[PATCH] Allow relayout_decl on FIELD_DECLs (PR c/72816)

[Jakub Jelinek]

Hi!

As the testcase shows, the C FE can call relayout_decl even on FIELD_DECLs
in certain cases.  Trying to call only layout_decl on FIELD_DECL and
relayout_decl on other decls would be insufficient, we'd need to repeat
there most of the relayout_decl code (except for SET_DECL_RTL, which
FIELD_DECLs don't have).

So I think it is better to allow relayout_decl also on FIELD_DECLs.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2016-08-06  Jakub Jelinek  <ja...@redhat.com>

        PR c/72816
        * stor-layout.c (layout_decl): Fix up formatting.
        (relayout_decl): Allow DECL to be FIELD_DECL.

        * gcc.dg/pr72816.c: New test.

--- gcc/stor-layout.c.jj        2016-08-06 12:11:56.000000000 +0200
+++ gcc/stor-layout.c   2016-08-06 13:04:43.662532852 +0200
@@ -596,7 +596,7 @@ layout_decl (tree decl, unsigned int kno
     return;
 
   gcc_assert (code == VAR_DECL || code == PARM_DECL || code == RESULT_DECL
-             || code == TYPE_DECL ||code == FIELD_DECL);
+             || code == TYPE_DECL || code == FIELD_DECL);
 
   rtl = DECL_RTL_IF_SET (decl);
 
@@ -768,8 +768,8 @@ layout_decl (tree decl, unsigned int kno
     }
 }
 
-/* Given a VAR_DECL, PARM_DECL or RESULT_DECL, clears the results of
-   a previous call to layout_decl and calls it again.  */
+/* Given a VAR_DECL, PARM_DECL, RESULT_DECL, or FIELD_DECL, clears the
+   results of a previous call to layout_decl and calls it again.  */
 
 void
 relayout_decl (tree decl)
@@ -778,7 +778,8 @@ relayout_decl (tree decl)
   DECL_MODE (decl) = VOIDmode;
   if (!DECL_USER_ALIGN (decl))
     SET_DECL_ALIGN (decl, 0);
-  SET_DECL_RTL (decl, 0);
+  if (DECL_RTL_SET_P (decl))
+    SET_DECL_RTL (decl, 0);
 
   layout_decl (decl, 0);
 }
--- gcc/testsuite/gcc.dg/pr72816.c.jj   2016-08-06 13:06:45.046003282 +0200
+++ gcc/testsuite/gcc.dg/pr72816.c      2016-08-06 13:07:57.217093845 +0200
@@ -0,0 +1,9 @@
+/* PR c/72816 */
+/* { dg-do compile } */
+/* { dg-options "-std=gnu11" } */
+
+typedef const int A[];
+struct S {
+  int a;
+  A b; /* { dg-error "array size missing" } */
+};

        Jakub