[Bug go/102908] New: [12 Regression] go.test/test/fixedbugs/issue16095.go hangs again

[Bug go/102908] New: [12 Regression] go.test/test/fixedbugs/issue16095.go hangs again

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102908

            Bug ID: 102908
           Summary: [12 Regression] go.test/test/fixedbugs/issue16095.go
                    hangs again
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: go
          Assignee: ian at airs dot com
          Reporter: hjl.tools at gmail dot com
                CC: cmang at google dot com
  Target Milestone: ---

On Linux/x86-64, go.test/test/fixedbugs/issue16095.go hangs again as of
r12-4629:

FAIL: go.test/test/fixedbugs/issue16095.go execution,  -O2 -g

[Bug go/102908] [12 Regression] go.test/test/fixedbugs/issue16095.go hangs again

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102908

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=102904
   Last reconfirmed|                            |2021-10-23
   Target Milestone|---                         |12.0
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |NEW

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
I saw it too as of r12-4626 on aarch64.  I filed PR 102904 as the hang didn't
trigger the timeout even.

[Bug tree-optimization/102908] [12 Regression] go.test/test/fixedbugs/issue16095.go hangs again

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102908

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|go                          |tree-optimization
           Keywords|                            |wrong-code
           Assignee|ian at airs dot com                |pinskia at gcc dot gnu.org
             Status|NEW                         |ASSIGNED

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
This might be a bug in simple_dce_from_worklist which does not check
stmt_unremovable_because_of_non_call_eh_p .

Let me check if that solves the issue.

[Bug tree-optimization/102908] [12 Regression] go.test/test/fixedbugs/issue16095.go hangs again

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102908

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #2)
> This might be a bug in simple_dce_from_worklist which does not check
> stmt_unremovable_because_of_non_call_eh_p .
> 
> Let me check if that solves the issue.

The only issue here is that tree-vect-generic uses this to delete statements
they have lowered but stmt_unremovable_because_of_non_call_eh_p might return
true for those.  So I might need an other argument to simple_dce_from_worklist
about that ...  Let me try without the argument first.

[Bug tree-optimization/102908] [12 Regression] go.test/test/fixedbugs/issue16095.go hangs again by r12-4598

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102908

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |patch
                URL|                            |https://gcc.gnu.org/piperma
                   |                            |il/gcc-patches/2021-October
                   |                            |/582419.html

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Patch submitted:
https://gcc.gnu.org/pipermail/gcc-patches/2021-October/582419.html

[Bug tree-optimization/102908] [12 Regression] go.test/test/fixedbugs/issue16095.go hangs again by r12-4598

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102908

--- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The trunk branch has been updated by Andrew Pinski <pinskia@gcc.gnu.org>:

https://gcc.gnu.org/g:7518e4c2f0758daac5d650d400565cf49ac3c8c5

commit r12-4661-g7518e4c2f0758daac5d650d400565cf49ac3c8c5
Author: Andrew Pinski <apinski@marvell.com>
Date:   Sat Oct 23 19:24:43 2021 +0000

    Fix PR 102908: wrongly removing null pointer loads

    Just like PR 100382, here we have a DCE removing a
    null pointer load which is needed still.
    In this case, execute_fixup_cfg removes a store (correctly)
    and then removes the null load (incorrectly) due to
    not checking stmt_unremovable_because_of_non_call_eh_p.
    This patch adds the check in the similar way as the patch
    to fix PR 100382 did.

    gcc/ChangeLog:

            * tree-ssa-dce.c (simple_dce_from_worklist):
            Check stmt_unremovable_because_of_non_call_eh_p also
            before removing the statement.

[Bug tree-optimization/102908] [12 Regression] go.test/test/fixedbugs/issue16095.go hangs again by r12-4598

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102908

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED

--- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Fixed.