PR tree-optimization/91457 - inconsistent warning for writing past the end of an array member

gcc/ChangeLog:

	PR tree-optimization/91457
	* builtins.c (component_size): New function.
	(compute_objsize): Add argument. Handle ARRAY_REF and COMPONENT_REF.
	* builtins.h (compute_objsize): Add argument.
	* tree-ssa-strlen.c (handle_store): Handle no-warning bit.
	* tree-vrp.c (vrp_prop::check_array_ref): Return warning result.
	(vrp_prop::check_mem_ref): Same.
	(vrp_prop::search_for_addr_array): Set no-warning bit.
	(check_array_bounds): Same.

gcc/testsuite/ChangeLog:

	PR tree-optimization/91457
	* c-c++-common/Wstringop-overflow-2.c: New test.
	* g++.dg/warn/Warray-bounds-8.C: New test.
	* g++.dg/warn/Wstringop-overflow-3.C: New test.
	* gcc.dg/Wstringop-overflow-15.c: New test.

From-SVN: r274997

1 files changed, 62 insertions, 0 deletions

diff --git a/gcc/testsuite/gcc.dg/Wstringop-overflow-15.c b/gcc/testsuite/gcc.dg/Wstringop-overflow-15.c
new file mode 100644
index 0000000..12f8f9d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/Wstringop-overflow-15.c
@@ -0,0 +1,62 @@
+/* PR middle-end/91458 - inconsistent warning for writing past the end
+   of an array member
+   Verify that the -Wstringop-overflow detection doesn't cause an ICE
+   for either kind of VLAs (member and non-member).
+   Diagnosing the accesses is the subject of pr82608.
+   { dg-do compile }
+   { dg-options "-O2 -Wall -Wno-array-bounds" } */
+
+void sink (void*);
+
+void vla_unbounded (int n)
+{
+  char a[n];
+
+  a[0] = 0;
+  a[1] = 1;
+  a[n] = n;         // { dg-warning "\\\[-Wstringop-overflow" "pr82608" { xfail *-*-* } }
+
+  sink (&a);
+}
+
+void vla_bounded (int n)
+{
+  if (n > 32)
+    n = 32;
+
+  char a[n];
+
+  a[0] = 0;
+  a[1] = 1;
+  a[n] = n;         // { dg-warning "\\\[-Wstringop-overflow" "pr82608" { xfail *-*-* } }
+  a[69] = n;        // { dg-warning "\\\[-Wstringop-overflow" "pr82608" { xfail *-*-* } }
+
+  sink (&a);
+}
+
+
+void member_vla_unbounded (int n)
+{
+  struct S { char i, a[n]; } s;
+
+  s.a[0] = 0;
+  s.a[1] = 1;
+  s.a[n] = n;       // { dg-warning "\\\[-Wstringop-overflow" "pr82608" { xfail *-*-* } }
+
+  sink (&s);
+}
+
+void member_vla_bounded (int n)
+{
+  if (n > 32)
+    n = 32;
+
+  struct S { char i, a[n]; } s;
+
+  s.a[0] = 0;
+  s.a[1] = 1;
+  s.a[n] = n;       // { dg-warning "\\\[-Wstringop-overflow" "pr82608" { xfail *-*-* } }
+  s.a[69] = n;      // { dg-warning "\\\[-Wstringop-overflow" "pr82608" { xfail *-*-* } }
+
+  sink (&s);
+}