Bug 131700

compiler bug.. attaching testcase..

(this bug breaks autobuild's time synchronisation). 

Created attachment 56161 [details]
testcase - -O1 or higher exposes the bug, -O0 works fine

-fno-tree-ch avoids the bug

-fno-tree-dce also

its caused by revision 101841: 

+2005-07-09  Diego Novillo  <dnovillo@redhat.com>
+
+       * Makefile.in (tree-ssa-alias.o): Depend on tree-ssa-structalias.h
+       * tree-cfg.c (CHECK_OP): Only test for is_gimple_val.
+       * tree-dfa.c (dump_subvars_for): New.
+       (debug_subvars_for): New.
+       (dump_variable): Show subvariables if VAR has them.
+       * tree-flow-inline.h (get_subvar_at): New.
+       (overlap_subvar): Change offset and size to unsigned HOST_WIDE_INT.
+       * tree-flow.h (struct ptr_info_def): Remove field pt_malloc.
+       Update all users.
+       (struct subvar): Change fields offset and size to unsigned
+       HOST_WIDE_INT.
+       (dump_subvars_for): Declare.
+       (debug_subvars_for): Declare.
+       (get_subvar_at): Declare.
+       (okay_component_ref_for_subvars): Change 2nd and 3rd argument
+       to unsigned HOST_WIDE_INT *.
+       (overlap_subvar): Likewise.
+       * tree-gimple.c (is_gimple_reg): Always return false for
+       SFTs and memory tags.
+       * tree-pass.h (pass_build_pta, pass_del_pta): Remove.
+       Update all callers.
+       * tree-ssa-alias.c: Include tree-ssa-structalias.h.
+       (compute_may_aliases): Call compute_points_to_sets.
+       (collect_points_to_info_for): Remove.
+       (compute_points_to_and_addr_escape): Remove.
+       (delete_alias_info): Call delete_points_to_sets.
+       (compute_flow_sensitive_aliasing): If the call to
+       find_what_p_points_to returns false, call set_pt_anything.
+       (add_may_alias): Set TREE_ADDRESSABLE when adding a new alias.
+       (set_pt_anything): Clear pi->pt_vars.
+       (set_pt_malloc): Remove.
+       (merge_pointed_to_info): Remove.
+       (add_pointed_to_expr): Remove.
+       (add_pointed_to_var): Remove.
+       (collect_points_to_info_r): Remove.
+       (is_escape_site): Make extern.
+       (create_sft): New.
+       (create_overlap_variables_for): Call it.
+       * tree-ssa-copy.c (merge_alias_info): Never merge
+       flow-sensitive alias information.
+       * tree-ssa-operands.c (get_expr_operands): Adjust variables
+       offset and size to be unsigned HOST_WIDE_INT.
+       (add_to_addressable_set): Rename from note_addressable.
+       Set TREE_ADDRESSABLE as the variables are added to the set.
+       Update all users.
+       (add_stmt_operand): Do not try to micro-optimize unmodifiable
+       operands into VUSEs when adding V_MAY_DEFs for members in an
+       alias set.
+       * tree-ssa-operands.h (add_to_addressable_set): Declare.
+       * tree-ssa-structalias.c: Include tree-ssa-structalias.h last.
+       (struct variable_info): Add bitfield is_heap_var.
+       (var_anyoffset, anyoffset_tree, anyoffset_id): Declare.
+       (new_var_info): Initialize is_heap_var.
+       (get_constraint_for): Add HEAP variables to the symbol table.
+       Mark them with is_heap_var.
+       (update_alias_info): New.  Taken mostly from the old
+       compute_points_to_and_addr_escape.
+       (handle_ptr_arith): New.
+       (find_func_aliases): Call update_alias_info.
+       Call handle_ptr_info for tcc_binary expressions.
+       Call mark_stmt_modified.
+       (create_variable_info_for): If DECL has subvars, do not create
+       variables for its subvars.  Always add all the fields.
+       (set_uids_in_ptset): If the solution includes ANYOFFSET and
+       SFTs, then add all the SFTs of the structure.
+       If VI->DECL is an aggregate with subvariables, add the SFT at
+       VI->OFFSET.
+       (find_what_p_points_to): If VI is an artificial variable,
+       translate to bitfields in SSA_NAME_PTR_INFO.
+       If the solution is empty, set pi->pt_vars to NULL
+       (init_base_vars): Create ANYOFFSET.
+       (compute_points_to_sets): Rename from create_alias_vars.
+       Make extern.
+       (pass_build_pta): Remove.
+       (delete_points_to_sets): Rename from delete_alias_vars.
+       (pass_del_pta): Remove.
+       * tree-ssa-structalias.h (struct alias_info): Move from
+       tree-ssa-alias.h.
+       (NUM_REFERENCES, NUM_REFERENCES_CLEAR, NUM_REFERENCES_INC,
+       NUM_REFERENCES_SET): Likewise.
+       (compute_points_to_sets, delete_points_to_sets): Declare.

http://gcc.gnu.org/ml/gcc-patches/2005-07/msg00612.html

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24627

This is FIXED in our gcc.