[Bug tree-optimization/61221] [4.10 Regression] ICE on valid code at -O1 and above on x86_64-linux-gnu

[Bug tree-optimization/61221] [4.10 Regression] ICE on valid code at -O1 and above on x86_64-linux-gnu

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61221

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2014-05-19
           Assignee|unassigned at gcc dot gnu.org      |rguenth at gcc dot gnu.org
   Target Milestone|---                         |4.10.0
            Summary|ICE on valid code at -O1    |[4.10 Regression] ICE on
                   |and above on                |valid code at -O1 and above
                   |x86_64-linux-gnu            |on x86_64-linux-gnu
     Ever confirmed|0                           |1

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed, mine.

[Bug tree-optimization/61221] [4.10 Regression] ICE on valid code at -O1 and above on x86_64-linux-gnu

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61221

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
Interesting ;)  We do some non-sensical simplification on dead code and ICE.
But our dead-CFG compute code in SCCVN isn't up to recognizing a dead loop
because it's conservative and not optimistic.

Ultimatively this all is because of replacing a call with sth that doesn't
have a VDEF and gsi_replace/update_stmt being called which releases an SSA
name which corrupts the value-numbering lattice.

[Bug tree-optimization/61221] [4.10 Regression] ICE on valid code at -O1 and above on x86_64-linux-gnu

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61221

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
Author: rguenth
Date: Mon May 19 14:33:31 2014
New Revision: 210614

URL: http://gcc.gnu.org/viewcvs?rev=210614&root=gcc&view=rev
Log:
2014-05-19  Richard Biener  <rguenther@suse.de>

    PR tree-optimization/61221
    * tree-ssa-pre.c (eliminate_dom_walker::before_dom_children):
    Do nothing for unreachable blocks.
    * tree-ssa-sccvn.c (cond_dom_walker::before_dom_children):
    Improve unreachability detection.

    * gcc.dg/torture/pr61221.c: New testcase.

Added:
    trunk/gcc/testsuite/gcc.dg/torture/pr61221.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-ssa-pre.c
    trunk/gcc/tree-ssa-sccvn.c

[Bug tree-optimization/61221] [4.10 Regression] ICE on valid code at -O1 and above on x86_64-linux-gnu

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61221

Richard Biener <rguenth at gcc dot gnu.org> changed:

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

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed (worked around, real fix in testing).

[Bug tree-optimization/61221] [4.10 Regression] ICE on valid code at -O1 and above on x86_64-linux-gnu

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61221

--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
Author: rguenth
Date: Tue May 20 08:16:13 2014
New Revision: 210633

URL: http://gcc.gnu.org/viewcvs?rev=210633&root=gcc&view=rev
Log:
2014-05-20  Richard Biener  <rguenther@suse.de>

    PR tree-optimization/61221
    * tree-ssa-pre.c (el_to_update): Remove.
    (eliminate_dom_walker::before_dom_children): Handle released
    VDEFs by value-numbering them to the associated VUSE.  Update
    stmt immediately for substituted call address.
    (eliminate): Remove delayed stmt updating code.
    * tree-ssa-sccvn.c (vuse_ssa_val): New function valueizing
    possibly late re-numbered vuses.
    (vn_reference_lookup_2): Adjust.
    (vn_reference_lookup_pieces): Likewise.
    (vn_reference_lookup): Likewise.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/tree-ssa-pre.c
    trunk/gcc/tree-ssa-sccvn.c