[C++ PATCH] Fix ICE with bitfields (PR c++/69164)

[Jakub Jelinek]

Hi!

We ICE on the following testcase during SRA, because it sees a field
with DECL_SIZE of 1 which is not DECL_BIT_FIELD.  The problem is that
layout_class_type in some cases copies fields, including DECL_SIZE, but does
not copy over DECL_BIT_FIELD flag.  The following patch copies even that
and also DECL_SIZE_UNIT and DEC_BIT_FIELD_TYPE that weren't copied either.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2016-01-07  Jakub Jelinek  <ja...@redhat.com>

        PR c++/69164
        * class.c (layout_class_type): Also copy DEC_SIZE_UNIT, DECL_BIT_FIELD
        and DEC_BIT_FIELD_TYPE.

        * g++.dg/opt/pr69164.C: New test.

--- gcc/cp/class.c.jj   2016-01-04 14:55:57.000000000 +0100
+++ gcc/cp/class.c      2016-01-07 13:59:13.895677297 +0100
@@ -6493,7 +6493,10 @@ layout_class_type (tree t, tree *virtual
            DECL_FIELD_BIT_OFFSET (*next_field)
              = DECL_FIELD_BIT_OFFSET (field);
            DECL_SIZE (*next_field) = DECL_SIZE (field);
+           DECL_SIZE_UNIT (*next_field) = DECL_SIZE_UNIT (field);
            DECL_MODE (*next_field) = DECL_MODE (field);
+           DECL_BIT_FIELD (*next_field) = DECL_BIT_FIELD (field);
+           DECL_BIT_FIELD_TYPE (*next_field) = DECL_BIT_FIELD_TYPE (field);
            next_field = &DECL_CHAIN (*next_field);
          }
 
--- gcc/testsuite/g++.dg/opt/pr69164.C.jj       2016-01-07 13:56:33.013915214 
+0100
+++ gcc/testsuite/g++.dg/opt/pr69164.C  2016-01-07 13:55:57.000000000 +0100
@@ -0,0 +1,30 @@
+// PR c++/69164
+// { dg-do compile { target c++11 } }
+// { dg-options "-O2" }
+
+struct A {
+  struct B {
+    B () {}
+    bool : 1;
+  };
+  B foo () { B r; return r; }
+};
+
+struct C {
+  struct D {
+    D (C *x) : d (x->c.foo ()) {}
+    A::B d;
+  };
+  A c;
+};
+
+struct F : C {
+  D f = this;
+  F (int, int) {}
+};
+
+void
+bar (int a, int b)
+{
+  F (b, a);
+}

        Jakub