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re PR tree-optimization/14303 ([tree-ssa] gcc.c-torture/execute/20020720-1.c is not fully folded)

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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.

From-SVN: r94977
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James A. Morrison 2005-02-13 06:21:35 +00:00
parent ea24f64b78
commit 60a8fb5ea9
2 changed files with 31 additions and 0 deletions
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8
gcc/ChangeLog
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@ -1,3 +1,11 @@
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,

23
gcc/fold-const.c
View file

@ -8973,6 +8973,29 @@ fold (tree expr)
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