[Bug c/20318] RFE: add attribute to specify that a function never returns NULL
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20318 Marc Glisse glisse at gcc dot gnu.org changed: What|Removed |Added Status|NEW |RESOLVED CC||glisse at gcc dot gnu.org Resolution|--- |FIXED --- Comment #11 from Marc Glisse glisse at gcc dot gnu.org --- Marking svn_fs_fs__id_parse and svn_error_create with the new __attribute__((__returns_nonnull__)) makes the warning about root_id disappear at -O3, so I am going to mark this bug as fixed, please reopen if necessary.
[Bug c/20318] RFE: add attribute to specify that a function never returns NULL
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20318
--- Comment #10 from Marc Glisse glisse at gcc dot gnu.org ---
Author: glisse
Date: Wed Oct 9 13:03:13 2013
New Revision: 203316
URL: http://gcc.gnu.org/viewcvs?rev=203316root=gccview=rev
Log:
2013-10-09 Marc Glisse marc.gli...@inria.fr
PR tree-optimization/20318
gcc/c-family/
* c-common.c (handle_returns_nonnull_attribute): New function.
(c_common_attribute_table): Add returns_nonnull.
gcc/
* doc/extend.texi (returns_nonnull): New function attribute.
* fold-const.c (tree_expr_nonzero_warnv_p): Look for returns_nonnull
attribute.
* tree-vrp.c (gimple_stmt_nonzero_warnv_p): Likewise.
(stmt_interesting_for_vrp): Accept all GIMPLE_CALL.
gcc/testsuite/
* c-c++-common/pr20318.c: New file.
* gcc.dg/tree-ssa/pr20318.c: New file.
Added:
trunk/gcc/testsuite/c-c++-common/pr20318.c (with props)
trunk/gcc/testsuite/gcc.dg/tree-ssa/pr20318.c (with props)
Modified:
trunk/gcc/ChangeLog
trunk/gcc/c-family/ChangeLog
trunk/gcc/c-family/c-common.c
trunk/gcc/doc/extend.texi
trunk/gcc/fold-const.c
trunk/gcc/testsuite/ChangeLog
trunk/gcc/tree-vrp.c
Propchange: trunk/gcc/testsuite/c-c++-common/pr20318.c
('svn:eol-style' added)
Propchange: trunk/gcc/testsuite/c-c++-common/pr20318.c
('svn:keywords' added)
Propchange: trunk/gcc/testsuite/gcc.dg/tree-ssa/pr20318.c
('svn:eol-style' added)
Propchange: trunk/gcc/testsuite/gcc.dg/tree-ssa/pr20318.c
('svn:keywords' added)
[Bug c/20318] RFE: add attribute to specify that a function never returns NULL
--- Comment #9 from pinskia at gcc dot gnu dot org 2006-01-09 18:34 --- No longer working on this, I am too busy working on the gfortran front-end. -- pinskia at gcc dot gnu dot org changed: What|Removed |Added AssignedTo|pinskia at gcc dot gnu dot |unassigned at gcc dot gnu |org |dot org Status|ASSIGNED|NEW http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20318
[Bug c/20318] RFE: add attribute to specify that a function never returns NULL
--- Comment #8 from pinskia at gcc dot gnu dot org 2005-11-12 19:26 --- I have a patch already. -- pinskia at gcc dot gnu dot org changed: What|Removed |Added AssignedTo|dnovillo at gcc dot gnu dot |pinskia at gcc dot gnu dot |org |org Status|NEW |ASSIGNED http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20318
[Bug c/20318] RFE: add attribute to specify that a function never returns NULL
--- Comment #7 from green at redhat dot com 2005-11-11 23:29 --- This feature would also be useful for java, as we can eliminate certain inlined null pointer checks when we know that a method can't return null. See http://gcc.gnu.org/ml/java/2005-11/msg00124.html -- green at redhat dot com changed: What|Removed |Added CC||green at redhat dot com http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20318
[Bug c/20318] RFE: add attribute to specify that a function never returns NULL
--- Additional Comments From pinskia at gcc dot gnu dot org 2005-06-03
14:20 ---
Here is a reduced testcase for the SVN code:
void *g();
static void *count_and_verify_instructions(int *ninst,const unsigned char *p)
{
if (p == ((void *)0))
return g();
*ninst = 0;
return 0;
}
void f(int);
void *decode_window(const unsigned char *data)
{
int ninst;
void *svn_err__temp = count_and_verify_instructions(ninst, data);
if (svn_err__temp)
return svn_err__temp;
f (ninst);
return 0;
}
- cut -
g returns only non null values.
This reduced testcase comes from PR 21320 which comes from OLH.
--
What|Removed |Added
Last reconfirmed|2005-03-04 15:38:22 |2005-06-03 14:20:19
date||
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20318
[Bug c/20318] RFE: add attribute to specify that a function never returns NULL
--- Additional Comments From pinskia at gcc dot gnu dot org 2005-03-04 15:38 --- Confirmed, PR 19476 is case which depends on this. -- What|Removed |Added CC||pinskia at gcc dot gnu dot ||org OtherBugsDependingO||19476 nThis|| Status|UNCONFIRMED |NEW Ever Confirmed||1 Keywords||diagnostic, missed- ||optimization Last reconfirmed|-00-00 00:00:00 |2005-03-04 15:38:22 date|| http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20318
[Bug c/20318] RFE: add attribute to specify that a function never returns NULL
--- Additional Comments From giovannibajo at libero dot it 2005-03-04 17:53 --- I don't object that this feature is indeed needed, but I would still like to see a reduced testcase from Subversion which shows a bogus warning that could be fixed with this attribute. BTW, Diego, once ASSERT_EXPR becomes a generic node, can't just the C++ FE uses it to assert that the return value for a CALL_EXPR to an allocation function is non-zero? -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20318
[Bug c/20318] RFE: add attribute to specify that a function never returns NULL
--- Additional Comments From dnovillo at redhat dot com 2005-03-04 17:59 --- Subject: Re: RFE: add attribute to specify that a function never returns NULL giovannibajo at libero dot it wrote: --- Additional Comments From giovannibajo at libero dot it 2005-03-04 17:53 --- I don't object that this feature is indeed needed, but I would still like to see a reduced testcase from Subversion which shows a bogus warning that could be fixed with this attribute. I have attached the pre-processed test case from Joe. BTW, Diego, once ASSERT_EXPR becomes a generic node, can't just the C++ FE uses it to assert that the return value for a CALL_EXPR to an allocation function is non-zero? The attribute would be enough. The FE need only set an ECF_ flag to the CALL_EXPR and the optimizers will pick it up from there. Diego. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20318
