[5/10] Add tree_to_shwi and tree_to_uhwi

[Richard Sandiford]

Add tree_to_shwi and tree_to_uhwi.  Initially tree_to_uhwi returns a
HOST_WIDE_INT, so that it's a direct replacement for tree_low_cst.
Patch 10 makes it return unsigned HOST_WIDE_INT instead.

Thanks,
Richard


gcc/
        * tree.h (tree_to_shwi, tree_to_uhwi): Declare, with inline expansions.
        * tree.c (tree_to_shwi, tree_to_uhwi): New functions.

Index: gcc/tree.c
===================================================================
--- gcc/tree.c  2013-11-15 16:46:27.420395607 +0000
+++ gcc/tree.c  2013-11-15 16:47:15.226216885 +0000
@@ -7027,6 +7027,28 @@ tree_low_cst (const_tree t, int pos)
   return TREE_INT_CST_LOW (t);
 }
 
+/* T is an INTEGER_CST whose numerical value (extended according to
+   TYPE_UNSIGNED) fits in a signed HOST_WIDE_INT.  Return that
+   HOST_WIDE_INT.  */
+
+HOST_WIDE_INT
+tree_to_shwi (const_tree t)
+{
+  gcc_assert (tree_fits_shwi_p (t));
+  return TREE_INT_CST_LOW (t);
+}
+
+/* T is an INTEGER_CST whose numerical value (extended according to
+   TYPE_UNSIGNED) fits in an unsigned HOST_WIDE_INT.  Return that
+   HOST_WIDE_INT.  */
+
+HOST_WIDE_INT
+tree_to_uhwi (const_tree t)
+{
+  gcc_assert (tree_fits_uhwi_p (t));
+  return TREE_INT_CST_LOW (t);
+}
+
 /* Return the most significant (sign) bit of T.  */
 
 int
Index: gcc/tree.h
===================================================================
--- gcc/tree.h  2013-11-15 16:46:26.263399881 +0000
+++ gcc/tree.h  2013-11-15 16:46:56.569287095 +0000
@@ -3662,6 +3662,8 @@ extern bool tree_fits_uhwi_p (const_tree
 #endif
   ;
 extern HOST_WIDE_INT tree_low_cst (const_tree, int);
+extern HOST_WIDE_INT tree_to_shwi (const_tree);
+extern HOST_WIDE_INT tree_to_uhwi (const_tree);
 #if !defined ENABLE_TREE_CHECKING && (GCC_VERSION >= 4003)
 extern inline __attribute__ ((__gnu_inline__)) HOST_WIDE_INT
 tree_low_cst (const_tree t, int pos)
@@ -3669,6 +3671,20 @@ tree_low_cst (const_tree t, int pos)
   gcc_assert (host_integerp (t, pos));
   return TREE_INT_CST_LOW (t);
 }
+
+extern inline __attribute__ ((__gnu_inline__)) HOST_WIDE_INT
+tree_to_shwi (const_tree t)
+{
+  gcc_assert (tree_fits_shwi_p (t));
+  return TREE_INT_CST_LOW (t);
+}
+
+extern inline __attribute__ ((__gnu_inline__)) HOST_WIDE_INT
+tree_to_uhwi (const_tree t)
+{
+  gcc_assert (tree_fits_uhwi_p (t));
+  return TREE_INT_CST_LOW (t);
+}
 #endif
 extern int tree_int_cst_sgn (const_tree);
 extern int tree_int_cst_sign_bit (const_tree);