[tree-ssa] invoke some cleanups at -O0

[Richard Henderson <rth at twiddle dot net>]

I think that long term we need for there to be exactly one way that
exceptions are handled.  Eventually we'll remove the -fno-gimple
option and that'll be able to happen.

In the near term this fixes a failure in g++.dg/eh/cleanup1.C that
happens on Alpha that did not happen on x86.  We blow the stack in
expand_expr handling the 8000 nested try_finally_exprs.  We still
timeout in this test, but I consider that better than an ICE.


r~


        * tree-optimize.c (optimize_function_tree): Move calls to
        remove_useless_stmts_and_vars and lower_eh_constructs ...
        (tree_rest_of_compilation): ... here.

Index: tree-optimize.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/tree-optimize.c,v
retrieving revision 1.1.4.52
diff -c -p -d -r1.1.4.52 tree-optimize.c
*** tree-optimize.c	28 Sep 2003 06:06:37 -0000	1.1.4.52
--- tree-optimize.c	30 Sep 2003 20:49:19 -0000
*************** optimize_function_tree (tree fndecl)
*** 61,83 ****
    /* Build the flowgraph.  */
    init_flow ();
  
-   /* Run a pass over the statements deleting any obviously useless
-      statements before we build the CFG.  */
-   remove_useless_stmts_and_vars (&DECL_SAVED_TREE (fndecl), false);
-   {
-     int flags;
-     FILE *file = dump_begin (TDI_useless, &flags);
-     if (file)
-       {
- 	dump_function_to_file (fndecl, file, flags);
- 	dump_end (TDI_useless, file);
-       }
-   }
- 
-   /* Run a pass to lower magic exception handling constructs into,
-      well, less magic though not completely mundane constructs.  */
-   lower_eh_constructs (&DECL_SAVED_TREE (fndecl));
- 
    build_tree_cfg (DECL_SAVED_TREE (fndecl));
  
    /* Begin analysis and optimization passes.  After the function is
--- 61,66 ----
*************** tree_rest_of_compilation (tree fndecl, b
*** 299,304 ****
--- 282,304 ----
        /* Debugging dump after gimplification.  */
        dump_function (TDI_gimple, fndecl);
  
+       /* Run a pass over the statements deleting any obviously useless
+ 	 statements before we build the CFG.  */
+       remove_useless_stmts_and_vars (&DECL_SAVED_TREE (fndecl), false);
+       {
+ 	int flags;
+ 	FILE *file = dump_begin (TDI_useless, &flags);
+ 	if (file)
+ 	  {
+ 	    dump_function_to_file (fndecl, file, flags);
+ 	    dump_end (TDI_useless, file);
+ 	  }
+       }
+ 
+       /* Run a pass to lower magic exception handling constructs into,
+ 	 well, less magic though not completely mundane constructs.  */
+       lower_eh_constructs (&DECL_SAVED_TREE (fndecl));
+ 
        /* Invoke the SSA tree optimizer.  */
        if (optimize >= 1 && !flag_disable_tree_ssa)
          optimize_function_tree (fndecl);