On 11/29/2013 05:24 AM, Richard Biener wrote:
On Thu, Nov 28, 2013 at 6:11 PM, Kenneth Zadeck
<zad...@naturalbridge.com> wrote:
This patch does three things in wide-int:
1) it cleans up some comments.
2) removes a small amount of trash.
3) it changes the max size of the wide int from being 4x of
MAX_BITSIZE_MODE_ANY_INT to 2x +1. This should improve large muls and divs
as well as perhaps help with some cache behavior.
@@ -235,8 +233,8 @@ along with GCC; see the file COPYING3.
range of a multiply. This code needs 2n + 2 bits. */
#define WIDE_INT_MAX_ELTS \
- ((4 * MAX_BITSIZE_MODE_ANY_INT + HOST_BITS_PER_WIDE_INT - 1) \
- / HOST_BITS_PER_WIDE_INT)
+ (((2 * MAX_BITSIZE_MODE_ANY_INT + HOST_BITS_PER_WIDE_INT - 1) \
+ / HOST_BITS_PER_WIDE_INT) + 1)
I always wondered why VRP (if that is the only reason we do 2*n+1)
cannot simply use FIXED_WIDE_INT(MAX_BITSIZE_MODE_ANY_INT*2 + 1)?
Other widest_int users should not suffer IMHO. widest_int should
strictly cover all modes that the target can do any arithmetic on
(thus not XImode or OImode on x86_64).
Richard.
ok to commit
enclosed is the code to change the large multiplies in tree-vrp as well
as sets the size of the WIDE_INT_MAX_ELTS as we have discussed.
Bootstrapped and tested on x86-64.
ok to commit?
kenny
Index: tree-vrp.c
===================================================================
--- tree-vrp.c (revision 205597)
+++ tree-vrp.c (working copy)
@@ -2611,22 +2611,28 @@ extract_range_from_binary_expr_1 (value_
signop sign = TYPE_SIGN (expr_type);
unsigned int prec = TYPE_PRECISION (expr_type);
- unsigned int prec2 = (prec * 2) + (sign == UNSIGNED ? 2 : 0);
if (range_int_cst_p (&vr0)
&& range_int_cst_p (&vr1)
&& TYPE_OVERFLOW_WRAPS (expr_type))
{
- wide_int sizem1 = wi::mask (prec, false, prec2);
- wide_int size = sizem1 + 1;
+ /* vrp_int is twice as wide as anything that the target
+ supports so it can support a full width multiply. No
+ need to add any more padding for an extra sign bit
+ because that comes with the way that WIDE_INT_MAX_ELTS is
+ defined. */
+ typedef FIXED_WIDE_INT (WIDE_INT_MAX_PRECISION * 2)
+ vrp_int;
+ vrp_int sizem1 = wi::mask <vrp_int> (prec, false);
+ vrp_int size = sizem1 + 1;
/* Extend the values using the sign of the result to PREC2.
From here on out, everthing is just signed math no matter
what the input types were. */
- wide_int min0 = wide_int::from (vr0.min, prec2, sign);
- wide_int max0 = wide_int::from (vr0.max, prec2, sign);
- wide_int min1 = wide_int::from (vr1.min, prec2, sign);
- wide_int max1 = wide_int::from (vr1.max, prec2, sign);
+ vrp_int min0 = wi::to_vrp (vr0.min);
+ vrp_int max0 = wi::to_vrp (vr0.max);
+ vrp_int min1 = wi::to_vrp (vr1.min);
+ vrp_int max1 = wi::to_vrp (vr1.max);
/* Canonicalize the intervals. */
if (sign == UNSIGNED)
@@ -2644,17 +2650,17 @@ extract_range_from_binary_expr_1 (value_
}
}
- wide_int prod0 = min0 * min1;
- wide_int prod1 = min0 * max1;
- wide_int prod2 = max0 * min1;
- wide_int prod3 = max0 * max1;
+ vrp_int prod0 = min0 * min1;
+ vrp_int prod1 = min0 * max1;
+ vrp_int prod2 = max0 * min1;
+ vrp_int prod3 = max0 * max1;
/* Sort the 4 products so that min is in prod0 and max is in
prod3. */
/* min0min1 > max0max1 */
if (wi::gts_p (prod0, prod3))
{
- wide_int tmp = prod3;
+ vrp_int tmp = prod3;
prod3 = prod0;
prod0 = tmp;
}
@@ -2662,21 +2668,21 @@ extract_range_from_binary_expr_1 (value_
/* min0max1 > max0min1 */
if (wi::gts_p (prod1, prod2))
{
- wide_int tmp = prod2;
+ vrp_int tmp = prod2;
prod2 = prod1;
prod1 = tmp;
}
if (wi::gts_p (prod0, prod1))
{
- wide_int tmp = prod1;
+ vrp_int tmp = prod1;
prod1 = prod0;
prod0 = tmp;
}
if (wi::gts_p (prod2, prod3))
{
- wide_int tmp = prod3;
+ vrp_int tmp = prod3;
prod3 = prod2;
prod2 = tmp;
}
Index: tree.h
===================================================================
--- tree.h (revision 205597)
+++ tree.h (working copy)
@@ -4565,10 +4565,12 @@ namespace wi
static const unsigned int precision = N;
};
- generic_wide_int <extended_tree <MAX_BITSIZE_MODE_ANY_INT> >
+ generic_wide_int <extended_tree <WIDE_INT_MAX_PRECISION> >
to_widest (const_tree);
generic_wide_int <extended_tree <ADDR_MAX_PRECISION> > to_offset (const_tree);
+
+ generic_wide_int <extended_tree <WIDE_INT_MAX_PRECISION * 2> > to_vrp (const_tree);
}
inline unsigned int
@@ -4586,7 +4588,7 @@ wi::int_traits <const_tree>::decompose (
precision);
}
-inline generic_wide_int <wi::extended_tree <MAX_BITSIZE_MODE_ANY_INT> >
+inline generic_wide_int <wi::extended_tree <WIDE_INT_MAX_PRECISION> >
wi::to_widest (const_tree t)
{
return t;
@@ -4597,6 +4599,12 @@ wi::to_offset (const_tree t)
{
return t;
}
+
+inline generic_wide_int <wi::extended_tree <WIDE_INT_MAX_PRECISION * 2> >
+wi::to_vrp (const_tree t)
+{
+ return t;
+}
template <int N>
inline wi::extended_tree <N>::extended_tree (const_tree t)
Index: wide-int.h
===================================================================
--- wide-int.h (revision 205599)
+++ wide-int.h (working copy)
@@ -228,15 +228,16 @@ along with GCC; see the file COPYING3.
#endif
/* The MAX_BITSIZE_MODE_ANY_INT is automatically generated by a very
- early examination of the target's mode file. Thus it is safe that
- some small multiple of this number is easily larger than any number
- that that target could compute. The place in the compiler that
- currently needs the widest ints is the code that determines the
- range of a multiply. This code needs 2n + 2 bits. */
-
+ early examination of the target's mode file. The WIDE_INT_MAX_ELTS
+ can accomodate at least 1 more bit so that unsigned numbers of that
+ mode can be represented. This will accomodate every place in the
+ compiler except for a multiply routine in tree-vrp. That function
+ makes its own arrangements for larger wide-ints. */
#define WIDE_INT_MAX_ELTS \
- ((4 * MAX_BITSIZE_MODE_ANY_INT + HOST_BITS_PER_WIDE_INT - 1) \
- / HOST_BITS_PER_WIDE_INT)
+ (((MAX_BITSIZE_MODE_ANY_INT + HOST_BITS_PER_WIDE_INT - 1) \
+ / HOST_BITS_PER_WIDE_INT) + 1)
+
+#define WIDE_INT_MAX_PRECISION (WIDE_INT_MAX_ELTS * HOST_BITS_PER_WIDE_INT)
/* This is the max size of any pointer on any machine. It does not
seem to be as easy to sniff this out of the machine description as
@@ -291,7 +292,7 @@ struct wide_int_storage;
typedef generic_wide_int <wide_int_storage> wide_int;
typedef FIXED_WIDE_INT (ADDR_MAX_PRECISION) offset_int;
-typedef FIXED_WIDE_INT (MAX_BITSIZE_MODE_ANY_INT) widest_int;
+typedef FIXED_WIDE_INT (WIDE_INT_MAX_PRECISION) widest_int;
template <bool SE>
struct wide_int_ref_storage;
