Support << and >> for offset_int and widest_int

Following on from the comparison patch, I think it makes sense to
support << and >> for offset_int (int128_t) and widest_int (intNNN_t),
with >> being arithmetic shift.  It doesn't make sense to use
logical right shift on a potentially negative offset_int, since
the precision of 128 bits has no meaning on the target.

Tested on x86_64-linux-gnu and aarch64-linux-gnu.

gcc/
	* wide-int.h: Update offset_int and widest_int documentation.
	(WI_SIGNED_SHIFT_RESULT): New macro.
	(wi::binary_shift): Define signed_shift_result_type for
	shifts on offset_int- and widest_int-like types.
	(generic_wide_int): Support <<= and >>= if << and >> are supported.
	* tree.h (int_bit_position): Use shift operators instead of wi::
	 shifts.
	* alias.c (adjust_offset_for_component_ref): Likewise.
	* expr.c (get_inner_reference): Likewise.
	* fold-const.c (fold_comparison): Likewise.
	* gimple-fold.c (fold_nonarray_ctor_reference): Likewise.
	* gimple-ssa-strength-reduction.c (restructure_reference): Likewise.
	* tree-dfa.c (get_ref_base_and_extent): Likewise.
	* tree-ssa-alias.c (indirect_ref_may_alias_decl_p): Likewise.
	(stmt_kills_ref_p): Likewise.
	* tree-ssa-ccp.c (bit_value_binop_1): Likewise.
	* tree-ssa-math-opts.c (find_bswap_or_nop_load): Likewise.
	* tree-ssa-sccvn.c (copy_reference_ops_from_ref): Likewise.
	(ao_ref_init_from_vn_reference): Likewise.

gcc/cp/
	* init.c (build_new_1): Use shift operators instead of wi:: shifts.

From-SVN: r235720

gcc/ChangeLog

@@ -1,3 +1,25 @@
+2016-05-02  Richard Sandiford  <richard.sandiford@arm.com>
+
+	* wide-int.h: Update offset_int and widest_int documentation.
+	(WI_SIGNED_SHIFT_RESULT): New macro.
+	(wi::binary_shift): Define signed_shift_result_type for
+	shifts on offset_int- and widest_int-like types.
+	(generic_wide_int): Support <<= and >>= if << and >> are supported.
+	* tree.h (int_bit_position): Use shift operators instead of wi::
+	 shifts.
+	* alias.c (adjust_offset_for_component_ref): Likewise.
+	* expr.c (get_inner_reference): Likewise.
+	* fold-const.c (fold_comparison): Likewise.
+	* gimple-fold.c (fold_nonarray_ctor_reference): Likewise.
+	* gimple-ssa-strength-reduction.c (restructure_reference): Likewise.
+	* tree-dfa.c (get_ref_base_and_extent): Likewise.
+	* tree-ssa-alias.c (indirect_ref_may_alias_decl_p): Likewise.
+	(stmt_kills_ref_p): Likewise.
+	* tree-ssa-ccp.c (bit_value_binop_1): Likewise.
+	* tree-ssa-math-opts.c (find_bswap_or_nop_load): Likewise.
+	* tree-ssa-sccvn.c (copy_reference_ops_from_ref): Likewise.
+	(ao_ref_init_from_vn_reference): Likewise.
+
 2016-05-02  Richard Sandiford  <richard.sandiford@arm.com>
 
 	* wide-int.h: Update offset_int and widest_int documentation.

gcc/alias.c

@@ -2651,8 +2651,8 @@ adjust_offset_for_component_ref (tree x, bool *known_p,
 
       offset_int woffset
 	= (wi::to_offset (xoffset)
-	   + wi::lrshift (wi::to_offset (DECL_FIELD_BIT_OFFSET (field)),
+	   + (wi::to_offset (DECL_FIELD_BIT_OFFSET (field))
-			  LOG2_BITS_PER_UNIT));
+	      >> LOG2_BITS_PER_UNIT));
       if (!wi::fits_uhwi_p (woffset))
 	{
 	  *known_p = false;

gcc/cp/ChangeLog

@@ -1,3 +1,7 @@
+2016-05-02  Richard Sandiford  <richard.sandiford@arm.com>
+
+	* init.c (build_new_1): Use shift operators instead of wi:: shifts.
+
 2016-05-02  Richard Biener  <rguenther@suse.de>
 
 	* decl.c (grokdeclarator): Properly insert a DECL_EXPR for

gcc/cp/init.c

@@ -2812,8 +2812,7 @@ build_new_1 (vec<tree, va_gc> **placement, tree type, tree nelts,
 
 	  unsigned shift = (max_outer_nelts.get_precision ()) - 7
 	    - wi::clz (max_outer_nelts);
-	  max_outer_nelts = wi::lshift (wi::lrshift (max_outer_nelts, shift),
+	  max_outer_nelts = (max_outer_nelts >> shift) << shift;
-				        shift);
 
           outer_nelts_check = fold_build2 (LE_EXPR, boolean_type_node,
 					   outer_nelts,

gcc/expr.c

@@ -6989,7 +6989,7 @@ get_inner_reference (tree exp, HOST_WIDE_INT *pbitsize,
 	      if (!integer_zerop (off))
 		{
 		  offset_int boff, coff = mem_ref_offset (exp);
-		  boff = wi::lshift (coff, LOG2_BITS_PER_UNIT);
+		  boff = coff << LOG2_BITS_PER_UNIT;
 		  bit_offset += boff;
 		}
 	      exp = TREE_OPERAND (TREE_OPERAND (exp, 0), 0);
@@ -7015,7 +7015,7 @@ get_inner_reference (tree exp, HOST_WIDE_INT *pbitsize,
     {
       offset_int tem = wi::sext (wi::to_offset (offset),
 				 TYPE_PRECISION (sizetype));
-      tem = wi::lshift (tem, LOG2_BITS_PER_UNIT);
+      tem <<= LOG2_BITS_PER_UNIT;
       tem += bit_offset;
       if (wi::fits_shwi_p (tem))
 	{
@@ -7035,7 +7035,7 @@ get_inner_reference (tree exp, HOST_WIDE_INT *pbitsize,
 	  /* TEM is the bitpos rounded to BITS_PER_UNIT towards -Inf.
 	     Subtract it to BIT_OFFSET and add it (scaled) to OFFSET.  */
 	  bit_offset -= tem;
-	  tem = wi::arshift (tem, LOG2_BITS_PER_UNIT);
+	  tem >>= LOG2_BITS_PER_UNIT;
 	  offset = size_binop (PLUS_EXPR, offset,
 			       wide_int_to_tree (sizetype, tem));
 	}

gcc/fold-const.c

@@ -8521,7 +8521,7 @@ fold_comparison (location_t loc, enum tree_code code, tree type,
 	    {
 	      offset_int tem = wi::sext (wi::to_offset (offset0),
 					 TYPE_PRECISION (sizetype));
-	      tem = wi::lshift (tem, LOG2_BITS_PER_UNIT);
+	      tem <<= LOG2_BITS_PER_UNIT;
 	      tem += bitpos0;
 	      if (wi::fits_shwi_p (tem))
 		{
@@ -8568,7 +8568,7 @@ fold_comparison (location_t loc, enum tree_code code, tree type,
 	    {
 	      offset_int tem = wi::sext (wi::to_offset (offset1),
 					 TYPE_PRECISION (sizetype));
-	      tem = wi::lshift (tem, LOG2_BITS_PER_UNIT);
+	      tem <<= LOG2_BITS_PER_UNIT;
 	      tem += bitpos1;
 	      if (wi::fits_shwi_p (tem))
 		{

gcc/gimple-fold.c

@@ -5435,8 +5435,7 @@ fold_nonarray_ctor_reference (tree type, tree ctor,
 
       /* Compute bit offset of the field.  */
       bitoffset = (wi::to_offset (field_offset)
-		   + wi::lshift (wi::to_offset (byte_offset),
+		   + (wi::to_offset (byte_offset) << LOG2_BITS_PER_UNIT));
-				 LOG2_BITS_PER_UNIT));
       /* Compute bit offset where the field ends.  */
       if (field_size != NULL_TREE)
 	bitoffset_end = bitoffset + wi::to_offset (field_size);

gcc/gimple-ssa-strength-reduction.c

@@ -951,7 +951,7 @@ restructure_reference (tree *pbase, tree *poffset, widest_int *pindex,
       c2 = 0;
     }
 
-  c4 = wi::lrshift (index, LOG2_BITS_PER_UNIT);
+  c4 = index >> LOG2_BITS_PER_UNIT;
   c5 = backtrace_base_for_ref (&t2);
 
   *pbase = t1;

gcc/tree-dfa.c

@@ -424,8 +424,8 @@ get_ref_base_and_extent (tree exp, HOST_WIDE_INT *poffset,
 
 	    if (this_offset && TREE_CODE (this_offset) == INTEGER_CST)
 	      {
-		offset_int woffset = wi::lshift (wi::to_offset (this_offset),
+		offset_int woffset = (wi::to_offset (this_offset)
-						 LOG2_BITS_PER_UNIT);
+				      << LOG2_BITS_PER_UNIT);
 		woffset += wi::to_offset (DECL_FIELD_BIT_OFFSET (field));
 		bit_offset += woffset;
 
@@ -453,7 +453,7 @@ get_ref_base_and_extent (tree exp, HOST_WIDE_INT *poffset,
 			  {
 			    offset_int tem = (wi::to_offset (ssize)
 					      - wi::to_offset (fsize));
-			    tem = wi::lshift (tem, LOG2_BITS_PER_UNIT);
+			    tem <<= LOG2_BITS_PER_UNIT;
 			    tem -= woffset;
 			    maxsize += tem;
 			  }
@@ -493,7 +493,7 @@ get_ref_base_and_extent (tree exp, HOST_WIDE_INT *poffset,
 		  = wi::sext (wi::to_offset (index) - wi::to_offset (low_bound),
 			      TYPE_PRECISION (TREE_TYPE (index)));
 		woffset *= wi::to_offset (unit_size);
-		woffset = wi::lshift (woffset, LOG2_BITS_PER_UNIT);
+		woffset <<= LOG2_BITS_PER_UNIT;
 		bit_offset += woffset;
 
 		/* An array ref with a constant index up in the structure
@@ -570,7 +570,7 @@ get_ref_base_and_extent (tree exp, HOST_WIDE_INT *poffset,
 	      else
 		{
 		  offset_int off = mem_ref_offset (exp);
-		  off = wi::lshift (off, LOG2_BITS_PER_UNIT);
+		  off <<= LOG2_BITS_PER_UNIT;
 		  off += bit_offset;
 		  if (wi::fits_shwi_p (off))
 		    {

gcc/tree-ssa-alias.c

@@ -1101,7 +1101,7 @@ indirect_ref_may_alias_decl_p (tree ref1 ATTRIBUTE_UNUSED, tree base1,
   /* The offset embedded in MEM_REFs can be negative.  Bias them
      so that the resulting offset adjustment is positive.  */
   offset_int moff = mem_ref_offset (base1);
-  moff = wi::lshift (moff, LOG2_BITS_PER_UNIT);
+  moff <<= LOG2_BITS_PER_UNIT;
   if (wi::neg_p (moff))
     offset2p += (-moff).to_short_addr ();
   else
@@ -1173,7 +1173,7 @@ indirect_ref_may_alias_decl_p (tree ref1 ATTRIBUTE_UNUSED, tree base1,
       || TREE_CODE (dbase2) == TARGET_MEM_REF)
     {
       offset_int moff = mem_ref_offset (dbase2);
-      moff = wi::lshift (moff, LOG2_BITS_PER_UNIT);
+      moff <<= LOG2_BITS_PER_UNIT;
       if (wi::neg_p (moff))
 	doffset1 -= (-moff).to_short_addr ();
       else
@@ -1271,13 +1271,13 @@ indirect_refs_may_alias_p (tree ref1 ATTRIBUTE_UNUSED, tree base1,
       /* The offset embedded in MEM_REFs can be negative.  Bias them
 	 so that the resulting offset adjustment is positive.  */
       moff = mem_ref_offset (base1);
-      moff = wi::lshift (moff, LOG2_BITS_PER_UNIT);
+      moff <<= LOG2_BITS_PER_UNIT;
       if (wi::neg_p (moff))
 	offset2 += (-moff).to_short_addr ();
       else
 	offset1 += moff.to_shwi ();
       moff = mem_ref_offset (base2);
-      moff = wi::lshift (moff, LOG2_BITS_PER_UNIT);
+      moff <<= LOG2_BITS_PER_UNIT;
       if (wi::neg_p (moff))
 	offset1 += (-moff).to_short_addr ();
       else
@@ -2358,10 +2358,10 @@ stmt_kills_ref_p (gimple *stmt, ao_ref *ref)
 				       TREE_OPERAND (ref->base, 1)))
 		{
 		  offset_int off1 = mem_ref_offset (base);
-		  off1 = wi::lshift (off1, LOG2_BITS_PER_UNIT);
+		  off1 <<= LOG2_BITS_PER_UNIT;
 		  off1 += offset;
 		  offset_int off2 = mem_ref_offset (ref->base);
-		  off2 = wi::lshift (off2, LOG2_BITS_PER_UNIT);
+		  off2 <<= LOG2_BITS_PER_UNIT;
 		  off2 += ref_offset;
 		  if (wi::fits_shwi_p (off1) && wi::fits_shwi_p (off2))
 		    {
@@ -2432,18 +2432,15 @@ stmt_kills_ref_p (gimple *stmt, ao_ref *ref)
 		  if (TREE_CODE (rbase) != MEM_REF)
 		    return false;
 		  // Compare pointers.
-		  offset += wi::lshift (mem_ref_offset (base),
+		  offset += mem_ref_offset (base) << LOG2_BITS_PER_UNIT;
-					LOG2_BITS_PER_UNIT);
+		  roffset += mem_ref_offset (rbase) << LOG2_BITS_PER_UNIT;
-		  roffset += wi::lshift (mem_ref_offset (rbase),
-					 LOG2_BITS_PER_UNIT);
 		  base = TREE_OPERAND (base, 0);
 		  rbase = TREE_OPERAND (rbase, 0);
 		}
 	      if (base == rbase
 		  && offset <= roffset
 		  && (roffset + ref->max_size
-		      <= offset + wi::lshift (wi::to_offset (len),
+		      <= offset + (wi::to_offset (len) << LOG2_BITS_PER_UNIT)))
-					      LOG2_BITS_PER_UNIT)))
 		return true;
 	      break;
 	    }

gcc/tree-ssa-ccp.c

@@ -1372,8 +1372,8 @@ bit_value_binop_1 (enum tree_code code, tree type,
 		}
 	      else
 		{
-		  *mask = wi::ext (wi::lshift (r1mask, shift), width, sgn);
+		  *mask = wi::ext (r1mask << shift, width, sgn);
-		  *val = wi::ext (wi::lshift (r1val, shift), width, sgn);
+		  *val = wi::ext (r1val << shift, width, sgn);
 		}
 	    }
 	}

gcc/tree-ssa-math-opts.c

@@ -2104,7 +2104,7 @@ find_bswap_or_nop_load (gimple *stmt, tree ref, struct symbolic_number *n)
       if (!integer_zerop (off))
 	{
 	  offset_int boff, coff = mem_ref_offset (base_addr);
-	  boff = wi::lshift (coff, LOG2_BITS_PER_UNIT);
+	  boff = coff << LOG2_BITS_PER_UNIT;
 	  bit_offset += boff;
 	}
 
@@ -2118,7 +2118,7 @@ find_bswap_or_nop_load (gimple *stmt, tree ref, struct symbolic_number *n)
 	  /* TEM is the bitpos rounded to BITS_PER_UNIT towards -Inf.
 	     Subtract it to BIT_OFFSET and add it (scaled) to OFFSET.  */
 	  bit_offset -= tem;
-	  tem = wi::arshift (tem, LOG2_BITS_PER_UNIT);
+	  tem >>= LOG2_BITS_PER_UNIT;
 	  if (offset)
 	    offset = size_binop (PLUS_EXPR, offset,
 				    wide_int_to_tree (sizetype, tem));

gcc/tree-ssa-sccvn.c

@@ -788,8 +788,7 @@ copy_reference_ops_from_ref (tree ref, vec<vn_reference_op_s> *result)
 		  {
 		    offset_int off
 		      = (wi::to_offset (this_offset)
-			 + wi::lrshift (wi::to_offset (bit_offset),
+			 + (wi::to_offset (bit_offset) >> LOG2_BITS_PER_UNIT));
-					LOG2_BITS_PER_UNIT));
 		    if (wi::fits_shwi_p (off)
 			/* Probibit value-numbering zero offset components
 			   of addresses the same before the pass folding
@@ -999,8 +998,8 @@ ao_ref_init_from_vn_reference (ao_ref *ref,
 	      max_size = -1;
 	    else
 	      {
-		offset_int woffset = wi::lshift (wi::to_offset (this_offset),
+		offset_int woffset = (wi::to_offset (this_offset)
-						 LOG2_BITS_PER_UNIT);
+				      << LOG2_BITS_PER_UNIT);
 		woffset += wi::to_offset (DECL_FIELD_BIT_OFFSET (field));
 		offset += woffset;
 	      }
@@ -1020,7 +1019,7 @@ ao_ref_init_from_vn_reference (ao_ref *ref,
 		= wi::sext (wi::to_offset (op->op0) - wi::to_offset (op->op1),
 			    TYPE_PRECISION (TREE_TYPE (op->op0)));
 	      woffset *= wi::to_offset (op->op2);
-	      woffset = wi::lshift (woffset, LOG2_BITS_PER_UNIT);
+	      woffset <<= LOG2_BITS_PER_UNIT;
 	      offset += woffset;
 	    }
 	  break;

gcc/tree.h

@@ -5375,7 +5375,7 @@ extern GTY(()) struct int_n_trees_t int_n_trees[NUM_INT_N_ENTS];
 inline HOST_WIDE_INT
 int_bit_position (const_tree field)
 { 
-  return (wi::lshift (wi::to_offset (DECL_FIELD_OFFSET (field)), BITS_PER_UNIT_LOG)
+  return ((wi::to_offset (DECL_FIELD_OFFSET (field)) << BITS_PER_UNIT_LOG)
 	  + wi::to_offset (DECL_FIELD_BIT_OFFSET (field))).to_shwi ();
 }
 

gcc/wide-int.h

@@ -68,6 +68,8 @@ along with GCC; see the file COPYING3.  If not see
      Since the values are logically signed, there is no need to
      distinguish between signed and unsigned operations.  Sign-sensitive
      comparison operators <, <=, > and >= are therefore supported.
+     Shift operators << and >> are also supported, with >> being
+     an _arithmetic_ right shift.
 
      [ Note that, even though offset_int is effectively int128_t,
        it can still be useful to use unsigned comparisons like
@@ -82,7 +84,8 @@ along with GCC; see the file COPYING3.  If not see
 
      Like offset_int, widest_int is wider than all the values that
      it needs to represent, so the integers are logically signed.
-     Sign-sensitive comparison operators <, <=, > and >= are supported.
+     Sign-sensitive comparison operators <, <=, > and >= are supported,
+     as are << and >>.
 
      There are several places in the GCC where this should/must be used:
 
@@ -259,6 +262,11 @@ along with GCC; see the file COPYING3.  If not see
 #define WI_BINARY_RESULT(T1, T2) \
   typename wi::binary_traits <T1, T2>::result_type
 
+/* The type of result produced by T1 << T2.  Leads to substitution failure
+   if the operation isn't supported.  Defined purely for brevity.  */
+#define WI_SIGNED_SHIFT_RESULT(T1, T2) \
+  typename wi::binary_traits <T1, T2>::signed_shift_result_type
+
 /* The type of result produced by a signed binary predicate on types T1 and T2.
    This is bool if signed comparisons make sense for T1 and T2 and leads to
    substitution failure otherwise.  */
@@ -405,6 +413,7 @@ namespace wi
        so as not to confuse gengtype.  */
     typedef generic_wide_int < fixed_wide_int_storage
 			       <int_traits <T1>::precision> > result_type;
+    typedef result_type signed_shift_result_type;
     typedef bool signed_predicate_result;
   };
 
@@ -416,6 +425,7 @@ namespace wi
     STATIC_ASSERT (int_traits <T1>::precision == int_traits <T2>::precision);
     typedef generic_wide_int < fixed_wide_int_storage
 			       <int_traits <T1>::precision> > result_type;
+    typedef result_type signed_shift_result_type;
     typedef bool signed_predicate_result;
   };
 
@@ -681,6 +691,11 @@ public:
   template <typename T> \
     generic_wide_int &OP (const T &c) { return (*this = wi::F (*this, c)); }
 
+/* Restrict these to cases where the shift operator is defined.  */
+#define SHIFT_ASSIGNMENT_OPERATOR(OP, OP2) \
+  template <typename T> \
+    generic_wide_int &OP (const T &c) { return (*this = *this OP2 c); }
+
 #define INCDEC_OPERATOR(OP, DELTA) \
   generic_wide_int &OP () { *this += DELTA; return *this; }
 
@@ -702,12 +717,15 @@ public:
   ASSIGNMENT_OPERATOR (operator +=, add)
   ASSIGNMENT_OPERATOR (operator -=, sub)
   ASSIGNMENT_OPERATOR (operator *=, mul)
+  SHIFT_ASSIGNMENT_OPERATOR (operator <<=, <<)
+  SHIFT_ASSIGNMENT_OPERATOR (operator >>=, >>)
   INCDEC_OPERATOR (operator ++, 1)
   INCDEC_OPERATOR (operator --, -1)
 
 #undef BINARY_PREDICATE
 #undef UNARY_OPERATOR
 #undef BINARY_OPERATOR
+#undef SHIFT_ASSIGNMENT_OPERATOR
 #undef ASSIGNMENT_OPERATOR
 #undef INCDEC_OPERATOR
 
@@ -857,7 +875,7 @@ generic_wide_int <storage>::elt (unsigned int i) const
 
 template <typename storage>
 template <typename T>
-generic_wide_int <storage> &
+inline generic_wide_int <storage> &
 generic_wide_int <storage>::operator = (const T &x)
 {
   storage::operator = (x);
@@ -3078,6 +3096,20 @@ SIGNED_BINARY_PREDICATE (operator >=, ges_p)
 
 #undef SIGNED_BINARY_PREDICATE
 
+template <typename T1, typename T2>
+inline WI_SIGNED_SHIFT_RESULT (T1, T2)
+operator << (const T1 &x, const T2 &y)
+{
+  return wi::lshift (x, y);
+}
+
+template <typename T1, typename T2>
+inline WI_SIGNED_SHIFT_RESULT (T1, T2)
+operator >> (const T1 &x, const T2 &y)
+{
+  return wi::arshift (x, y);
+}
+
 template<typename T>
 void
 gt_ggc_mx (generic_wide_int <T> *)