Re: [RFC] Bug lto/78140

[kugan <kugan dot vivekanandarajah at linaro dot org>]

Hi Richard,

On 30/01/17 21:08, Richard Biener wrote:
> On Mon, Jan 30, 2017 at 12:23 AM, kugan
> <kugan.vivekanandarajah@linaro.org> wrote:
> > lto1: internal compiler error: Segmentation fault
> > 0xdedc4b crash_signal
> >         ../../gcc/gcc/toplev.c:333
> > 0xb46680 ipa_node_params_t::duplicate(cgraph_node*, cgraph_node*,
> > ipa_node_params*, ipa_node_params*)
> >         ../../gcc/gcc/ipa-prop.c:3819
> > 0xb306a3
> > function_summary<ipa_node_params*>::symtab_duplication(cgraph_node*,
> > cgraph_node*, void*)
> >         ../../gcc/gcc/symbol-summary.h:187
> > 0x85aba7 symbol_table::call_cgraph_duplication_hooks(cgraph_node*,
> > cgraph_node*)
> >         ../../gcc/gcc/cgraph.c:488
> > 0x8765bf cgraph_node::create_clone(tree_node*, long, int, bool,
> > vec<cgraph_edge*, va_heap, vl_ptr>, bool, cgraph_node*, bitmap_head*, char
> > const*)
> >         ../../gcc/gcc/cgraphclones.c:522
> > 0x166fb3b clone_inlined_nodes(cgraph_edge*, bool, bool, int*, int)
> >         ../../gcc/gcc/ipa-inline-transform.c:227
> > 0x166fbd7 clone_inlined_nodes(cgraph_edge*, bool, bool, int*, int)
> >         ../../gcc/gcc/ipa-inline-transform.c:242
> > 0x1670893 inline_call(cgraph_edge*, bool, vec<cgraph_edge*, va_heap,
> > vl_ptr>*, int*, bool, bool*)
> >         ../../gcc/gcc/ipa-inline-transform.c:449
> > 0x1665bd3 inline_small_functions
> >         ../../gcc/gcc/ipa-inline.c:2024
> > 0x1667157 ipa_inline
> >         ../../gcc/gcc/ipa-inline.c:2434
> > 0x1667fa7 execute
> >         ../../gcc/gcc/ipa-inline.c:2845

This is due to an existing issue. That is, in ipa_node_params_t::remove, 
m_vr and bits vectors are not set to null such that the gc can claim it.

I also noticed that we don't create m_vr and bits vectors. Attached 
patch does this. This was bootstrapped and regression tested with the 
above patch. I am now testing the attached patch alone.  Is this OK if 
no regressions?


gcc/ChangeLog:

2017-02-02  Kugan Vivekanandarajah  <kuganv@linaro.org>

        * ipa-cp.c (ipcp_store_bits_results): Construct bits vector.
        (ipcp_store_vr_results): Constrict m_vr vector.
        * ipa-prop.c (ipa_node_params_t::remove): Set transaction 
summary to null.
        (ipa_node_params_t::duplicate): Construct bits and m_vr vector.
        (read_ipcp_transformation_info): Likewise.


Thanks,
Kugan

> > I tried similar think without variable structure like:
> > diff --git a/gcc/ipa-prop.h b/gcc/ipa-prop.h
> > index 93a2390c..b0cc832 100644
> > --- a/gcc/ipa-prop.h
> > +++ b/gcc/ipa-prop.h
> > @@ -525,7 +525,7 @@ struct GTY(()) ipcp_transformation_summary
> >    /* Known bits information.  */
> >    vec<ipa_bits, va_gc> *bits;
> >    /* Value range information.  */
> > -  vec<ipa_vr, va_gc> *m_vr;
> > +  vec<ipa_vr *, va_gc> *m_vr;
> >  };
> >
> > This also has the same issue so I don't think it has anything to do with
> > variable structure.
>
> You have to debug that detail yourself but I wonder why the transformation
> summary has a different representation than the jump function (and I think
> the jump function size is the issue).
>
> The JF has
>
>   /* Information about zero/non-zero bits.  */
>   struct ipa_bits bits;
>
>   /* Information about value range, containing valid data only when vr_known is
>      true.  */
>   value_range m_vr;
>   bool vr_known;
>
> with ipa_bits having two widest_ints and value_range having two trees
> and an unused bitmap and ipa_vr having two wide_ints (widest_ints are
> smaller!).
>
> Richard.
>
> > Thanks,
> > Kugan

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