[Bug rtl-optimization/41862] New: valgrind warns about using uninitialized variable with -fgcse-sm

[Bug rtl-optimization/41862] New: valgrind warns about using uninitialized variable with -fgcse-sm

[zsojka at seznam dot cz]

4.5.0 r153685 

Command line:
$ valgrind --track-origins=yes -v
/mnt/svn/gcc-trunk/binary-153685-lto/libexec/gcc/x86_64-unknown-linux-gnu/4.5.0/cc1
-fpreprocessed testcase.i -m32 -O1 -version -fgcse-sm -o tmp.o

...

GNU C (GCC) version 4.5.0 20091028 (experimental) (x86_64-unknown-linux-gnu)    
        compiled by GNU C version 4.5.0 20091028 (experimental), GMP version
4.3.1, MPFR version 2.4.1-p5, MPC version 0.7 

...

==5211== 43 errors in context 1 of 2:                                           
==5211== Conditional jump or move depends on uninitialised value(s)             
==5211==    at 0x7B2215: store_killed_after (store-motion.c:270)                
==5211==    by 0x7B3221: execute_rtl_store_motion (store-motion.c:1084)         
==5211==    by 0x71349C: execute_one_pass (passes.c:1519)                       
==5211==    by 0x7136C4: execute_pass_list (passes.c:1568)                      
==5211==    by 0x7136D6: execute_pass_list (passes.c:1569)                      
==5211==    by 0x80B8B0: tree_rest_of_compilation (tree-optimize.c:392)         
==5211==    by 0x9836AB: cgraph_expand_function (cgraphunit.c:1160)             
==5211==    by 0x985524: cgraph_optimize (cgraphunit.c:1219)                    
==5211==    by 0x985A5E: cgraph_finalize_compilation_unit (cgraphunit.c:1089)   
==5211==    by 0x4AE2DA: c_write_global_declarations (c-decl.c:9489)            
==5211==    by 0x7B8CAB: toplev_main (toplev.c:1061)                            
==5211==    by 0x6587A25: (below main) (in /lib64/libc-2.10.1.so)               
==5211==  Uninitialised value was created by a heap allocation                  
==5211==    at 0x4C270AC: malloc (in
/usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)                          
==5211==    by 0xC90C27: xmalloc (xmalloc.c:147)                                
==5211==    by 0x7B30CB: execute_rtl_store_motion (store-motion.c:1066)         
==5211==    by 0x71349C: execute_one_pass (passes.c:1519)                       
==5211==    by 0x7136C4: execute_pass_list (passes.c:1568)                      
==5211==    by 0x7136D6: execute_pass_list (passes.c:1569)                      
==5211==    by 0x80B8B0: tree_rest_of_compilation (tree-optimize.c:392)         
==5211==    by 0x9836AB: cgraph_expand_function (cgraphunit.c:1160)             
==5211==    by 0x985524: cgraph_optimize (cgraphunit.c:1219)                    
==5211==    by 0x985A5E: cgraph_finalize_compilation_unit (cgraphunit.c:1089)   
==5211==    by 0x4AE2DA: c_write_global_declarations (c-decl.c:9489)            
==5211==    by 0x7B8CAB: toplev_main (toplev.c:1061)                            
==5211==                                                                        
==5211==                                                                        
==5211== 2273 errors in context 2 of 2:                                         
==5211== Conditional jump or move depends on uninitialised value(s)             
==5211==    at 0x7B21FD: store_killed_after (store-motion.c:270)                
==5211==    by 0x7B3221: execute_rtl_store_motion (store-motion.c:1084)         
==5211==    by 0x71349C: execute_one_pass (passes.c:1519)                       
==5211==    by 0x7136C4: execute_pass_list (passes.c:1568)                      
==5211==    by 0x7136D6: execute_pass_list (passes.c:1569)                      
==5211==    by 0x80B8B0: tree_rest_of_compilation (tree-optimize.c:392)         
==5211==    by 0x9836AB: cgraph_expand_function (cgraphunit.c:1160)             
==5211==    by 0x985524: cgraph_optimize (cgraphunit.c:1219)                    
==5211==    by 0x985A5E: cgraph_finalize_compilation_unit (cgraphunit.c:1089)   
==5211==    by 0x4AE2DA: c_write_global_declarations (c-decl.c:9489)            
==5211==    by 0x7B8CAB: toplev_main (toplev.c:1061)                            
==5211==    by 0x6587A25: (below main) (in /lib64/libc-2.10.1.so)               
==5211==  Uninitialised value was created by a heap allocation                  
==5211==    at 0x4C270AC: malloc (in
/usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)                          
==5211==    by 0xC90C27: xmalloc (xmalloc.c:147)                                
==5211==    by 0x7B30CB: execute_rtl_store_motion (store-motion.c:1066)         
==5211==    by 0x71349C: execute_one_pass (passes.c:1519)                       
==5211==    by 0x7136C4: execute_pass_list (passes.c:1568)                      
==5211==    by 0x7136D6: execute_pass_list (passes.c:1569)                      
==5211==    by 0x80B8B0: tree_rest_of_compilation (tree-optimize.c:392)         
==5211==    by 0x9836AB: cgraph_expand_function (cgraphunit.c:1160)             
==5211==    by 0x985524: cgraph_optimize (cgraphunit.c:1219)                    
==5211==    by 0x985A5E: cgraph_finalize_compilation_unit (cgraphunit.c:1089)   
==5211==    by 0x4AE2DA: c_write_global_declarations (c-decl.c:9489)            
==5211==    by 0x7B8CAB: toplev_main (toplev.c:1061)


-- 
           Summary: valgrind warns about using uninitialized variable with -
                    fgcse-sm
           Product: gcc
           Version: 4.5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: zsojka at seznam dot cz
  GCC host triplet: i686-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41862

[Bug rtl-optimization/41862] valgrind warns about using uninitialized variable with -fgcse-sm

[zsojka at seznam dot cz]

------- Comment #1 from zsojka at seznam dot cz  2009-10-29 00:04 -------
Created an attachment (id=18928)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=18928&action=view)
partially reduced testcase


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41862

[Bug rtl-optimization/41862] valgrind warns about using uninitialized variable with -fgcse-sm

[zsojka at seznam dot cz]

------- Comment #2 from zsojka at seznam dot cz  2009-10-29 00:06 -------
Created an attachment (id=18929)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=18929&action=view)
warning disappears when this diff is applied


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41862

[Bug rtl-optimization/41862] valgrind warns about using uninitialized variable with -fgcse-sm

[rguenth at gcc dot gnu dot org]

------- Comment #3 from rguenth at gcc dot gnu dot org  2009-10-29 10:25 -------
Steven knows this code best.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |stevenb dot gcc at gmail dot
                   |                            |com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41862

[Bug rtl-optimization/41862] valgrind warns about using uninitialized variable with -fgcse-sm

[steven at gcc dot gnu dot org]

------- Comment #4 from steven at gcc dot gnu dot org  2009-10-29 10:57 -------
Mine. Investigating.


-- 

steven at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|stevenb dot gcc at gmail dot|
                   |com                         |
         AssignedTo|unassigned at gcc dot gnu   |steven at gcc dot gnu dot
                   |dot org                     |org
             Status|UNCONFIRMED                 |ASSIGNED
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2009-10-29 10:57:51
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41862

[Bug rtl-optimization/41862] valgrind warns about using uninitialized variable with -fgcse-sm

[zsojka at seznam dot cz]

------- Comment #5 from zsojka at seznam dot cz  2009-11-17 18:34 -------
Created an attachment (id=19029)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=19029&action=view)
reduced testcase

BINARY=/mnt/svn/gcc-trunk/binary-154190-lto/libexec/gcc/x86_64-unknown-linux-gnu/4.5.0/cc1

valgrind --malloc-fill=0x00 $BINARY -O1 -fgcse-sm -fPIC -m32 -o malloc-00.S
pr41862.i
valgrind --malloc-fill=0xff $BINARY -O1 -fgcse-sm -fPIC -m32 -o malloc-ff.S
pr41862.i
diff malloc-00.S malloc-ff.S

Gives:
13a14
>       movl    %esi, gm@GOTOFF(%ebx)
21,22c22,23
<       leal    1(%esi), %eax
<       movl    %eax, gm@GOTOFF(%ebx)
---
>       addl    $1, %esi
>       movl    %esi, gm@GOTOFF(%ebx)

The first store is redundant, caused by using uninitialised memory by gcc.


-- 

zsojka at seznam dot cz changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  Attachment #18928|0                           |1
        is obsolete|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41862

[Bug rtl-optimization/41862] valgrind warns about using uninitialized variable with -fgcse-sm

[zsojka at seznam dot cz]

------- Comment #6 from zsojka at seznam dot cz  2009-11-25 10:45 -------
Also it causes bootstrap comparison failures for me at x86_64-pc-linux-gnu,
r154643

export CFLAGS="-O2 -fgcse-sm"
export CXXFLAGS="-O2 -fgcse-sm"
../configure --enable-languages=c,c++
--prefix=/mnt/svn/gcc-trunk/binary-154643-O2-gcse-sm
make

...

Comparing stages 2 and 3
warning: gcc/cc1plus-checksum.o differs
warning: gcc/cc1-checksum.o differs
Bootstrap comparison failure!
x86_64-unknown-linux-gnu/32/libgcc/multf3_s.o differs
x86_64-unknown-linux-gnu/32/libgcc/bid128_div.o differs
x86_64-unknown-linux-gnu/32/libgcc/addtf3_s.o differs
x86_64-unknown-linux-gnu/32/libgcc/fixtfsi.o differs
make[2]: *** [compare] Error 1

Should this be marked as regression?


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41862

[Bug rtl-optimization/41862] [4.5 Regression] -fgcse-sm causes bootstrap comparison failures

[zsojka at seznam dot cz]

------- Comment #7 from zsojka at seznam dot cz  2009-11-27 11:23 -------
My fault for not using -fgcse-sm in BOOT_CFLAGS. With that, it gets worse:
$ nice -n 19 make -j3 BOOT_CFLAGS="-O2 -fgcse-sm"

Comparing stages 2 and 3
warning: gcc/cc1plus-checksum.o differs
warning: gcc/cc1-checksum.o differs
Bootstrap comparison failure!
gcc/cp/pt.o differs
gcc/explow.o differs
gcc/tree-into-ssa.o differs
gcc/bitmap.o differs
gcc/dwarf2out.o differs
gcc/double-int.o differs
gcc/ipa-prop.o differs
gcc/stor-layout.o differs
libdecnumber/decimal128.o differs
libdecnumber/decimal32.o differs
libdecnumber/decimal64.o differs
libdecnumber/decNumber.o differs
x86_64-unknown-linux-gnu/32/libgcc/trunctfxf2_s.o differs
x86_64-unknown-linux-gnu/32/libgcc/multf3_s.o differs
x86_64-unknown-linux-gnu/32/libgcc/multf3.o differs
x86_64-unknown-linux-gnu/32/libgcc/fixtfsi_s.o differs
x86_64-unknown-linux-gnu/32/libgcc/bid128_div.o differs


-- 

zsojka at seznam dot cz changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|valgrind warns about using  |[4.5 Regression] -fgcse-sm
                   |uninitialized variable with |causes bootstrap comparison
                   |-fgcse-sm                   |failures


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41862

[Bug rtl-optimization/41862] [4.5 Regression] -fgcse-sm causes bootstrap comparison failures

[rguenth at gcc dot gnu dot org]

-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.5.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41862

[Bug rtl-optimization/41862] [4.5 Regression] -fgcse-sm causes bootstrap comparison failures

[steven at gcc dot gnu dot org]

------- Comment #8 from steven at gcc dot gnu dot org  2009-12-24 13:12 -------
http://gcc.gnu.org/ml/gcc-patches/2009-12/msg01114.html fixes part of this bug,
but I still get a bootstrap comparison failure.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41862

[Bug rtl-optimization/41862] [4.5 Regression] -fgcse-sm causes bootstrap comparison failures

[zsojka at seznam dot cz]

------- Comment #9 from zsojka at seznam dot cz  2009-12-24 20:24 -------
Thank you for commiting that patch. I am also receiving bootstrap comparison
failures at x86_64 (r155455, -O2 -fgcse-sm):
gcc/double-int.o differs
libcpp/expr.o differs

r155434 without -fgcse-sm bootstraps fine (I didn't test r155455 without
-fgcse-sm, yet)
When I applied patch from comment #2 (it does the same as the commited patch)
to r153685, it bootstraped fine as well.
There are (used to be?) "random" cfgloopmanip.o comparison failures appearing
when building from gentoo's sources (not vanilla, so I didn't report it, and I
wasn't able to reproduce it) (those sources are weekly snapshots - some
snapshots managed to compile, some didn't).
I hope this information can be in some way useful.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41862

[Bug rtl-optimization/41862] [4.5 Regression] -fgcse-sm causes bootstrap comparison failures

[zsojka at seznam dot cz]

------- Comment #10 from zsojka at seznam dot cz  2009-12-24 20:35 -------
(In reply to comment #9)
> When I applied patch from comment #2 (it does the same as the commited patch)
> to r153685, it bootstraped fine as well.

With -O2 -fgcse-sm, that is. (I don't know if that was a luck, some latent bug
that wasn't visible in that revision, or a new bug has been introduced to trunk
since then)


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41862

[Bug rtl-optimization/41862] [4.5 Regression] -fgcse-sm causes bootstrap comparison failures

[rguenth at gcc dot gnu dot org]

------- Comment #11 from rguenth at gcc dot gnu dot org  2010-01-02 15:57 -------
Can you try with --without-build-config?  It might be just a compare-debug
failure.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41862

[Bug rtl-optimization/41862] [4.5 Regression] -fgcse-sm causes bootstrap comparison failures

[steven at gcc dot gnu dot org]

------- Comment #12 from steven at gcc dot gnu dot org  2010-01-03 17:15 -------
Re. comment #11: If I configure with "--without-build-config" on
ia64-unknown-linux-gnu, with -fgcse-sm enabled, then the bootstrap completes
successfully (all languages except ada). If I configure without the extra
option, the bootstrap fails. You say that it might be "just a compare-debug
failure" -- what does that mean and what can/should I do about it?


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41862

[Bug rtl-optimization/41862] [4.5 Regression] -fgcse-sm causes bootstrap comparison failures

[steven at gcc dot gnu dot org]

------- Comment #13 from steven at gcc dot gnu dot org  2010-01-03 17:22 -------
For traceability: http://gcc.gnu.org/ml/gcc-patches/2009-12/msg01114.html
I somehow forgot to add the PR number to the commit.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41862

[Bug rtl-optimization/41862] [4.5 Regression] -fgcse-sm causes bootstrap comparison failures

[rguenth at gcc dot gnu dot org]

------- Comment #14 from rguenth at gcc dot gnu dot org  2010-01-03 18:25 -------
It means that gcse-sm generates different code with -g vs. -g0 which likely
means that it is confused by the extra DEBUG_INSNs that appear with -g or
that its generated code depends on things like insn uids.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41862

[Bug rtl-optimization/41862] [4.5 Regression] -fgcse-sm causes bootstrap-debug comparison failures

[steven at gcc dot gnu dot org]

------- Comment #15 from steven at gcc dot gnu dot org  2010-01-03 20:02 -------
Created an attachment (id=19457)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=19457&action=view)
Ignore all DEBUG_INSNs in store-motion.c

With this patch I can complete a bootstrap on ia64-unknown-linux-gnu with
-fgcse-sm. Can't tell whether the patch makes sense, though :-)


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41862

[Bug rtl-optimization/41862] [4.5 Regression] -fgcse-sm causes bootstrap-debug comparison failures

[rguenth at gcc dot gnu dot org]

------- Comment #16 from rguenth at gcc dot gnu dot org  2010-01-03 22:33 -------
If it also passes testing it is ok for trunk (it does make sense to me).


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41862

[Bug rtl-optimization/41862] [4.5 Regression] -fgcse-sm causes bootstrap-debug comparison failures

[steven at gcc dot gnu dot org]

------- Comment #17 from steven at gcc dot gnu dot org  2010-01-03 22:41 -------
Subject: Bug 41862

Author: steven
Date: Sun Jan  3 22:41:22 2010
New Revision: 155596

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=155596
Log:
        PR rtl-optimization/41862
        * store-motion.c (store_killed_in_insn, compute_store_table,
        remove_reachable_equiv_notes, replace_store_insn,
        build_store_vectors): Ignore all DEBUG_INSNs.


Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/store-motion.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41862

[Bug rtl-optimization/41862] [4.5 Regression] -fgcse-sm causes bootstrap-debug comparison failures

[steven at gcc dot gnu dot org]

------- Comment #18 from steven at gcc dot gnu dot org  2010-01-03 22:46 -------
Works for me now.


-- 

steven at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41862