From 158cdc7bd97d7ccca5bc8adaaf80fe51eacdc038 Mon Sep 17 00:00:00 2001
From: Martin Sebor <msebor@redhat.com>
Date: Tue, 4 May 2021 13:46:37 -0600
Subject: [PATCH] PR middle-end/100307 - spurious -Wplacement-new with negative
pointer offset
gcc/ChangeLog:
PR middle-end/100307
* builtins.c (compute_objsize_r): Clear base0 for pointers.
gcc/testsuite/ChangeLog:
PR middle-end/100307
* g++.dg/warn/Wplacement-new-size-9.C: New test.
* gcc.dg/tree-ssa/builtin-sprintf-warn-26.c: New test.
---
gcc/builtins.c | 4 +-
.../g++.dg/warn/Wplacement-new-size-9.C | 39 +++++++++++++++++++
.../gcc.dg/tree-ssa/builtin-sprintf-warn-26.c | 38 ++++++++++++++++++
3 files changed, 80 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/g++.dg/warn/Wplacement-new-size-9.C
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/builtin-sprintf-warn-26.c
diff --git a/gcc/builtins.c b/gcc/builtins.c
index 0db4090c434e..6f67eb7eeb55 100644
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -5447,8 +5447,10 @@ compute_objsize_r (tree ptr, int ostype, access_ref *pref,
if (!addr && POINTER_TYPE_P (TREE_TYPE (ptr)))
{
/* Set the maximum size if the reference is to the pointer
- itself (as opposed to what it points to). */
+ itself (as opposed to what it points to), and clear
+ BASE0 since the offset isn't necessarily zero-based. */
pref->set_max_size_range ();
+ pref->base0 = false;
return true;
}
diff --git a/gcc/testsuite/g++.dg/warn/Wplacement-new-size-9.C b/gcc/testsuite/g++.dg/warn/Wplacement-new-size-9.C
new file mode 100644
index 000000000000..a6b5870be645
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/Wplacement-new-size-9.C
@@ -0,0 +1,39 @@
+/* PR middle-end/100307 - spurious -Wplacement-new with negative pointer
+ offset
+ { dg-do compile }
+ { dg-options "-O0 -Wall" } */
+
+void* operator new (__SIZE_TYPE__, void *p) { return p; }
+void* operator new[] (__SIZE_TYPE__, void *p) { return p; }
+
+static char a[2];
+
+void* nowarn_scalar ()
+{
+ char* p = a + 1;
+ char *q = new (p - 1) char (); // { dg-bogus "-Wplacement-new" }
+ return q;
+}
+
+
+void* nowarn_array ()
+{
+ char* p = a + 1;
+ char *q = new (p - 1) char[2]; // { dg-bogus "-Wplacement-new" }
+ return q;
+}
+
+void* warn_scalar ()
+{
+ char* p = a + 1;
+ char *q = new (p - 2) char (); // { dg-warning "-Wplacement-new" "pr100325" { xfail *-*-* } }
+ return q;
+}
+
+
+void* warn_array ()
+{
+ char* p = a + 1;
+ char *q = new (p - 1) char[2]; // { dg-warning "-Wplacement-new" "pr100325" { xfail *-*-* } }
+ return q;
+}
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/builtin-sprintf-warn-26.c b/gcc/testsuite/gcc.dg/tree-ssa/builtin-sprintf-warn-26.c
new file mode 100644
index 000000000000..16a551d9c8da
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/builtin-sprintf-warn-26.c
@@ -0,0 +1,38 @@
+/* PR middle-end/100307 - spurious -Wplacement-new with negative pointer
+ offset
+ { dg-do compile }
+ { dg-options "-O0 -Wall" } */
+
+extern int sprintf (char*, const char*, ...);
+
+char a[4];
+
+void nowarn_1m1 ()
+{
+ char *p = a + 1;
+ sprintf (p - 1, "%i", 123); // { dg-bogus "-Wformat-overflow" }
+}
+
+void nowarn_4m3 ()
+{
+ char *p = a + 4;
+ sprintf (p - 3, "%i", 12); // { dg-bogus "-Wformat-overflow" }
+}
+
+void warn_2m1 ()
+{
+ char *p = a + 2;
+ sprintf (p - 1, "%i", 123); // { dg-warning "-Wformat-overflow" "pr100325" { xfail *-*-* } }
+}
+
+void warn_3m1 ()
+{
+ char *p = a + 3;
+ sprintf (p - 1, "%i", 12); // { dg-warning "-Wformat-overflow" "pr100325" { xfail *-*-* } }
+}
+
+void warn_4m1 ()
+{
+ char *p = a + 4;
+ sprintf (p - 1, "%i", 1); // { dg-warning "-Wformat-overflow" "pr100325" { xfail *-*-* } }
+}
--
GitLab