Refactor wi::bswap as a function (instead of a method).

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.

2023-05-31  Roger Sayle  <roger@nextmovesoftware.com>
	    Richard Sandiford  <richard.sandiford@arm.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.

diff --git a/gcc/fold-const-call.cc b/gcc/fold-const-call.cc
index 340cb667f6a9ed8516697a1a148bcf3f0ce0d1c1..663eae2fa7f7c8647f5cefdf4dd6cd3cf23c5d6a 100644 (file)
--- 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 8b48bd3553e8064562f4099e7baa993f3f2d15a5..4e20a34197717c7267e7ab991dadc65a3752fcda 100644 (file)
--- 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 6fb371c26297ea121f1501dbef8bc1cc6d89f2a9..26d5e445abd55244117fbbe2b6034f63ec22b629 100644 (file)
--- 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 c0987aa4d63a07892e5a8f05ac436208e69a3c3f..1e4c0460b743404a9d9320e13d5ea06f61b05272 100644 (file)
--- 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 3d9b87cd91a12a91d6770e2d5e0a8297e66eea16..e4723adce2c88ef4bd61ec7d66c1a120e86eedb3 100644 (file)
--- 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 +2266,21 @@ wi::set_bit (const T &x, unsigned int bit)
   return result;
 }
 
+/* Byte swap the integer X.
+   ??? This always swaps 8-bit octets, regardless of BITS_PER_UNIT.
+   This function requires X's precision to be a multiple of 16 bits,
+   so care needs to be taken for targets where BITS_PER_UNIT != 8.  */
+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>