PR 33593

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

diff --git a/gcc/tree-ssa-ter.c b/gcc/tree-ssa-ter.c
index 513fbda..f0fef24 100644 (file)
--- a/gcc/tree-ssa-ter.c
+++ b/gcc/tree-ssa-ter.c
@@ -1,12 +1,12 @@
 /* Routines for performing Temporary Expression Replacement (TER) in SSA trees.
-   Copyright (C) 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
+   Copyright (C) 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
    Contributed by Andrew MacLeod  <amacleod@redhat.com>
 
 This file is part of GCC.
 
 GCC is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
-the Free Software Foundation; either version 2, or (at your option)
+the Free Software Foundation; either version 3, or (at your option)
 any later version.
 
 GCC is distributed in the hope that it will be useful,
@@ -15,9 +15,8 @@ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.
 
 You should have received a copy of the GNU General Public License
-along with GCC; see the file COPYING.  If not, write to
-the Free Software Foundation, 51 Franklin Street, Fifth Floor,
-Boston, MA 02110-1301, USA.  */
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
 
 
 #include "config.h"
@@ -80,13 +79,13 @@ Boston, MA 02110-1301, USA.  */
    v_9 = a_2 * n_12
    <...>
 
-   If b_5, b_8 and b_14 are all colaesced together...
+   If b_5, b_8 and b_14 are all coalesced together...
    The expression b_5 + 6 CANNOT replace the use in the statement defining v_9
    because b_8 is in fact killing the value of b_5 since they share a partition
-   and will be assigned the same memory or regster location.
+   and will be assigned the same memory or register location.
    
    TER implements this but stepping through the instructions in a block and
-   tracking potential expressions for replacement, and the paritions they are
+   tracking potential expressions for replacement, and the partitions they are
    dependent on.  Expressions are represented by the SSA_NAME_VERSION of the
    DEF on the LHS of a GIMPLE_MODIFY_STMT and the expression is the RHS.
 
@@ -110,8 +109,8 @@ Boston, MA 02110-1301, USA.  */
    an expression from the partition kill lists when a decision is made whether
    to replace it or not.  This is indexed by ssa version number as well, and
    indicates a partition number.  virtual operands are not tracked individually,
-   but they are summarized by an artifical partition called VIRTUAL_PARTITION.
-   This means a MAY or MUST def will kill *ALL* expressions that are dependant
+   but they are summarized by an artificial partition called VIRTUAL_PARTITION.
+   This means a MAY or MUST def will kill *ALL* expressions that are dependent
    on a virtual operand.
    Note that the EXPR_DECL_UID and this bitmap represent very similar 
    information, but the info in one is not easy to obtain from the other.
@@ -121,11 +120,11 @@ Boston, MA 02110-1301, USA.  */
    longer be valid if a definition into this partition takes place.
 
    PARTITION_IN_USE is simply a bitmap which is used to track which partitions
-   currently have sokmething in their kill list.  This is used at the end of 
+   currently have something in their kill list.  This is used at the end of 
    a block to clear out the KILL_LIST bitmaps at the end of each block.
 
    NEW_REPLACEABLE_DEPENDENCIES is used as a temporary place to store 
-   dependencies which will be reused by the current defintion. ALl the uses
+   dependencies which will be reused by the current definition. ALl the uses
    on an expression are processed before anything else is done. If a use is
    determined to be a replaceable expression AND the current stmt is also going
    to be replaceable, all the dependencies of this replaceable use will be
@@ -161,8 +160,8 @@ typedef struct temp_expr_table_d
   tree *replaceable_expressions;       /* Replacement expression table.  */
   bitmap *expr_decl_uids;              /* Base uids of exprs.  */
   bitmap *kill_list;                   /* Expr's killed by a partition.  */
-  int virtual_partition;               /* Psuedo partition for virtual ops.  */
-  bitmap partition_in_use;             /* Partitions with kill entires.  */
+  int virtual_partition;               /* Pseudo partition for virtual ops.  */
+  bitmap partition_in_use;             /* Partitions with kill entries.  */
   bitmap new_replaceable_dependencies; /* Holding place for pending dep's.  */
   int *num_in_part;                    /* # of ssa_names in a partition.  */
 } *temp_expr_table_p;
@@ -256,7 +255,7 @@ version_to_be_replaced_p (temp_expr_table_p tab, int version)
 }
 
 
-/* Add partition P to the list if partititons VERSION is dependent on.  TAB is 
+/* Add partition P to the list if partitions VERSION is dependent on.  TAB is 
    the expression table */
 
 static inline void
@@ -367,6 +366,10 @@ is_replaceable_p (tree stmt)
   if (TREE_CODE (stmt) != GIMPLE_MODIFY_STMT)
     return false;
 
+  /* If the statement may throw an exception, it cannot be replaced.  */
+  if (tree_could_throw_p (stmt))
+    return false;
+
   /* Punt if there is more than 1 def.  */
   def = SINGLE_SSA_TREE_OPERAND (stmt, SSA_OP_DEF);
   if (!def)
@@ -393,6 +396,12 @@ is_replaceable_p (tree stmt)
       && FLOAT_TYPE_P (TREE_TYPE (GENERIC_TREE_OPERAND (stmt, 1))))
     return false;
 
+  /* An assignment with a register variable on the RHS is not
+     replaceable.  */
+  if (TREE_CODE (GENERIC_TREE_OPERAND (stmt, 1)) == VAR_DECL
+      && DECL_HARD_REGISTER (GENERIC_TREE_OPERAND (stmt, 1)))
+    return false;
+
   /* Calls to functions with side-effects cannot be replaced.  */
   if ((call_expr = get_call_expr_in (stmt)) != NULL_TREE)
     {
@@ -402,7 +411,7 @@ is_replaceable_p (tree stmt)
        return false;
     }
 
-  /* Leave any stmt with voltile operands alone as well.  */
+  /* Leave any stmt with volatile operands alone as well.  */
   if (stmt_ann (stmt)->has_volatile_ops)
     return false;