[debug-early] rearrange some checks in gen_subprogram_die

[Aldy Hernandez]

I'm rearranging some code in Michael's original patch to minimize the 
difference with mainline.

It seems that the check for DECL_STRUCT_FUNCTION (decl)->gimple_df, was 
merely a check to see if we had already set the FDE bits for the decl in 
question.  I've moved the check inside the original DECL_EXTERNAL check, 
thus making it obvious what is being accomplished.

I also got rid of mainline's gcc_checking_assert of fun.  We're 
dereferencing it immediately after.  That should be enough to trigger an 
ICE.

Also I removed Michael's check for DECL_STRUCT_FUNCTION(decl), since 
mainline drops into this codepath regardless, and has/had that 
gcc_checking_assert anyhow.

No regressions.

Committed to branch.

Aldy
commit a23ae1821d5c45b2c56ea5db6940ea8982f8fd69
Author: Aldy Hernandez <al...@redhat.com>
Date:   Mon Sep 29 11:48:41 2014 -0700

        * dwarf2out.c (gen_subprogram_die): Do not check
        DECL_STRUCT_FUNCTION, thus leaving the check as mainline.  Test
        for fun>-fde instead of fun->gimple_df.

diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c
index 41c4feb..c92101f 100644
--- a/gcc/dwarf2out.c
+++ b/gcc/dwarf2out.c
@@ -18441,9 +18441,7 @@ gen_subprogram_die (tree decl, dw_die_ref context_die)
 
       equate_decl_number_to_die (decl, subr_die);
     }
-  else if (!DECL_EXTERNAL (decl)
-          && (!DECL_STRUCT_FUNCTION (decl)
-              || DECL_STRUCT_FUNCTION (decl)->gimple_df))
+  else if (!DECL_EXTERNAL (decl))
     {
       HOST_WIDE_INT cfa_fb_offset;
 
@@ -18452,7 +18450,9 @@ gen_subprogram_die (tree decl, dw_die_ref context_die)
       if (!old_die || !get_AT (old_die, DW_AT_inline))
        equate_decl_number_to_die (decl, subr_die);
 
-      gcc_checking_assert (fun);
+      if (!fun->fde)
+       goto no_fde_continue;
+
       if (!flag_reorder_blocks_and_partition)
        {
          dw_fde_ref fde = fun->fde;
@@ -18608,11 +18608,8 @@ gen_subprogram_die (tree decl, dw_die_ref context_die)
       if (fun->static_chain_decl)
        add_AT_location_description (subr_die, DW_AT_static_link,
                 loc_list_from_tree (fun->static_chain_decl, 2));
-    }
-  else if (!DECL_EXTERNAL (decl))
-    {
-      if (!old_die || !get_AT (old_die, DW_AT_inline))
-       equate_decl_number_to_die (decl, subr_die);
+    no_fde_continue:
+      ;
     }
 
   /* Generate child dies for template paramaters.  */