[Bug bootstrap/62009] Bootstrap failure in vec.h::splice

["jgreenhalgh at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset="UTF-8", Size: 10013 bytes --]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62009

jgreenhalgh at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Target|i686                        |i686,
                   |                            |arm-none-linux-gnueabihf
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2014-08-04
                 CC|                            |jgreenhalgh at gcc dot gnu.org
            Summary|Bootstrap failure on i686   |Bootstrap failure in
                   |                            |vec.h::splice
     Ever confirmed|0                           |1

--- Comment #1 from jgreenhalgh at gcc dot gnu.org ---
I saw something very similar on ARM, but I couldn't reproduce it across two
other bootstraps with the same configuration, nor did I see the ICE when trying
to resume the build by typing "make".

.../configure --with-cpu=cortex-a9 --with-fpu=neon-fp16 --with-mode=thumb
--with-float=hard --enable-languages=c,c++,fortran

/work/jamgre01//gcc-src/gcc/tree-ssa-pre.c: In function ‘pre_expr_d*
bitmap_find_leader(bitmap_set_t, unsigned int)’:
/work/jamgre01//gcc-src/gcc/tree-ssa-pre.c:1837:1: internal compiler error: in
splice, at vec.h:844
 bitmap_find_leader (bitmap_set_t set, unsigned int val)
 ^
0xaa2927 vec<_edge_var_map, va_heap, vl_embed>::splice(vec<_edge_var_map,
va_heap, vl_embed>&)
    /work/jamgre01//gcc-src/gcc/vec.h:844
0xaa253d vec<_edge_var_map, va_heap, vl_ptr>::splice(vec<_edge_var_map,
va_heap, vl_ptr>&)
    /work/jamgre01//gcc-src/gcc/vec.h:1495
0xaa1fab vec<_edge_var_map, va_heap, vl_ptr>::safe_splice(vec<_edge_var_map,
va_heap, vl_ptr>&)
    /work/jamgre01//gcc-src/gcc/vec.h:1512
0xa9ddbb redirect_edge_var_map_dup(edge_def*, edge_def*)
    /work/jamgre01//gcc-src/gcc/tree-ssa.c:113
0x4d8bfd redirect_edge_succ_nodup(edge_def*, basic_block_def*)
    /work/jamgre01//gcc-src/gcc/cfghooks.c:437
0xa9dee5 ssa_redirect_edge(edge_def*, basic_block_def*)
    /work/jamgre01//gcc-src/gcc/tree-ssa.c:173
0x8fd663 gimple_try_redirect_by_replacing_jump
    /work/jamgre01//gcc-src/gcc/tree-cfg.c:5419
0x8fd6e7 gimple_redirect_edge_and_branch
    /work/jamgre01//gcc-src/gcc/tree-cfg.c:5450
0x4d89d5 redirect_edge_and_branch(edge_def*, basic_block_def*)
    /work/jamgre01//gcc-src/gcc/cfghooks.c:356
0x907a79 remove_forwarder_block
    /work/jamgre01//gcc-src/gcc/tree-cfgcleanup.c:445
0x9080a7 cleanup_tree_cfg_bb
    /work/jamgre01//gcc-src/gcc/tree-cfgcleanup.c:633
0x90818d cleanup_tree_cfg_1
    /work/jamgre01//gcc-src/gcc/tree-cfgcleanup.c:675
0x9082cb cleanup_tree_cfg_noloop
    /work/jamgre01//gcc-src/gcc/tree-cfgcleanup.c:731
0x9083bd cleanup_tree_cfg()
    /work/jamgre01//gcc-src/gcc/tree-cfgcleanup.c:786
0x90897f execute_cleanup_cfg_post_optimizing
    /work/jamgre01//gcc-src/gcc/tree-cfgcleanup.c:1081
0x908b29 execute
    /work/jamgre01//gcc-src/gcc/tree-cfgcleanup.c:1143
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.
>From gcc-bugs-return-457698-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org Mon Aug 04 12:51:59 2014
Return-Path: <gcc-bugs-return-457698-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org>
Delivered-To: listarch-gcc-bugs@gcc.gnu.org
Received: (qmail 2104 invoked by alias); 4 Aug 2014 12:51:58 -0000
Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm
Precedence: bulk
List-Id: <gcc-bugs.gcc.gnu.org>
List-Archive: <http://gcc.gnu.org/ml/gcc-bugs/>
List-Post: <mailto:gcc-bugs@gcc.gnu.org>
List-Help: <mailto:gcc-bugs-help@gcc.gnu.org>
Sender: gcc-bugs-owner@gcc.gnu.org
Delivered-To: mailing list gcc-bugs@gcc.gnu.org
Received: (qmail 2073 invoked by uid 48); 4 Aug 2014 12:51:55 -0000
From: "tkoeppe at google dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/62006] Bad code generation with -O3 (possibly due to -ftree-partial-pre)
Date: Mon, 04 Aug 2014 12:51:00 -0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: tree-optimization
X-Bugzilla-Version: 4.9.1
X-Bugzilla-Keywords: wrong-code
X-Bugzilla-Severity: normal
X-Bugzilla-Who: tkoeppe at google dot com
X-Bugzilla-Status: ASSIGNED
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: rguenth at gcc dot gnu.org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Flags:
X-Bugzilla-Changed-Fields: attachments.created
Message-ID: <bug-62006-4-RQywpmZvUV@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-62006-4@http.gcc.gnu.org/bugzilla/>
References: <bug-62006-4@http.gcc.gnu.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
X-SW-Source: 2014-08/txt/msg00195.txt.bz2
Content-length: 459

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62006

--- Comment #6 from Thomas Köppe <tkoeppe at google dot com> ---
Created attachment 33236
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=33236&action=edit
Fixed demo that doesn't have UB on account of invalid pointer arithmetic

Here's a (very lazily) fixed version of the code that allocates from an arena
that is a single, large array.

The same problem persists in both GCC and Clang.
>From gcc-bugs-return-457699-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org Mon Aug 04 12:58:03 2014
Return-Path: <gcc-bugs-return-457699-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org>
Delivered-To: listarch-gcc-bugs@gcc.gnu.org
Received: (qmail 7417 invoked by alias); 4 Aug 2014 12:58:03 -0000
Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm
Precedence: bulk
List-Id: <gcc-bugs.gcc.gnu.org>
List-Archive: <http://gcc.gnu.org/ml/gcc-bugs/>
List-Post: <mailto:gcc-bugs@gcc.gnu.org>
List-Help: <mailto:gcc-bugs-help@gcc.gnu.org>
Sender: gcc-bugs-owner@gcc.gnu.org
Delivered-To: mailing list gcc-bugs@gcc.gnu.org
Received: (qmail 6813 invoked by uid 48); 4 Aug 2014 12:57:59 -0000
From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/61672] Less redundant instructions deleted by pre_delete after r208113.
Date: Mon, 04 Aug 2014 12:58:00 -0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: rtl-optimization
X-Bugzilla-Version: 4.10.0
X-Bugzilla-Keywords:
X-Bugzilla-Severity: normal
X-Bugzilla-Who: rguenth at gcc dot gnu.org
X-Bugzilla-Status: ASSIGNED
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: rguenth at gcc dot gnu.org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Flags:
X-Bugzilla-Changed-Fields: bug_status cf_reconfirmed_on assigned_to everconfirmed attachments.created
Message-ID: <bug-61672-4-gWyFopWkNR@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-61672-4@http.gcc.gnu.org/bugzilla/>
References: <bug-61672-4@http.gcc.gnu.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 7bit
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
X-SW-Source: 2014-08/txt/msg00196.txt.bz2
Content-length: 2530

https://gcc.gnu.org/bugzilla/show_bug.cgi?ida672

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2014-08-04
           Assignee|unassigned at gcc dot gnu.org      |rguenth at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> ---
Created attachment 33237
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id3237&actioníit
patch

Ok, I see stuff like the following in the 179r.pre dump differences

@@ -1524,6 +1524,11 @@
         Loads : (insn_list:REG_DEP_TRUE 21 (nil))
        Stores : (nil)

+  Pattern (  0): (mem/f:SI (plus:SI (reg/v/f:SI 93 [ pfile ])
+        (const_int 12 [0xc])) [3 pfile_5(D)->u_buff+0 S4 A32])
+        Loads : (insn_list:REG_DEP_TRUE 19 (nil))
+       Stores : (nil)
+
   Pattern (  0): (mem/f:SI (plus:SI (reg/v/f:SI 83 [ buff ])
         (const_int 12 [0xc])) [3 buff_6->limit+0 S4 A32])
         Loads : (insn_list:REG_DEP_TRUE 9 (nil))
@@ -1536,11 +1541,11 @@

   Pattern (  0): (mem/f:SI (plus:SI (reg/v/f:SI 93 [ pfile ])
         (const_int 12 [0xc])) [3 pfile_5(D)->u_buff+0 S4 A32])
-        Loads : (insn_list:REG_DEP_TRUE 19 (insn_list:REG_DEP_TRUE 7 (nil)))
+        Loads : (insn_list:REG_DEP_TRUE 7 (nil))
        Stores : (nil)

Ah, gcse ends up calling exp_equiv_p which does

          /* Can't merge two expressions in different alias sets, since we
             can decide that the expression is transparent in a block when
             it isn't, due to it being set with the different alias set.

             Also, can't merge two expressions with different MEM_ATTRS.
             They could e.g. be two different entities allocated into the
             same space on the stack (see e.g. PR25130).  In that case, the
             MEM addresses can be the same, even though the two MEMs are
             absolutely not equivalent.

             But because really all MEM attributes should be the same for
             equivalent MEMs, we just use the invariant that MEMs that have
             the same attributes share the same mem_attrs data structure.  */
          if (MEM_ATTRS (x) != MEM_ATTRS (y))
            return 0;

cfgcleanup.c has similar code.

Untested fix attached, with this we create the same code for the pr58464
testcase.