[Bug target/85401] segfault building code for VAX

[coypu at sdf dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85401

coypu  changed:

   What|Removed |Added

 Status|UNCONFIRMED |RESOLVED
 Resolution|--- |FIXED

--- Comment #9 from coypu  ---
Fixed, also the very related second failure (that creduce managed to find, when
reducing this test case).
https://gcc.gnu.org/viewcvs/gcc?view=revision=276587

[Bug target/85401] segfault building code for VAX

[law at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85401

--- Comment #8 from Jeffrey A. Law  ---
Author: law
Date: Tue Oct  1 19:25:31 2019
New Revision: 276426

URL: https://gcc.gnu.org/viewcvs?rev=276426=gcc=rev
Log:
PR target/85401
* ira-color.c (allocno_copy_cost_saving): Call
ira_init_register_move_cost_if_necessary.

Modified:
trunk/gcc/ChangeLog
trunk/gcc/ira-color.c

[Bug target/85401] segfault building code for VAX

[coypu at sdf dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85401

--- Comment #7 from coypu  ---
I sent a patch to gcc-patches.
https://gcc.gnu.org/ml/gcc-patches/2019-09/msg00896.html

[Bug target/85401] segfault building code for VAX

[coypu at sdf dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85401

--- Comment #6 from coypu  ---
I imagine I didn't write scheduling for the broken instruction, so it doesn't
ever happen. something silly like that, rather than it being a valid fix.

[Bug target/85401] segfault building code for VAX

[coypu at sdf dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85401

--- Comment #5 from coypu  ---
Created attachment 46872
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=46872=edit
providing instruction scheduling avoids this crash

So, I am trying to beat gcc/vax into shape and incorporate changes from
netbsd's patches.
I noticed one of the changes I made for another reason avoids this crash. It is
providing a (trivial) instruction scheduling.

[Bug target/85401] segfault building code for VAX

[martin at netbsd dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85401

--- Comment #4 from Martin Husemann  ---
The costs are missing for various modes:

(gdb) p (default_target_ira_int->x_ira_register_move_cost)
$6 = {0x0, 0x0, 0x0, 0x0, 0x0, 0x7f7ff7b8c8b0, 0x7f7ff7b8c8b0, 0x0 }

(that is: only HImode and SImode costs are available)

[Bug target/85401] segfault building code for VAX

[martin at netbsd dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85401

--- Comment #3 from Martin Husemann  ---
Indeed. Digging a bit with gdb (but in our local 6.4 version) shows:

#0  0x009fa7be in allocno_copy_cost_saving (allocno=0x7f7ff679a178,
hard_regno=11)
at /usr/src/tools/gcc/../../external/gpl3/gcc/dist/gcc/ira-color.c:2763
2763  cost += cp->freq *
ira_register_move_cost[allocno_mode][rclass][rclass];
(gdb) p (default_target_ira_int->x_ira_register_move_cost)[allocno_mode]
$5 = (move_table *) 0x0


Where is that table supposed to be setup?

[Bug target/85401] segfault building code for VAX

[thopre01 at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85401

Thomas Preud'homme  changed:

   What|Removed |Added

 Status|ASSIGNED|UNCONFIRMED
 CC||m...@3am-software.com
   Assignee|thopre01 at gcc dot gnu.org|unassigned at gcc dot 
gnu.org
 Ever confirmed|1   |0

--- Comment #2 from Thomas Preud'homme  ---
Actually given where the fault occurs this does not seem to be related to
bswap. Might be a missing pattern or cost in the vax backend.

[Bug target/85401] segfault building code for VAX

[thopre01 at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85401

Thomas Preud'homme  changed:

   What|Removed |Added

 Status|UNCONFIRMED |ASSIGNED
   Last reconfirmed||2018-04-25
 Ever confirmed|0   |1

[Bug target/85401] segfault building code for VAX

[coypu at sdf dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85401

--- Comment #1 from coypu  ---
Threw computing resources at the problem, so now I have an "offending" commit.
Before this commit, it doesn't segfault.
After, it does.

commit bbb9b536dd58015b5712a867954d34aae9d9dae5 (HEAD, refs/bisect/bad)
Author: thopre01 
Date:   Tue Jan 6 11:51:16 2015 +

2015-01-06  Thomas Preud'homme  

gcc/
PR tree-optimization/63259
* tree-ssa-math-opts.c (pass_optimize_bswap::execute): Stop checking
if optab exists for 16bit byteswap.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@219256
138bc75d-0d04-0410-961f-82ee72b054a4