Add a wi::to_wide helper function

As Richard says, we ought to have a convenient way of converting
an INTEGER_CST to a wide_int of a particular precision without
having to extract the sign of the INTEGER_CST's type each time.
This patch adds a wi::to_wide helper for that, alongside the
existing wi::to_offset and wi::to_widest.

Tested on x86_64-linux-gnu and aarch64-linux-gnu.

gcc/
	* tree.h (wi::to_wide): New function.
	* expr.c (expand_expr_real_1): Use wi::to_wide.
	* fold-const.c (int_const_binop_1): Likewise.
	(extract_muldiv_1): Likewise.

gcc/c-family/
	* c-common.c (shorten_compare): Use wi::to_wide.

From-SVN: r235721

1 files changed, 12 insertions, 0 deletions

diff --git a/gcc/tree.h b/gcc/tree.h
index 024cf3d..6e52e3d 100644
--- a/gcc/tree.h
+++ b/gcc/tree.h
@@ -5211,6 +5211,8 @@ namespace wi
   to_widest (const_tree);
 
   generic_wide_int <extended_tree <ADDR_MAX_PRECISION> > to_offset (const_tree);
+
+  wide_int to_wide (const_tree, unsigned int);
 }
 
 inline unsigned int
@@ -5240,6 +5242,16 @@ wi::to_offset (const_tree t)
   return t;
 }
 
+/* Convert INTEGER_CST T to a wide_int of precision PREC, extending or
+   truncating as necessary.  When extending, use sign extension if T's
+   type is signed and zero extension if T's type is unsigned.  */
+
+inline wide_int
+wi::to_wide (const_tree t, unsigned int prec)
+{
+  return wide_int::from (t, prec, TYPE_SIGN (TREE_TYPE (t)));
+}
+
 template <int N>
 inline wi::extended_tree <N>::extended_tree (const_tree t)
   : m_t (t)