[ast-optimizer-branch]: Allow temp variables to have differentprefixes

[Daniel Berlin <dberlin at dberlin dot org>]

Ugly, but I couldn't think of a better way to do it, since the prefix 
passed in could be some VAR_DECL's identifier, and thus, can't be modified 
directly.  We could use alloca if you want to add another parameter to 
create_tmp_var.

I have left out the changes to simple-break-elim.c, simple-goto-elim.c, 
and tree-ssa-pre.c, because I can't extricate it from some other changes i've 
made.
There are two uses of create_tmp_var in simple-break-elim.c to be updated, 
one in simple-goto-elim.c, and one in tree-ssa-pre.c

Index: c-simplify.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/Attic/c-simplify.c,v
retrieving revision 1.1.2.19
diff -u -3 -p -w -B -b -r1.1.2.19 c-simplify.c
--- c-simplify.c	28 May 2002 01:29:55 -0000	1.1.2.19
+++ c-simplify.c	30 May 2002 17:33:02 -0000
@@ -84,6 +84,7 @@ static tree convert_to_stmt_chain    PAR
 static int  stmt_has_effect          PARAMS ((tree));
 static int  expr_has_effect          PARAMS ((tree));
 static tree mostly_copy_tree_r       PARAMS ((tree *, int *, void *));
+static inline void strip_off_ending  PARAMS ((char *, int));
 
 /* Local variables.  */
 static FILE *dump_file;
@@ -98,6 +99,26 @@ static int stmt_expr_level;
 /* }}} */
 
 
+/* Strip off a legitimate source ending from the input string NAME of
+   length LEN.  Rather than having to know the names used by all of
+   our front ends, we strip off an ending of a period followed by
+   up to five characters.  (Java uses ".class".)  */
+
+static inline void
+strip_off_ending (name, len)
+     char *name;
+     int len;
+{
+  int i;
+  for (i = 2;  i < 8 && len > i;  i++)
+    {
+      if (name[len - i] == '.')
+	{
+	  name[len - i] = '\0';
+	  break;
+	}
+    }
+}
 /* Simplification of statement trees.  */
 
 /** {{{ simplify_tree ()
@@ -894,7 +915,7 @@ simplify_return_stmt (stmt, pre_p)
 	return;
 
       /* Create the assignment 'T = ret_expr'.  */
-      tmp = create_tmp_var (TREE_TYPE (ret_expr));
+      tmp = create_tmp_var (TREE_TYPE (ret_expr), "return");
       expr = build_modify_expr (tmp, NOP_EXPR, ret_expr);
 
       /* Simplify it.  */
@@ -949,6 +970,8 @@ simplify_expr (expr_p, pre_p, post_p, si
      int (*simple_test_f) PARAMS ((tree));
      tree stmt;
 {
+  const char *prefix = NULL;
+  tree stripped_decl;
   if (simple_test_f == NULL)
     abort ();
 
@@ -1132,11 +1155,15 @@ simplify_expr (expr_p, pre_p, post_p, si
       abort ();
     }
 
+  stripped_decl = *expr_p;
+  STRIP_NOPS (stripped_decl);
+  if (DECL_P (stripped_decl))
+    prefix = IDENTIFIER_POINTER (DECL_NAME (stripped_decl));
   /* If the simplified expression can be assigned into a new temporary TMP,
      do so and replace the original expression with TMP.  */
   if (!VOID_TYPE_P (TREE_TYPE (*expr_p)))
     {
-      tree tmp = create_tmp_var (TREE_TYPE (*expr_p));
+      tree tmp = create_tmp_var (TREE_TYPE (*expr_p), prefix);
       add_tree (build_modify_expr (tmp, NOP_EXPR, *expr_p), pre_p);
       *expr_p = tmp;
     }
@@ -1410,7 +1437,7 @@ simplify_cond_expr (expr_p, pre_p, stmt)
   expr_type = TREE_TYPE (*expr_p);
 
   if (!VOID_TYPE_P (expr_type))
-    tmp = create_tmp_var (TREE_TYPE (*expr_p));
+    tmp = create_tmp_var (TREE_TYPE (*expr_p), "iftmp");
   else
     tmp = void_zero_node;
 
@@ -1526,7 +1553,7 @@ simplify_boolean_expr (expr_p, pre_p, st
   rhs = TREE_OPERAND (*expr_p, 1);
 
   /* Build 'T = a'  */
-  t = create_tmp_var (TREE_TYPE (*expr_p));
+  t = create_tmp_var (TREE_TYPE (*expr_p), "booltmp");
   mod_expr = build_modify_expr (t, NOP_EXPR, lhs);
 
   /* Build the body for the if() statement that conditionally evaluates the
@@ -1765,7 +1792,7 @@ simplify_lvalue_expr (expr_p, pre_p, pos
       
       base = TREE_OPERAND (*expr_p, 0);
       lvalue = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (base)), base);
-      tmp = create_tmp_var (TREE_TYPE (lvalue));
+      tmp = create_tmp_var (TREE_TYPE (lvalue), "compref");
       add_tree (build_modify_expr (tmp, NOP_EXPR, lvalue), pre_p);
       
       /* Re-write the base of the structure with a reference to the new
@@ -2038,14 +2065,23 @@ insert_before_first (t, body)
    newly created decl and pushes it into the current binding.  */
 
 tree
-create_tmp_var (type)
+create_tmp_var (type, prefix)
      tree type;
+     const char *prefix;
 {
   static unsigned int id_num = 1;
   char *tmp_name;
+  char *preftmp = NULL;
   tree tmp_var;
 
-  ASM_FORMAT_PRIVATE_NAME (tmp_name, "T", id_num++);
+  /* prefix[0] != 0 to avoid an allocated string that happens to only contain a  NULL */
+  if (prefix)
+    {
+      preftmp = xstrdup (prefix); 
+      strip_off_ending (preftmp, strlen (preftmp));
+      prefix = preftmp;
+    }
+  ASM_FORMAT_PRIVATE_NAME (tmp_name, (prefix ? prefix : "T"), id_num++);
 
   /* If the type is an array, use TYPE_POINTER_TO to create a valid pointer
      that can be used in the LHS of an assignment.  */
@@ -2069,6 +2105,8 @@ create_tmp_var (type)
 
   pushdecl (tmp_var);
 
+  if (preftmp)
+    free (preftmp);
   return tmp_var;
 }
 
Index: tree-simple.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/Attic/tree-simple.h,v
retrieving revision 1.1.2.7
diff -u -3 -p -w -B -b -r1.1.2.7 tree-simple.h
--- tree-simple.h	27 Apr 2002 22:54:22 -0000	1.1.2.7
+++ tree-simple.h	30 May 2002 17:33:02 -0000
@@ -25,7 +25,7 @@ Boston, MA 02111-1307, USA.  */
 /* Interface used in [break/goto]-elimination: to be declared in a .h file. */
 extern void insert_before_continue_end PARAMS ((tree, tree, int));
 extern void tree_build_scope           PARAMS ((tree *));
-extern tree create_tmp_var             PARAMS ((tree));
+extern tree create_tmp_var             PARAMS ((tree, const char *));
 extern tree declare_tmp_vars           PARAMS ((tree, tree));
 extern tree deep_copy_list             PARAMS ((tree));
 extern tree deep_copy_node             PARAMS ((tree));