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[Bug c/16684] New: GCC should not warn about redundant redeclarations of built-ins
- From: "gcc-bugzilla at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 23 Jul 2004 03:26:09 -0000
- Subject: [Bug c/16684] New: GCC should not warn about redundant redeclarations of built-ins
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
Every built-in function is expected to have a matching prototype
in at least one header file and completely matching prototypes are
something that _should_ happen. Therefore, warning about that probably
does not serve any useful purpose but only generates an unwanted noice.
Environment:
System: FreeBSD k8.dnsalias.net 5.2-CURRENT FreeBSD 5.2-CURRENT #0: Mon Jul 12 00:28:33 EDT 2004 kan@k8.dnsalias.net:/usr/src/sys/amd64/compile/KAN amd64
<machine, os, target, libraries (multiple lines)>
host: x86_64-portbld-freebsd5.2
build: x86_64-portbld-freebsd5.2
target: x86_64-portbld-freebsd5.2
configured with: ./..//gcc-3.4-20040709/configure --disable-nls --with-system-zlib --with-libiconv-prefix=/usr/local --program-suffix=34 --with-gxx-include-dir=/usr/local/lib/gcc/x86_64-portbld-freebsd5.2/3.4.2/include/c++/ --disable-shared --disable-libgcj --prefix=/usr/local x86_64-portbld-freebsd5.2
How-To-Repeat:
Simplified test case for amd64 (replace long long with int for i386):
% cat test.c
void * malloc(unsigned long long size);
% gcc34 -save-temps -Wredundant-decls -c test.c
test.c:1: warning: redundant redeclaration of 'malloc'
------- Additional Comments From kan at FreeBSD dot ORG 2004-07-23 03:26 -------
Fix:
Disable warning if built-in function declaration is being redeclared
by normal declaration in user source files.
Index: c-decl.c
===================================================================
RCS file: /usr/download/ncvs/src/contrib/gcc/c-decl.c,v
retrieving revision 1.1.1.18
diff -u -r1.1.1.18 c-decl.c
--- c-decl.c 21 Jun 2004 23:47:45 -0000 1.1.1.18
+++ c-decl.c 22 Jul 2004 01:55:22 -0000
@@ -1253,6 +1255,9 @@
definition. */
&& !(TREE_CODE (newdecl) == FUNCTION_DECL
&& DECL_INITIAL (newdecl) && !DECL_INITIAL (olddecl))
+ /* Don't warn about redundant redeclarations of builtins. */
+ && !(TREE_CODE (newdecl) == FUNCTION_DECL
+ && !DECL_BUILT_IN (newdecl) && DECL_BUILT_IN (olddecl))
/* Don't warn about an extern followed by a definition. */
&& !(DECL_EXTERNAL (olddecl) && !DECL_EXTERNAL (newdecl))
/* Don't warn about forward parameter decls. */
--
Summary: GCC should not warn about redundant redeclarations of
built-ins
Product: gcc
Version: 3.4.2
Status: UNCONFIRMED
Severity: enhancement
Priority: P3
Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: kan at FreeBSD dot ORG
CC: gcc-bugs at gcc dot gnu dot org
GCC build triplet: x86_64-portbld-freebsd5.2
GCC host triplet: x86_64-portbld-freebsd5.2
GCC target triplet: x86_64-portbld-freebsd5.2
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16684