* [PATCH] Refactor wi::bswap as a function (instead of a method).
@ 2023-05-28 18:55 Roger Sayle
2023-05-30 19:09 ` Richard Sandiford
0 siblings, 1 reply; 2+ messages in thread
From: Roger Sayle @ 2023-05-28 18:55 UTC (permalink / raw)
To: gcc-patches; +Cc: 'Richard Sandiford'
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This patch implements Richard Sandiford's suggestion from
https://gcc.gnu.org/pipermail/gcc-patches/2023-May/618215.html
that wi::bswap (and a new wi::bitreverse) should be functions,
and ideally only accessors are member functions. This patch
implements the first step, moving/refactoring wi::bswap.
This patch has been tested on x86_64-pc-linux-gnu with make bootstrap
and make -k check, both with and without --target_board=unix{-m32}
with no new failures. Ok for mainline?
2023-05-28 Roger Sayle <roger@nextmovesoftware.com>
gcc/ChangeLog
* fold-const-call.cc (fold_const_call_ss) <CFN_BUILT_IN_BSWAP*>:
Update call to wi::bswap.
* simplify-rtx.cc (simplify_const_unary_operation) <case BSWAP>:
Update call to wi::bswap.
* tree-ssa-ccp.cc (evaluate_stmt) <case BUILT_IN_BSWAP*>:
Update calls to wi::bswap.
* wide-int.cc (wide_int_storage::bswap): Remove/rename to...
(wi::bswap_large): New function, with revised API.
* wide-int.h (wi::bswap): New (template) function prototype.
(wide_int_storage::bswap): Remove method.
(sext_large, zext_large): Consistent indentation/line wrapping.
(bswap_large): Prototype helper function containing implementation.
(wi::bswap): New template wrapper around bswap_large.
Thanks,
Roger
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diff --git a/gcc/fold-const-call.cc b/gcc/fold-const-call.cc
index 340cb66..663eae2 100644
--- a/gcc/fold-const-call.cc
+++ b/gcc/fold-const-call.cc
@@ -1060,7 +1060,8 @@ fold_const_call_ss (wide_int *result, combined_fn fn, const wide_int_ref &arg,
case CFN_BUILT_IN_BSWAP32:
case CFN_BUILT_IN_BSWAP64:
case CFN_BUILT_IN_BSWAP128:
- *result = wide_int::from (arg, precision, TYPE_SIGN (arg_type)).bswap ();
+ *result = wi::bswap (wide_int::from (arg, precision,
+ TYPE_SIGN (arg_type)));
return true;
default:
diff --git a/gcc/simplify-rtx.cc b/gcc/simplify-rtx.cc
index d4aeebc..d93d632 100644
--- a/gcc/simplify-rtx.cc
+++ b/gcc/simplify-rtx.cc
@@ -2111,7 +2111,7 @@ simplify_const_unary_operation (enum rtx_code code, machine_mode mode,
break;
case BSWAP:
- result = wide_int (op0).bswap ();
+ result = wi::bswap (op0);
break;
case TRUNCATE:
diff --git a/gcc/tree-ssa-ccp.cc b/gcc/tree-ssa-ccp.cc
index 6fb371c..26d5e44 100644
--- a/gcc/tree-ssa-ccp.cc
+++ b/gcc/tree-ssa-ccp.cc
@@ -2401,11 +2401,12 @@ evaluate_stmt (gimple *stmt)
wide_int wval = wi::to_wide (val.value);
val.value
= wide_int_to_tree (type,
- wide_int::from (wval, prec,
- UNSIGNED).bswap ());
+ wi::bswap (wide_int::from (wval, prec,
+ UNSIGNED)));
val.mask
- = widest_int::from (wide_int::from (val.mask, prec,
- UNSIGNED).bswap (),
+ = widest_int::from (wi::bswap (wide_int::from (val.mask,
+ prec,
+ UNSIGNED)),
UNSIGNED);
if (wi::sext (val.mask, prec) != -1)
break;
diff --git a/gcc/wide-int.cc b/gcc/wide-int.cc
index c0987aa..1e4c046 100644
--- a/gcc/wide-int.cc
+++ b/gcc/wide-int.cc
@@ -731,16 +731,13 @@ wi::set_bit_large (HOST_WIDE_INT *val, const HOST_WIDE_INT *xval,
}
}
-/* bswap THIS. */
-wide_int
-wide_int_storage::bswap () const
+/* Byte swap the integer represented by XVAL and LEN into VAL. Return
+ the number of blocks in VAL. Both XVAL and VAL have PRECISION bits. */
+unsigned int
+wi::bswap_large (HOST_WIDE_INT *val, const HOST_WIDE_INT *xval,
+ unsigned int len, unsigned int precision)
{
- wide_int result = wide_int::create (precision);
unsigned int i, s;
- unsigned int len = BLOCKS_NEEDED (precision);
- unsigned int xlen = get_len ();
- const HOST_WIDE_INT *xval = get_val ();
- HOST_WIDE_INT *val = result.write_val ();
/* This is not a well defined operation if the precision is not a
multiple of 8. */
@@ -758,7 +755,7 @@ wide_int_storage::bswap () const
unsigned int block = s / HOST_BITS_PER_WIDE_INT;
unsigned int offset = s & (HOST_BITS_PER_WIDE_INT - 1);
- byte = (safe_uhwi (xval, xlen, block) >> offset) & 0xff;
+ byte = (safe_uhwi (xval, len, block) >> offset) & 0xff;
block = d / HOST_BITS_PER_WIDE_INT;
offset = d & (HOST_BITS_PER_WIDE_INT - 1);
@@ -766,8 +763,7 @@ wide_int_storage::bswap () const
val[block] |= byte << offset;
}
- result.set_len (canonize (val, len, precision));
- return result;
+ return canonize (val, len, precision);
}
/* Fill VAL with a mask where the lower WIDTH bits are ones and the bits
diff --git a/gcc/wide-int.h b/gcc/wide-int.h
index 3d9b87c..a2b3371 100644
--- a/gcc/wide-int.h
+++ b/gcc/wide-int.h
@@ -552,6 +552,7 @@ namespace wi
UNARY_FUNCTION sext (const T &, unsigned int);
UNARY_FUNCTION zext (const T &, unsigned int);
UNARY_FUNCTION set_bit (const T &, unsigned int);
+ UNARY_FUNCTION bswap (const T &);
BINARY_FUNCTION min (const T1 &, const T2 &, signop);
BINARY_FUNCTION smin (const T1 &, const T2 &);
@@ -1086,9 +1087,6 @@ public:
static wide_int from_array (const HOST_WIDE_INT *, unsigned int,
unsigned int, bool = true);
static wide_int create (unsigned int);
-
- /* FIXME: target-dependent, so should disappear. */
- wide_int bswap () const;
};
namespace wi
@@ -1743,13 +1741,14 @@ namespace wi
int cmpu_large (const HOST_WIDE_INT *, unsigned int, unsigned int,
const HOST_WIDE_INT *, unsigned int);
unsigned int sext_large (HOST_WIDE_INT *, const HOST_WIDE_INT *,
- unsigned int,
- unsigned int, unsigned int);
+ unsigned int, unsigned int, unsigned int);
unsigned int zext_large (HOST_WIDE_INT *, const HOST_WIDE_INT *,
- unsigned int,
- unsigned int, unsigned int);
+ unsigned int, unsigned int, unsigned int);
unsigned int set_bit_large (HOST_WIDE_INT *, const HOST_WIDE_INT *,
unsigned int, unsigned int, unsigned int);
+ unsigned int bswap_large (HOST_WIDE_INT *, const HOST_WIDE_INT *,
+ unsigned int, unsigned int);
+
unsigned int lshift_large (HOST_WIDE_INT *, const HOST_WIDE_INT *,
unsigned int, unsigned int, unsigned int);
unsigned int lrshift_large (HOST_WIDE_INT *, const HOST_WIDE_INT *,
@@ -2267,6 +2266,18 @@ wi::set_bit (const T &x, unsigned int bit)
return result;
}
+/* Byte swap the integer X. */
+template <typename T>
+inline WI_UNARY_RESULT (T)
+wi::bswap (const T &x)
+{
+ WI_UNARY_RESULT_VAR (result, val, T, x);
+ unsigned int precision = get_precision (result);
+ WIDE_INT_REF_FOR (T) xi (x, precision);
+ result.set_len (bswap_large (val, xi.val, xi.len, precision));
+ return result;
+}
+
/* Return the mininum of X and Y, treating them both as having
signedness SGN. */
template <typename T1, typename T2>
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] Refactor wi::bswap as a function (instead of a method).
2023-05-28 18:55 [PATCH] Refactor wi::bswap as a function (instead of a method) Roger Sayle
@ 2023-05-30 19:09 ` Richard Sandiford
0 siblings, 0 replies; 2+ messages in thread
From: Richard Sandiford @ 2023-05-30 19:09 UTC (permalink / raw)
To: Roger Sayle; +Cc: gcc-patches
"Roger Sayle" <roger@nextmovesoftware.com> writes:
> This patch implements Richard Sandiford's suggestion from
> https://gcc.gnu.org/pipermail/gcc-patches/2023-May/618215.html
> that wi::bswap (and a new wi::bitreverse) should be functions,
> and ideally only accessors are member functions. This patch
> implements the first step, moving/refactoring wi::bswap.
>
> This patch has been tested on x86_64-pc-linux-gnu with make bootstrap
> and make -k check, both with and without --target_board=unix{-m32}
> with no new failures. Ok for mainline?
Thanks for doing this. OK with a minor change:
> diff --git a/gcc/wide-int.h b/gcc/wide-int.h
> index 3d9b87c..a2b3371 100644
> --- a/gcc/wide-int.h
> +++ b/gcc/wide-int.h
> @@ -552,6 +552,7 @@ namespace wi
> UNARY_FUNCTION sext (const T &, unsigned int);
> UNARY_FUNCTION zext (const T &, unsigned int);
> UNARY_FUNCTION set_bit (const T &, unsigned int);
> + UNARY_FUNCTION bswap (const T &);
>
> BINARY_FUNCTION min (const T1 &, const T2 &, signop);
> BINARY_FUNCTION smin (const T1 &, const T2 &);
> @@ -1086,9 +1087,6 @@ public:
> static wide_int from_array (const HOST_WIDE_INT *, unsigned int,
> unsigned int, bool = true);
> static wide_int create (unsigned int);
> -
> - /* FIXME: target-dependent, so should disappear. */
> - wide_int bswap () const;
> };
I think the comment was referring to the fact that the function
swaps octets regardless of BITS_PER_UNIT. That might be the right
behaviour, but it might not. It's difficult to say when there are
no BITS_PER_UNIT!=8 targets left.
The patch is moving in the right direction by defining the function
outside the class. If it turns out that BITS_PER_UNIT should matter,
we could later move the implementation to somewhere that is sensitive
to the target.
So...
> @@ -2267,6 +2266,18 @@ wi::set_bit (const T &x, unsigned int bit)
> return result;
> }
>
> +/* Byte swap the integer X. */
...how about adding:
/* ??? This always swaps octets, regardless of BITS_PER_UNIT. If the
function should instead be sensitive to BITS_PER_UNIT, we should either
pass that in or move the function to somewhere where the target
configuration is available. */
Feel free to reword to something you think is clearer.
OK with that or a similar change, thanks.
Richard
> +template <typename T>
> +inline WI_UNARY_RESULT (T)
> +wi::bswap (const T &x)
> +{
> + WI_UNARY_RESULT_VAR (result, val, T, x);
> + unsigned int precision = get_precision (result);
> + WIDE_INT_REF_FOR (T) xi (x, precision);
> + result.set_len (bswap_large (val, xi.val, xi.len, precision));
> + return result;
> +}
> +
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