re PR rtl-optimization/6189 (Regression from 3.0.x: g++ -O3 generates wrong code)

PR optimization/6189
        * semantics.c (genrtl_start_function): Don't free
        DECL_SAVED_FUNCTION_DATA for inline functions.

[[Split portion of a mixed commit.]]

From-SVN: r52083.2

gcc/testsuite/g++.dg/opt/nrv3.C

@@ -0,0 +1,24 @@
+// PR optimization/6189
+// Bug: we forgot about foo's nrv after writing it out.
+// { dg-options -O3 }
+// { dg-do run }
+
+struct A
+{
+  int i;
+};
+
+
+A foo ()
+{
+  A a;
+  a.i = 42;
+  return a;
+}
+
+
+int main()
+{
+  A b = foo();
+  return b.i != 42;
+}