[tree-ssa] live analysis on local static functions

[Andrew MacLeod]

On Tue, 2003-10-14 at 13:34, law@redhat.com wrote:
> In message <1066151692.19104.2006.camel@p4>, Andrew MacLeod writes:
>  >On Tue, 2003-10-14 at 13:05, Andrew MacLeod wrote:
>  >> On Tue, 2003-10-14 at 13:03, law@redhat.com wrote:
>  >> > In message <1066149766.10504.1982.camel@p4>, Andrew MacLeod writes:
>  >> 
>  >> >  >
>  >> >  >I get out of ssa producing:
>  >> >  >
>  >> >  >q ()
>  >> >  >{
>  >> >  >  char * <U1244>;
>  >> >  >  char * retval.2;
>  >> >  >  char * T.1;
>  >> >  >
>  >> >  >
>  >> >  >  # BLOCK 0.  PRED: -1.  SUCC: 1.
>  >> >  >  {
>  >> >  >    {
>  >> >  >      static char * a = (char *)"";
>  >> >  >
>  >> >  >
>  >> >  >      #   VUSE <a_1>;
>  >> >  >      <U1244> = a;
>  >> >  >      goto <U11d0>;;
>  >> >  >    };
>  >> >  >
>  >> >  >    # BLOCK 1.  PRED: 0.  SUCC: 2.
>  >> >  >    <U11d0>:;;
>  >> >  >    (void)0;
>  >> >  >  };
>  >> >  >
>  >> >  >  # BLOCK 2.  PRED: 1.  SUCC: -2.
>  >> >  >  (void)0;
>  >> >  >  return <U1244>;;
>  >> >  >}
>  >> >  >
>  >> 
>  >> > But it still seems to me that something is missing the fact that "a"
>  >> > is actually used.  If "a" is marked as used, then everything ought to
>  >> > work as expected.
>  >> 
>  >> I am currently looking at why the VUSE <a_1> didnt mark 'a' as used.
>  >> 
>  >INterestingly, the 'a' in the BIND  has address 
>  >$7 = (union tree_node *) 0x400b12b8
>  >and the 'a' used as a base for 'a_1' is:
>  >$9 = (union tree_node *) 0x400adbc8
>  >
>  >so used is set on the one in $9, but never set on the one in $7.
> Which explains a whole lot :-)
> 
>  >Diego, any idea why we're using a different VAR_DECL?
> Probably an artifact of inlining I'd guess.  Does either one of them
> have DECL_ABSTRACT_ORIGIN set, and if so, what tree does that point to?
> 

nope. both are 0. Oh wait, yeah. the one in the BIND_EXPR does ($7). It
points to the one we are using in a_1. (the $9 value)

Andrew

(gdb) p $9->decl
$13 = {common = {chain = 0x0, type = 0x40025074, ann = 0x4001d528, 
    code = VAR_DECL, side_effects_flag = 0, constant_flag = 0, 
    addressable_flag = 0, volatile_flag = 0, readonly_flag = 0, 
    unsigned_flag = 1, asm_written_flag = 0, not_gimple_flag = 0, 
    used_flag = 1, nothrow_flag = 0, static_flag = 1, public_flag = 0, 
    private_flag = 0, protected_flag = 0, deprecated_flag = 0, unused_1 = 0, 
    lang_flag_0 = 0, lang_flag_1 = 0, lang_flag_2 = 0, lang_flag_3 = 0, 
    lang_flag_4 = 0, lang_flag_5 = 0, lang_flag_6 = 0, visited = 0}, locus = {
    file = 0x84d1ad8 "j.c", line = 4}, uid = 1002, size = 0x4001c978, 
  mode = SImode, external_flag = 0, nonlocal_flag = 0, regdecl_flag = 0, 
  inline_flag = 0, bit_field_flag = 0, virtual_flag = 0, ignored_flag = 0, 
  abstract_flag = 0, in_system_header_flag = 0, common_flag = 0, 
  defer_output = 0, transparent_union = 0, static_ctor_flag = 0, 
  static_dtor_flag = 0, artificial_flag = 0, weak_flag = 0, 
  non_addr_const_p = 0, no_instrument_function_entry_exit = 0, 
  comdat_flag = 0, malloc_flag = 0, no_limit_stack = 0, 
  built_in_class = NOT_BUILT_IN, pure_flag = 0, non_addressable = 0, 
  user_align = 0, uninlinable = 0, thread_local_flag = 0, 
  declared_inline_flag = 0, unused = 0, lang_flag_0 = 0, lang_flag_1 = 0, 
  lang_flag_2 = 0, lang_flag_3 = 0, lang_flag_4 = 0, lang_flag_5 = 0, 
  lang_flag_6 = 0, lang_flag_7 = 0, u1 = {f = BUILT_IN_COSH, i = 32, a = {
      align = 32, off_align = 0}}, size_unit = 0x4001c9d8, name = 0x400b0180, 
  context = 0x400ad9f8, arguments = 0x0, result = 0x0, initial = 0x40059800, 
  abstract_origin = 0x0, assembler_name = 0x400b0300, section_name = 0x0, 
  attributes = 0x0, rtl = 0x0, u2 = {f = 0x0, r = 0x0, t = 0x0, i = 0}, 
  saved_tree = 0x0, inlined_fns = 0x0, vindex = 0x0, pointer_alias_set = -1, 
  typevar = 0x0, lang_specific = 0x0}

(gdb) p $7->decl
$14 = {common = {chain = 0x0, type = 0x40025074, ann = 0x4001d398, 
    code = VAR_DECL, side_effects_flag = 0, constant_flag = 0, 
    addressable_flag = 0, volatile_flag = 0, readonly_flag = 0, 
    unsigned_flag = 1, asm_written_flag = 0, not_gimple_flag = 0, 
    used_flag = 1, nothrow_flag = 0, static_flag = 1, public_flag = 0, 
    private_flag = 0, protected_flag = 0, deprecated_flag = 0, unused_1 = 0, 
    lang_flag_0 = 0, lang_flag_1 = 0, lang_flag_2 = 0, lang_flag_3 = 0, 
    lang_flag_4 = 0, lang_flag_5 = 0, lang_flag_6 = 0, visited = 0}, locus = {
    file = 0x84d1ad8 "j.c", line = 4}, uid = 1008, size = 0x400b20f0, 
  mode = SImode, external_flag = 0, nonlocal_flag = 0, regdecl_flag = 0, 
  inline_flag = 0, bit_field_flag = 0, virtual_flag = 0, ignored_flag = 0, 
  abstract_flag = 0, in_system_header_flag = 0, common_flag = 0, 
  defer_output = 0, transparent_union = 0, static_ctor_flag = 0, 
  static_dtor_flag = 0, artificial_flag = 0, weak_flag = 0, 
  non_addr_const_p = 0, no_instrument_function_entry_exit = 0, 
  comdat_flag = 0, malloc_flag = 0, no_limit_stack = 0, 
  built_in_class = NOT_BUILT_IN, pure_flag = 0, non_addressable = 0, 
  user_align = 0, uninlinable = 0, thread_local_flag = 0, 
  declared_inline_flag = 0, unused = 0, lang_flag_0 = 0, lang_flag_1 = 0, 
  lang_flag_2 = 0, lang_flag_3 = 0, lang_flag_4 = 0, lang_flag_5 = 0, 
  lang_flag_6 = 0, lang_flag_7 = 0, u1 = {f = BUILT_IN_COSH, i = 32, a = {
      align = 32, off_align = 0}}, size_unit = 0x400b2108, name = 0x400b0180, 
  context = 0x400ad9f8, arguments = 0x0, result = 0x0, initial = 0x40059ba0, 
  abstract_origin = 0x400adbc8, assembler_name = 0x400b0300, 
  section_name = 0x0, attributes = 0x0, rtl = 0x0, u2 = {f = 0x0, r = 0x0, 
    t = 0x0, i = 0}, saved_tree = 0x0, inlined_fns = 0x0, vindex = 0x0, 
  pointer_alias_set = -1, typevar = 0x0, lang_specific = 0x0}