Ajit Agarwal <aagar...@linux.ibm.com> writes:
> On 19/06/24 2:40 pm, Richard Sandiford wrote:
>> Ajit Agarwal <aagar...@linux.ibm.com> writes:
>>> Hello Richard:
>>>
>>> On 19/06/24 1:54 pm, Richard Sandiford wrote:
>>>> Ajit Agarwal <aagar...@linux.ibm.com> writes:
>>>>>> What happens if you leave the assert alone? When does it fire? Is it
>>>>>> still for uses in debug insns? If so, it's the fusion pass's
>>>>>> responsibility
>>>>>> to update those, as mentioned above. And it must update them before,
>>>>>> or at the same time as, it deletes the definition.
>>>>>>
>>>>>
>>>>> For debug insn I call reset_debug_use and now I dont see issues
>>>>> with debug insn and issues I see with non debug insn where
>>>>> def is there in old_defs and use has to be removed for the insn
>>>>> that we modify load with OO UNSPEC to generate lxvp.
>>>>
>>>> Can you walk me through it step-by-step? If you leave the assert
>>>> alone, when does it fire? What set of insn_changes are being made
>>>> when the assert fires? (Calling debug on the changes will show this.)
>>>> And what use does the assert fire on? (Again, calling debug on the use
>>>> will show this.)
>>>>
>>>
>>> (insn 660 735 739 50 (set (reg:OO 405 [ MEM[(_Float128 *)src_196] ])
>>> (unspec:OO [
>>> (mem:OO (reg/v/f:DI 197 [ base ]) [9 MEM[(_Float128
>>> *)src_196]+0 S16 A128])
>>> ] UNSPEC_LXVP)) 2188 {*movoo1}
>>> (nil))
>>>
>>> This is definition.
>>>
>>> (insn 661 659 662 50 (set (reg:TF 179 [ result$imag ])
>>> (plus:TF (reg:TF 179 [ result$imag ])
>>> (subreg:TF (reg:OO 405 [ MEM[(_Float128 *)src_196] ]) 0)))
>>> {addtf3}
>>>
>>> This is use.
>>>
>>> change has the above definition and the assert fires at the
>>> above use.
>>
>> But can you call debug on the insn_change that contains the deleted def,
>> and call debug on the access_info that triggers the assert?
>>
>
> I am afraid I am not getting what exactly you meant here.
One way would be to apply a patch like the below and quote the
output from the last "Changes:" onward.
Richard
diff --git a/gcc/rtl-ssa/changes.cc b/gcc/rtl-ssa/changes.cc
index 11639e81bb7..694760138bb 100644
--- a/gcc/rtl-ssa/changes.cc
+++ b/gcc/rtl-ssa/changes.cc
@@ -249,6 +249,8 @@ function_info::process_uses_of_deleted_def (set_info *set)
}
else
{
+ if (!use->is_live_out_use ())
+ debug (use);
gcc_assert (use->is_live_out_use ());
remove_use (use);
}
@@ -830,6 +832,9 @@ function_info::change_insns (array_slice<insn_change *>
changes)
//
// In particular, this means that consumers must handle debug
// instructions before removing a set.
+ fprintf (stderr, "Changes:\n");
+ for (insn_change *change : changes)
+ debug (*change);
for (insn_change *change : changes)
for (def_info *def : change->old_defs ())
if (def->m_has_been_superceded)
