[Bug tree-optimization/66729] New: Segfault starting with r224967

[Bug tree-optimization/66729] New: Segfault starting with r224967

[pthaugen at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66729

            Bug ID: 66729
           Summary: Segfault starting with r224967
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pthaugen at gcc dot gnu.org
                CC: bergner at gcc dot gnu.org, dje at gcc dot gnu.org,
                    rsandifo at gcc dot gnu.org
  Target Milestone: ---
              Host: powerpc64-unknown-linux-gnu
            Target: powerpc64-unknown-linux-gnu
             Build: powerpc64-unknown-linux-gnu

Ran in to following error starting with subject revision while trying to
bootstrap.

Config:
/home/pthaugen/src/gcc/gcc_hunt/gcc/configure
--prefix=/home/pthaugen/install/gcc/gcc_hunt --enable-decimal-float
--enable-lto --with-as=/home/pthaugen/install/binutils/binutils-2.25/bin/as
--with-ld=/home/pthaugen/install/binutils/binutils-2.25/bin/ld
--with-gmp=/home/pthaugen/install/gcc-host-libs --without-ppl --without-cloog
--enable-languages=c,c++,fortran


/home/pthaugen/work/build/gcc/gcc_hunt/./gcc/xgcc
-B/home/pthaugen/work/build/gcc/gcc_hunt/./gcc/
-B/home/pthaugen/install/gcc/gcc_hunt/powerpc64-unknown-linux-gnu/bin/
-B/home/pthaugen/install/gcc/gcc_hunt/powerpc64-unknown-linux-gnu/lib/ -isystem
/home/pthaugen/install/gcc/gcc_hunt/powerpc64-unknown-linux-gnu/include
-isystem
/home/pthaugen/install/gcc/gcc_hunt/powerpc64-unknown-linux-gnu/sys-include   
-g -O2 -m32 -O2  -g -O2 -DIN_GCC    -W -Wall -Wwrite-strings -Wcast-qual
-Wno-format -Wstrict-prototypes -Wmissing-prototypes -Wold-style-definition 
-isystem ./include   -fPIC -mlong-double-128 -mno-minimal-toc -g -DIN_LIBGCC2
-fbuilding-libgcc -fno-stack-protector   -fPIC -mlong-double-128
-mno-minimal-toc -I. -I. -I../../.././gcc
-I/home/pthaugen/src/gcc/gcc_hunt/gcc/libgcc
-I/home/pthaugen/src/gcc/gcc_hunt/gcc/libgcc/.
-I/home/pthaugen/src/gcc/gcc_hunt/gcc/libgcc/../gcc
-I/home/pthaugen/src/gcc/gcc_hunt/gcc/libgcc/../include
-I/home/pthaugen/src/gcc/gcc_hunt/gcc/libgcc/../libdecnumber/dpd
-I/home/pthaugen/src/gcc/gcc_hunt/gcc/libgcc/../libdecnumber -DHAVE_CC_TLS  -o
decContext.o -MT decContext.o -MD -MP -MF decContext.dep -c
/home/pthaugen/src/gcc/gcc_hunt/gcc/libgcc/../libdecnumber/decContext.c
In file included from
/home/pthaugen/src/gcc/gcc_hunt/gcc/libgcc/../libdecnumber/decContext.h:246:0,
                 from
/home/pthaugen/src/gcc/gcc_hunt/gcc/libgcc/../libdecnumber/decContext.c:38:
/home/pthaugen/src/gcc/gcc_hunt/gcc/libgcc/../libdecnumber/decContext.c: In
function ‘__decContextStatusToString’:
/home/pthaugen/src/gcc/gcc_hunt/gcc/libgcc/../libdecnumber/decContextSymbols.h:16:34:
internal compiler error: Segmentation fault
 #define decContextStatusToString __decContextStatusToString
                                  ^
/home/pthaugen/src/gcc/gcc_hunt/gcc/libgcc/../libdecnumber/decContext.c:352:13:
note: in expansion of macro ‘decContextStatusToString’
 const char *decContextStatusToString(const decContext *context) {
             ^
0x10d2ed5f crash_signal
        /home/pthaugen/src/gcc/gcc_hunt/gcc/gcc/toplev.c:366
0x117fee78 trim_filename(char const*)
        /home/pthaugen/src/gcc/gcc_hunt/gcc/gcc/diagnostic.c:944
0x117fff87 fancy_abort(char const*, int, char const*)
        /home/pthaugen/src/gcc/gcc_hunt/gcc/gcc/diagnostic.c:1340
0x111d635f inchash::add_expr(tree_node const*, inchash::hash&)
        /home/pthaugen/src/gcc/gcc_hunt/gcc/gcc/tree.c:7708
0x10d7b167 iterative_hash_expr
        /home/pthaugen/src/gcc/gcc_hunt/gcc/gcc/tree.h:4519
0x10d7e7df tree_operand_hash::hash(tree_node const*)
        /home/pthaugen/src/gcc/gcc_hunt/gcc/gcc/tree-hash-traits.h:33
0x10d802f7 simple_hashmap_traits<tree_operand_hash>::hash(tree_node* const&)
        /home/pthaugen/src/gcc/gcc_hunt/gcc/gcc/hash-map-traits.h:126
0x110c9f9f hash_map<tree_node*, vec<tree_node*, va_heap, vl_ptr>,
val_ssa_equiv_hash_traits>::get(tree_node* const&)
        /home/pthaugen/src/gcc/gcc_hunt/gcc/gcc/hash-map.h:141
0x110c9367 uncprop_into_successor_phis
        /home/pthaugen/src/gcc/gcc_hunt/gcc/gcc/tree-ssa-uncprop.c:408
0x110c9737 uncprop_dom_walker::before_dom_children(basic_block_def*)
        /home/pthaugen/src/gcc/gcc_hunt/gcc/gcc/tree-ssa-uncprop.c:495
0x11628d93 dom_walker::walk(basic_block_def*)
        /home/pthaugen/src/gcc/gcc_hunt/gcc/gcc/domwalk.c:183
0x110c9933 execute
        /home/pthaugen/src/gcc/gcc_hunt/gcc/gcc/tree-ssa-uncprop.c:544
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.
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From: "dje at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/66729] Segfault starting with r224967
Date: Wed, 01 Jul 2015 18:58:00 -0000
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X-Bugzilla-Component: tree-optimization
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https://gcc.gnu.org/bugzilla/show_bug.cgi?idf729

--- Comment #1 from David Edelsohn <dje at gcc dot gnu.org> ---
Is this the bootstrap failure that Segher tracked to Richard Sandiford?
Richard already posted a patch.

[Bug tree-optimization/66729] Segfault starting with r224967

[rsandifo at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66729

rsandifo at gcc dot gnu.org <rsandifo at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |WAITING
   Last reconfirmed|                            |2015-07-01
     Ever confirmed|0                           |1

--- Comment #2 from rsandifo at gcc dot gnu.org <rsandifo at gcc dot gnu.org> ---
(In reply to David Edelsohn from comment #1)
> Is this the bootstrap failure that Segher tracked to Richard Sandiford? 
> Richard already posted a patch.

Yeah, it sounds like it.  I committed the patch as r225263 -- please let
me know if that didn't fix it.

[Bug tree-optimization/66729] Segfault starting with r224967

[pthaugen at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66729

--- Comment #3 from Pat Haugen <pthaugen at gcc dot gnu.org> ---
(In reply to rsandifo@gcc.gnu.org from comment #2)
> (In reply to David Edelsohn from comment #1)
> > Is this the bootstrap failure that Segher tracked to Richard Sandiford? 
> > Richard already posted a patch.
> 
> Yeah, it sounds like it.  I committed the patch as r225263 -- please let
> me know if that didn't fix it.

I still see the ICE with r225263.

[Bug tree-optimization/66729] Segfault starting with r224967

[rsandifo at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66729

--- Comment #4 from rsandifo at gcc dot gnu.org <rsandifo at gcc dot gnu.org> ---
(In reply to Pat Haugen from comment #3)
> (In reply to rsandifo@gcc.gnu.org from comment #2)
> > (In reply to David Edelsohn from comment #1)
> > > Is this the bootstrap failure that Segher tracked to Richard Sandiford? 
> > > Richard already posted a patch.
> > 
> > Yeah, it sounds like it.  I committed the patch as r225263 -- please let
> > me know if that didn't fix it.
> 
> I still see the ICE with r225263.

Hmm, bootstrap succeeded for me on gcc110.  I used r225278, but I don't
think anything significant changed between the two.

[Bug tree-optimization/66729] Segfault starting with r224967

[meissner at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66729

Michael Meissner <meissner at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |meissner at gcc dot gnu.org

--- Comment #5 from Michael Meissner <meissner at gcc dot gnu.org> ---
FWIW, I bootstrapped the compiler on the same system Pat is using internally,
and it worked (using the various configuration hacks I've developed over the
years).

[Bug tree-optimization/66729] Segfault starting with r224967

[pthaugen at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66729

--- Comment #6 from Pat Haugen <pthaugen at gcc dot gnu.org> ---
(In reply to rsandifo@gcc.gnu.org from comment #4)
> 
> Hmm, bootstrap succeeded for me on gcc110.  I used r225278, but I don't
> think anything significant changed between the two.

Mike Meissner and I ran various builds since he was not seeing any problem on
the same machine I was building on. From what I can tell, this is starting to
look like an issue when building with older compiler versions.

I can recreate the problem on machines with 4.3 and 4.4 versions of GCC as the
default distro compiler but if I modify my path so a 4.8 version of the
compiler is found first my bootstrap succeeds. Looks like gcc110 is a 4.7
distro compiler, and appears not an issue there.

[Bug tree-optimization/66729] Segfault starting with r224967

[rsandifo at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66729

--- Comment #7 from rsandifo at gcc dot gnu.org <rsandifo at gcc dot gnu.org> ---
(In reply to Pat Haugen from comment #6)
> (In reply to rsandifo@gcc.gnu.org from comment #4)
> > 
> > Hmm, bootstrap succeeded for me on gcc110.  I used r225278, but I don't
> > think anything significant changed between the two.
> 
> Mike Meissner and I ran various builds since he was not seeing any problem
> on the same machine I was building on. From what I can tell, this is
> starting to look like an issue when building with older compiler versions.
> 
> I can recreate the problem on machines with 4.3 and 4.4 versions of GCC as
> the default distro compiler but if I modify my path so a 4.8 version of the
> compiler is found first my bootstrap succeeds. Looks like gcc110 is a 4.7
> distro compiler, and appears not an issue there.

Thanks for narrowing it down.  I tried a 4.4 compiler on gcc110 and yeah,
it fails for me too.  I think the problem is due to inc_hash::add_expr
being entered with the wrong TOC pointer:

Breakpoint 1, inchash::add_expr (t=0x3fffafc8a2f0, hstate=...) at
/home/rsandifo/gcc/HEAD/gcc/gcc/tree.c:7697
7697          tclass = TREE_CODE_CLASS (code);
(gdb) p/x $r2
$1 = 0x123af688
(gdb) cond 1 $r2 != 0x123af688
(gdb) cont
Continuing.

Breakpoint 1, inchash::add_expr (t=0x3fffaf816000, hstate=...) at
/home/rsandifo/gcc/HEAD/gcc/gcc/tree.c:7697
7697          tclass = TREE_CODE_CLASS (code);
(gdb) bt
#0  inchash::add_expr (t=0x3fffaf816000, hstate=...) at
/home/rsandifo/gcc/HEAD/gcc/gcc/tree.c:7697
#1  0x0000000010ef9118 in iterative_hash_expr (tree=0x3fffaf816000, seed=0) at
/home/rsandifo/gcc/HEAD/gcc/gcc/tree.h:4519
#2  0x0000000010efc99c in tree_operand_hash::hash (t=0x3fffaf816000) at
/home/rsandifo/gcc/HEAD/gcc/gcc/tree-hash-traits.h:33
#3  0x000000001124bc7c in simple_hashmap_traits<tree_operand_hash>::hash
(h=@0x3fffffffdb30: 0x3fffaf816000)
    at /home/rsandifo/gcc/HEAD/gcc/gcc/hash-map-traits.h:48
#4  0x000000001124b7f4 in hash_map<tree_node*, vec<tree_node*, va_heap,
vl_ptr>, val_ssa_equiv_hash_traits>::get (
    this=0x125e0670, k=@0x3fffffffdb30: 0x3fffaf816000) at
/home/rsandifo/gcc/HEAD/gcc/gcc/hash-map.h:142
#5  0x000000001124ab3c in uncprop_into_successor_phis (bb=0x3fffaf850340)
    at /home/rsandifo/gcc/HEAD/gcc/gcc/tree-ssa-uncprop.c:408

So we end up loading an incorrect value of tree_code_type and thus end
up with an invalid tclass:

Dump of assembler code from 0x113575e0 to 0x11357620:
=> 0x00000000113575e0 <inchash::add_expr(tree_node const*,
inchash::hash&)+1776>:       lwz     r0,156(r31)
   0x00000000113575e4 <inchash::add_expr(tree_node const*,
inchash::hash&)+1780>:       clrldi  r0,r0,32
   0x00000000113575e8 <inchash::add_expr(tree_node const*,
inchash::hash&)+1784>:       extsw   r0,r0
   0x00000000113575ec <inchash::add_expr(tree_node const*,
inchash::hash&)+1788>:       ld      r9,-25616(r2)
(gdb) x/1a $r2-25616
0x123b9130:     0x11f86ba0
<_ZZN3vecIP21ipa_agg_jump_function7va_heap8vl_embedE10quick_pushERKS1_E12__FUNCTION__>
(gdb) p/x tree_code_type
$2 = 0x11d9131c <tree_code_type>
(gdb) print code
$3 = ADDR_EXPR
(gdb) print tclass
$4 = 1969711199

[Bug tree-optimization/66729] Segfault starting with r224967

[rsandifo at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66729

--- Comment #8 from rsandifo at gcc dot gnu.org <rsandifo at gcc dot gnu.org> ---
(In reply to rsandifo@gcc.gnu.org from comment #7)
> (gdb) print code
> $3 = ADDR_EXPR
> (gdb) print tclass
> $4 = 1969711199

Er, to be clear, this was part _after_ typing "next".  Guess I should
have quoted the full debug session.

[Bug tree-optimization/66729] Segfault starting with r224967

[rsandifo at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66729

--- Comment #9 from rsandifo at gcc dot gnu.org <rsandifo at gcc dot gnu.org> ---
Turns out to be a linker bug that is still present in binutils
mainline.  I'm testing a patch.

[Bug tree-optimization/66729] Segfault starting with r224967

[rsandifo at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66729

rsandifo at gcc dot gnu.org <rsandifo at gcc dot gnu.org> changed:

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

--- Comment #10 from rsandifo at gcc dot gnu.org <rsandifo at gcc dot gnu.org> ---
Fixed with: https://www.sourceware.org/ml/binutils/2015-07/msg00035.html
(92a9c616e496f41c3d1da949078d5739add79161).  FWIW, a workaround for
unpatched binutils is to build stage 1 with more optimisation,
via STAGE1_CFLAGS.