Re: [ast-optimizer-branch] More simplification fixes [patch]

[Diego Novillo <dnovillo at redhat dot com>]

On Wed, 01 May 2002, Daniel Berlin wrote:

> On Tue, 30 Apr 2002, Diego Novillo wrote:
> 
> > This patch gets us almost all the way through stage1.  There is
> > no new functionality, just bug fixes.
> 
> Are you bootstrapping without checking on?
> 
Yup.  I caught several bugs that way.

$ grep _CHECKING auto-host.h
#define ENABLE_CHECKING 1
#define ENABLE_TREE_CHECKING 1
/* #undef ENABLE_RTL_CHECKING */
#define ENABLE_GC_CHECKING 1

> All the checking macros use statement expressions, and you didn't seem to 
> add proper support for them yet in the patch below, so i can't see how it 
> gets you that far with checking on.
> 
Statement expressions are handled by recursively simplifying the
body of the expression from simplify_expr().  Here's an example
function from c-semantics.c:

-----------------------------------------------------------------------------
add_stmt()    (ORIGINAL)
{
  [ ... ]
  if (current_function_decl != 0)
     ++*(
    {
      union tree_node * __t = current_function_decl;
      if (*__t.common.code != 30)
        tree_check_failed (__t, 30, "/home/dnovillo/ast-optimizer-branch/src/gcc/c-semantics.c", 95, "add_stmt");
      __t;
    }
    ).decl.u1.i;
  return t;
}

add_stmt()    (SIMPLIFIED)
{
  [ ... ]
  if (current_function_decl != 0)
    {
      T.23 = (
      {
        union tree_node * __t = current_function_decl;
        T.21 = *__t.common.code;
        T.22 = T.21 != 30;
        if (T.22 != 0)
          {
            T.17 = "/home/dnovillo/ast-optimizer-branch/src/gcc/c-semantics.c";
            T.18 = T.17;
            T.19 = "add_stmt";
            T.20 = T.19;
            tree_check_failed (__t, 30, T.18, 95, T.20);
          }
        __t;
      }
      );
      T.24 = *T.23.decl.u1.i;
      *T.23.decl.u1.i = T.24 + 1;
      *T.23.decl.u1.i;
    }
  return t;
}
-----------------------------------------------------------------------------

But maybe there's something I'm missing?  I don't particularly
like the way we deal with stmt expressions now.  I'd like the
simplifier to make them go away, but ignoring them now is easier.


Thanks.  Diego.