Fix df-core to not look for df info on notes

[Steven Bosscher <stevenb dot gcc at gmail dot com>]

Hi,

This is the bit of the fwprop patch which had to be posted separately.
It changes df-core.c to not look for DF_INSN_UID_GET on notes.  Dan
already said this should work.  Kenny, iiuc this should be applied
on the dataflow branch as well.

Bootstrapped all except Ada on x86_64-suse-linux-gnu with and without
the fwprop patch.  Without fwprop there are no new regressions.

OK for mainline?  And for the dataflow branch?

(With the fwprop patch I get two extra failures which are caused by
bugs in fwprop that were hidden with the previous df-core.c diff, see
http://gcc.gnu.org/ml/gcc-testresults/2006-05/msg00727.html.  It seems
that fwprop introduces a new JUMP_INSN that sets nothing but (pc), and
somehow that insn isn't getting DF info attached to it.  Working on it,
but it's irrelevant for this df-core.c patch...)

Gr.
Steven

	* df-core.c (df_bb_regno_last_use_find): Do not look for dataflow
	information attached to non-INSNs such as NOTEs.
	(df_bb_regno_first_def_find, df_bb_regno_last_def_find): Likewise.

Index: df-core.c
===================================================================
--- df-core.c	(revision 113736)
+++ df-core.c	(working copy)
@@ -915,10 +915,14 @@ df_bb_regno_last_use_find (struct df *df
 {
   rtx insn;
   struct df_ref *use;
+  unsigned int uid;
 
   FOR_BB_INSNS_REVERSE (bb, insn)
     {
-      unsigned int uid = INSN_UID (insn);
+      if (!INSN_P (insn))
+	continue;
+
+      uid = INSN_UID (insn);
       for (use = DF_INSN_UID_GET (df, uid)->uses; use; use = use->next_ref)
 	if (DF_REF_REGNO (use) == regno)
 	  return use;
@@ -934,10 +938,14 @@ df_bb_regno_first_def_find (struct df *d
 {
   rtx insn;
   struct df_ref *def;
+  unsigned int uid;
 
   FOR_BB_INSNS (bb, insn)
     {
-      unsigned int uid = INSN_UID (insn);
+      if (!INSN_P (insn))
+	continue;
+
+      uid = INSN_UID (insn);
       for (def = DF_INSN_UID_GET (df, uid)->defs; def; def = def->next_ref)
 	if (DF_REF_REGNO (def) == regno)
 	  return def;
@@ -953,11 +961,14 @@ df_bb_regno_last_def_find (struct df *df
 {
   rtx insn;
   struct df_ref *def;
+  unsigned int uid;
 
   FOR_BB_INSNS_REVERSE (bb, insn)
     {
-      unsigned int uid = INSN_UID (insn);
+      if (!INSN_P (insn))
+	continue;
 
+      uid = INSN_UID (insn);
       for (def = DF_INSN_UID_GET (df, uid)->defs; def; def = def->next_ref)
 	if (DF_REF_REGNO (def) == regno)
 	  return def;