> On Fri, Mar 29, 2013 at 1:05 PM, Steven Bosscher wrote:
>> It looks like there are places in the middle end that use remove_insn
>> on insns that are not actually emitted. This breaks the assert I added
>> in df_insn_delete. The patch disables the assert for now. The comment
>> before the assert is now even messier than before but I think it's
>> better to explain why the assert cannot work than to remove the
>> comment and the assert altogether.
This is no longer necessary, now that remove_insn doesn't use
df_insn_delete. Only a small patch to lower-subreg.c is needed to
restore the check.
Bootstrapped&tested (unix{,-m32}) on powerpc64-unknown-linux-gnu.
OK for trunk?
Ciao!
Steven
* lower-subreg.c (resolve_simple_move): If called self-recursive,
do not delete_insn insns that have not yet been emitted, only
unlink them with remove_insn.
* df-scan.c (df_insn_delete): Revert r197492.
Index: lower-subreg.c
===================================================================
--- lower-subreg.c (revision 198002)
+++ lower-subreg.c (working copy)
@@ -1069,7 +1069,13 @@ resolve_simple_move (rtx set, rtx insn)
emit_insn_before (insns, insn);
- delete_insn (insn);
+ /* If we get here via self-recursion, then INSN is not yet in the insns
+ chain and delete_insn will fail. We only want to remove INSN from the
+ current sequence. See PR56738. */
+ if (in_sequence_p ())
+ remove_insn (insn);
+ else
+ delete_insn (insn);
return insns;
}
Index: df-scan.c
===================================================================
--- df-scan.c (revision 198002)
+++ df-scan.c (working copy)
@@ -1158,17 +1158,7 @@ df_insn_delete (rtx insn)
In any case, we expect BB to be non-NULL at least up to register
allocation, so disallow a non-NULL BB up to there. Not perfect
but better than nothing... */
- /* ??? bb can also be NULL if lower-subreg.c:resolve_simple_mov emits
- an insn into a sequence and then does delete_insn on it. Not sure
- if that makes sense, but for now it means this assert cannot work.
- See PR56738.
- Disable for now but revisit before the end of GCC 4.9 stage1. */
-#if 0
gcc_checking_assert (bb != NULL || reload_completed);
-#else
- if (bb == NULL)
- return;
-#endif
df_grow_bb_info (df_scan);
df_grow_reg_info ();
