[tree-ssa] live analysis on local static functions

[law@redhat.com]

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?


jeff