Adding some random cc: to people who might be affected. Hopefully I am not
breaking any of your stuff...
Ulrich Weigand (address space)
Ilya Enkovich (pointer bound check)
DJ Delorie (target with 24-bit partial mode pointer)
If you want to give it a try, or just take a quick look to check that you
are obviously not affected, that would be nice, but don't feel forced.
Here is an updated version of the patch, with just a few more
transformations in match.pd, to match some MINUS_EXPR optimizations I
missed the first time:
-(A-B), X-Z<Y-Z, (X-Z)-(Y-Z), Z-X<Z-Y, (Z-X)-(Z-Y), (A-B)+(C-A)
The exact undefined-behavior status should probably be clarified more.
First, I'd like to say that POINTER_DIFF_EXPR may only take 2 pointers
into the same "object" (like in C/C++), so they differ by at most half the
size of the address space, and a-b is not allowed to be the minimum
negative value (so I can safely use b-a), and if we compute a-b and b-c,
then a and c are in the same object so I can safely compute a-c, etc.
Second, we probably need modes without undefined behavior, wrapping with
either -fwrapv or a new -fwrapp, or sanitized. For the sanitized version,
we could keep using POINTER_DIFF_EXPR and check TYPE_OVERFLOW_SANITIZED on
the pointer type as we currently do for integers. For wrapping, either we
say that POINTER_DIFF_EXPR has wrapping semantics when that option is in
effect, or we do not use POINTER_DIFF_EXPR and instead cast to unsigned
before applying a MINUS_EXPR (my preference).
On Sat, 28 Oct 2017, Marc Glisse wrote:
Hello,
first, if you are doing anything unusual with pointers (address spaces,
pointer/sizetype with weird sizes, instrumentation, etc), it would be great
if you could give this patch a try. It was bootstrapped and regtested on
powerpc64le-unknown-linux-gnu (gcc112), and a slightly older version on
x86_64-pc-linux-gnu (skylake laptop). I also built bare cross-compilers (no
sysroot or anything) for avr, m32c, alpha64-vms, s390-linux, and visium to
check that on trivial examples it behaves as expected (by the way, m32c seems
broken for unrelated reasons at the moment), but I wouldn't count that as
complete testing.
This was previously discussed in the thread "Fix pointer diff (was:
-fsanitize=pointer-overflow support (PR sanitizer/80998))" (
https://gcc.gnu.org/ml/gcc-patches/2017-10/msg02128.html for the latest
message).
Front-ends other than C/C++ can be changed later (I took a quick look at
fortran and ada, but they are way too unfamiliar to me), I did not remove any
handling for the other representations.
2017-10-28 Marc Glisse <marc.gli...@inria.fr>
gcc/c/
* c-fold.c (c_fully_fold_internal): Handle POINTER_DIFF_EXPR.
* c-typeck.c (pointer_diff): Use POINTER_DIFF_EXPR.
gcc/c-family/
* c-pretty-print.c (pp_c_additive_expression,
c_pretty_printer::expression): Handle POINTER_DIFF_EXPR.
gcc/cp/
* constexpr.c (cxx_eval_constant_expression,
potential_constant_expression_1): Handle POINTER_DIFF_EXPR.
* cp-gimplify.c (cp_fold): Likewise.
* error.c (dump_expr): Likewise.
* typeck.c (cp_build_binary_op): Likewise.
(pointer_diff): Use POINTER_DIFF_EXPR.
gcc/
* doc/generic.texi: Document POINTER_DIFF_EXPR, update
POINTER_PLUS_EXPR.
* cfgexpand.c (expand_debug_expr): Handle POINTER_DIFF_EXPR.
* expr.c (expand_expr_real_2): Likewise.
* fold-const.c (const_binop, const_binop,
fold_addr_of_array_ref_difference, fold_binary_loc): Likewise.
* match.pd (X-X, P+(Q-P), &D-P, (P+N)-P, P-(P+N), (P+M)-(P+N),
P-Q==0): New transformations for POINTER_DIFF_EXPR, based on
MINUS_EXPR transformations.
* optabs-tree.c (optab_for_tree_code): Handle POINTER_DIFF_EXPR.
* tree-cfg.c (verify_expr, verify_gimple_assign_binary): Likewise.
* tree-inline.c (estimate_operator_cost): Likewise.
* tree-pretty-print.c (dump_generic_node, op_code_prio,
op_symbol_code): Likewise.
* tree-vect-stmts.c (vectorizable_operation): Likewise.
* tree-vrp.c (extract_range_from_binary_expr): Likewise.
* varasm.c (initializer_constant_valid_p_1): Likewise.
* tree.def: New tree code POINTER_DIFF_EXPR.
--
Marc Glisse
Index: gcc/c/c-fold.c
===================================================================
--- gcc/c/c-fold.c (revision 254495)
+++ gcc/c/c-fold.c (working copy)
@@ -238,20 +238,21 @@ c_fully_fold_internal (tree expr, bool i
case COMPOUND_EXPR:
case MODIFY_EXPR:
case PREDECREMENT_EXPR:
case PREINCREMENT_EXPR:
case POSTDECREMENT_EXPR:
case POSTINCREMENT_EXPR:
case PLUS_EXPR:
case MINUS_EXPR:
case MULT_EXPR:
case POINTER_PLUS_EXPR:
+ case POINTER_DIFF_EXPR:
case TRUNC_DIV_EXPR:
case CEIL_DIV_EXPR:
case FLOOR_DIV_EXPR:
case TRUNC_MOD_EXPR:
case RDIV_EXPR:
case EXACT_DIV_EXPR:
case LSHIFT_EXPR:
case RSHIFT_EXPR:
case BIT_IOR_EXPR:
case BIT_XOR_EXPR:
Index: gcc/c/c-typeck.c
===================================================================
--- gcc/c/c-typeck.c (revision 254495)
+++ gcc/c/c-typeck.c (working copy)
@@ -3771,21 +3771,21 @@ parser_build_binary_op (location_t locat
&& TREE_CODE (type2) == ENUMERAL_TYPE
&& TYPE_MAIN_VARIANT (type1) != TYPE_MAIN_VARIANT (type2))
warning_at (location, OPT_Wenum_compare,
"comparison between %qT and %qT",
type1, type2);
return result;
}
/* Return a tree for the difference of pointers OP0 and OP1.
- The resulting tree has type int. */
+ The resulting tree has type ptrdiff_t. */
static tree
pointer_diff (location_t loc, tree op0, tree op1)
{
tree restype = ptrdiff_type_node;
tree result, inttype;
addr_space_t as0 = TYPE_ADDR_SPACE (TREE_TYPE (TREE_TYPE (op0)));
addr_space_t as1 = TYPE_ADDR_SPACE (TREE_TYPE (TREE_TYPE (op1)));
tree target_type = TREE_TYPE (TREE_TYPE (op0));
@@ -3803,43 +3803,50 @@ pointer_diff (location_t loc, tree op0,
to exist because the caller verified that comp_target_types
returned non-zero. */
if (!addr_space_superset (as0, as1, &as_common))
gcc_unreachable ();
common_type = common_pointer_type (TREE_TYPE (op0), TREE_TYPE (op1));
op0 = convert (common_type, op0);
op1 = convert (common_type, op1);
}
- /* Determine integer type to perform computations in. This will usually
+ /* Determine integer type result of the subtraction. This will usually
be the same as the result type (ptrdiff_t), but may need to be a wider
type if pointers for the address space are wider than ptrdiff_t. */
if (TYPE_PRECISION (restype) < TYPE_PRECISION (TREE_TYPE (op0)))
inttype = c_common_type_for_size (TYPE_PRECISION (TREE_TYPE (op0)), 0);
else
inttype = restype;
if (TREE_CODE (target_type) == VOID_TYPE)
pedwarn (loc, OPT_Wpointer_arith,
"pointer of type %<void *%> used in subtraction");
if (TREE_CODE (target_type) == FUNCTION_TYPE)
pedwarn (loc, OPT_Wpointer_arith,
"pointer to a function used in subtraction");
- /* First do the subtraction as integers;
- then drop through to build the divide operator.
- Do not do default conversions on the minus operator
- in case restype is a short type. */
-
- op0 = build_binary_op (loc,
- MINUS_EXPR, convert (inttype, op0),
- convert (inttype, op1), false);
+ /* First do the subtraction, then build the divide operator
+ and only convert at the very end.
+ Do not do default conversions in case restype is a short type. */
+
+ /* POINTER_DIFF_EXPR requires a signed integer type of the same size as
+ pointers. If some platform cannot provide that, or has a larger
+ ptrdiff_type to support differences larger than half the address
+ space, cast the pointers to some larger integer type and do the
+ computations in that type. */
+ if (TYPE_PRECISION (inttype) > TYPE_PRECISION (TREE_TYPE (op0)))
+ op0 = build_binary_op (loc, MINUS_EXPR, convert (inttype, op0),
+ convert (inttype, op1), false);
+ else
+ op0 = build2_loc (loc, POINTER_DIFF_EXPR, inttype, op0, op1);
+
/* This generates an error if op1 is pointer to incomplete type. */
if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (TREE_TYPE (orig_op1))))
error_at (loc, "arithmetic on pointer to an incomplete type");
op1 = c_size_in_bytes (target_type);
if (pointer_to_zero_sized_aggr_p (TREE_TYPE (orig_op1)))
error_at (loc, "arithmetic on pointer to an empty aggregate");
/* Divide by the size, in easiest possible way. */
Index: gcc/c-family/c-pretty-print.c
===================================================================
--- gcc/c-family/c-pretty-print.c (revision 254495)
+++ gcc/c-family/c-pretty-print.c (working copy)
@@ -1869,20 +1869,21 @@ c_pretty_printer::multiplicative_express
additive-expression - multiplicative-expression */
static void
pp_c_additive_expression (c_pretty_printer *pp, tree e)
{
enum tree_code code = TREE_CODE (e);
switch (code)
{
case POINTER_PLUS_EXPR:
case PLUS_EXPR:
+ case POINTER_DIFF_EXPR:
case MINUS_EXPR:
pp_c_additive_expression (pp, TREE_OPERAND (e, 0));
pp_c_whitespace (pp);
if (code == PLUS_EXPR || code == POINTER_PLUS_EXPR)
pp_plus (pp);
else
pp_minus (pp);
pp_c_whitespace (pp);
pp->multiplicative_expression (TREE_OPERAND (e, 1));
break;
@@ -2285,20 +2286,21 @@ c_pretty_printer::expression (tree e)
case NE_EXPR:
pp_c_equality_expression (this, e);
break;
case COND_EXPR:
conditional_expression (e);
break;
case POINTER_PLUS_EXPR:
case PLUS_EXPR:
+ case POINTER_DIFF_EXPR:
case MINUS_EXPR:
pp_c_additive_expression (this, e);
break;
case MODIFY_EXPR:
case INIT_EXPR:
assignment_expression (e);
break;
case COMPOUND_EXPR:
Index: gcc/cfgexpand.c
===================================================================
--- gcc/cfgexpand.c (revision 254495)
+++ gcc/cfgexpand.c (working copy)
@@ -4616,20 +4616,21 @@ expand_debug_expr (tree exp)
/* We always sign-extend, regardless of the signedness of
the operand, because the operand is always unsigned
here even if the original C expression is signed. */
op1 = simplify_gen_unary (SIGN_EXTEND, op0_mode, op1, op1_mode);
}
/* Fall through. */
case PLUS_EXPR:
return simplify_gen_binary (PLUS, mode, op0, op1);
case MINUS_EXPR:
+ case POINTER_DIFF_EXPR:
return simplify_gen_binary (MINUS, mode, op0, op1);
case MULT_EXPR:
return simplify_gen_binary (MULT, mode, op0, op1);
case RDIV_EXPR:
case TRUNC_DIV_EXPR:
case EXACT_DIV_EXPR:
if (unsignedp)
return simplify_gen_binary (UDIV, mode, op0, op1);
Index: gcc/cp/constexpr.c
===================================================================
--- gcc/cp/constexpr.c (revision 254495)
+++ gcc/cp/constexpr.c (working copy)
@@ -4292,20 +4292,21 @@ cxx_eval_constant_expression (const cons
return t;
op1 = TREE_OPERAND (t, 1);
r = cxx_eval_constant_expression (ctx, op1,
lval, non_constant_p, overflow_p,
jump_target);
}
}
break;
case POINTER_PLUS_EXPR:
+ case POINTER_DIFF_EXPR:
case PLUS_EXPR:
case MINUS_EXPR:
case MULT_EXPR:
case TRUNC_DIV_EXPR:
case CEIL_DIV_EXPR:
case FLOOR_DIV_EXPR:
case ROUND_DIV_EXPR:
case TRUNC_MOD_EXPR:
case CEIL_MOD_EXPR:
case ROUND_MOD_EXPR:
@@ -5526,20 +5527,21 @@ potential_constant_expression_1 (tree t,
&& TYPE_POLYMORPHIC_P (TREE_TYPE (e)))
{
if (flags & tf_error)
error_at (loc, "typeid-expression is not a constant expression "
"because %qE is of polymorphic type", e);
return false;
}
return true;
}
+ case POINTER_DIFF_EXPR:
case MINUS_EXPR:
want_rval = true;
goto binary;
case LT_EXPR:
case LE_EXPR:
case GT_EXPR:
case GE_EXPR:
case EQ_EXPR:
case NE_EXPR:
Index: gcc/cp/cp-gimplify.c
===================================================================
--- gcc/cp/cp-gimplify.c (revision 254495)
+++ gcc/cp/cp-gimplify.c (working copy)
@@ -2213,20 +2213,21 @@ cp_fold (tree x)
case POSTINCREMENT_EXPR:
case INIT_EXPR:
case PREDECREMENT_EXPR:
case PREINCREMENT_EXPR:
case COMPOUND_EXPR:
case MODIFY_EXPR:
rval_ops = false;
/* FALLTHRU */
case POINTER_PLUS_EXPR:
case PLUS_EXPR:
+ case POINTER_DIFF_EXPR:
case MINUS_EXPR:
case MULT_EXPR:
case TRUNC_DIV_EXPR:
case CEIL_DIV_EXPR:
case FLOOR_DIV_EXPR:
case ROUND_DIV_EXPR:
case TRUNC_MOD_EXPR:
case CEIL_MOD_EXPR:
case ROUND_MOD_EXPR:
case RDIV_EXPR:
Index: gcc/cp/error.c
===================================================================
--- gcc/cp/error.c (revision 254495)
+++ gcc/cp/error.c (working copy)
@@ -2220,20 +2220,24 @@ dump_expr (cxx_pretty_printer *pp, tree
default argument. Note we may have cleared out the first
operand in expand_expr, so don't go killing ourselves. */
if (TREE_OPERAND (t, 1))
dump_expr (pp, TREE_OPERAND (t, 1), flags | TFF_EXPR_IN_PARENS);
break;
case POINTER_PLUS_EXPR:
dump_binary_op (pp, "+", t, flags);
break;
+ case POINTER_DIFF_EXPR:
+ dump_binary_op (pp, "-", t, flags);
+ break;
+
case INIT_EXPR:
case MODIFY_EXPR:
dump_binary_op (pp, OVL_OP_INFO (true, NOP_EXPR)->name, t, flags);
break;
case PLUS_EXPR:
case MINUS_EXPR:
case MULT_EXPR:
case TRUNC_DIV_EXPR:
case TRUNC_MOD_EXPR:
Index: gcc/cp/typeck.c
===================================================================
--- gcc/cp/typeck.c (revision 254495)
+++ gcc/cp/typeck.c (working copy)
@@ -4305,20 +4305,21 @@ cp_build_binary_op (location_t location,
converted = 1;
break;
}
default:
break;
}
}
switch (code)
{
+ case POINTER_DIFF_EXPR:
case MINUS_EXPR:
/* Subtraction of two similar pointers.
We must subtract them as integers, then divide by object size. */
if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
&& same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (type0),
TREE_TYPE (type1)))
return pointer_diff (location, op0, op1,
common_pointer_type (type0, type1), complain);
/* In all other cases except pointer - int, the usual arithmetic
rules apply. */
@@ -5362,21 +5363,21 @@ cp_pointer_int_sum (location_t loc, enum
intop, complain & tf_warning_or_error);
}
/* Return a tree for the difference of pointers OP0 and OP1.
The resulting tree has type int. */
static tree
pointer_diff (location_t loc, tree op0, tree op1, tree ptrtype,
tsubst_flags_t complain)
{
- tree result;
+ tree result, inttype;
tree restype = ptrdiff_type_node;
tree target_type = TREE_TYPE (ptrtype);
if (!complete_type_or_else (target_type, NULL_TREE))
return error_mark_node;
if (VOID_TYPE_P (target_type))
{
if (complain & tf_error)
permerror (loc, "ISO C++ forbids using pointer of "
@@ -5394,28 +5395,45 @@ pointer_diff (location_t loc, tree op0,
}
if (TREE_CODE (target_type) == METHOD_TYPE)
{
if (complain & tf_error)
permerror (loc, "ISO C++ forbids using pointer to "
"a method in subtraction");
else
return error_mark_node;
}
- /* First do the subtraction as integers;
- then drop through to build the divide operator. */
+ /* Determine integer type result of the subtraction. This will usually
+ be the same as the result type (ptrdiff_t), but may need to be a wider
+ type if pointers for the address space are wider than ptrdiff_t. */
+ if (TYPE_PRECISION (restype) < TYPE_PRECISION (TREE_TYPE (op0)))
+ inttype = c_common_type_for_size (TYPE_PRECISION (TREE_TYPE (op0)), 0);
+ else
+ inttype = restype;
- op0 = cp_build_binary_op (loc,
- MINUS_EXPR,
- cp_convert (restype, op0, complain),
- cp_convert (restype, op1, complain),
- complain);
+ /* First do the subtraction, then build the divide operator
+ and only convert at the very end.
+ Do not do default conversions in case restype is a short type. */
+
+ /* POINTER_DIFF_EXPR requires a signed integer type of the same size as
+ pointers. If some platform cannot provide that, or has a larger
+ ptrdiff_type to support differences larger than half the address
+ space, cast the pointers to some larger integer type and do the
+ computations in that type. */
+ if (TYPE_PRECISION (inttype) > TYPE_PRECISION (TREE_TYPE (op0)))
+ op0 = cp_build_binary_op (loc,
+ MINUS_EXPR,
+ cp_convert (inttype, op0, complain),
+ cp_convert (inttype, op1, complain),
+ complain);
+ else
+ op0 = build2_loc (loc, POINTER_DIFF_EXPR, inttype, op0, op1);
/* This generates an error if op1 is a pointer to an incomplete type. */
if (!COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (op1))))
{
if (complain & tf_error)
error_at (loc, "invalid use of a pointer to an incomplete type in "
"pointer arithmetic");
else
return error_mark_node;
}
@@ -5427,23 +5445,23 @@ pointer_diff (location_t loc, tree op0,
else
return error_mark_node;
}
op1 = (TYPE_PTROB_P (ptrtype)
? size_in_bytes_loc (loc, target_type)
: integer_one_node);
/* Do the division. */
- result = build2_loc (loc, EXACT_DIV_EXPR, restype, op0,
- cp_convert (restype, op1, complain));
- return result;
+ result = build2_loc (loc, EXACT_DIV_EXPR, inttype, op0,
+ cp_convert (inttype, op1, complain));
+ return cp_convert (restype, result, complain);
}
/* Construct and perhaps optimize a tree representation
for a unary operation. CODE, a tree_code, specifies the operation
and XARG is the operand. */
tree
build_x_unary_op (location_t loc, enum tree_code code, cp_expr xarg,
tsubst_flags_t complain)
{
Index: gcc/doc/generic.texi
===================================================================
--- gcc/doc/generic.texi (revision 254495)
+++ gcc/doc/generic.texi (working copy)
@@ -1217,20 +1217,21 @@ the byte offset of the field, but should
@tindex RSHIFT_EXPR
@tindex BIT_IOR_EXPR
@tindex BIT_XOR_EXPR
@tindex BIT_AND_EXPR
@tindex TRUTH_ANDIF_EXPR
@tindex TRUTH_ORIF_EXPR
@tindex TRUTH_AND_EXPR
@tindex TRUTH_OR_EXPR
@tindex TRUTH_XOR_EXPR
@tindex POINTER_PLUS_EXPR
+@tindex POINTER_DIFF_EXPR
@tindex PLUS_EXPR
@tindex MINUS_EXPR
@tindex MULT_EXPR
@tindex MULT_HIGHPART_EXPR
@tindex RDIV_EXPR
@tindex TRUNC_DIV_EXPR
@tindex FLOOR_DIV_EXPR
@tindex CEIL_DIV_EXPR
@tindex ROUND_DIV_EXPR
@tindex TRUNC_MOD_EXPR
@@ -1406,22 +1407,26 @@ always of @code{BOOLEAN_TYPE} or @code{I
These nodes represent logical and, logical or, and logical exclusive or.
They are strict; both arguments are always evaluated. There are no
corresponding operators in C or C++, but the front end will sometimes
generate these expressions anyhow, if it can tell that strictness does
not matter. The type of the operands and that of the result are
always of @code{BOOLEAN_TYPE} or @code{INTEGER_TYPE}.
@item POINTER_PLUS_EXPR
This node represents pointer arithmetic. The first operand is always
a pointer/reference type. The second operand is always an unsigned
-integer type compatible with sizetype. This is the only binary
-arithmetic operand that can operate on pointer types.
+integer type compatible with sizetype. This and POINTER_DIFF_EXPR are
+the only binary arithmetic operators that can operate on pointer types.
+
+@item POINTER_DIFF_EXPR
+This node represents pointer subtraction. The two operands always
+have pointer/reference type. It returns a signed integer.
@item PLUS_EXPR
@itemx MINUS_EXPR
@itemx MULT_EXPR
These nodes represent various binary arithmetic operations.
Respectively, these operations are addition, subtraction (of the second
operand from the first) and multiplication. Their operands may have
either integral or floating type, but there will never be case in which
one operand is of floating type and the other is of integral type.
Index: gcc/expr.c
===================================================================
--- gcc/expr.c (revision 254495)
+++ gcc/expr.c (working copy)
@@ -8545,20 +8545,21 @@ expand_expr_real_2 (sepops ops, rtx targ
if (op1 == const0_rtx)
return op0;
goto binop2;
}
expand_operands (treeop0, treeop1,
subtarget, &op0, &op1, modifier);
return REDUCE_BIT_FIELD (simplify_gen_binary (PLUS, mode, op0, op1));
case MINUS_EXPR:
+ case POINTER_DIFF_EXPR:
do_minus:
/* For initializers, we are allowed to return a MINUS of two
symbolic constants. Here we handle all cases when both operands
are constant. */
/* Handle difference of two symbolic constants,
for the sake of an initializer. */
if ((modifier == EXPAND_SUM || modifier == EXPAND_INITIALIZER)
&& really_constant_p (treeop0)
&& really_constant_p (treeop1))
{
Index: gcc/fold-const.c
===================================================================
--- gcc/fold-const.c (revision 254495)
+++ gcc/fold-const.c (working copy)
@@ -1134,20 +1134,29 @@ const_binop (enum tree_code code, tree a
STRIP_NOPS (arg1);
STRIP_NOPS (arg2);
if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg2) == INTEGER_CST)
{
if (code == POINTER_PLUS_EXPR)
return int_const_binop (PLUS_EXPR,
arg1, fold_convert (TREE_TYPE (arg1), arg2));
+ /* It is better if the caller provides the return type. */
+ if (code == POINTER_DIFF_EXPR)
+ {
+ offset_int res = wi::sub (wi::to_offset (arg1),
+ wi::to_offset (arg2));
+ return force_fit_type (signed_type_for (TREE_TYPE (arg1)), res, 1,
+ TREE_OVERFLOW (arg1) | TREE_OVERFLOW (arg2));
+ }
+
return int_const_binop (code, arg1, arg2);
}
if (TREE_CODE (arg1) == REAL_CST && TREE_CODE (arg2) == REAL_CST)
{
machine_mode mode;
REAL_VALUE_TYPE d1;
REAL_VALUE_TYPE d2;
REAL_VALUE_TYPE value;
REAL_VALUE_TYPE result;
@@ -1476,20 +1485,31 @@ const_binop (enum tree_code code, tree t
switch (code)
{
case COMPLEX_EXPR:
if ((TREE_CODE (arg1) == REAL_CST
&& TREE_CODE (arg2) == REAL_CST)
|| (TREE_CODE (arg1) == INTEGER_CST
&& TREE_CODE (arg2) == INTEGER_CST))
return build_complex (type, arg1, arg2);
return NULL_TREE;
+ /* Use the return type, in case it might be larger than ptrdiff_t. */
+ case POINTER_DIFF_EXPR:
+ if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg2) == INTEGER_CST)
+ {
+ offset_int res = wi::sub (wi::to_offset (arg1),
+ wi::to_offset (arg2));
+ return force_fit_type (type, res, 1,
+ TREE_OVERFLOW (arg1) | TREE_OVERFLOW (arg2));
+ }
+ return NULL_TREE;
+
case VEC_PACK_TRUNC_EXPR:
case VEC_PACK_FIX_TRUNC_EXPR:
{
unsigned int out_nelts, in_nelts, i;
if (TREE_CODE (arg1) != VECTOR_CST
|| TREE_CODE (arg2) != VECTOR_CST)
return NULL_TREE;
in_nelts = VECTOR_CST_NELTS (arg1);
@@ -8794,40 +8814,47 @@ fold_vec_perm (tree type, tree arg0, tre
else
return build_vector (type, out_elts);
}
/* Try to fold a pointer difference of type TYPE two address expressions of
array references AREF0 and AREF1 using location LOC. Return a
simplified expression for the difference or NULL_TREE. */
static tree
fold_addr_of_array_ref_difference (location_t loc, tree type,
- tree aref0, tree aref1)
+ tree aref0, tree aref1,
+ bool use_pointer_diff)
{
tree base0 = TREE_OPERAND (aref0, 0);
tree base1 = TREE_OPERAND (aref1, 0);
tree base_offset = build_int_cst (type, 0);
/* If the bases are array references as well, recurse. If the bases
are pointer indirections compute the difference of the pointers.
If the bases are equal, we are set. */
if ((TREE_CODE (base0) == ARRAY_REF
&& TREE_CODE (base1) == ARRAY_REF
&& (base_offset
- = fold_addr_of_array_ref_difference (loc, type, base0, base1)))
+ = fold_addr_of_array_ref_difference (loc, type, base0, base1,
+ use_pointer_diff)))
|| (INDIRECT_REF_P (base0)
&& INDIRECT_REF_P (base1)
&& (base_offset
- = fold_binary_loc (loc, MINUS_EXPR, type,
- fold_convert (type, TREE_OPERAND (base0, 0)),
- fold_convert (type,
- TREE_OPERAND (base1, 0)))))
+ = use_pointer_diff
+ ? fold_binary_loc (loc, POINTER_DIFF_EXPR, type,
+ TREE_OPERAND (base0, 0),
+ TREE_OPERAND (base1, 0))
+ : fold_binary_loc (loc, MINUS_EXPR, type,
+ fold_convert (type,
+ TREE_OPERAND (base0, 0)),
+ fold_convert (type,
+ TREE_OPERAND (base1, 0)))))
|| operand_equal_p (base0, base1, OEP_ADDRESS_OF))
{
tree op0 = fold_convert_loc (loc, type, TREE_OPERAND (aref0, 1));
tree op1 = fold_convert_loc (loc, type, TREE_OPERAND (aref1, 1));
tree esz = fold_convert_loc (loc, type, array_ref_element_size (aref0));
tree diff = fold_build2_loc (loc, MINUS_EXPR, type, op0, op1);
return fold_build2_loc (loc, PLUS_EXPR, type,
base_offset,
fold_build2_loc (loc, MULT_EXPR, type,
diff, esz));
@@ -9687,21 +9714,41 @@ fold_binary_loc (location_t loc,
}
return
fold_convert_loc (loc, type, associate_trees (loc, var0, con0,
code, atype));
}
}
return NULL_TREE;
+ case POINTER_DIFF_EXPR:
case MINUS_EXPR:
+ /* Fold &a[i] - &a[j] to i-j. */
+ if (TREE_CODE (arg0) == ADDR_EXPR
+ && TREE_CODE (TREE_OPERAND (arg0, 0)) == ARRAY_REF
+ && TREE_CODE (arg1) == ADDR_EXPR
+ && TREE_CODE (TREE_OPERAND (arg1, 0)) == ARRAY_REF)
+ {
+ tree tem = fold_addr_of_array_ref_difference (loc, type,
+ TREE_OPERAND (arg0, 0),
+ TREE_OPERAND (arg1, 0),
+ code
+ == POINTER_DIFF_EXPR);
+ if (tem)
+ return tem;
+ }
+
+ /* Further transformations are not for pointers. */
+ if (code == POINTER_DIFF_EXPR)
+ return NULL_TREE;
+
/* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
if (TREE_CODE (arg0) == NEGATE_EXPR
&& negate_expr_p (op1))
return fold_build2_loc (loc, MINUS_EXPR, type,
negate_expr (op1),
fold_convert_loc (loc, type,
TREE_OPERAND (arg0, 0)));
/* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
__complex__ ( x, -y ). This is not the same for SNaNs or if
@@ -9745,33 +9792,20 @@ fold_binary_loc (location_t loc,
&& ! TYPE_OVERFLOW_SANITIZED (type)
&& ((FLOAT_TYPE_P (type)
/* Avoid this transformation if B is a positive REAL_CST. */
&& (TREE_CODE (op1) != REAL_CST
|| REAL_VALUE_NEGATIVE (TREE_REAL_CST (op1))))
|| INTEGRAL_TYPE_P (type)))
return fold_build2_loc (loc, PLUS_EXPR, type,
fold_convert_loc (loc, type, arg0),
negate_expr (op1));
- /* Fold &a[i] - &a[j] to i-j. */
- if (TREE_CODE (arg0) == ADDR_EXPR
- && TREE_CODE (TREE_OPERAND (arg0, 0)) == ARRAY_REF
- && TREE_CODE (arg1) == ADDR_EXPR
- && TREE_CODE (TREE_OPERAND (arg1, 0)) == ARRAY_REF)
- {
- tree tem = fold_addr_of_array_ref_difference (loc, type,
- TREE_OPERAND (arg0, 0),
- TREE_OPERAND (arg1, 0));
- if (tem)
- return tem;
- }
-
/* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the same or
one. Make sure the type is not saturating and has the signedness of
the stripped operands, as fold_plusminus_mult_expr will re-associate.
??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
if ((TREE_CODE (arg0) == MULT_EXPR
|| TREE_CODE (arg1) == MULT_EXPR)
&& !TYPE_SATURATING (type)
&& TYPE_UNSIGNED (type) == TYPE_UNSIGNED (TREE_TYPE (arg0))
&& TYPE_UNSIGNED (type) == TYPE_UNSIGNED (TREE_TYPE (arg1))
&& (!FLOAT_TYPE_P (type) || flag_associative_math))
Index: gcc/match.pd
===================================================================
--- gcc/match.pd (revision 254495)
+++ gcc/match.pd (working copy)
@@ -117,20 +117,23 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
/* Simplify x - x.
This is unsafe for certain floats even in non-IEEE formats.
In IEEE, it is unsafe because it does wrong for NaNs.
Also note that operand_equal_p is always false if an operand
is volatile. */
(simplify
(minus @0 @0)
(if (!FLOAT_TYPE_P (type) || !HONOR_NANS (type))
{ build_zero_cst (type); }))
+(simplify
+ (pointer_diff @@0 @0)
+ { build_zero_cst (type); })
(simplify
(mult @0 integer_zerop@1)
@1)
/* Maybe fold x * 0 to 0. The expressions aren't the same
when x is NaN, since x * 0 is also NaN. Nor are they the
same in modes with signed zeros, since multiplying a
negative value by 0 gives -0, not +0. */
(simplify
@@ -1016,20 +1019,24 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
(minus (negate @1) @0)))
/* -(A - B) -> B - A. */
(simplify
(negate (minus @0 @1))
(if ((ANY_INTEGRAL_TYPE_P (type) && !TYPE_OVERFLOW_SANITIZED (type))
|| (FLOAT_TYPE_P (type)
&& !HONOR_SIGN_DEPENDENT_ROUNDING (type)
&& !HONOR_SIGNED_ZEROS (type)))
(minus @1 @0)))
+(simplify
+ (negate (pointer_diff @0 @1))
+ (if (TYPE_OVERFLOW_UNDEFINED (type))
+ (pointer_diff @1 @0)))
/* A - B -> A + (-B) if B is easily negatable. */
(simplify
(minus @0 negate_expr_p@1)
(if (!FIXED_POINT_TYPE_P (type))
(plus @0 (negate @1))))
/* Try to fold (type) X op CST -> (type) (X op ((type-x) CST))
when profitable.
For bitwise binary operations apply operand conversions to the
@@ -1318,36 +1325,58 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
&& TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (@0)))
(op @0 @1))))
/* For equality and subtraction, this is also true with wrapping overflow. */
(for op (eq ne minus)
(simplify
(op (minus @0 @2) (minus @1 @2))
(if (ANY_INTEGRAL_TYPE_P (TREE_TYPE (@0))
&& (TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (@0))
|| TYPE_OVERFLOW_WRAPS (TREE_TYPE (@0))))
(op @0 @1))))
+/* And for pointers... */
+(for op (simple_comparison)
+ (simplify
+ (op (pointer_diff@3 @0 @2) (pointer_diff @1 @2))
+ (if (!TYPE_OVERFLOW_SANITIZED (TREE_TYPE (@2)))
+ (op @0 @1))))
+(simplify
+ (minus (pointer_diff@3 @0 @2) (pointer_diff @1 @2))
+ (if (TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (@3))
+ && !TYPE_OVERFLOW_SANITIZED (TREE_TYPE (@2)))
+ (pointer_diff @0 @1)))
/* Z - X < Z - Y is the same as Y < X when there is no overflow. */
(for op (lt le ge gt)
(simplify
(op (minus @2 @0) (minus @2 @1))
(if (ANY_INTEGRAL_TYPE_P (TREE_TYPE (@0))
&& TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (@0)))
(op @1 @0))))
/* For equality and subtraction, this is also true with wrapping overflow. */
(for op (eq ne minus)
(simplify
(op (minus @2 @0) (minus @2 @1))
(if (ANY_INTEGRAL_TYPE_P (TREE_TYPE (@0))
&& (TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (@0))
|| TYPE_OVERFLOW_WRAPS (TREE_TYPE (@0))))
(op @1 @0))))
+/* And for pointers... */
+(for op (simple_comparison)
+ (simplify
+ (op (pointer_diff@3 @2 @0) (pointer_diff @2 @1))
+ (if (!TYPE_OVERFLOW_SANITIZED (TREE_TYPE (@2)))
+ (op @1 @0))))
+(simplify
+ (minus (pointer_diff@3 @2 @0) (pointer_diff @2 @1))
+ (if (TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (@3))
+ && !TYPE_OVERFLOW_SANITIZED (TREE_TYPE (@2)))
+ (pointer_diff @1 @0)))
/* X + Y < Y is the same as X < 0 when there is no overflow. */
(for op (lt le gt ge)
(simplify
(op:c (plus:c@2 @0 @1) @1)
(if (ANY_INTEGRAL_TYPE_P (TREE_TYPE (@0))
&& TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (@0))
&& (CONSTANT_CLASS_P (@0) || single_use (@2)))
(op @0 { build_zero_cst (TREE_TYPE (@0)); }))))
/* For equality, this is also true with wrapping overflow. */
@@ -1482,20 +1511,24 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
tem5 = ptr1 + tem4;
and produce
tem5 = ptr2; */
(simplify
(pointer_plus @0 (convert?@2 (minus@3 (convert @1) (convert @0))))
/* Conditionally look through a sign-changing conversion. */
(if (TYPE_PRECISION (TREE_TYPE (@2)) == TYPE_PRECISION (TREE_TYPE (@3))
&& ((GIMPLE && useless_type_conversion_p (type, TREE_TYPE (@1)))
|| (GENERIC && type == TREE_TYPE (@1))))
@1))
+(simplify
+ (pointer_plus @0 (convert?@2 (pointer_diff@3 @1 @@0)))
+ (if (TYPE_PRECISION (TREE_TYPE (@2)) >= TYPE_PRECISION (TREE_TYPE (@3)))
+ (convert @1)))
/* Pattern match
tem = (sizetype) ptr;
tem = tem & algn;
tem = -tem;
... = ptr p+ tem;
and produce the simpler and easier to analyze with respect to alignment
... = ptr & ~algn; */
(simplify
(pointer_plus @0 (negate (bit_and (convert @0) INTEGER_CST@1)))
@@ -1508,20 +1541,34 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
(if (tree_nop_conversion_p (type, TREE_TYPE (@0)))
(with { HOST_WIDE_INT diff; }
(if (ptr_difference_const (@0, @1, &diff))
{ build_int_cst_type (type, diff); }))))
(simplify
(minus (convert @0) (convert ADDR_EXPR@1))
(if (tree_nop_conversion_p (type, TREE_TYPE (@0)))
(with { HOST_WIDE_INT diff; }
(if (ptr_difference_const (@0, @1, &diff))
{ build_int_cst_type (type, diff); }))))
+(simplify
+ (pointer_diff (convert?@2 ADDR_EXPR@0) (convert?@3 @1))
+ (if (tree_nop_conversion_p (TREE_TYPE(@2), TREE_TYPE (@0))
+ && tree_nop_conversion_p (TREE_TYPE(@3), TREE_TYPE (@1)))
+ (with { HOST_WIDE_INT diff; }
+ (if (ptr_difference_const (@0, @1, &diff))
+ { build_int_cst_type (type, diff); }))))
+(simplify
+ (pointer_diff (convert?@2 @0) (convert?@3 ADDR_EXPR@1))
+ (if (tree_nop_conversion_p (TREE_TYPE(@2), TREE_TYPE (@0))
+ && tree_nop_conversion_p (TREE_TYPE(@3), TREE_TYPE (@1)))
+ (with { HOST_WIDE_INT diff; }
+ (if (ptr_difference_const (@0, @1, &diff))
+ { build_int_cst_type (type, diff); }))))
/* If arg0 is derived from the address of an object or function, we may
be able to fold this expression using the object or function's
alignment. */
(simplify
(bit_and (convert? @0) INTEGER_CST@1)
(if (POINTER_TYPE_P (TREE_TYPE (@0))
&& tree_nop_conversion_p (type, TREE_TYPE (@0)))
(with
{
@@ -1620,20 +1667,25 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
/* (A +- B) + (C - A) -> C +- B */
/* (A + B) - (A - C) -> B + C */
/* More cases are handled with comparisons. */
(simplify
(plus:c (plus:c @0 @1) (minus @2 @0))
(plus @2 @1))
(simplify
(plus:c (minus @0 @1) (minus @2 @0))
(minus @2 @1))
(simplify
+ (plus:c (pointer_diff @0 @1) (pointer_diff @2 @0))
+ (if (TYPE_OVERFLOW_UNDEFINED (type)
+ && !TYPE_OVERFLOW_SANITIZED (TREE_TYPE (@0)))
+ (pointer_diff @2 @1)))
+ (simplify
(minus (plus:c @0 @1) (minus @0 @2))
(plus @1 @2))
/* (A +- CST1) +- CST2 -> A + CST3
Use view_convert because it is safe for vectors and equivalent for
scalars. */
(for outer_op (plus minus)
(for inner_op (plus minus)
neg_inner_op (minus plus)
(simplify
@@ -1724,20 +1776,26 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
|| (INTEGRAL_TYPE_P (TREE_TYPE (@0))
&& TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (@0)))
/* For pointer types, if the conversion of A to the
final type requires a sign- or zero-extension,
then we have to punt - it is not defined which
one is correct. */
|| (POINTER_TYPE_P (TREE_TYPE (@0))
&& TREE_CODE (@1) == INTEGER_CST
&& tree_int_cst_sign_bit (@1) == 0))
(convert @1))))
+ (simplify
+ (pointer_diff (pointer_plus @@0 @1) @0)
+ /* The second argument of pointer_plus must be interpreted as signed, and
+ thus sign-extended if necessary. */
+ (with { tree stype = signed_type_for (TREE_TYPE (@1)); }
+ (convert (convert:stype @1))))
/* (T)P - (T)(P + A) -> -(T) A */
(for add (plus pointer_plus)
(simplify
(minus (convert @0)
(convert (add @@0 @1)))
(if (element_precision (type) <= element_precision (TREE_TYPE (@1))
/* For integer types, if A has a smaller type
than T the result depends on the possible
overflow in P + A.
@@ -1748,20 +1806,26 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
|| (INTEGRAL_TYPE_P (TREE_TYPE (@0))
&& TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (@0)))
/* For pointer types, if the conversion of A to the
final type requires a sign- or zero-extension,
then we have to punt - it is not defined which
one is correct. */
|| (POINTER_TYPE_P (TREE_TYPE (@0))
&& TREE_CODE (@1) == INTEGER_CST
&& tree_int_cst_sign_bit (@1) == 0))
(negate (convert @1)))))
+ (simplify
+ (pointer_diff @0 (pointer_plus @@0 @1))
+ /* The second argument of pointer_plus must be interpreted as signed, and
+ thus sign-extended if necessary. */
+ (with { tree stype = signed_type_for (TREE_TYPE (@1)); }
+ (negate (convert (convert:stype @1)))))
/* (T)(P + A) - (T)(P + B) -> (T)A - (T)B */
(for add (plus pointer_plus)
(simplify
(minus (convert (add @@0 @1))
(convert (add @0 @2)))
(if (element_precision (type) <= element_precision (TREE_TYPE (@1))
/* For integer types, if A has a smaller type
than T the result depends on the possible
overflow in P + A.
@@ -1774,20 +1838,26 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
/* For pointer types, if the conversion of A to the
final type requires a sign- or zero-extension,
then we have to punt - it is not defined which
one is correct. */
|| (POINTER_TYPE_P (TREE_TYPE (@0))
&& TREE_CODE (@1) == INTEGER_CST
&& tree_int_cst_sign_bit (@1) == 0
&& TREE_CODE (@2) == INTEGER_CST
&& tree_int_cst_sign_bit (@2) == 0))
(minus (convert @1) (convert @2)))))))
+ (simplify
+ (pointer_diff (pointer_plus @@0 @1) (pointer_plus @0 @2))
+ /* The second argument of pointer_plus must be interpreted as signed, and
+ thus sign-extended if necessary. */
+ (with { tree stype = signed_type_for (TREE_TYPE (@1)); }
+ (minus (convert (convert:stype @1)) (convert (convert:stype @2)))))
/* Simplifications of MIN_EXPR, MAX_EXPR, fmin() and fmax(). */
(for minmax (min max FMIN FMAX)
(simplify
(minmax @0 @0)
@0))
/* min(max(x,y),y) -> y. */
(simplify
@@ -2767,24 +2837,25 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
(icmp @0 @1)
(if (ic == ncmp)
(ncmp @0 @1))))))
/* Transform comparisons of the form X - Y CMP 0 to X CMP Y.
??? The transformation is valid for the other operators if overflow
is undefined for the type, but performing it here badly interacts
with the transformation in fold_cond_expr_with_comparison which
attempts to synthetize ABS_EXPR. */
(for cmp (eq ne)
- (simplify
- (cmp (minus@2 @0 @1) integer_zerop)
- (if (single_use (@2))
- (cmp @0 @1))))
+ (for sub (minus pointer_diff)
+ (simplify
+ (cmp (sub@2 @0 @1) integer_zerop)
+ (if (single_use (@2))
+ (cmp @0 @1)))))
/* Transform comparisons of the form X * C1 CMP 0 to X CMP 0 in the
signed arithmetic case. That form is created by the compiler
often enough for folding it to be of value. One example is in
computing loop trip counts after Operator Strength Reduction. */
(for cmp (simple_comparison)
scmp (swapped_simple_comparison)
(simplify
(cmp (mult@3 @0 INTEGER_CST@1) integer_zerop@2)
/* Handle unfolded multiplication by zero. */
Index: gcc/optabs-tree.c
===================================================================
--- gcc/optabs-tree.c (revision 254495)
+++ gcc/optabs-tree.c (working copy)
@@ -216,20 +216,21 @@ optab_for_tree_code (enum tree_code code
trapv = INTEGRAL_TYPE_P (type) && TYPE_OVERFLOW_TRAPS (type);
switch (code)
{
case POINTER_PLUS_EXPR:
case PLUS_EXPR:
if (TYPE_SATURATING (type))
return TYPE_UNSIGNED (type) ? usadd_optab : ssadd_optab;
return trapv ? addv_optab : add_optab;
+ case POINTER_DIFF_EXPR:
case MINUS_EXPR:
if (TYPE_SATURATING (type))
return TYPE_UNSIGNED (type) ? ussub_optab : sssub_optab;
return trapv ? subv_optab : sub_optab;
case MULT_EXPR:
if (TYPE_SATURATING (type))
return TYPE_UNSIGNED (type) ? usmul_optab : ssmul_optab;
return trapv ? smulv_optab : smul_optab;
Index: gcc/tree-cfg.c
===================================================================
--- gcc/tree-cfg.c (revision 254495)
+++ gcc/tree-cfg.c (working copy)
@@ -3133,20 +3133,31 @@ verify_expr (tree *tp, int *walk_subtree
POINTER_PLUS_EXPR. */
if (POINTER_TYPE_P (TREE_TYPE (t)))
{
error ("invalid operand to plus/minus, type is a pointer");
return t;
}
CHECK_OP (0, "invalid operand to binary operator");
CHECK_OP (1, "invalid operand to binary operator");
break;
+ case POINTER_DIFF_EXPR:
+ if (!POINTER_TYPE_P (TREE_TYPE (TREE_OPERAND (t, 0)))
+ || !POINTER_TYPE_P (TREE_TYPE (TREE_OPERAND (t, 1))))
+ {
+ error ("invalid operand to pointer diff, operand is not a pointer");
+ return t;
+ }
+ CHECK_OP (0, "invalid operand to pointer diff");
+ CHECK_OP (1, "invalid operand to pointer diff");
+ break;
+
case POINTER_PLUS_EXPR:
/* Check to make sure the first operand is a pointer or reference type. */
if (!POINTER_TYPE_P (TREE_TYPE (TREE_OPERAND (t, 0))))
{
error ("invalid operand to pointer plus, first operand is not a pointer");
return t;
}
/* Check to make sure the second operand is a ptrofftype. */
if (!ptrofftype_p (TREE_TYPE (TREE_OPERAND (t, 1))))
{
@@ -3968,20 +3979,39 @@ verify_gimple_assign_binary (gassign *st
error ("type mismatch in pointer plus expression");
debug_generic_stmt (lhs_type);
debug_generic_stmt (rhs1_type);
debug_generic_stmt (rhs2_type);
return true;
}
return false;
}
+ case POINTER_DIFF_EXPR:
+ {
+ if (!POINTER_TYPE_P (rhs1_type)
+ || !POINTER_TYPE_P (rhs2_type)
+ || !types_compatible_p (rhs1_type, rhs2_type)
+ || TREE_CODE (lhs_type) != INTEGER_TYPE
+ || TYPE_UNSIGNED (lhs_type)
+ || TYPE_PRECISION (lhs_type) != TYPE_PRECISION (rhs1_type))
+ {
+ error ("type mismatch in pointer diff expression");
+ debug_generic_stmt (lhs_type);
+ debug_generic_stmt (rhs1_type);
+ debug_generic_stmt (rhs2_type);
+ return true;
+ }
+
+ return false;
+ }
+
case TRUTH_ANDIF_EXPR:
case TRUTH_ORIF_EXPR:
case TRUTH_AND_EXPR:
case TRUTH_OR_EXPR:
case TRUTH_XOR_EXPR:
gcc_unreachable ();
case LT_EXPR:
case LE_EXPR:
Index: gcc/tree-inline.c
===================================================================
--- gcc/tree-inline.c (revision 254495)
+++ gcc/tree-inline.c (working copy)
@@ -3861,20 +3861,21 @@ estimate_operator_cost (enum tree_code c
return 0;
/* Assign cost of 1 to usual operations.
??? We may consider mapping RTL costs to this. */
case COND_EXPR:
case VEC_COND_EXPR:
case VEC_PERM_EXPR:
case PLUS_EXPR:
case POINTER_PLUS_EXPR:
+ case POINTER_DIFF_EXPR:
case MINUS_EXPR:
case MULT_EXPR:
case MULT_HIGHPART_EXPR:
case FMA_EXPR:
case ADDR_SPACE_CONVERT_EXPR:
case FIXED_CONVERT_EXPR:
case FIX_TRUNC_EXPR:
case NEGATE_EXPR:
Index: gcc/tree-pretty-print.c
===================================================================
--- gcc/tree-pretty-print.c (revision 254495)
+++ gcc/tree-pretty-print.c (working copy)
@@ -2301,20 +2301,21 @@ dump_generic_node (pretty_printer *pp, t
pp_greater (pp);
break;
/* Binary arithmetic and logic expressions. */
case WIDEN_SUM_EXPR:
case WIDEN_MULT_EXPR:
case MULT_EXPR:
case MULT_HIGHPART_EXPR:
case PLUS_EXPR:
case POINTER_PLUS_EXPR:
+ case POINTER_DIFF_EXPR:
case MINUS_EXPR:
case TRUNC_DIV_EXPR:
case CEIL_DIV_EXPR:
case FLOOR_DIV_EXPR:
case ROUND_DIV_EXPR:
case TRUNC_MOD_EXPR:
case CEIL_MOD_EXPR:
case FLOOR_MOD_EXPR:
case ROUND_MOD_EXPR:
case RDIV_EXPR:
@@ -3535,20 +3536,21 @@ op_code_prio (enum tree_code code)
case LROTATE_EXPR:
case RROTATE_EXPR:
case VEC_WIDEN_LSHIFT_HI_EXPR:
case VEC_WIDEN_LSHIFT_LO_EXPR:
case WIDEN_LSHIFT_EXPR:
return 11;
case WIDEN_SUM_EXPR:
case PLUS_EXPR:
case POINTER_PLUS_EXPR:
+ case POINTER_DIFF_EXPR:
case MINUS_EXPR:
return 12;
case VEC_WIDEN_MULT_HI_EXPR:
case VEC_WIDEN_MULT_LO_EXPR:
case WIDEN_MULT_EXPR:
case DOT_PROD_EXPR:
case WIDEN_MULT_PLUS_EXPR:
case WIDEN_MULT_MINUS_EXPR:
case MULT_EXPR:
@@ -3721,20 +3723,21 @@ op_symbol_code (enum tree_code code)
return "w+";
case WIDEN_MULT_EXPR:
return "w*";
case MULT_HIGHPART_EXPR:
return "h*";
case NEGATE_EXPR:
case MINUS_EXPR:
+ case POINTER_DIFF_EXPR:
return "-";
case BIT_NOT_EXPR:
return "~";
case TRUTH_NOT_EXPR:
return "!";
case MULT_EXPR:
case INDIRECT_REF:
Index: gcc/tree-vect-stmts.c
===================================================================
--- gcc/tree-vect-stmts.c (revision 254495)
+++ gcc/tree-vect-stmts.c (working copy)
@@ -5258,24 +5258,26 @@ vectorizable_operation (gimple *stmt, gi
/* Is STMT a vectorizable binary/unary operation? */
if (!is_gimple_assign (stmt))
return false;
if (TREE_CODE (gimple_assign_lhs (stmt)) != SSA_NAME)
return false;
code = gimple_assign_rhs_code (stmt);
- /* For pointer addition, we should use the normal plus for
- the vector addition. */
+ /* For pointer addition and subtraction, we should use the normal
+ plus and minus for the vector operation. */
if (code == POINTER_PLUS_EXPR)
code = PLUS_EXPR;
+ if (code == POINTER_DIFF_EXPR)
+ code = MINUS_EXPR;
/* Support only unary or binary operations. */
op_type = TREE_CODE_LENGTH (code);
if (op_type != unary_op && op_type != binary_op && op_type != ternary_op)
{
if (dump_enabled_p ())
dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
"num. args = %d (not unary/binary/ternary op).\n",
op_type);
return false;
Index: gcc/tree-vrp.c
===================================================================
--- gcc/tree-vrp.c (revision 254495)
+++ gcc/tree-vrp.c (working copy)
@@ -3101,29 +3101,29 @@ extract_range_from_binary_expr (value_ra
set_value_range (&n_vr0, VR_RANGE, op0, op0, NULL);
extract_range_from_binary_expr_1 (vr, code, expr_type, &n_vr0, &vr1);
}
/* If we didn't derive a range for MINUS_EXPR, and
op1's range is ~[op0,op0] or vice-versa, then we
can derive a non-null range. This happens often for
pointer subtraction. */
if (vr->type == VR_VARYING
- && code == MINUS_EXPR
+ && (code == MINUS_EXPR || code == POINTER_DIFF_EXPR)
&& TREE_CODE (op0) == SSA_NAME
&& ((vr0.type == VR_ANTI_RANGE
&& vr0.min == op1
&& vr0.min == vr0.max)
|| (vr1.type == VR_ANTI_RANGE
&& vr1.min == op0
&& vr1.min == vr1.max)))
- set_value_range_to_nonnull (vr, TREE_TYPE (op0));
+ set_value_range_to_nonnull (vr, expr_type);
}
/* Extract range information from a unary operation CODE based on
the range of its operand *VR0 with type OP0_TYPE with resulting type TYPE.
The resulting range is stored in *VR. */
void
extract_range_from_unary_expr (value_range *vr,
enum tree_code code, tree type,
value_range *vr0_, tree op0_type)
Index: gcc/tree.def
===================================================================
--- gcc/tree.def (revision 254495)
+++ gcc/tree.def (working copy)
@@ -669,20 +669,27 @@ DEFTREECODE (PLACEHOLDER_EXPR, "placehol
/* Simple arithmetic. */
DEFTREECODE (PLUS_EXPR, "plus_expr", tcc_binary, 2)
DEFTREECODE (MINUS_EXPR, "minus_expr", tcc_binary, 2)
DEFTREECODE (MULT_EXPR, "mult_expr", tcc_binary, 2)
/* Pointer addition. The first operand is always a pointer and the
second operand is an integer of type sizetype. */
DEFTREECODE (POINTER_PLUS_EXPR, "pointer_plus_expr", tcc_binary, 2)
+/* Pointer subtraction. The two arguments are pointers, and the result
+ is a signed integer of the same precision. Pointers are interpreted
+ as unsigned, the difference is computed as if in infinite signed
+ precision. Behavior is undefined if the difference does not fit in
+ the result type. */
+DEFTREECODE (POINTER_DIFF_EXPR, "pointer_diff_expr", tcc_binary, 2)
+
/* Highpart multiplication. For an integral type with precision B,
returns bits [2B-1, B] of the full 2*B product. */
DEFTREECODE (MULT_HIGHPART_EXPR, "mult_highpart_expr", tcc_binary, 2)
/* Division for integer result that rounds the quotient toward zero. */
DEFTREECODE (TRUNC_DIV_EXPR, "trunc_div_expr", tcc_binary, 2)
/* Division for integer result that rounds it toward plus infinity. */
DEFTREECODE (CEIL_DIV_EXPR, "ceil_div_expr", tcc_binary, 2)
Index: gcc/varasm.c
===================================================================
--- gcc/varasm.c (revision 254495)
+++ gcc/varasm.c (working copy)
@@ -4608,20 +4608,21 @@ initializer_constant_valid_p_1 (tree val
else
/* Support narrowing pointer differences. */
ret = narrowing_initializer_constant_valid_p (value, endtype, NULL);
if (cache)
{
cache[0] = value;
cache[1] = ret;
}
return ret;
+ case POINTER_DIFF_EXPR:
case MINUS_EXPR:
if (TREE_CODE (endtype) == REAL_TYPE)
return NULL_TREE;
if (cache && cache[0] == value)
return cache[1];
if (! INTEGRAL_TYPE_P (endtype)
|| TYPE_PRECISION (endtype) >= TYPE_PRECISION (TREE_TYPE (value)))
{
tree ncache[4] = { NULL_TREE, NULL_TREE, NULL_TREE, NULL_TREE };
tree valid0
