remove unused files

[platform/upstream/gcc48.git] / gcc / tree-ssa-dse.c

diff --git a/gcc/tree-ssa-dse.c b/gcc/tree-ssa-dse.c
index 285d08c..223682b 100644 (file)
--- a/gcc/tree-ssa-dse.c
+++ b/gcc/tree-ssa-dse.c
@@ -1,6 +1,5 @@
 /* Dead store elimination
-   Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010
-   Free Software Foundation, Inc.
+   Copyright (C) 2004-2013 Free Software Foundation, Inc.
 
 This file is part of GCC.
 
@@ -26,11 +25,9 @@ along with GCC; see the file COPYING3.  If not see
 #include "tree.h"
 #include "tm_p.h"
 #include "basic-block.h"
-#include "timevar.h"
 #include "gimple-pretty-print.h"
 #include "tree-flow.h"
 #include "tree-pass.h"
-#include "tree-dump.h"
 #include "domwalk.h"
 #include "flags.h"
 #include "langhooks.h"
@@ -94,7 +91,7 @@ dse_possible_dead_store_p (gimple stmt, gimple *use_stmt)
   temp = stmt;
   do
     {
-      gimple use_stmt;
+      gimple use_stmt, defvar_def;
       imm_use_iterator ui;
       bool fail = false;
       tree defvar;
@@ -108,6 +105,7 @@ dse_possible_dead_store_p (gimple stmt, gimple *use_stmt)
        defvar = PHI_RESULT (temp);
       else
        defvar = gimple_vdef (temp);
+      defvar_def = temp;
       temp = NULL;
       FOR_EACH_IMM_USE_STMT (use_stmt, ui, defvar)
        {
@@ -139,7 +137,14 @@ dse_possible_dead_store_p (gimple stmt, gimple *use_stmt)
                  fail = true;
                  BREAK_FROM_IMM_USE_STMT (ui);
                }
-             temp = use_stmt;
+             /* Do not consider the PHI as use if it dominates the 
+                stmt defining the virtual operand we are processing,
+                we have processed it already in this case.  */
+             if (gimple_bb (defvar_def) != gimple_bb (use_stmt)
+                 && !dominated_by_p (CDI_DOMINATORS,
+                                     gimple_bb (defvar_def),
+                                     gimple_bb (use_stmt)))
+               temp = use_stmt;
            }
          /* If the statement is a use the store is not dead.  */
          else if (ref_maybe_used_by_stmt_p (use_stmt,
@@ -169,7 +174,7 @@ dse_possible_dead_store_p (gimple stmt, gimple *use_stmt)
         just pretend the stmt makes itself dead.  Otherwise fail.  */
       if (!temp)
        {
-         if (is_hidden_global_store (stmt))
+         if (stmt_may_clobber_global_p (stmt))
            return false;
 
          temp = stmt;
@@ -199,9 +204,9 @@ dse_possible_dead_store_p (gimple stmt, gimple *use_stmt)
    post dominates the first store, then the first store is dead.  */
 
 static void
-dse_optimize_stmt (gimple_stmt_iterator gsi)
+dse_optimize_stmt (gimple_stmt_iterator *gsi)
 {
-  gimple stmt = gsi_stmt (gsi);
+  gimple stmt = gsi_stmt (*gsi);
 
   /* If this statement has no virtual defs, then there is nothing
      to do.  */
@@ -232,6 +237,8 @@ dse_optimize_stmt (gimple_stmt_iterator gsi)
                                gimple_get_lhs (use_stmt), 0)))
          || stmt_kills_ref_p (use_stmt, gimple_assign_lhs (stmt)))
        {
+         basic_block bb;
+
          /* If use_stmt is or might be a nop assignment, e.g. for
             struct { ... } S a, b, *p; ...
             b = a; b = b;
@@ -250,17 +257,17 @@ dse_optimize_stmt (gimple_stmt_iterator gsi)
          if (dump_file && (dump_flags & TDF_DETAILS))
             {
               fprintf (dump_file, "  Deleted dead store '");
-              print_gimple_stmt (dump_file, gsi_stmt (gsi), dump_flags, 0);
+              print_gimple_stmt (dump_file, gsi_stmt (*gsi), dump_flags, 0);
               fprintf (dump_file, "'\n");
             }
 
          /* Then we need to fix the operand of the consuming stmt.  */
          unlink_stmt_vdef (stmt);
 
-         bitmap_set_bit (need_eh_cleanup, gimple_bb (stmt)->index);
-
          /* Remove the dead store.  */
-         gsi_remove (&gsi, true);
+         bb = gimple_bb (stmt);
+         if (gsi_remove (gsi, true))
+           bitmap_set_bit (need_eh_cleanup, bb->index);
 
          /* And release any SSA_NAMEs set in this statement back to the
             SSA_NAME manager.  */
@@ -275,8 +282,14 @@ dse_enter_block (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED,
 {
   gimple_stmt_iterator gsi;
 
-  for (gsi = gsi_last (bb_seq (bb)); !gsi_end_p (gsi); gsi_prev (&gsi))
-    dse_optimize_stmt (gsi);
+  for (gsi = gsi_last_bb (bb); !gsi_end_p (gsi);)
+    {
+      dse_optimize_stmt (&gsi);
+      if (gsi_end_p (gsi))
+       gsi = gsi_last_bb (bb);
+      else
+       gsi_prev (&gsi);
+    }
 }
 
 /* Main entry point.  */
@@ -342,6 +355,7 @@ struct gimple_opt_pass pass_dse =
  {
   GIMPLE_PASS,
   "dse",                       /* name */
+  OPTGROUP_NONE,                /* optinfo_flags */
   gate_dse,                    /* gate */
   tree_ssa_dse,                        /* execute */
   NULL,                                /* sub */