+2005-02-13 James A. Morrison <phython@gcc.gnu.org>
+
+ PR tree-optimization/14303
+ PR tree-optimization/15784
+ * fold-const.c (fold): Fold ABS_EXPR<x> >= 0 to true, when possible.
+ Fold ABS_EXPR<x> < 0 to false. Fold ABS_EXPR<x> == 0 to x == 0 and
+ ABS_EXPR<x> != 0 to x != 0.
+
2005-02-12 Kazu Hirata <kazu@cs.umass.edu>
* c-tree.h, combine.c, expmed.c, flow.c, libgcc2.c,
build2 (LE_EXPR, type,
TREE_OPERAND (arg0, 0), arg1)));
+ /* Convert ABS_EXPR<x> >= 0 to true. */
+ else if (code == GE_EXPR
+ && tree_expr_nonnegative_p (arg0)
+ && ! TREE_SIDE_EFFECTS (arg0)
+ && (integer_zerop (arg1)
+ || (! HONOR_NANS (TYPE_MODE (TREE_TYPE (arg0)))
+ && real_zerop (arg1))))
+ return constant_boolean_node (true, type);
+
+ /* Convert ABS_EXPR<x> < 0 to false. */
+ else if (code == LT_EXPR
+ && tree_expr_nonnegative_p (arg0)
+ && ! TREE_SIDE_EFFECTS (arg0)
+ && (integer_zerop (arg1) || real_zerop (arg1)))
+ return constant_boolean_node (false, type);
+
+ /* Convert ABS_EXPR<x> == 0 or ABS_EXPR<x> != 0 to x == 0 or x != 0. */
+ else if ((code == EQ_EXPR || code == NE_EXPR)
+ && TREE_CODE (arg0) == ABS_EXPR
+ && ! TREE_SIDE_EFFECTS (arg0)
+ && (integer_zerop (arg1) || real_zerop (arg1)))
+ return fold (build2 (code, type, TREE_OPERAND (arg0, 0), arg1));
+
/* If this is an EQ or NE comparison with zero and ARG0 is
(1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
two operations, but the latter can be done in one less insn