Replace exact_log2(x & -x) in favor of more direct computation.

	* toplev.h (ctz_hwi, clz_hwi, ffs_hwi): New.
	(floor_log2): Use clz_hwi.
	(exact_log2): Use ctz_hwi.
	* toplev.c (ctz_hwi, clz_hwi, ffs_hwi): New.
	* builtins.c (fold_builtin_bitop): Use them.
	* simplify-rtx.c (simplify_const_unary_operation): Likewise.
	* combine.c (get_pos_from_mask): Use ctz_hwi.
	* double-int.c (double_int_ctz): Likewise.
	* explow.c (force_reg): Likewise.
	* tree.h (SET_DECL_OFFSET_ALIGN): Use ffs_hwi.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@162920 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 1 insertions, 9 deletions

diff --git a/gcc/double-int.c b/gcc/double-int.c
index 29e720b2919..cb63f856df3 100644
--- a/gcc/double-int.c
+++ b/gcc/double-int.c
@@ -859,15 +859,7 @@ double_int_ctz (double_int a)
   unsigned bits = a.low ? 0 : HOST_BITS_PER_WIDE_INT;
   if (!w)
     return HOST_BITS_PER_DOUBLE_INT;
-#if (GCC_VERSION >= 3004)
-  bits += CTZ_HWI (w);
-#else
-  while (!(w & 1))
-    {
-      w >>= 1;
-      bits += 1;
-    }
-#endif
+  bits += ctz_hwi (w);
   return bits;
 }