1 files changed, 39 insertions, 0 deletions
diff --git a/SingleSource/Regression/C/gcc-c-torture/execute/pr78170.c b/SingleSource/Regression/C/gcc-c-torture/execute/pr78170.c
new file mode 100644
index 00000000..dce8a3ee
--- /dev/null
+++ b/SingleSource/Regression/C/gcc-c-torture/execute/pr78170.c
@@ -0,0 +1,39 @@
+/* { dg-require-effective-target int32plus } */
+
+/* PR tree-optimization/78170.
+   Check that sign-extended store to a bitfield
+   doesn't overwrite other fields.  */
+
+int a, b, d;
+
+struct S0
+{
+  int f0;
+  int f1;
+  int f2;
+  int f3;
+  int f4;
+  int f5:15;
+  int f6:17;
+  int f7:2;
+  int f8:30;
+} c;
+
+void fn1 ()
+{
+  d = b = 1;
+  for (; b; b = a)
+    {
+      struct S0 e = { 0, 0, 0, 0, 0, 0, 1, 0, 1 };
+      c = e;
+      c.f6 = -1;
+    }
+}
+
+int main ()
+{
+  fn1 ();
+  if (c.f7 != 0)
+    __builtin_abort ();
+  return 0;
+}