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fold-const.c (fold_binary): Fold (X & Y) ^ Y as the equivalent ~X & Y, and the symmetry related transformations. 

* fold-const.c (fold_binary) <BIT_XOR_EXPR>: Fold (X & Y) ^ Y as
	the equivalent ~X & Y, and the symmetry related transformations.
	(fold_binary) <BIT_AND_EXPR>: Similarly, fold (X ^ Y) & Y as 
	~X & Y, and symmetry related transforms.

	* gcc.dg/fold-andxor-1.c: New test case.
	* gcc.dg/fold-xorand-1.c: Likewise.

From-SVN: r112459
This commit is contained in:
Roger Sayle 2006-03-28 17:55:26 +00:00 committed by Roger Sayle
parent 3cc82eea2b
commit dd2c62dcb6
5 changed files with 148 additions and 0 deletions
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7
gcc/ChangeLog
View File

@ -1,3 +1,10 @@
2006-03-28 Roger Sayle <roger@eyesopen.com>
* fold-const.c (fold_binary) <BIT_XOR_EXPR>: Fold (X & Y) ^ Y as
the equivalent ~X & Y, and the symmetry related transformations.
(fold_binary) <BIT_AND_EXPR>: Similarly, fold (X ^ Y) & Y as
~X & Y, and symmetry related transforms.
2006-03-28 Maxim Kuvyrkov <mkuvyrkov@ispras.ru>
Revert my 2006-03-27 patches.

78
gcc/fold-const.c
View File

@ -8803,6 +8803,45 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1)
return fold_build2 (EQ_EXPR, type, arg0,
build_int_cst (TREE_TYPE (arg0), 0));
/* Fold (X & Y) ^ Y as ~X & Y. */
if (TREE_CODE (arg0) == BIT_AND_EXPR
&& operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0))
{
tem = fold_convert (type, TREE_OPERAND (arg0, 0));
return fold_build2 (BIT_AND_EXPR, type,
fold_build1 (BIT_NOT_EXPR, type, tem),
fold_convert (type, arg1));
}
/* Fold (X & Y) ^ X as ~Y & X. */
if (TREE_CODE (arg0) == BIT_AND_EXPR
&& operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0)
&& reorder_operands_p (TREE_OPERAND (arg0, 1), arg1))
{
tem = fold_convert (type, TREE_OPERAND (arg0, 1));
return fold_build2 (BIT_AND_EXPR, type,
fold_build1 (BIT_NOT_EXPR, type, tem),
fold_convert (type, arg1));
}
/* Fold X ^ (X & Y) as X & ~Y. */
if (TREE_CODE (arg1) == BIT_AND_EXPR
&& operand_equal_p (arg0, TREE_OPERAND (arg1, 0), 0))
{
tem = fold_convert (type, TREE_OPERAND (arg1, 1));
return fold_build2 (BIT_AND_EXPR, type,
fold_convert (type, arg0),
fold_build1 (BIT_NOT_EXPR, type, tem));
}
/* Fold X ^ (Y & X) as ~Y & X. */
if (TREE_CODE (arg1) == BIT_AND_EXPR
&& operand_equal_p (arg0, TREE_OPERAND (arg1, 1), 0)
&& reorder_operands_p (arg0, TREE_OPERAND (arg1, 0)))
{
tem = fold_convert (type, TREE_OPERAND (arg1, 0));
return fold_build2 (BIT_AND_EXPR, type,
fold_build1 (BIT_NOT_EXPR, type, tem),
fold_convert (type, arg0));
}
/* See if this can be simplified into a rotate first. If that
is unsuccessful continue in the association code. */
goto bit_rotate;
@ -8877,6 +8916,45 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1)
build_int_cst (TREE_TYPE (tem), 0));
}
/* Fold (X ^ Y) & Y as ~X & Y. */
if (TREE_CODE (arg0) == BIT_XOR_EXPR
&& operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0))
{
tem = fold_convert (type, TREE_OPERAND (arg0, 0));
return fold_build2 (BIT_AND_EXPR, type,
fold_build1 (BIT_NOT_EXPR, type, tem),
fold_convert (type, arg1));
}
/* Fold (X ^ Y) & X as ~Y & X. */
if (TREE_CODE (arg0) == BIT_XOR_EXPR
&& operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0)
&& reorder_operands_p (TREE_OPERAND (arg0, 1), arg1))
{
tem = fold_convert (type, TREE_OPERAND (arg0, 1));
return fold_build2 (BIT_AND_EXPR, type,
fold_build1 (BIT_NOT_EXPR, type, tem),
fold_convert (type, arg1));
}
/* Fold X & (X ^ Y) as X & ~Y. */
if (TREE_CODE (arg1) == BIT_XOR_EXPR
&& operand_equal_p (arg0, TREE_OPERAND (arg1, 0), 0))
{
tem = fold_convert (type, TREE_OPERAND (arg1, 1));
return fold_build2 (BIT_AND_EXPR, type,
fold_convert (type, arg0),
fold_build1 (BIT_NOT_EXPR, type, tem));
}
/* Fold X & (Y ^ X) as ~Y & X. */
if (TREE_CODE (arg1) == BIT_XOR_EXPR
&& operand_equal_p (arg0, TREE_OPERAND (arg1, 1), 0)
&& reorder_operands_p (arg0, TREE_OPERAND (arg1, 0)))
{
tem = fold_convert (type, TREE_OPERAND (arg1, 0));
return fold_build2 (BIT_AND_EXPR, type,
fold_build1 (BIT_NOT_EXPR, type, tem),
fold_convert (type, arg0));
}
t1 = distribute_bit_expr (code, type, arg0, arg1);
if (t1 != NULL_TREE)
return t1;

5
gcc/testsuite/ChangeLog
View File

@ -1,3 +1,8 @@
2006-03-28 Roger Sayle <roger@eyesopen.com>
* gcc.dg/fold-andxor-1.c: New test case.
* gcc.dg/fold-xorand-1.c: Likewise.
2006-03-28 Roger Sayle <roger@eyesopen.com>
* gcc.dg/fold-convnotconv-1.c: New test case.

29
gcc/testsuite/gcc.dg/fold-andxor-1.c Normal file
View File

@ -0,0 +1,29 @@
/* { dg-do compile } */
/* { dg-options "-O2 -fdump-tree-original" } */
int test1(int a, int b)
{
return (a ^ b) & a;
}
int test2(int c, int d)
{
return (c ^ d) & d;
}
int test3(int e, int f)
{
return e & (e ^ f);
}
int test4(int g, int h)
{
return g & (h ^ g);
}
/* { dg-final { scan-tree-dump-times "~b \& a" 1 "original" } } */
/* { dg-final { scan-tree-dump-times "~c \& d" 1 "original" } } */
/* { dg-final { scan-tree-dump-times "~f \& e" 1 "original" } } */
/* { dg-final { scan-tree-dump-times "~h \& g" 1 "original" } } */
/* { dg-final { cleanup-tree-dump "original" } } */

29
gcc/testsuite/gcc.dg/fold-xorand-1.c Normal file
View File

@ -0,0 +1,29 @@
/* { dg-do compile } */
/* { dg-options "-O2 -fdump-tree-original" } */
int test1(int a, int b)
{
return (a & b) ^ a;
}
int test2(int c, int d)
{
return (c & d) ^ d;
}
int test3(int e, int f)
{
return e ^ (e & f);
}
int test4(int g, int h)
{
return g ^ (h & g);
}
/* { dg-final { scan-tree-dump-times "~b \& a" 1 "original" } } */
/* { dg-final { scan-tree-dump-times "~c \& d" 1 "original" } } */
/* { dg-final { scan-tree-dump-times "~f \& e" 1 "original" } } */
/* { dg-final { scan-tree-dump-times "~h \& g" 1 "original" } } */
/* { dg-final { cleanup-tree-dump "original" } } */