ipa-fnsummary: Remove inconsistent bp_pack_value

  Hi,

When changing target_info with bitfield, I happened to find this
inconsistent streaming in and out.  We have the streaming in:

	  bp_pack_value (&bp, info->inlinable, 1);
	  bp_pack_value (&bp, false, 1);
	  bp_pack_value (&bp, info->fp_expressions, 1);

while the streaming out:

          info->inlinable = bp_unpack_value (&bp, 1);
          info->fp_expressions = bp_unpack_value (&bp, 1)

The cleanup of Cilk Plus support seemed to miss to remove the bit
streaming out but change with streaming false.

By hacking fp_expression_p to return true always, I can see it
reads the wrong fp_expressions value (false) out in wpa dumping.

Bootstrapped and regress-tested on powerpc64le-linux-gnu Power9.

Is it ok for trunk?

BR,
Kewen
-----
gcc/ChangeLog:

	* ipa-fnsummary.c (ipa_fn_summary_write): Remove inconsistent
	bitfield streaming out.
  

On Fri, Sep 17, 2021 at 11:43 AM Kewen.Lin <linkw@linux.ibm.com> wrote:
>
> Hi,
>
> When changing target_info with bitfield, I happened to find this
> inconsistent streaming in and out.  We have the streaming in:
>
>           bp_pack_value (&bp, info->inlinable, 1);
>           bp_pack_value (&bp, false, 1);
>           bp_pack_value (&bp, info->fp_expressions, 1);
>
> while the streaming out:
>
>           info->inlinable = bp_unpack_value (&bp, 1);
>           info->fp_expressions = bp_unpack_value (&bp, 1)
>
> The cleanup of Cilk Plus support seemed to miss to remove the bit
> streaming out but change with streaming false.
>
> By hacking fp_expression_p to return true always, I can see it
> reads the wrong fp_expressions value (false) out in wpa dumping.
>
> Bootstrapped and regress-tested on powerpc64le-linux-gnu Power9.
>
> Is it ok for trunk?

OK for trunk and all affected branches (note we need to bump the
LTO minor version there).  The issue comes from the removal
of cilk+ in r8-4956 which removed the bp_unpack but replaced
the bp_pack ...

It's a correctness issue as we'll read fp_expressions as always 'false'

Thanks,
Richard.

>
> BR,
> Kewen
> -----
> gcc/ChangeLog:
>
>         * ipa-fnsummary.c (ipa_fn_summary_write): Remove inconsistent
>         bitfield streaming out.
>
> diff --git a/gcc/ipa-fnsummary.c b/gcc/ipa-fnsummary.c
> index 2470937460f..31199919405 100644
> --- a/gcc/ipa-fnsummary.c
> +++ b/gcc/ipa-fnsummary.c
> @@ -4652,7 +4652,6 @@ ipa_fn_summary_write (void)
>            info->time.stream_out (ob);
>            bp = bitpack_create (ob->main_stream);
>            bp_pack_value (&bp, info->inlinable, 1);
> -          bp_pack_value (&bp, false, 1);
>            bp_pack_value (&bp, info->fp_expressions, 1);
>            streamer_write_bitpack (&bp);
>            streamer_write_uhwi (ob, vec_safe_length (info->conds));
  

On Fri, Sep 17, 2021 at 12:03 PM Richard Biener
<richard.guenther@gmail.com> wrote:
>
> On Fri, Sep 17, 2021 at 11:43 AM Kewen.Lin <linkw@linux.ibm.com> wrote:
> >
> > Hi,
> >
> > When changing target_info with bitfield, I happened to find this
> > inconsistent streaming in and out.  We have the streaming in:
> >
> >           bp_pack_value (&bp, info->inlinable, 1);
> >           bp_pack_value (&bp, false, 1);
> >           bp_pack_value (&bp, info->fp_expressions, 1);
> >
> > while the streaming out:
> >
> >           info->inlinable = bp_unpack_value (&bp, 1);
> >           info->fp_expressions = bp_unpack_value (&bp, 1)
> >
> > The cleanup of Cilk Plus support seemed to miss to remove the bit
> > streaming out but change with streaming false.
> >
> > By hacking fp_expression_p to return true always, I can see it
> > reads the wrong fp_expressions value (false) out in wpa dumping.
> >
> > Bootstrapped and regress-tested on powerpc64le-linux-gnu Power9.
> >
> > Is it ok for trunk?
>
> OK for trunk and all affected branches (note we need to bump the
> LTO minor version there).  The issue comes from the removal
> of cilk+ in r8-4956 which removed the bp_unpack but replaced
> the bp_pack ...
>
> It's a correctness issue as we'll read fp_expressions as always 'false'

Btw, on branches we could also simply unpack a dummy bit to avoid
changing the format.

> Thanks,
> Richard.
>
> >
> > BR,
> > Kewen
> > -----
> > gcc/ChangeLog:
> >
> >         * ipa-fnsummary.c (ipa_fn_summary_write): Remove inconsistent
> >         bitfield streaming out.
> >
> > diff --git a/gcc/ipa-fnsummary.c b/gcc/ipa-fnsummary.c
> > index 2470937460f..31199919405 100644
> > --- a/gcc/ipa-fnsummary.c
> > +++ b/gcc/ipa-fnsummary.c
> > @@ -4652,7 +4652,6 @@ ipa_fn_summary_write (void)
> >            info->time.stream_out (ob);
> >            bp = bitpack_create (ob->main_stream);
> >            bp_pack_value (&bp, info->inlinable, 1);
> > -          bp_pack_value (&bp, false, 1);
> >            bp_pack_value (&bp, info->fp_expressions, 1);
> >            streamer_write_bitpack (&bp);
> >            streamer_write_uhwi (ob, vec_safe_length (info->conds));
  

Hi Richi,

Thanks for the review!

on 2021/9/17 下午6:04, Richard Biener wrote:
> On Fri, Sep 17, 2021 at 12:03 PM Richard Biener
> <richard.guenther@gmail.com> wrote:
>>
>> On Fri, Sep 17, 2021 at 11:43 AM Kewen.Lin <linkw@linux.ibm.com> wrote:
>>>
>>> Hi,
>>>
>>> When changing target_info with bitfield, I happened to find this
>>> inconsistent streaming in and out.  We have the streaming in:
>>>
>>>           bp_pack_value (&bp, info->inlinable, 1);
>>>           bp_pack_value (&bp, false, 1);
>>>           bp_pack_value (&bp, info->fp_expressions, 1);
>>>
>>> while the streaming out:
>>>
>>>           info->inlinable = bp_unpack_value (&bp, 1);
>>>           info->fp_expressions = bp_unpack_value (&bp, 1)
>>>
>>> The cleanup of Cilk Plus support seemed to miss to remove the bit
>>> streaming out but change with streaming false.
>>>
>>> By hacking fp_expression_p to return true always, I can see it
>>> reads the wrong fp_expressions value (false) out in wpa dumping.
>>>
>>> Bootstrapped and regress-tested on powerpc64le-linux-gnu Power9.
>>>
>>> Is it ok for trunk?
>>
>> OK for trunk and all affected branches (note we need to bump the
>> LTO minor version there).  The issue comes from the removal
>> of cilk+ in r8-4956 which removed the bp_unpack but replaced
>> the bp_pack ...
>>
>> It's a correctness issue as we'll read fp_expressions as always 'false'
> 
> Btw, on branches we could also simply unpack a dummy bit to avoid
> changing the format.
> 

Committed in r12-3721.  Thanks!

As suggested, the patch for branches is listed below.

Is ok for branches 9, 10 and 11 after some trunk burn in time?

BR,
Kewen
-----
gcc/ChangeLog:

	* ipa-fnsummary.c (inline_read_section): Unpack a dummy bit
	to keep consistent with the side of streaming out.

---
diff --git a/gcc/ipa-fnsummary.c b/gcc/ipa-fnsummary.c
index 18bbae145b9..bf635c1f78a 100644
--- a/gcc/ipa-fnsummary.c
+++ b/gcc/ipa-fnsummary.c
@@ -4403,13 +4403,20 @@ inline_read_section (struct lto_file_decl_data *file_data, const char *data,
       bp = streamer_read_bitpack (&ib);
       if (info)
 	{
-          info->inlinable = bp_unpack_value (&bp, 1);
-          info->fp_expressions = bp_unpack_value (&bp, 1);
+	  info->inlinable = bp_unpack_value (&bp, 1);
+	  /* On the side of streaming out, there is still one bit
+	     streamed out between inlinable and fp_expressions bits,
+	     which was used for cilk+ before but now always false.
+	     To remove the bit packing need to bump LTO minor version,
+	     so unpack a dummy bit here to keep consistent instead.  */
+	  bp_unpack_value (&bp, 1);
+	  info->fp_expressions = bp_unpack_value (&bp, 1);
 	}
       else
 	{
-          bp_unpack_value (&bp, 1);
-          bp_unpack_value (&bp, 1);
+	  bp_unpack_value (&bp, 1);
+	  bp_unpack_value (&bp, 1);
+	  bp_unpack_value (&bp, 1);
 	}

       count2 = streamer_read_uhwi (&ib);
  

On Tue, Sep 21, 2021 at 4:09 AM Kewen.Lin <linkw@linux.ibm.com> wrote:
>
> Hi Richi,
>
> Thanks for the review!
>
> on 2021/9/17 下午6:04, Richard Biener wrote:
> > On Fri, Sep 17, 2021 at 12:03 PM Richard Biener
> > <richard.guenther@gmail.com> wrote:
> >>
> >> On Fri, Sep 17, 2021 at 11:43 AM Kewen.Lin <linkw@linux.ibm.com> wrote:
> >>>
> >>> Hi,
> >>>
> >>> When changing target_info with bitfield, I happened to find this
> >>> inconsistent streaming in and out.  We have the streaming in:
> >>>
> >>>           bp_pack_value (&bp, info->inlinable, 1);
> >>>           bp_pack_value (&bp, false, 1);
> >>>           bp_pack_value (&bp, info->fp_expressions, 1);
> >>>
> >>> while the streaming out:
> >>>
> >>>           info->inlinable = bp_unpack_value (&bp, 1);
> >>>           info->fp_expressions = bp_unpack_value (&bp, 1)
> >>>
> >>> The cleanup of Cilk Plus support seemed to miss to remove the bit
> >>> streaming out but change with streaming false.
> >>>
> >>> By hacking fp_expression_p to return true always, I can see it
> >>> reads the wrong fp_expressions value (false) out in wpa dumping.
> >>>
> >>> Bootstrapped and regress-tested on powerpc64le-linux-gnu Power9.
> >>>
> >>> Is it ok for trunk?
> >>
> >> OK for trunk and all affected branches (note we need to bump the
> >> LTO minor version there).  The issue comes from the removal
> >> of cilk+ in r8-4956 which removed the bp_unpack but replaced
> >> the bp_pack ...
> >>
> >> It's a correctness issue as we'll read fp_expressions as always 'false'
> >
> > Btw, on branches we could also simply unpack a dummy bit to avoid
> > changing the format.
> >
>
> Committed in r12-3721.  Thanks!
>
> As suggested, the patch for branches is listed below.
>
> Is ok for branches 9, 10 and 11 after some trunk burn in time?

It's OK for branches without waiting, maybe you can do a LTO bootstrap
on the branches for extra safety (just in case we're triggering some hidden
issues due to the fix).

Thanks,
Richard.

> BR,
> Kewen
> -----
> gcc/ChangeLog:
>
>         * ipa-fnsummary.c (inline_read_section): Unpack a dummy bit
>         to keep consistent with the side of streaming out.
>
> ---
> diff --git a/gcc/ipa-fnsummary.c b/gcc/ipa-fnsummary.c
> index 18bbae145b9..bf635c1f78a 100644
> --- a/gcc/ipa-fnsummary.c
> +++ b/gcc/ipa-fnsummary.c
> @@ -4403,13 +4403,20 @@ inline_read_section (struct lto_file_decl_data *file_data, const char *data,
>        bp = streamer_read_bitpack (&ib);
>        if (info)
>         {
> -          info->inlinable = bp_unpack_value (&bp, 1);
> -          info->fp_expressions = bp_unpack_value (&bp, 1);
> +         info->inlinable = bp_unpack_value (&bp, 1);
> +         /* On the side of streaming out, there is still one bit
> +            streamed out between inlinable and fp_expressions bits,
> +            which was used for cilk+ before but now always false.
> +            To remove the bit packing need to bump LTO minor version,
> +            so unpack a dummy bit here to keep consistent instead.  */
> +         bp_unpack_value (&bp, 1);
> +         info->fp_expressions = bp_unpack_value (&bp, 1);
>         }
>        else
>         {
> -          bp_unpack_value (&bp, 1);
> -          bp_unpack_value (&bp, 1);
> +         bp_unpack_value (&bp, 1);
> +         bp_unpack_value (&bp, 1);
> +         bp_unpack_value (&bp, 1);
>         }
>
>        count2 = streamer_read_uhwi (&ib);
>
  

on 2021/9/21 下午2:16, Richard Biener wrote:
> On Tue, Sep 21, 2021 at 4:09 AM Kewen.Lin <linkw@linux.ibm.com> wrote:
>>
>> Hi Richi,
>>
>> Thanks for the review!
>>
>> on 2021/9/17 下午6:04, Richard Biener wrote:
>>> On Fri, Sep 17, 2021 at 12:03 PM Richard Biener
>>> <richard.guenther@gmail.com> wrote:
>>>>
>>>> On Fri, Sep 17, 2021 at 11:43 AM Kewen.Lin <linkw@linux.ibm.com> wrote:
>>>>>
>>>>> Hi,
>>>>>
>>>>> When changing target_info with bitfield, I happened to find this
>>>>> inconsistent streaming in and out.  We have the streaming in:
>>>>>
>>>>>           bp_pack_value (&bp, info->inlinable, 1);
>>>>>           bp_pack_value (&bp, false, 1);
>>>>>           bp_pack_value (&bp, info->fp_expressions, 1);
>>>>>
>>>>> while the streaming out:
>>>>>
>>>>>           info->inlinable = bp_unpack_value (&bp, 1);
>>>>>           info->fp_expressions = bp_unpack_value (&bp, 1)
>>>>>
>>>>> The cleanup of Cilk Plus support seemed to miss to remove the bit
>>>>> streaming out but change with streaming false.
>>>>>
>>>>> By hacking fp_expression_p to return true always, I can see it
>>>>> reads the wrong fp_expressions value (false) out in wpa dumping.
>>>>>
>>>>> Bootstrapped and regress-tested on powerpc64le-linux-gnu Power9.
>>>>>
>>>>> Is it ok for trunk?
>>>>
>>>> OK for trunk and all affected branches (note we need to bump the
>>>> LTO minor version there).  The issue comes from the removal
>>>> of cilk+ in r8-4956 which removed the bp_unpack but replaced
>>>> the bp_pack ...
>>>>
>>>> It's a correctness issue as we'll read fp_expressions as always 'false'
>>>
>>> Btw, on branches we could also simply unpack a dummy bit to avoid
>>> changing the format.
>>>
>>
>> Committed in r12-3721.  Thanks!
>>
>> As suggested, the patch for branches is listed below.
>>
>> Is ok for branches 9, 10 and 11 after some trunk burn in time?
> 
> It's OK for branches without waiting, maybe you can do a LTO bootstrap
> on the branches for extra safety (just in case we're triggering some hidden
> issues due to the fix).

Thanks!  LTO bootstrapped on the branches, separately committed via
r11-9024, r10-10146 and r9-9740.

BR,
Kewen

> 
> Thanks,
> Richard.
> 
>> BR,
>> Kewen
>> -----
>> gcc/ChangeLog:
>>
>>         * ipa-fnsummary.c (inline_read_section): Unpack a dummy bit
>>         to keep consistent with the side of streaming out.
>>
>> ---
>> diff --git a/gcc/ipa-fnsummary.c b/gcc/ipa-fnsummary.c
>> index 18bbae145b9..bf635c1f78a 100644
>> --- a/gcc/ipa-fnsummary.c
>> +++ b/gcc/ipa-fnsummary.c
>> @@ -4403,13 +4403,20 @@ inline_read_section (struct lto_file_decl_data *file_data, const char *data,
>>        bp = streamer_read_bitpack (&ib);
>>        if (info)
>>         {
>> -          info->inlinable = bp_unpack_value (&bp, 1);
>> -          info->fp_expressions = bp_unpack_value (&bp, 1);
>> +         info->inlinable = bp_unpack_value (&bp, 1);
>> +         /* On the side of streaming out, there is still one bit
>> +            streamed out between inlinable and fp_expressions bits,
>> +            which was used for cilk+ before but now always false.
>> +            To remove the bit packing need to bump LTO minor version,
>> +            so unpack a dummy bit here to keep consistent instead.  */
>> +         bp_unpack_value (&bp, 1);
>> +         info->fp_expressions = bp_unpack_value (&bp, 1);
>>         }
>>        else
>>         {
>> -          bp_unpack_value (&bp, 1);
>> -          bp_unpack_value (&bp, 1);
>> +         bp_unpack_value (&bp, 1);
>> +         bp_unpack_value (&bp, 1);
>> +         bp_unpack_value (&bp, 1);
>>         }
>>
>>        count2 = streamer_read_uhwi (&ib);
>>