[lra] patch to fix an arm testsuite degradation

[Vladimir Makarov]

The following patch fixes a degradation of 20060102-1.c  on ARM.  Not 
updating REG notes resulted in removing an insn after LRA as it was 
wrongly considered dead.

The patch was successfully bootstrapped on x86/x86-64.
Committed as rev. 182664.

2011-12-23  Vladimir Makarov <vmaka...@redhat.com>

        * lra.c (update_auto_inc_notes): Rename to update_reg_notes.  Make
        it unconditional.  Remove REG_DEAD and REG_UNUSED too.  Make call
        of add_auto_inc_notes conditional.

Index: lra.c
===================================================================
--- lra.c       (revision 182663)
+++ lra.c       (working copy)
@@ -2032,10 +2032,14 @@ add_auto_inc_notes (rtx insn, rtx x)
     }
 }
 
-/* DF infrastructure does not deal with REG_INC notes -- so update
-   them here.  */
+#endif
+
+/* Remove all REG_DEAD and REG_UNUSED notes and regenerate REG_INC.
+   We change pseudos by hard registers without notification of DF and
+   that can make the notes obsolete.  DF-infrastructure does not deal
+   with REG_INC notes -- so we should regenerate them here.  */
 static void
-update_auto_inc_notes (void)
+update_reg_notes (void)
 {
   rtx *pnote;
   basic_block bb;
@@ -2048,17 +2052,19 @@ update_auto_inc_notes (void)
        pnote = &REG_NOTES (insn);
        while (*pnote != 0)
          {
-           if (REG_NOTE_KIND (*pnote) == REG_INC)
+           if (REG_NOTE_KIND (*pnote) == REG_DEAD
+               || REG_NOTE_KIND (*pnote) == REG_UNUSED
+               || REG_NOTE_KIND (*pnote) == REG_INC)
              *pnote = XEXP (*pnote, 1);
            else
              pnote = &XEXP (*pnote, 1);
          }
+#ifdef AUTO_INC_DEC
        add_auto_inc_notes (insn, PATTERN (insn));
+#endif
       }
 }
 
-#endif
-
 /* Set to 1 while in lra.  */
 int lra_in_progress;
 
@@ -2204,9 +2210,7 @@ lra (FILE *f)
   regstat_free_n_sets_and_refs ();
   regstat_free_ri ();
   reload_completed = 1;
-#ifdef AUTO_INC_DEC
-  update_auto_inc_notes ();
-#endif
+  update_reg_notes ();
   finish_subregs_of_mode ();
 
   inserted_p = fixup_abnormal_edges ();