[Bug bootstrap/67761] [6 Regression] Bootstrap failure on x86

["ienkovich at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67761

Ilya Enkovich <ienkovich at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2015-09-29
           Assignee|unassigned at gcc dot gnu.org      |ienkovich at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #1 from Ilya Enkovich <ienkovich at gcc dot gnu.org> ---
The problem is in debug insns which are not ignored by introduced
transformation. It results in cost model affected by debug info and causes
these comparison failures.  I'm testing this fix:

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index 6f2380f..7b3ffb0 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -2919,6 +2919,10 @@ scalar_chain::analyze_register_chain (bitmap candidates,
df_ref ref)
   for (chain = DF_REF_CHAIN (ref); chain; chain = chain->next)
     {
       unsigned uid = DF_REF_INSN_UID (chain->ref);
+
+      if (!NONDEBUG_INSN_P (DF_REF_INSN (chain->ref)))
+       continue;
+
       if (!DF_REF_REG_MEM_P (chain->ref))
        {
          if (bitmap_bit_p (insns, uid))
@@ -3279,7 +3283,7 @@ scalar_chain::convert_reg (unsigned regno)
            bitmap_clear_bit (conv, DF_REF_INSN_UID (ref));
          }
       }
-    else
+    else if (NONDEBUG_INSN_P (DF_REF_INSN (ref)))
       {
        replace_rtx (DF_REF_INSN (ref), reg, scopy);
        df_insn_rescan (DF_REF_INSN (ref));