From 64b663f8bd8abd190e9f2f2aa47dddf60769b8e3 Mon Sep 17 00:00:00 2001 From: Roger Sayle Date: Sun, 27 Jun 2004 15:23:46 +0000 Subject: [PATCH] fold-const.c (fold): Optimize ~X|X and X|~X as -1. * fold-const.c (fold) : Optimize ~X|X and X|~X as -1. : Optimize ~X|X and X|~X as -1. : Optimize ~X&X and X&~X as 0. : Optimize !X&&X and X&&!X as false. : Optimize !X||X and !X||X as true. : Optimize !X^X and X^X! as true. Now that TRUTH_XOR_EXPR is a commutative tree code, don't test whether arg0 is a constant. * gcc.dg/20040527-1.c: New test case. From-SVN: r83733 --- gcc/ChangeLog | 11 +++++ gcc/fold-const.c | 90 ++++++++++++++++++++++++++++++++++++--- gcc/testsuite/ChangeLog | 4 ++ gcc/testsuite/gcc.dg/20040627-1.c | 42 ++++++++++++++++++ 4 files changed, 141 insertions(+), 6 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/20040627-1.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index b37f066..69f8d32 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,14 @@ +2004-06-27 Roger Sayle + + * fold-const.c (fold) : Optimize ~X|X and X|~X as -1. + : Optimize ~X|X and X|~X as -1. + : Optimize ~X&X and X&~X as 0. + : Optimize !X&&X and X&&!X as false. + : Optimize !X||X and !X||X as true. + : Optimize !X^X and X^X! as true. Now that + TRUTH_XOR_EXPR is a commutative tree code, don't test whether arg0 + is a constant. + 2004-06-26 Andrew Pinski PR 13334 diff --git a/gcc/fold-const.c b/gcc/fold-const.c index 24bde0f..21cb85d 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -7185,6 +7185,27 @@ fold (tree expr) return non_lvalue (fold_convert (type, arg0)); if (operand_equal_p (arg0, arg1, 0)) return non_lvalue (fold_convert (type, arg0)); + + /* ~X | X is -1. */ + if (TREE_CODE (arg0) == BIT_NOT_EXPR + && operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0)) + { + t1 = build_int_2 (-1, -1); + TREE_TYPE (t1) = type; + force_fit_type (t1, 0); + return omit_one_operand (type, t1, arg1); + } + + /* X | ~X is -1. */ + if (TREE_CODE (arg1) == BIT_NOT_EXPR + && operand_equal_p (arg0, TREE_OPERAND (arg1, 0), 0)) + { + t1 = build_int_2 (-1, -1); + TREE_TYPE (t1) = type; + force_fit_type (t1, 0); + return omit_one_operand (type, t1, arg0); + } + t1 = distribute_bit_expr (code, type, arg0, arg1); if (t1 != NULL_TREE) return t1; @@ -7216,6 +7237,26 @@ fold (tree expr) if (operand_equal_p (arg0, arg1, 0)) return omit_one_operand (type, integer_zero_node, arg0); + /* ~X ^ X is -1. */ + if (TREE_CODE (arg0) == BIT_NOT_EXPR + && operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0)) + { + t1 = build_int_2 (-1, -1); + TREE_TYPE (t1) = type; + force_fit_type (t1, 0); + return omit_one_operand (type, t1, arg1); + } + + /* X ^ ~X is -1. */ + if (TREE_CODE (arg1) == BIT_NOT_EXPR + && operand_equal_p (arg0, TREE_OPERAND (arg1, 0), 0)) + { + t1 = build_int_2 (-1, -1); + TREE_TYPE (t1) = type; + force_fit_type (t1, 0); + return omit_one_operand (type, t1, 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, we should treat this as a BIT_IOR_EXPR since this may produce more @@ -7243,6 +7284,17 @@ fold (tree expr) return omit_one_operand (type, arg1, arg0); if (operand_equal_p (arg0, arg1, 0)) return non_lvalue (fold_convert (type, arg0)); + + /* ~X & X is always zero. */ + if (TREE_CODE (arg0) == BIT_NOT_EXPR + && operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0)) + return omit_one_operand (type, integer_zero_node, arg1); + + /* X & ~X is always zero. */ + if (TREE_CODE (arg1) == BIT_NOT_EXPR + && operand_equal_p (arg0, TREE_OPERAND (arg1, 0), 0)) + return omit_one_operand (type, integer_zero_node, arg0); + t1 = distribute_bit_expr (code, type, arg0, arg1); if (t1 != NULL_TREE) return t1; @@ -7625,6 +7677,15 @@ fold (tree expr) if (integer_zerop (arg0)) return omit_one_operand (type, arg0, arg1); + /* !X && X is always false. */ + if (TREE_CODE (arg0) == TRUTH_NOT_EXPR + && operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0)) + return omit_one_operand (type, integer_zero_node, arg1); + /* X && !X is always false. */ + if (TREE_CODE (arg1) == TRUTH_NOT_EXPR + && operand_equal_p (arg0, TREE_OPERAND (arg1, 0), 0)) + return omit_one_operand (type, integer_zero_node, arg0); + truth_andor: /* We only do these simplifications if we are optimizing. */ if (!optimize) @@ -7712,22 +7773,39 @@ fold (tree expr) TRUTH_OR_EXPR. */ if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0)) return omit_one_operand (type, arg0, arg1); + + /* !X || X is always true. */ + if (TREE_CODE (arg0) == TRUTH_NOT_EXPR + && operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0)) + return omit_one_operand (type, integer_one_node, arg1); + /* X || !X is always true. */ + if (TREE_CODE (arg1) == TRUTH_NOT_EXPR + && operand_equal_p (arg0, TREE_OPERAND (arg1, 0), 0)) + return omit_one_operand (type, integer_one_node, arg0); + goto truth_andor; case TRUTH_XOR_EXPR: - /* If either arg is constant zero, drop it. */ - if (integer_zerop (arg0)) - return non_lvalue (fold_convert (type, arg1)); + /* If the second arg is constant zero, drop it. */ if (integer_zerop (arg1)) return non_lvalue (fold_convert (type, arg0)); - /* If either arg is constant true, this is a logical inversion. */ - if (integer_onep (arg0)) - return non_lvalue (fold_convert (type, invert_truthvalue (arg1))); + /* If the second arg is constant true, this is a logical inversion. */ if (integer_onep (arg1)) return non_lvalue (fold_convert (type, invert_truthvalue (arg0))); /* Identical arguments cancel to zero. */ if (operand_equal_p (arg0, arg1, 0)) return omit_one_operand (type, integer_zero_node, arg0); + + /* !X ^ X is always true. */ + if (TREE_CODE (arg0) == TRUTH_NOT_EXPR + && operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0)) + return omit_one_operand (type, integer_one_node, arg1); + + /* X ^ !X is always true. */ + if (TREE_CODE (arg1) == TRUTH_NOT_EXPR + && operand_equal_p (arg0, TREE_OPERAND (arg1, 0), 0)) + return omit_one_operand (type, integer_one_node, arg0); + return t; case EQ_EXPR: diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 16661d3..ab98b2a 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,7 @@ +2004-06-27 Roger Sayle + + * gcc.dg/20040527-1.c: New test case. + 2004-06-26 Bud Davis PR gfortran/pr16196 diff --git a/gcc/testsuite/gcc.dg/20040627-1.c b/gcc/testsuite/gcc.dg/20040627-1.c new file mode 100644 index 0000000..2b4f09f --- /dev/null +++ b/gcc/testsuite/gcc.dg/20040627-1.c @@ -0,0 +1,42 @@ +/* { dg-do link } */ +/* { dg-options "-O2" } */ + +extern void link_error (void); + + +void test(int x) +{ + if ((x & ~x) != 0) + link_error (); + if ((~x & x) != 0) + link_error (); + + if ((x ^ ~x) != -1) + link_error (); + if ((~x ^ x) != -1) + link_error (); + + if ((x | ~x) != -1) + link_error (); + if ((~x | x) != -1) + link_error (); + + if (x && !x) + link_error (); + if (!x && x) + link_error (); + + if (!(x || !x)) + link_error (); + if (!(!x || x)) + link_error (); +} + +int main() +{ + test (0); + test (1); + test (-1); + return 0; +} + -- 2.7.4