "pr121133-1.C"
--- gcc/testsuite/g++.dg/warn/pr121133-3.C.jj 2025-07-28 14:36:56.196655111
+0200
+++ gcc/testsuite/g++.dg/warn/pr121133-3.C 2025-07-28 14:37:36.997128637
+0200
@@ -0,0 +1,5 @@
+// PR c++/121133
+// { dg-do compile { target c++11 } }
+// { dg-options "-pedantic-errors" }
+
+#include "pr121133-1.C"
--- gcc/testsuite/g++.dg/warn/pr121133-4.C.jj 2025-07-28 14:37:45.208022686
+0200
+++ gcc/testsuite/g++.dg/warn/pr121133-4.C 2025-07-28 14:38:06.653745963
+0200
@@ -0,0 +1,5 @@
+// PR c++/121133
+// { dg-do compile { target c++11 } }
+// { dg-options "-pedantic-errors -Wlong-long" }
+
+#include "pr121133-1.C"
Jakub
