[Bug tree-optimization/47060] New: [4.6 Regression] ICE: SIGSEGV in reduction_phi (tree-parloops.c:212) with -O -ffast-math -ftree-parallelize-loops=2 -fno-tree-dce

["zsojka at seznam dot cz" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47060

           Summary: [4.6 Regression] ICE: SIGSEGV in reduction_phi
                    (tree-parloops.c:212) with -O -ffast-math
                    -ftree-parallelize-loops=2 -fno-tree-dce
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: zsojka@seznam.cz
              Host: x86_64-pc-linux-gnu
            Target: x86_64-pc-linux-gnu


Created attachment 22849
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=22849
gcc.dg/graphite/id-14.c

Compiler output:
$ gcc -O -ffast-math -ftree-parallelize-loops=2 -fno-tree-dce id-14.c
==27629== Invalid read of size 4
==27629==    at 0x9348B3: reduction_phi (tree-parloops.c:212)
==27629==    by 0x936C9F: parallelize_loops (tree-parloops.c:1912)
==27629==    by 0x9B75B8: tree_parallelize_loops (tree-ssa-loop.c:589)
==27629==    by 0x7F1745: execute_one_pass (passes.c:1553)
==27629==    by 0x7F1A34: execute_pass_list (passes.c:1608)
==27629==    by 0x7F1A46: execute_pass_list (passes.c:1609)
==27629==    by 0x7F1A46: execute_pass_list (passes.c:1609)
==27629==    by 0x931D25: tree_rest_of_compilation (tree-optimize.c:422)
==27629==    by 0xAF7311: cgraph_expand_function (cgraphunit.c:1508)
==27629==    by 0xAF99E9: cgraph_optimize (cgraphunit.c:1567)
==27629==    by 0xAF9F69: cgraph_finalize_compilation_unit (cgraphunit.c:1031)
==27629==    by 0x50983B: c_write_global_declarations (c-decl.c:9845)
==27629==    by 0x8DB515: toplev_main (toplev.c:591)
==27629==    by 0x6369BBC: (below main) (in /lib64/libc-2.11.2.so)
==27629==  Address 0x4 is not stack'd, malloc'd or (recently) free'd
==27629== 
id-14.c: In function 'foo':
id-14.c:7:1: internal compiler error: Segmentation fault
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.


Program received signal SIGSEGV, Segmentation fault.
reduction_phi (reduction_list=0x17b9630, phi=0x0) at
/mnt/svn/gcc-trunk/gcc/tree-parloops.c:212
212       tmpred.reduc_version = gimple_uid (phi);
(gdb) bt
#0  reduction_phi (reduction_list=0x17b9630, phi=0x0) at
/mnt/svn/gcc-trunk/gcc/tree-parloops.c:212
#1  0x0000000000936ca0 in try_create_reduction_list () at
/mnt/svn/gcc-trunk/gcc/tree-parloops.c:1912
#2  parallelize_loops () at /mnt/svn/gcc-trunk/gcc/tree-parloops.c:2035
#3  0x00000000009b75b9 in tree_parallelize_loops () at
/mnt/svn/gcc-trunk/gcc/tree-ssa-loop.c:589
#4  tree_parallelize_loops () at /mnt/svn/gcc-trunk/gcc/tree-ssa-loop.c:584
#5  0x00000000007f1746 in execute_one_pass (pass=0x16375a0) at
/mnt/svn/gcc-trunk/gcc/passes.c:1553
#6  0x00000000007f1a35 in execute_pass_list (pass=0x16375a0) at
/mnt/svn/gcc-trunk/gcc/passes.c:1608
#7  0x00000000007f1a47 in execute_pass_list (pass=0x1637b40) at
/mnt/svn/gcc-trunk/gcc/passes.c:1609
#8  0x00000000007f1a47 in execute_pass_list (pass=0x1636d60) at
/mnt/svn/gcc-trunk/gcc/passes.c:1609
#9  0x0000000000931d26 in tree_rest_of_compilation (fndecl=0x7ffff5cc4f00) at
/mnt/svn/gcc-trunk/gcc/tree-optimize.c:422
#10 0x0000000000af7312 in cgraph_expand_function (node=0x7ffff5ce4000) at
/mnt/svn/gcc-trunk/gcc/cgraphunit.c:1508
#11 0x0000000000af99ea in cgraph_expand_all_functions () at
/mnt/svn/gcc-trunk/gcc/cgraphunit.c:1567
#12 cgraph_optimize () at /mnt/svn/gcc-trunk/gcc/cgraphunit.c:1827
#13 0x0000000000af9f6a in cgraph_finalize_compilation_unit () at
/mnt/svn/gcc-trunk/gcc/cgraphunit.c:1031
#14 0x000000000050983c in c_write_global_declarations () at
/mnt/svn/gcc-trunk/gcc/c-decl.c:9845
#15 0x00000000008db516 in compile_file (argc=17, argv=0x7fffffffda88) at
/mnt/svn/gcc-trunk/gcc/toplev.c:591
#16 do_compile (argc=17, argv=0x7fffffffda88) at
/mnt/svn/gcc-trunk/gcc/toplev.c:1874
#17 toplev_main (argc=17, argv=0x7fffffffda88) at
/mnt/svn/gcc-trunk/gcc/toplev.c:1937
#18 0x00007ffff6586bbd in __libc_start_main () from /lib/libc.so.6
#19 0x00000000004f0415 in _start ()


Tested revisions:
r168214 - crash
r165699 - OK
4.5 r168062 - OK