Speedup int_bit_from_pos

Jan Hubicka hubicka@ucw.cz
Mon Sep 22 19:20:00 GMT 2014


Hi,
it now seems to work, finaly :)
Bootstrapped/regtested x86_64-linux, OK?

	* tree.c (int_bit_position): Move to...
	* tree.h (int_bit_position): ... here; implement using
	direct wide_int calculation instead of folding.
Index: tree.c
===================================================================
--- tree.c	(revision 215421)
+++ tree.c	(working copy)
@@ -2831,16 +2831,6 @@ bit_position (const_tree field)
   return bit_from_pos (DECL_FIELD_OFFSET (field),
 		       DECL_FIELD_BIT_OFFSET (field));
 }
-
-/* Likewise, but return as an integer.  It must be representable in
-   that way (since it could be a signed value, we don't have the
-   option of returning -1 like int_size_in_byte can.  */
-
-HOST_WIDE_INT
-int_bit_position (const_tree field)
-{
-  return tree_to_shwi (bit_position (field));
-}
 
 /* Return the byte position of FIELD, in bytes from the start of the record.
    This is a tree of type sizetype.  */
Index: tree.h
===================================================================
--- tree.h	(revision 215421)
+++ tree.h	(working copy)
@@ -3877,10 +3877,9 @@ extern tree size_in_bytes (const_tree);
 extern HOST_WIDE_INT int_size_in_bytes (const_tree);
 extern HOST_WIDE_INT max_int_size_in_bytes (const_tree);
 extern tree bit_position (const_tree);
-extern HOST_WIDE_INT int_bit_position (const_tree);
 extern tree byte_position (const_tree);
 extern HOST_WIDE_INT int_byte_position (const_tree);
 
 #define sizetype sizetype_tab[(int) stk_sizetype]
 #define bitsizetype sizetype_tab[(int) stk_bitsizetype]
 #define ssizetype sizetype_tab[(int) stk_ssizetype]
@@ -4797,4 +4797,14 @@ extern tree get_inner_reference (tree, H
    EXP, an ARRAY_REF or an ARRAY_RANGE_REF.  */
 extern tree array_ref_low_bound (tree);
 
+/* Like bit_position, but return as an integer.  It must be representable in
+   that way (since it could be a signed value, we don't have the
+   option of returning -1 like int_size_in_byte can.  */
+
+static inline HOST_WIDE_INT
+int_bit_position (const_tree field)
+{ 
+  return (wi::lrshift (wi::to_offset (DECL_FIELD_OFFSET (field)), BITS_PER_UNIT_LOG)
+	  + wi::to_offset (DECL_FIELD_BIT_OFFSET (field))).to_shwi ();
+}
 #endif  /* GCC_TREE_H  */



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