[Bug rtl-optimization/105455] New: ICE: verify_flow_info failed (error: verify_flow_info: REG_BR_PROB does not match cfg)

[Bug rtl-optimization/105455] New: ICE: verify_flow_info failed (error: verify_flow_info: REG_BR_PROB does not match cfg)

[asolokha at gmx dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105455

            Bug ID: 105455
           Summary: ICE: verify_flow_info failed (error: verify_flow_info:
                    REG_BR_PROB does not match cfg)
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: asolokha at gmx dot com
  Target Milestone: ---

gcc 12.0.1 20220424 snapshot (g:6b7441a46c771aa6ecdc0c8ed96197417d036b9a) ICEs
when compiling the following testcase w/ -O1 -fharden-conditional-branches
-funroll-loops --param max-loop-header-insns=1:

__attribute__ ((cold)) void
bar (void);

void
foo (int x)
{
  if (x)
    {
      int i;

      for (i = 0; i < 101; ++i)
        bar ();
    }
}

% gcc-12.0.1 -O1 -fharden-conditional-branches -funroll-loops --param
max-loop-header-insns=1 -c hkihrvjs.c
hkihrvjs.c: In function 'foo':
hkihrvjs.c:14:1: error: verify_flow_info: REG_BR_PROB does not match cfg
1073741831 7
   14 | }
      | ^
during RTL pass: loop2_unroll
hkihrvjs.c:14:1: internal compiler error: verify_flow_info failed
0x9df59e verify_flow_info()
       
/var/tmp/portage/sys-devel/gcc-12.0.1_p20220424/work/gcc-12-20220424/gcc/cfghooks.cc:284
0xde0a8a execute_function_todo
       
/var/tmp/portage/sys-devel/gcc-12.0.1_p20220424/work/gcc-12-20220424/gcc/passes.cc:2097
0xde0f9e execute_todo
       
/var/tmp/portage/sys-devel/gcc-12.0.1_p20220424/work/gcc-12-20220424/gcc/passes.cc:2139

[Bug rtl-optimization/105455] ICE: verify_flow_info failed (error: verify_flow_info: REG_BR_PROB does not match cfg)

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105455

Martin Liška <marxin at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |marxin at gcc dot gnu.org
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2022-05-03

[Bug rtl-optimization/105455] ICE: verify_flow_info failed (error: verify_flow_info: REG_BR_PROB does not match cfg)

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105455

--- Comment #1 from Martin Liška <marxin at gcc dot gnu.org> ---
Started with introduction of -fharden-conditional-branches in
r12-4759-g95bb87b2458bfab4.

[Bug rtl-optimization/105455] ICE: verify_flow_info failed (error: verify_flow_info: REG_BR_PROB does not match cfg)

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105455

Alexandre Oliva <aoliva at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
           Assignee|unassigned at gcc dot gnu.org      |aoliva at gcc dot gnu.org

--- Comment #2 from Alexandre Oliva <aoliva at gcc dot gnu.org> ---
Created attachment 52951
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=52951&action=edit
Candidate patch

Mine.  This patch appears to cure it.  Regstrapping...

[Bug rtl-optimization/105455] ICE: verify_flow_info failed (error: verify_flow_info: REG_BR_PROB does not match cfg)

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105455

--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Alexandre Oliva <aoliva@gcc.gnu.org>:

https://gcc.gnu.org/g:90a8eab4a1292430467f68b65e5127f7760acc94

commit r13-380-g90a8eab4a1292430467f68b65e5127f7760acc94
Author: Alexandre Oliva <oliva@adacore.com>
Date:   Wed May 11 04:27:42 2022 -0300

    [PR105455] Set edge probabilities when hardening conditionals

    When turning unconditional edges into conditional, as in
    gimple-harden-conditionals.cc:insert_check_and_trap, the newly-created
    edge's probability comes out uninitialized, while the previously
    unconditional edge's probability is presumably
    profile_probability::always.

    Mixing initialized and uninitialized probabilities before expand
    breaks predict.cc:force_edge_cold: the initialized probability may end
    up copied to a REG_BR_PROB note in a conditional branch insn, but if
    force_edge_cold is called on that edge, it will find another edge with
    uninitialized probability and assume the note is absent.  Later on,
    rtl_verify_edges complains that the note does not match the
    probability modified by force_edge_cold in the edge.

    This patch sets probabilities for edges affected by hardening of
    conditionals, both the newly-created edges to trap blocks and the
    previously-unconditional edges, so that the former are considered
    never taken, while the latter are confirmed as always taken.


    for  gcc/ChangeLog

            PR rtl-optimization/105455
            * gimple-harden-conditionals.cc (insert_check_and_trap): Set
            probabilities for newly-conditional edges.

    for  gcc/testsuite/ChangeLog

            PR rtl-optimization/105455
            * gcc.dg/pr105455.c: New.

[Bug rtl-optimization/105455] ICE: verify_flow_info failed (error: verify_flow_info: REG_BR_PROB does not match cfg)

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105455

--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-12 branch has been updated by Alexandre Oliva
<aoliva@gcc.gnu.org>:

https://gcc.gnu.org/g:e628690d6333f0cc4d338cd8b796408f35e07ced

commit r12-8372-ge628690d6333f0cc4d338cd8b796408f35e07ced
Author: Alexandre Oliva <oliva@adacore.com>
Date:   Fri May 13 03:05:46 2022 -0300

    [PR105455] Set edge probabilities when hardening conditionals

    When turning unconditional edges into conditional, as in
    gimple-harden-conditionals.cc:insert_check_and_trap, the newly-created
    edge's probability comes out uninitialized, while the previously
    unconditional edge's probability is presumably
    profile_probability::always.

    Mixing initialized and uninitialized probabilities before expand
    breaks predict.cc:force_edge_cold: the initialized probability may end
    up copied to a REG_BR_PROB note in a conditional branch insn, but if
    force_edge_cold is called on that edge, it will find another edge with
    uninitialized probability and assume the note is absent.  Later on,
    rtl_verify_edges complains that the note does not match the
    probability modified by force_edge_cold in the edge.

    This patch sets probabilities for edges affected by hardening of
    conditionals, both the newly-created edges to trap blocks and the
    previously-unconditional edges, so that the former are considered
    never taken, while the latter are confirmed as always taken.


    for  gcc/ChangeLog

            PR rtl-optimization/105455
            * gimple-harden-conditionals.cc (insert_check_and_trap): Set
            probabilities for newly-conditional edges.

    for  gcc/testsuite/ChangeLog

            PR rtl-optimization/105455
            * gcc.dg/pr105455.c: New.

    (cherry picked from commit 90a8eab4a1292430467f68b65e5127f7760acc94)

[Bug rtl-optimization/105455] ICE: verify_flow_info failed (error: verify_flow_info: REG_BR_PROB does not match cfg)

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105455

Alexandre Oliva <aoliva at gcc dot gnu.org> changed:

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

--- Comment #5 from Alexandre Oliva <aoliva at gcc dot gnu.org> ---
Fixed, trunk and gcc-12.

[Bug rtl-optimization/105455] ICE: verify_flow_info failed (error: verify_flow_info: REG_BR_PROB does not match cfg)

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105455

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |12.2
      Known to fail|                            |12.1.0
      Known to work|                            |12.2.0, 13.0