re PR rtl-optimization/13400 (Compiled code crashes storing to read-only location)

	PR middle-end/13400
	* ifcvt.c (noce_process_if_block): Disable unconditional write
	optimizations if we could introduce a store to trapping memory
	that wasn't present previously.

	* gcc.c-torture/execute/20031215-1.c: New test case.

From-SVN: r74663

1 files changed, 38 insertions, 0 deletions

diff --git a/gcc/testsuite/gcc.c-torture/execute/20031215-1.c b/gcc/testsuite/gcc.c-torture/execute/20031215-1.c
new file mode 100644
index 0000000..d62177b
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/20031215-1.c
@@ -0,0 +1,38 @@
+/* PR middle-end/13400 */
+/* The following test used to fail at run-time with a write to read-only
+   memory, caused by if-conversion converting a conditional write into an
+   unconditional write.  */
+
+typedef struct {int c, l; char ch[3];} pstr;
+const pstr ao = {2, 2, "OK"};
+const pstr * const a = &ao;
+
+void test1(void)
+{
+    if (a->ch[a->l]) {
+        ((char *)a->ch)[a->l] = 0;
+    }
+}
+
+void test2(void)
+{
+    if (a->ch[a->l]) {
+        ((char *)a->ch)[a->l] = -1;
+    }
+}
+
+void test3(void)
+{
+    if (a->ch[a->l]) {
+        ((char *)a->ch)[a->l] = 1;
+    }
+}
+
+int main(void)
+{
+    test1();
+    test2();
+    test3();
+    return 0;
+}
+