[PATCH] Remove BITS_PER_UNIT_LOG

[Bernd Edlinger <bernd dot edlinger at hotmail dot de>]

Hi!

I've noticed that there are two defines for log2 of BITS_PER_UNIT:
BITS_PER_UNIT_LOG and LOG2_BITS_PER_UNIT.
At least this wheel was apparently invented more than once :)

Thus I'd say the most simple wheel will do for us as well.

This patch removes BITS_PER_UNIT_LOG as this is
less often used, and moves LOG2_BITS_PER_UNIT
to tree.h because default.h is obviously not always included
before tree.h.


Bootstrap and reg-test on x86_64-pc-linux-gnu.
Is it OK for trunk?


Thanks
Bernd.

gcc:
2016-07-27  Bernd Edlinger  <bernd.edlinger@hotmail.de>

	* defaults.h (LOG2_BITS_PER_UNIT): Move from here...
	* tree.h (LOG2_BITS_PER_UNIT): ...to here.
	(BITS_PER_UNIT_LOG): Remove.
	(int_bit_position): Use LOG2_BITS_PER_UNIT instead of BITS_PER_UNIT_LOG.
	* expr.c (expand_assignment): Likewise.
	* stor-layout.c (initialize_sizetypes): Likewise.

c-family:
2016-07-27  Bernd Edlinger  <bernd.edlinger@hotmail.de>

	* c-common.c (check_user_alignment): Use LOG2_BITS_PER_UNIT instead of
	BITS_PER_UNIT_LOG.

Index: gcc/c-family/c-common.c
===================================================================
--- gcc/c-family/c-common.c	(revision 238784)
+++ gcc/c-family/c-common.c	(working copy)
@@ -7679,7 +7679,7 @@ check_user_alignment (const_tree align, bool allow
       error ("requested alignment is not a positive power of 2");
       return -1;
     }
-  else if (i >= HOST_BITS_PER_INT - BITS_PER_UNIT_LOG)
+  else if (i >= HOST_BITS_PER_INT - LOG2_BITS_PER_UNIT)
     {
       error ("requested alignment is too large");
       return -1;
Index: gcc/defaults.h
===================================================================
--- gcc/defaults.h	(revision 238784)
+++ gcc/defaults.h	(working copy)
@@ -491,14 +491,6 @@ see the files COPYING3 and COPYING.RUNTIME respect
    your target, you should override these values by defining the
    appropriate symbols in your tm.h file.  */
 
-#if BITS_PER_UNIT == 8
-#define LOG2_BITS_PER_UNIT 3
-#elif BITS_PER_UNIT == 16
-#define LOG2_BITS_PER_UNIT 4
-#else
-#error Unknown BITS_PER_UNIT
-#endif
-
 #ifndef BITS_PER_WORD
 #define BITS_PER_WORD (BITS_PER_UNIT * UNITS_PER_WORD)
 #endif
Index: gcc/expr.c
===================================================================
--- gcc/expr.c	(revision 238784)
+++ gcc/expr.c	(working copy)
@@ -4990,8 +4990,7 @@ expand_assignment (tree to, tree from, bool nontem
       if (bitpos < 0)
 	{
 	  gcc_assert (offset == NULL_TREE);
-	  offset = size_int (bitpos >> (BITS_PER_UNIT == 8
-					? 3 : exact_log2 (BITS_PER_UNIT)));
+	  offset = size_int (bitpos >> LOG2_BITS_PER_UNIT);
 	  bitpos &= BITS_PER_UNIT - 1;
 	}
 
Index: gcc/stor-layout.c
===================================================================
--- gcc/stor-layout.c	(revision 238784)
+++ gcc/stor-layout.c	(working copy)
@@ -2572,7 +2572,7 @@ initialize_sizetypes (void)
     }
 
   bprecision
-    = MIN (precision + BITS_PER_UNIT_LOG + 1, MAX_FIXED_MODE_SIZE);
+    = MIN (precision + LOG2_BITS_PER_UNIT + 1, MAX_FIXED_MODE_SIZE);
   bprecision
     = GET_MODE_PRECISION (smallest_mode_for_size (bprecision, MODE_INT));
   if (bprecision > HOST_BITS_PER_DOUBLE_INT)
Index: gcc/tree.h
===================================================================
--- gcc/tree.h	(revision 238784)
+++ gcc/tree.h	(working copy)
@@ -4235,6 +4235,8 @@ extern tree bit_position (const_tree);
 extern tree byte_position (const_tree);
 extern HOST_WIDE_INT int_byte_position (const_tree);
 
+/* Type for sizes of data-type.  */
+
 #define sizetype sizetype_tab[(int) stk_sizetype]
 #define bitsizetype sizetype_tab[(int) stk_bitsizetype]
 #define ssizetype sizetype_tab[(int) stk_ssizetype]
@@ -4244,12 +4246,15 @@ extern HOST_WIDE_INT int_byte_position (const_tree
 #define bitsize_int(L) size_int_kind (L, stk_bitsizetype)
 #define sbitsize_int(L) size_int_kind (L, stk_sbitsizetype)
 
-/* Type for sizes of data-type.  */
+/* Log2 of BITS_PER_UNIT.  */
 
-#define BITS_PER_UNIT_LOG \
-  ((BITS_PER_UNIT > 1) + (BITS_PER_UNIT > 2) + (BITS_PER_UNIT > 4) \
-   + (BITS_PER_UNIT > 8) + (BITS_PER_UNIT > 16) + (BITS_PER_UNIT > 32) \
-   + (BITS_PER_UNIT > 64) + (BITS_PER_UNIT > 128) + (BITS_PER_UNIT > 256))
+#if BITS_PER_UNIT == 8
+#define LOG2_BITS_PER_UNIT 3
+#elif BITS_PER_UNIT == 16
+#define LOG2_BITS_PER_UNIT 4
+#else
+#error Unknown BITS_PER_UNIT
+#endif
 
 /* Concatenate two lists (chains of TREE_LIST nodes) X and Y
    by making the last node in X point to Y.
@@ -5400,8 +5405,8 @@ extern GTY(()) struct int_n_trees_t int_n_trees[NU
 
 inline HOST_WIDE_INT
 int_bit_position (const_tree field)
-{ 
-  return ((wi::to_offset (DECL_FIELD_OFFSET (field)) << BITS_PER_UNIT_LOG)
+{
+  return ((wi::to_offset (DECL_FIELD_OFFSET (field)) << LOG2_BITS_PER_UNIT)
 	  + wi::to_offset (DECL_FIELD_BIT_OFFSET (field))).to_shwi ();
 }