[Bug rtl-optimization/44169] Wrong code while generating TLS offsets

[Bug rtl-optimization/44169] Wrong code while generating TLS offsets

[gcc at breakpoint dot cc]

------- Comment #1 from gcc at breakpoint dot cc  2010-05-17 15:44 -------
Created an attachment (id=20683)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=20683&action=view)
test case


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44169

[Bug rtl-optimization/44169] New: Wrong code while generating TLS offsets

[gcc at breakpoint dot cc]

libgomp testsuite fails with a segfault. It segfaults in
gomp_resolve_num_threads(), accessing the second TLS value.

The first access:
 .LBB28:
         .file 2 "../../../src/libgomp/libgomp.h"
         .loc 2 380 0
         bcl 20,31,$+8
         .long _GLOBAL_OFFSET_TABLE_-$
         mflr 9
         lwz 0,0(9)
         add 9,9,0
         lwz 9,gomp_tls_data@got@tprel(9)
         add 9,9,gomp_tls_data@tls
         lwz 9,40(9)

The second:
.LBE27:
         .loc 1 47 0
         cmpwi 7,3,1
         beq- 7,.L37
 .LVL32:
         .loc 1 49 0
         bcl 20,31,$+8
         .long _GLOBAL_OFFSET_TABLE_-$
         mflr 9
         add 9,9,0
         lwz 9,gomp_tls_data@got@tprel(9)
         add 9,9,gomp_tls_data@tls
         lwz 0,28(9)

After mflr, the lwz is missing. r0 has the offset from last lr which is wrong 
here.
The RTL in tc.c.185r.cprop_hardreg has the lwz included, the next pass  
tc.c.186r.dce does not anymore.

lwz gets not killed if I used -mcpu=power or -mcpu=e300c3. I used -mcpu=8540
which is default for powerpc-linux-gnuspe. -O1 was used in the test case.
The complete cmd line:

 /build/bigeasy/gcc-4.4-4.4.4/build/./gcc/xgcc   \
         -B/build/bigeasy/gcc-4.4-4.4.4/build/./gcc/ \
         -B/usr/powerpc-linux-gnuspe/bin/ \
         -B/usr/powerpc-linux-gnuspe/lib/ \
         -isystem \
         /usr/powerpc-linux-gnuspe/include \
         -isystem \
         /usr/powerpc-linux-gnuspe/sys-include \
         -Werror \
         -pthread \
         -ftls-model=initial-exec \
         -O2 \
         -pthread \
         -fPIC \
         -DPIC \
         tc.c \
         -o \
         tc.S \
         -S \
         -mcpu=8540 \
         -O1 \
         -fdump-rtl-all \
         -c \

A side note: the complete file (parallel.c from libgomp) was compiled with -O2
and the lwz was killed between parallel.c.174r.postreload and
parallel.c.176r.split2.


-- 
           Summary: Wrong code while generating TLS offsets
           Product: gcc
           Version: 4.4.4
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: gcc at breakpoint dot cc
 GCC build triplet: powerpc-linux-gnuspe
  GCC host triplet: powerpc-linux-gnuspe
GCC target triplet: powerpc-linux-gnuspe


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44169

[Bug rtl-optimization/44169] Wrong code while generating TLS offsets

[gcc at breakpoint dot cc]

------- Comment #2 from gcc at breakpoint dot cc  2010-05-17 15:44 -------
Created an attachment (id=20684)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=20684&action=view)
rtl pass 185r.cprop_hardreg


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44169

[Bug rtl-optimization/44169] Wrong code while generating TLS offsets

[gcc at breakpoint dot cc]

------- Comment #3 from gcc at breakpoint dot cc  2010-05-17 15:45 -------
Created an attachment (id=20685)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=20685&action=view)
rtl pass 186r.dce


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44169

[Bug rtl-optimization/44169] Wrong code while generating TLS offsets

[segher at gcc dot gnu dot org]

------- Comment #4 from segher at gcc dot gnu dot org  2010-05-18 08:26 -------
Confirmed with current 4.4 branch and mainline.

-mabi=nospe -mno=spe doesn't make the problem go away; only
changing -mcpu does.


-- 

segher at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |segher at gcc dot gnu dot
                   |                            |org
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
      Known to fail|                            |4.4.4 4.6.0
   Last reconfirmed|0000-00-00 00:00:00         |2010-05-18 08:26:21
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44169

[Bug rtl-optimization/44169] Wrong code while generating TLS offsets

[Kyle dot D dot Moffett at boeing dot com]

------- Comment #5 from Kyle dot D dot Moffett at boeing dot com  2010-05-20 04:53 -------
I am not able to reproduce this with a cross-compiling GCC 4.4.3 or 4.4.4 built
from Debian sources.  Configuration parameters for GCC 4.4.4 were:

-v
--with-pkgversion='Debian 4.4.4-2'
--with-bugurl='file:///usr/share/doc/gcc-4.4/README.Bugs'
--prefix=/usr
--enable-shared
--enable-multiarch
--enable-linker-build-id
--with-system-zlib
--libexecdir=/usr/lib
--without-included-gettext
--enable-threads=posix
--with-gxx-include-dir=/usr/powerpc-linux-gnuspe/include/c++/4.4.4
--program-suffix=-4.4
--enable-nls
--enable-clocale=gnu
--enable-libstdcxx-debug
--enable-objc-gc
--with-cpu=8548
--enable-e500_double
--with-long-double-128
--disable-multilib
--enable-checking=release
--program-prefix=powerpc-linux-gnuspe-
--includedir=/usr/powerpc-linux-gnuspe/include
--with-headers=/usr/powerpc-linux-gnuspe/include
--with-libs=/usr/powerpc-linux-gnuspe/lib
--build=x86_64-linux-gnu
--host=x86_64-linux-gnu
--target=powerpc-linux-gnuspe
CC=gcc
build_alias=x86_64-linux-gnu
host_alias=x86_64-linux-gnu
target_alias=powerpc-linux-gnuspe
--enable-languages=c,c++,fortran,objc,obj-c++

Versions are:
  powerpc-linux-gnuspe-gcc-4.3 (Debian 4.3.4-10 with a patch to debian/rules)
4.3.4
  powerpc-linux-gnuspe-gcc-4.4 (Debian 4.4.4-2 with a patch to debian/rules)
4.4.4

The C file was compiled as follows in both cases:
  powerpc-linux-gnuspe-gcc -Werror -pthread -ftls-model=initial-exec -O2
-pthread -fPIC -DPIC tc.c -o tc.S -S -mcpu=8540 -O1 -fdump-rtl-all -c

I'm not very familiar with the RTL passes, but if somebody can tell me what
else to look for or test I'll go scrounge around to see if I can find what's
hiding the problem for me.

Cheers,
Kyle Moffett


-- 

Kyle dot D dot Moffett at boeing dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |Kyle dot D dot Moffett at
                   |                            |boeing dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44169

[Bug rtl-optimization/44169] Wrong code while generating TLS offsets

[segher at gcc dot gnu dot org]

------- Comment #6 from segher at gcc dot gnu dot org  2010-05-20 12:10 -------
I don't see the problem with 4.3 .

Kyle, are you sure it doesn't happen for you with 4.4?

I use

powerpc-linux-gnuspe-gcc -Wall -W -O1 -pthread -ftls-model=initial-exec
-mcpu=8540 -fPIC -S t.c -fverbose-asm

paste your output of that?


-- 

segher at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to work|                            |4.3.5


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44169

[Bug rtl-optimization/44169] Wrong code while generating TLS offsets

[Kyle dot D dot Moffett at boeing dot com]

------- Comment #7 from Kyle dot D dot Moffett at boeing dot com  2010-05-20 12:17 -------
Created an attachment (id=20707)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=20707&action=view)
Assembled tc.c output from Debian-built powerpc-linux-gnuspe-gcc 4.3.4


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44169

[Bug rtl-optimization/44169] Wrong code while generating TLS offsets

[Kyle dot D dot Moffett at boeing dot com]

------- Comment #8 from Kyle dot D dot Moffett at boeing dot com  2010-05-20 12:19 -------
Created an attachment (id=20708)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=20708&action=view)
Assembled tc.c output from Debian-built powerpc-linux-gnuspe-gcc 4.4.4


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44169

[Bug rtl-optimization/44169] Wrong code while generating TLS offsets

[Kyle dot D dot Moffett at boeing dot com]

------- Comment #9 from Kyle dot D dot Moffett at boeing dot com  2010-05-20 12:29 -------
Created an attachment (id=20710)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=20710&action=view)
Assembled tc.c output from Debian-built powerpc-linux-gnuspe-gcc 4.4.2


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44169

[Bug rtl-optimization/44169] Wrong code while generating TLS offsets

[Kyle dot D dot Moffett at boeing dot com]

------- Comment #10 from Kyle dot D dot Moffett at boeing dot com  2010-05-20 12:37 -------
Ok, it looks like the bug was introduced in the 4.4 branch between 4.4.2 and
4.4.4, because my old GCC 4.4.2 compiler works, but the 4.4.4 I built yesterday
after I noticed this report does not.

If needed I can spend some time to track down exactly which optimization
flag(s) cause the problem, but hopefully we've narrowed down the versions
closely enough for it to be easy to find. :-D

Cheers,
Kyle Moffett


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44169

[Bug rtl-optimization/44169] Wrong code while generating TLS offsets

[gcc at breakpoint dot cc]

------- Comment #11 from gcc at breakpoint dot cc  2010-05-21 15:21 -------
Reverting the change in PR39254 makes the issue go away.

Any ideas?


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44169

[Bug rtl-optimization/44169] Wrong code while generating TLS offsets

[amodra at gmail dot com]

------- Comment #12 from amodra at gmail dot com  2010-05-28 02:28 -------
This problem can be seen on powerpc-linux-gcc with the options -O1 -fPIC
-ftls-model=initial-exec -misel.

The error occurs between 172r.ira and 174r.postreload, not at 186r.dce as
previously reported.


-- 

amodra at gmail dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
 GCC target triplet|powerpc-linux-gnuspe        |powerpc-*


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44169

[Bug rtl-optimization/44169] Wrong code while generating TLS offsets

[amodra at gmail dot com]

------- Comment #13 from amodra at gmail dot com  2010-05-28 02:31 -------
Created an attachment (id=20765)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=20765&action=view)
ok at this point


-- 

amodra at gmail dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  Attachment #20684|0                           |1
        is obsolete|                            |
  Attachment #20685|0                           |1
        is obsolete|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44169

[Bug rtl-optimization/44169] Wrong code while generating TLS offsets

[amodra at gmail dot com]

------- Comment #14 from amodra at gmail dot com  2010-05-28 02:32 -------
Created an attachment (id=20766)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=20766&action=view)
broken here, see insn 27


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44169

[Bug rtl-optimization/44169] Wrong code while generating TLS offsets

[amodra at gmail dot com]

-- 

amodra at gmail dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |amodra at gmail dot com
                   |dot org                     |
             Status|NEW                         |ASSIGNED
   Last reconfirmed|2010-05-18 08:26:21         |2010-05-28 07:30:15
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44169

[Bug rtl-optimization/44169] Wrong code while generating TLS offsets

[amodra at gmail dot com]

------- Comment #15 from amodra at gmail dot com  2010-05-28 13:16 -------
Created an attachment (id=20768)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=20768&action=view)
gcc-4.4 patch

The underlying problem is that the load_toc_v4_PIC_1b rtl doesn't properly
describe that its output depends both on the value of a symbol,
_GLOBAL_OFFSET_TABLE_, and on its location.  This could be fixed by using an
unspec_volatile rather than unspec.  I chose instead to add a label to the rtl.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44169

[Bug rtl-optimization/44169] Wrong code while generating TLS offsets

[amodra at gcc dot gnu dot org]

------- Comment #16 from amodra at gcc dot gnu dot org  2010-06-03 02:47 -------
Subject: Bug 44169

Author: amodra
Date: Thu Jun  3 02:47:11 2010
New Revision: 160206

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=160206
Log:
        PR target/44169
        * config/rs6000/rs6000.md (load_toc_v4_PIC_1b): Add label operand.
        * config/rs6000/rs6000.c (rs6000_legitimize_tls_address): Pass label
        rtx to gen_load_toc_v4_PIC_1b.  Tidy.
        (rs6000_emit_load_toc_table): Likewise.


Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/config/rs6000/rs6000.c
    trunk/gcc/config/rs6000/rs6000.md


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44169

[Bug rtl-optimization/44169] Wrong code while generating TLS offsets

[amodra at gcc dot gnu dot org]

------- Comment #17 from amodra at gcc dot gnu dot org  2010-06-03 02:57 -------
Subject: Bug 44169

Author: amodra
Date: Thu Jun  3 02:57:19 2010
New Revision: 160207

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=160207
Log:
        PR target/44169
        * config/rs6000/rs6000.md (load_toc_v4_PIC_1b): Add label operand.
        * config/rs6000/rs6000.c (rs6000_legitimize_tls_address): Pass label
        rtx to gen_load_toc_v4_PIC_1b.  Tidy.
        (rs6000_emit_load_toc_table): Likewise.


Modified:
    branches/gcc-4_5-branch/gcc/ChangeLog
    branches/gcc-4_5-branch/gcc/config/rs6000/rs6000.c
    branches/gcc-4_5-branch/gcc/config/rs6000/rs6000.md


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44169

[Bug rtl-optimization/44169] Wrong code while generating TLS offsets

[amodra at gcc dot gnu dot org]

------- Comment #18 from amodra at gcc dot gnu dot org  2010-06-03 03:09 -------
Subject: Bug 44169

Author: amodra
Date: Thu Jun  3 03:08:32 2010
New Revision: 160208

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=160208
Log:
        PR target/44169
        * config/rs6000/rs6000.md (load_toc_v4_PIC_1b): Add label operand.
        * config/rs6000/rs6000.c (rs6000_legitimize_tls_address): Pass label
        rtx to gen_load_toc_v4_PIC_1b.  Tidy.
        (rs6000_emit_load_toc_table): Likewise.


Modified:
    branches/gcc-4_4-branch/gcc/ChangeLog
    branches/gcc-4_4-branch/gcc/config/rs6000/rs6000.c
    branches/gcc-4_4-branch/gcc/config/rs6000/rs6000.md


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44169

[Bug rtl-optimization/44169] Wrong code while generating TLS offsets

[amodra at gmail dot com]

------- Comment #19 from amodra at gmail dot com  2010-06-03 03:26 -------
Fixed all active branches


-- 

amodra at gmail dot com changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44169