[Bug rtl-optimization/46585] [4.6 Regression] ICE: SIGSEGV in vinsn_create (sel-sched-ir.c:1189) with -fno-dce -fschedule-insns -fselective-scheduling

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

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46585

--- Comment #4 from Alexander Monakov <amonakov at gcc dot gnu.org> 2010-11-24 14:19:09 UTC ---
sel-sched doesn't expect to see nops in the function, and uses them internally
as markers in place of recently removed insns;  luckily, we can easily switch
to some other pattern, and even use an unrecognizable pattern this time
(const_int -1)

diff --git a/gcc/sel-sched-ir.c b/gcc/sel-sched-ir.c
index 71c02c4..e6e8d44 100644
--- a/gcc/sel-sched-ir.c
+++ b/gcc/sel-sched-ir.c
@@ -942,6 +942,7 @@ get_clear_regset_from_pool (void)
 void
 return_regset_to_pool (regset rs)
 {
+  gcc_assert (rs);
   regset_pool.diff--;

   if (regset_pool.n == regset_pool.s)
@@ -1175,6 +1176,9 @@ vinsn_init (vinsn_t vi, insn_t insn, bool force_unique_p)
   VINSN_COUNT (vi) = 0;
   vi->cost = -1;

+  if (INSN_NOP_P (insn))
+    return;
+
   if (DF_INSN_UID_SAFE_GET (INSN_UID (insn)) != NULL)
     init_id_from_df (VINSN_ID (vi), insn, force_unique_p);
   else
@@ -1256,9 +1260,12 @@ vinsn_delete (vinsn_t vi)
 {
   gcc_assert (VINSN_COUNT (vi) == 0);

-  return_regset_to_pool (VINSN_REG_SETS (vi));
-  return_regset_to_pool (VINSN_REG_USES (vi));
-  return_regset_to_pool (VINSN_REG_CLOBBERS (vi));
+  if (!INSN_NOP_P (VINSN_INSN_RTX (vi)))
+    {
+      return_regset_to_pool (VINSN_REG_SETS (vi));
+      return_regset_to_pool (VINSN_REG_USES (vi));
+      return_regset_to_pool (VINSN_REG_CLOBBERS (vi));
+    }

   free (vi);
 }
@@ -5606,7 +5614,7 @@ setup_nop_and_exit_insns (void)
   gcc_assert (nop_pattern == NULL_RTX
           && exit_insn == NULL_RTX);

-  nop_pattern = gen_nop ();
+  nop_pattern = gen_rtx_CONST_INT (VOIDmode, -1);

   start_sequence ();
   emit_insn (nop_pattern);