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fold-const.c (fold): Fold x | x as x.

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* fold-const.c (fold) <IOR_EXPR>: Fold x | x as x.
	<XOR_EXPR>: Fold x ^ x as zero.
	<AND_EXPR>: Fold x & x as x.

From-SVN: r79065
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Roger Sayle 2004-03-07 20:13:50 +00:00 • committed by Roger Sayle
parent 350f4ea897
commit cd2f1c7a62
2 changed files with 12 additions and 0 deletions
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6
gcc/ChangeLog
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@ -1,3 +1,9 @@
2004-03-07 Roger Sayle <roger@eyesopen.com>
* fold-const.c (fold) <IOR_EXPR>: Fold x | x as x.
<XOR_EXPR>: Fold x ^ x as zero.
<AND_EXPR>: Fold x & x as x.
2004-03-07 Roger Sayle <roger@eyesopen.com>
* fold-const.c (fold) <EQ_EXPR>: Rewrite optimization to transform

6
gcc/fold-const.c
View file

@ -6605,6 +6605,8 @@ fold (tree expr)
return omit_one_operand (type, arg1, arg0);
if (integer_zerop (arg1))
return non_lvalue (fold_convert (type, arg0));
if (operand_equal_p (arg0, arg1, 0))
return non_lvalue (fold_convert (type, arg0));
t1 = distribute_bit_expr (code, type, arg0, arg1);
if (t1 != NULL_TREE)
return t1;
@ -6633,6 +6635,8 @@ fold (tree expr)
return non_lvalue (fold_convert (type, arg0));
if (integer_all_onesp (arg1))
return fold (build1 (BIT_NOT_EXPR, type, arg0));
if (operand_equal_p (arg0, arg1, 0))
return omit_one_operand (type, integer_zero_node, arg0);
/* If we are XORing two BIT_AND_EXPR's, both of which are and'ing
with a constant, and the two constants have no bits in common,
@ -6659,6 +6663,8 @@ fold (tree expr)
return non_lvalue (fold_convert (type, arg0));
if (integer_zerop (arg1))
return omit_one_operand (type, arg1, arg0);
if (operand_equal_p (arg0, arg1, 0))
return non_lvalue (fold_convert (type, arg0));
t1 = distribute_bit_expr (code, type, arg0, arg1);
if (t1 != NULL_TREE)
return t1;