[ARM][1/4] Replace uses of int_log2 by exact_log2

	* config/arm/arm.c (int_log2): Delete definition and prototype.
	(shift_op): Use exact_log2 instead of int_log2.
	(vfp3_const_double_for_fract_bits): Likewise.

From-SVN: r237757

gcc/ChangeLog

+2016-06-24  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
+
+	* config/arm/arm.c (int_log2): Delete definition and prototype.
+	(shift_op): Use exact_log2 instead of int_log2.
+	(vfp3_const_double_for_fract_bits): Likewise.
+
 2016-06-24  Jakub Jelinek  <jakub@redhat.com>
 
 	* internal-fn.c (expand_arith_set_overflow): New function.

gcc/config/arm/arm.c

@@ -104,7 +104,6 @@ static void arm_print_operand_address (FILE *, machine_mode, rtx);
 static bool arm_print_operand_punct_valid_p (unsigned char code);
 static const char *fp_const_from_val (REAL_VALUE_TYPE *);
 static arm_cc get_arm_condition_code (rtx);
-static HOST_WIDE_INT int_log2 (HOST_WIDE_INT);
 static const char *output_multi_immediate (rtx *, const char *, const char *,
 					   int, HOST_WIDE_INT);
 static const char *shift_op (rtx, HOST_WIDE_INT *);
@@ -19094,7 +19093,8 @@ shift_op (rtx op, HOST_WIDE_INT *amountp)
 	  return NULL;
 	}
 
-      *amountp = int_log2 (*amountp);
+      *amountp = exact_log2 (*amountp);
+      gcc_assert (IN_RANGE (*amountp, 0, 31));
       return ARM_LSL_NAME;
 
     default:
@@ -19126,22 +19126,6 @@ shift_op (rtx op, HOST_WIDE_INT *amountp)
   return mnem;
 }
 
-/* Obtain the shift from the POWER of two.  */
-
-static HOST_WIDE_INT
-int_log2 (HOST_WIDE_INT power)
-{
-  HOST_WIDE_INT shift = 0;
-
-  while ((((HOST_WIDE_INT) 1 << shift) & power) == 0)
-    {
-      gcc_assert (shift <= 31);
-      shift++;
-    }
-
-  return shift;
-}
-
 /* Output a .ascii pseudo-op, keeping track of lengths.  This is
    because /bin/as is horribly restrictive.  The judgement about
    whether or not each character is 'printable' (and can be output as
@@ -27931,7 +27915,11 @@ vfp3_const_double_for_fract_bits (rtx operand)
 	  HOST_WIDE_INT value = real_to_integer (&r0);
 	  value = value & 0xffffffff;
 	  if ((value != 0) && ( (value & (value - 1)) == 0))
-	    return int_log2 (value);
+	    {
+	      int ret = exact_log2 (value);
+	      gcc_assert (IN_RANGE (ret, 0, 31));
+	      return ret;
+	    }
 	}
     }
   return 0;