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fold-const.c (fold_binary_loc): Add folding of (PTR0 - (PTR1 p+ A) -> (PTR0 - PTR1) - A. 

* fold-const.c (fold_binary_loc): Add folding of 
	(PTR0 - (PTR1 p+ A) -> (PTR0 - PTR1) - A.
c/
	* c-typeck.c (pointer_diff): Remove P - (P + CST) optimization.
testsuite/
	* gcc.dg/fold-reassoc-3.c: New test.

From-SVN: r213700
This commit is contained in:
Marek Polacek 2014-08-07 08:12:04 +00:00 committed by Marek Polacek
parent ce597aedd7
commit 044331a86c
6 changed files with 43 additions and 46 deletions
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5
gcc/ChangeLog
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@ -1,3 +1,8 @@
2014-08-07 Marek Polacek <polacek@redhat.com>
* fold-const.c (fold_binary_loc): Add folding of
(PTR0 - (PTR1 p+ A) -> (PTR0 - PTR1) - A.
2013-08-07 Ilya Enkovich <ilya.enkovich@intel.com>
* config/elfos.h (ASM_DECLARE_OBJECT_NAME): Use decl size

4
gcc/c/ChangeLog
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@ -1,3 +1,7 @@
2014-08-07 Marek Polacek <polacek@redhat.com>
* c-typeck.c (pointer_diff): Remove P - (P + CST) optimization.
2014-08-02 Trevor Saunders <tsaunders@mozilla.com>
* c-typeck.c: Use hash_map instead of pointer_map.

46
gcc/c/c-typeck.c
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@ -3460,7 +3460,6 @@ pointer_diff (location_t loc, tree op0, tree op1)
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));
tree con0, con1, lit0, lit1;
tree orig_op1 = op1;
/* If the operands point into different address spaces, we need to
@ -3490,7 +3489,6 @@ pointer_diff (location_t loc, tree op0, tree op1)
else
inttype = restype;
if (TREE_CODE (target_type) == VOID_TYPE)
pedwarn (loc, OPT_Wpointer_arith,
"pointer of type %<void *%> used in subtraction");
@ -3498,50 +3496,6 @@ pointer_diff (location_t loc, tree op0, tree op1)
pedwarn (loc, OPT_Wpointer_arith,
"pointer to a function used in subtraction");
/* If the conversion to ptrdiff_type does anything like widening or
converting a partial to an integral mode, we get a convert_expression
that is in the way to do any simplifications.
(fold-const.c doesn't know that the extra bits won't be needed.
split_tree uses STRIP_SIGN_NOPS, which leaves conversions to a
different mode in place.)
So first try to find a common term here 'by hand'; we want to cover
at least the cases that occur in legal static initializers. */
if (CONVERT_EXPR_P (op0)
&& (TYPE_PRECISION (TREE_TYPE (op0))
== TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op0, 0)))))
con0 = TREE_OPERAND (op0, 0);
else
con0 = op0;
if (CONVERT_EXPR_P (op1)
&& (TYPE_PRECISION (TREE_TYPE (op1))
== TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op1, 0)))))
con1 = TREE_OPERAND (op1, 0);
else
con1 = op1;
if (TREE_CODE (con0) == POINTER_PLUS_EXPR)
{
lit0 = TREE_OPERAND (con0, 1);
con0 = TREE_OPERAND (con0, 0);
}
else
lit0 = integer_zero_node;
if (TREE_CODE (con1) == POINTER_PLUS_EXPR)
{
lit1 = TREE_OPERAND (con1, 1);
con1 = TREE_OPERAND (con1, 0);
}
else
lit1 = integer_zero_node;
if (operand_equal_p (con0, con1, 0))
{
op0 = lit0;
op1 = lit1;
}
/* First do the subtraction as integers;
then drop through to build the divide operator.
Do not do default conversions on the minus operator

13
gcc/fold-const.c
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@ -10831,6 +10831,19 @@ fold_binary_loc (location_t loc,
if (tmp)
return fold_build2_loc (loc, PLUS_EXPR, type, tmp, arg01);
}
/* PTR0 - (PTR1 p+ A) -> (PTR0 - PTR1) - A, assuming PTR0 - PTR1
simplifies. */
else if (TREE_CODE (arg1) == POINTER_PLUS_EXPR)
{
tree arg10 = fold_convert_loc (loc, type,
TREE_OPERAND (arg1, 0));
tree arg11 = fold_convert_loc (loc, type,
TREE_OPERAND (arg1, 1));
tree tmp = fold_binary_loc (loc, MINUS_EXPR, type, arg0,
fold_convert_loc (loc, type, arg10));
if (tmp)
return fold_build2_loc (loc, MINUS_EXPR, type, tmp, arg11);
}
}
/* A - (-B) -> A + B */
if (TREE_CODE (arg1) == NEGATE_EXPR)

4
gcc/testsuite/ChangeLog
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@ -1,3 +1,7 @@
2014-08-07 Marek Polacek <polacek@redhat.com>
* gcc.dg/fold-reassoc-3.c: New test.
2013-08-07 Ilya Enkovich <ilya.enkovich@intel.com>
* gcc.target/i386/struct-size.c: New.

17
gcc/testsuite/gcc.dg/fold-reassoc-3.c Normal file
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@ -0,0 +1,17 @@
/* { dg-do compile } */
/* { dg-options "-fdump-tree-original" } */
int i;
int *p = &i;
static __PTRDIFF_TYPE__ d = p - (p + 1);
void
foo (void)
{
int *q = &i;
static __PTRDIFF_TYPE__ e = q - (q + 1);
}
/* { dg-final { scan-tree-dump-not " - " "original" } } */
/* { dg-final { scan-tree-dump-not " \\\+ " "original" } } */
/* { dg-final { cleanup-tree-dump "orginal" } } */