[Bug tree-optimization/37868] [4.3 Regression] code that breaks TBAA is misoptimized even with -fno-strict-aliasing

["rguenth at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org>]

------- Comment #8 from rguenth at gcc dot gnu dot org  2008-11-20 12:13 -------
Subject: Bug 37868

Author: rguenth
Date: Thu Nov 20 12:12:01 2008
New Revision: 142040

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=142040
Log:
2008-11-20  Richard Guenther  <rguenther@suse.de>

        PR tree-optimization/37868
        * tree-ssa-structalias.c (set_uids_in_ptset): Add SFTs based on
        pointed to variable and access size.

        * gcc.dg/torture/pr37868.c: New testcase.
        * gcc.c-torture/execute/pr38048-1.c: Likewise.
        * gcc.c-torture/execute/pr38048-2.c: Likewise.

        Backport from mainline:
        2008-07-07  Richard Guenther  <rguenther@suse.de>

        * tree-ssa-structalias.c (struct variable_info): Add is_full_var flag.
        (new_var_info): Set it to false.
        (solution_set_add): Correctly handle pointers outside a var and
        inside a field.
        (type_safe): Treat variables with is_full_var properly.
        (do_sd_constraint): Likewise.
        (do_ds_constraint): Likewise.
        (process_constraint): Remove zeroing offset for !use_field_sensitive.
        (get_constraint_for_ptr_offset): New function.
        (get_constraint_for_component_ref): Handle is_full_vars properly.
        (get_constraint_for): Handle POINTER_PLUS_EXPR.
        (handle_ptr_arith): Remove.
        (find_func_aliases): Handle POINTER_PLUS_EXPR through generic
        get_constraint_for code.
        (create_function_info_for): For parameter and result varinfos set
        is_full_var flag.
        (create_variable_info_for): Set is_full_var flag whenever we
        just created a single varinfo for a decl.
        (init_alias_vars): Initialize use_field_sensitive from
        max-fields-for-field-sensitive parameter.

        * gcc.dg/torture/pta-ptrarith-1.c: New testcase.
        * gcc.dg/torture/pta-ptrarith-2.c: Likewise.

Added:
    branches/gcc-4_3-branch/gcc/testsuite/gcc.c-torture/execute/pr38048-1.c
    branches/gcc-4_3-branch/gcc/testsuite/gcc.c-torture/execute/pr38048-2.c
    branches/gcc-4_3-branch/gcc/testsuite/gcc.dg/torture/pr37868.c
    branches/gcc-4_3-branch/gcc/testsuite/gcc.dg/torture/pta-ptrarith-1.c
    branches/gcc-4_3-branch/gcc/testsuite/gcc.dg/torture/pta-ptrarith-2.c
Modified:
    branches/gcc-4_3-branch/gcc/ChangeLog
    branches/gcc-4_3-branch/gcc/testsuite/ChangeLog
    branches/gcc-4_3-branch/gcc/tree-ssa-structalias.c


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37868