[gcc r12-756] Add test for PR middle-end/100571.

[gcc r12-756] Add test for PR middle-end/100571.

[Martin Sebor]

https://gcc.gnu.org/g:db514f98a383b2ebdcfe74feb80f98f406cec174

commit r12-756-gdb514f98a383b2ebdcfe74feb80f98f406cec174
Author: Martin Sebor <msebor@redhat.com>
Date:   Wed May 12 15:57:34 2021 -0600

    Add test for PR middle-end/100571.
    
    gcc/testsuite:
            PR middle-end/100571
            * gcc.dg/Wstringop-overflow-67.c: New test.

Diff:
---
 gcc/testsuite/gcc.dg/Wstringop-overflow-67.c | 92 ++++++++++++++++++++++++++++
 1 file changed, 92 insertions(+)

diff --git a/gcc/testsuite/gcc.dg/Wstringop-overflow-67.c b/gcc/testsuite/gcc.dg/Wstringop-overflow-67.c
new file mode 100644
index 00000000000..7b8f3f014c6
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/Wstringop-overflow-67.c
@@ -0,0 +1,92 @@
+/* PR middle-end/100571 - bogus -Wstringop-overflow with VLA of elements
+   larger than byte
+   { dg-do compile }
+   { dg-options "-O2 -Wall" } */
+
+__attribute__ ((access (read_only, 1, 2))) void fro (int *, int);
+__attribute__ ((access (write_only, 1, 2))) void fwo (int *, int);
+__attribute__ ((access (read_write, 1, 2))) void frw (int *, int);
+
+extern __SIZE_TYPE__ n;
+
+void alloca_ro (void)
+{
+  int *a = __builtin_alloca (n * sizeof *a);
+  a[0] = 0;
+  fro (a, n);
+}
+
+void alloca_wo (void)
+{
+  int *a = __builtin_alloca (n * sizeof *a);
+  fwo (a, n);
+}
+
+void alloca_rw (void)
+{
+  int *a = __builtin_alloca (n * sizeof *a);
+  a[0] = 0;
+  frw (a, n);
+}
+
+
+void calloc_ro (void)
+{
+  int *a = __builtin_calloc (n, sizeof *a);
+  fro (a, n);
+}
+
+void calloc_wo (void)
+{
+  int *a = __builtin_calloc (n, sizeof *a);
+  fwo (a, n);
+}
+
+void calloc_rw (void)
+{
+  int *a = __builtin_calloc (n, sizeof *a);
+  a[0] = 0;
+  frw (a, n);
+}
+
+
+void malloc_ro (void)
+{
+  int *a = __builtin_malloc (n * sizeof *a);
+  a[0] = 0;
+  fro (a, n);
+}
+
+void malloc_wo (void)
+{
+  int *a = __builtin_malloc (n * sizeof *a);
+  fwo (a, n);
+}
+
+void malloc_rw (void)
+{
+  int *a = __builtin_malloc (n * sizeof *a);
+  a[0] = 0;
+  frw (a, n);
+}
+
+
+void vla_ro (void)
+{
+  int a[n];
+  a[0] = 0;
+  fro (a, n);
+}
+
+void vla_wo (void)
+{
+  int a[n];
+  fwo (a, n);
+}
+
+void vla_rw (void)
+{
+  int a[n];
+  a[0] = 0;
+  frw (a, n);
+}