public inbox for gcc-cvs@sourceware.org
help / color / mirror / Atom feed
* [gcc r13-3287] Fix bogus -Wstringop-overflow warning
@ 2022-10-13 23:02 Eric Botcazou
0 siblings, 0 replies; only message in thread
From: Eric Botcazou @ 2022-10-13 23:02 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:c26d335fffc689051ee5826455c9d54d1fcf1816
commit r13-3287-gc26d335fffc689051ee5826455c9d54d1fcf1816
Author: Eric Botcazou <ebotcazou@adacore.com>
Date: Fri Oct 14 00:55:40 2022 +0200
Fix bogus -Wstringop-overflow warning
If you compile the testcase with -O2 -fno-inline -Wall, you get:
In function 'process_array3':
cc1: warning: 'process_array4' accessing 4 bytes in a region of size 3 [-
Wstringop-overflow=]
cc1: note: referencing argument 1 of type 'char[4]'
t.c:6:6: note: in a call to function 'process_array4'
6 | void process_array4 (char a[4], int n)
| ^~~~~~~~~~~~~~
cc1: warning: 'process_array4' accessing 4 bytes in a region of size 3 [-
Wstringop-overflow=]
cc1: note: referencing argument 1 of type 'char[4]'
t.c:6:6: note: in a call to function 'process_array4'
That's because the ICF IPA pass has identified the two functions and turned
process_array3 into a wrapper of process_array4.
gcc/
* gimple-ssa-warn-access.cc (pass_waccess::check_call): Return
early for calls made from thunks.
gcc/testsuite/
* gcc.dg/Wstringop-overflow-89.c: New test.
Diff:
---
gcc/gimple-ssa-warn-access.cc | 8 ++++++--
gcc/testsuite/gcc.dg/Wstringop-overflow-89.c | 16 ++++++++++++++++
2 files changed, 22 insertions(+), 2 deletions(-)
diff --git a/gcc/gimple-ssa-warn-access.cc b/gcc/gimple-ssa-warn-access.cc
index 04aa849a4b1..59a70530600 100644
--- a/gcc/gimple-ssa-warn-access.cc
+++ b/gcc/gimple-ssa-warn-access.cc
@@ -4291,14 +4291,18 @@ pass_waccess::check_pointer_uses (gimple *stmt, tree ptr,
void
pass_waccess::check_call (gcall *stmt)
{
- if (gimple_call_builtin_p (stmt, BUILT_IN_NORMAL))
- check_builtin (stmt);
+ /* Skip special calls generated by the compiler. */
+ if (gimple_call_from_thunk_p (stmt))
+ return;
/* .ASAN_MARK doesn't access any vars, only modifies shadow memory. */
if (gimple_call_internal_p (stmt)
&& gimple_call_internal_fn (stmt) == IFN_ASAN_MARK)
return;
+ if (gimple_call_builtin_p (stmt, BUILT_IN_NORMAL))
+ check_builtin (stmt);
+
if (!m_early_checks_p)
if (tree callee = gimple_call_fndecl (stmt))
{
diff --git a/gcc/testsuite/gcc.dg/Wstringop-overflow-89.c b/gcc/testsuite/gcc.dg/Wstringop-overflow-89.c
new file mode 100644
index 00000000000..ba25a9386a7
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/Wstringop-overflow-89.c
@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fno-inline -Wall" } */
+
+extern void process (char);
+
+void process_array4 (char a[4], int n)
+{
+ for (int i = 0; i < n; i++)
+ process (a[i]);
+}
+
+void process_array3 (char a[3], int n)
+{
+ for (int i = 0; i < n; i++)
+ process (a[i]);
+}
^ permalink raw reply [flat|nested] only message in thread
only message in thread, other threads:[~2022-10-13 23:02 UTC | newest]
Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-10-13 23:02 [gcc r13-3287] Fix bogus -Wstringop-overflow warning Eric Botcazou
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).