2008-04-30 Paul Thomas <pault@gcc.gnu.org>

[pf3gnuchains/gcc-fork.git] / gcc / tree-ssa-pre.c

diff --git a/gcc/tree-ssa-pre.c b/gcc/tree-ssa-pre.c
index 616627c..13c4e97 100644 (file)
--- a/gcc/tree-ssa-pre.c
+++ b/gcc/tree-ssa-pre.c
@@ -3369,7 +3369,6 @@ make_values_for_stmt (tree stmt, basic_block block)
            && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs))
           || is_gimple_min_invariant (rhs)
           || TREE_CODE (rhs) == ADDR_EXPR
-          || TREE_INVARIANT (rhs)
           || DECL_P (rhs))
     {
 
@@ -3605,10 +3604,11 @@ do_SCCVN_insertion (tree stmt, tree ssa_vn)
 
 /* Eliminate fully redundant computations.  */
 
-static void
+static unsigned int
 eliminate (void)
 {
   basic_block b;
+  unsigned int todo = 0;
 
   FOR_EACH_BB (b)
     {
@@ -3689,8 +3689,46 @@ eliminate (void)
                    }
                }
            }
+         /* Visit COND_EXPRs and fold the comparison with the
+            available value-numbers.  */
+         else if (TREE_CODE (stmt) == COND_EXPR
+                  && COMPARISON_CLASS_P (COND_EXPR_COND (stmt)))
+           {
+             tree cond = COND_EXPR_COND (stmt);
+             tree op0 = TREE_OPERAND (cond, 0);
+             tree op1 = TREE_OPERAND (cond, 1);
+             tree result;
+
+             if (TREE_CODE (op0) == SSA_NAME)
+               op0 = VN_INFO (op0)->valnum;
+             if (TREE_CODE (op1) == SSA_NAME)
+               op1 = VN_INFO (op1)->valnum;
+             result = fold_binary (TREE_CODE (cond), TREE_TYPE (cond),
+                                   op0, op1);
+             if (result && TREE_CODE (result) == INTEGER_CST)
+               {
+                 COND_EXPR_COND (stmt) = result;
+                 update_stmt (stmt);
+                 todo = TODO_cleanup_cfg;
+               }
+           }
+         else if (TREE_CODE (stmt) == COND_EXPR
+                  && TREE_CODE (COND_EXPR_COND (stmt)) == SSA_NAME)
+           {
+             tree op = COND_EXPR_COND (stmt);
+             op = VN_INFO (op)->valnum;
+             if (TREE_CODE (op) == INTEGER_CST)
+               {
+                 COND_EXPR_COND (stmt) = integer_zerop (op)
+                   ? boolean_false_node : boolean_true_node;
+                 update_stmt (stmt);
+                 todo = TODO_cleanup_cfg;
+               }
+           }
        }
     }
+
+  return todo;
 }
 
 /* Borrow a bit of tree-ssa-dce.c for the moment.
@@ -3931,9 +3969,10 @@ fini_pre (void)
 /* Main entry point to the SSA-PRE pass.  DO_FRE is true if the caller
    only wants to do full redundancy elimination.  */
 
-static void
+static unsigned int
 execute_pre (bool do_fre)
 {
+  unsigned int todo = 0;
 
   do_partial_partial = optimize > 2;
   init_pre (do_fre);
@@ -3947,7 +3986,7 @@ execute_pre (bool do_fre)
       if (!do_fre)
        remove_dead_inserted_code ();
       fini_pre ();
-      return;
+      return 0;
     }
   switch_to_PRE_table ();
   compute_avail ();
@@ -3978,7 +4017,7 @@ execute_pre (bool do_fre)
     }
 
   /* Remove all the redundant expressions.  */
-  eliminate ();
+  todo |= eliminate ();
 
   if (dump_file && (dump_flags & TDF_STATS))
     {
@@ -3999,6 +4038,8 @@ execute_pre (bool do_fre)
     }
 
   fini_pre ();
+
+  return todo;
 }
 
 /* Gate and execute functions for PRE.  */
@@ -4006,8 +4047,7 @@ execute_pre (bool do_fre)
 static unsigned int
 do_pre (void)
 {
-  execute_pre (false);
-  return TODO_rebuild_alias;
+  return TODO_rebuild_alias | execute_pre (false);
 }
 
 static bool
@@ -4016,8 +4056,10 @@ gate_pre (void)
   return flag_tree_pre != 0;
 }
 
-struct tree_opt_pass pass_pre =
+struct gimple_opt_pass pass_pre =
 {
+ {
+  GIMPLE_PASS,
   "pre",                               /* name */
   gate_pre,                            /* gate */
   do_pre,                              /* execute */
@@ -4031,8 +4073,8 @@ struct tree_opt_pass pass_pre =
   0,                                   /* properties_destroyed */
   0,                                   /* todo_flags_start */
   TODO_update_ssa_only_virtuals | TODO_dump_func | TODO_ggc_collect
-  | TODO_verify_ssa, /* todo_flags_finish */
-  0                                    /* letter */
+  | TODO_verify_ssa /* todo_flags_finish */
+ }
 };
 
 
@@ -4041,8 +4083,7 @@ struct tree_opt_pass pass_pre =
 static unsigned int
 execute_fre (void)
 {
-  execute_pre (true);
-  return 0;
+  return execute_pre (true);
 }
 
 static bool
@@ -4051,8 +4092,10 @@ gate_fre (void)
   return flag_tree_fre != 0;
 }
 
-struct tree_opt_pass pass_fre =
+struct gimple_opt_pass pass_fre =
 {
+ {
+  GIMPLE_PASS,
   "fre",                               /* name */
   gate_fre,                            /* gate */
   execute_fre,                         /* execute */
@@ -4064,6 +4107,6 @@ struct tree_opt_pass pass_fre =
   0,                                   /* properties_provided */
   0,                                   /* properties_destroyed */
   0,                                   /* todo_flags_start */
-  TODO_dump_func | TODO_ggc_collect | TODO_verify_ssa, /* todo_flags_finish */
-  0                                    /* letter */
+  TODO_dump_func | TODO_ggc_collect | TODO_verify_ssa /* todo_flags_finish */
+ }
 };