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[patch] fold-const.c: Reorganize fold - Part 6/n
- From: Kazu Hirata <kazu at cs dot umass dot edu>
- To: gcc-patches at gcc dot gnu dot org
- Date: Sat, 05 Mar 2005 12:38:46 -0500 (EST)
- Subject: [patch] fold-const.c: Reorganize fold - Part 6/n
Hi,
Attached is part 6 of my patch to reorganize fold.
This patch extracts handling of binary expressions out of fold and
creates a new function fold_binary.
I deliberately did not remove handling of binary expressions from
fold. If I did, the diff would be messed up. I'll address this issue
in a subsequent patch.
Tested on i686-pc-linux-gnu. OK to apply?
Kazu Hirata
2005-03-05 Kazu Hirata <kazu@cs.umass.edu>
* fold-const.c (fold_binary): New.
(fold): Call fold_binary on binary expressions.
Index: fold-const.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/fold-const.c,v
retrieving revision 1.524
diff -u -d -p -r1.524 fold-const.c
--- fold-const.c 4 Mar 2005 19:59:45 -0000 1.524
+++ fold-const.c 4 Mar 2005 20:30:18 -0000
@@ -7014,6 +7014,2621 @@ fold_unary (tree expr)
} /* switch (code) */
}
+/* Fold a binary expression EXPR. Return the folded expression if
+ folding is successful. Otherwise, return the original
+ expression. */
+
+static tree
+fold_binary (tree expr)
+{
+ const tree t = expr;
+ const tree type = TREE_TYPE (expr);
+ tree t1 = NULL_TREE;
+ tree tem;
+ tree arg0 = NULL_TREE, arg1 = NULL_TREE;
+ enum tree_code code = TREE_CODE (t);
+ enum tree_code_class kind = TREE_CODE_CLASS (code);
+
+ /* WINS will be nonzero when the switch is done
+ if all operands are constant. */
+ int wins = 1;
+ int i;
+
+ gcc_assert (IS_EXPR_CODE_CLASS (kind)
+ && TREE_CODE_LENGTH (code) == 2);
+
+ for (i = 0; i < 2; i++)
+ {
+ tree op = TREE_OPERAND (t, i);
+ tree subop;
+
+ if (op == 0)
+ continue; /* Valid for CALL_EXPR, at least. */
+
+ /* Strip any conversions that don't change the mode. This is
+ safe for every expression, except for a comparison expression
+ because its signedness is derived from its operands. So, in
+ the latter case, only strip conversions that don't change the
+ signedness.
+
+ Note that this is done as an internal manipulation within the
+ constant folder, in order to find the simplest representation
+ of the arguments so that their form can be studied. In any
+ cases, the appropriate type conversions should be put back in
+ the tree that will get out of the constant folder. */
+ if (kind == tcc_comparison)
+ STRIP_SIGN_NOPS (op);
+ else
+ STRIP_NOPS (op);
+
+ if (TREE_CODE (op) == COMPLEX_CST)
+ subop = TREE_REALPART (op);
+ else
+ subop = op;
+
+ if (TREE_CODE (subop) != INTEGER_CST
+ && TREE_CODE (subop) != REAL_CST)
+ /* Note that TREE_CONSTANT isn't enough:
+ static var addresses are constant but we can't
+ do arithmetic on them. */
+ wins = 0;
+
+ if (i == 0)
+ arg0 = op;
+ else if (i == 1)
+ arg1 = op;
+ }
+
+ /* If this is a commutative operation, and ARG0 is a constant, move it
+ to ARG1 to reduce the number of tests below. */
+ if (commutative_tree_code (code)
+ && tree_swap_operands_p (arg0, arg1, true))
+ return fold (build2 (code, type, TREE_OPERAND (t, 1),
+ TREE_OPERAND (t, 0)));
+
+ /* Now WINS is set as described above,
+ ARG0 is the first operand of EXPR,
+ and ARG1 is the second operand (if it has more than one operand).
+
+ First check for cases where an arithmetic operation is applied to a
+ compound, conditional, or comparison operation. Push the arithmetic
+ operation inside the compound or conditional to see if any folding
+ can then be done. Convert comparison to conditional for this purpose.
+ The also optimizes non-constant cases that used to be done in
+ expand_expr.
+
+ Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
+ one of the operands is a comparison and the other is a comparison, a
+ BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
+ code below would make the expression more complex. Change it to a
+ TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
+ TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
+
+ if ((code == BIT_AND_EXPR || code == BIT_IOR_EXPR
+ || code == EQ_EXPR || code == NE_EXPR)
+ && ((truth_value_p (TREE_CODE (arg0))
+ && (truth_value_p (TREE_CODE (arg1))
+ || (TREE_CODE (arg1) == BIT_AND_EXPR
+ && integer_onep (TREE_OPERAND (arg1, 1)))))
+ || (truth_value_p (TREE_CODE (arg1))
+ && (truth_value_p (TREE_CODE (arg0))
+ || (TREE_CODE (arg0) == BIT_AND_EXPR
+ && integer_onep (TREE_OPERAND (arg0, 1)))))))
+ {
+ tem = fold (build2 (code == BIT_AND_EXPR ? TRUTH_AND_EXPR
+ : code == BIT_IOR_EXPR ? TRUTH_OR_EXPR
+ : TRUTH_XOR_EXPR,
+ type, fold_convert (boolean_type_node, arg0),
+ fold_convert (boolean_type_node, arg1)));
+
+ if (code == EQ_EXPR)
+ tem = invert_truthvalue (tem);
+
+ return tem;
+ }
+
+ if (TREE_CODE_CLASS (code) == tcc_comparison
+ && TREE_CODE (arg0) == COMPOUND_EXPR)
+ return build2 (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
+ fold (build2 (code, type, TREE_OPERAND (arg0, 1), arg1)));
+ else if (TREE_CODE_CLASS (code) == tcc_comparison
+ && TREE_CODE (arg1) == COMPOUND_EXPR)
+ return build2 (COMPOUND_EXPR, type, TREE_OPERAND (arg1, 0),
+ fold (build2 (code, type, arg0, TREE_OPERAND (arg1, 1))));
+ else if (TREE_CODE_CLASS (code) == tcc_binary
+ || TREE_CODE_CLASS (code) == tcc_comparison)
+ {
+ if (TREE_CODE (arg0) == COMPOUND_EXPR)
+ return build2 (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
+ fold (build2 (code, type, TREE_OPERAND (arg0, 1),
+ arg1)));
+ if (TREE_CODE (arg1) == COMPOUND_EXPR
+ && reorder_operands_p (arg0, TREE_OPERAND (arg1, 0)))
+ return build2 (COMPOUND_EXPR, type, TREE_OPERAND (arg1, 0),
+ fold (build2 (code, type,
+ arg0, TREE_OPERAND (arg1, 1))));
+
+ if (TREE_CODE (arg0) == COND_EXPR || COMPARISON_CLASS_P (arg0))
+ {
+ tem = fold_binary_op_with_conditional_arg (t, code, arg0, arg1,
+ /*cond_first_p=*/1);
+ if (tem != NULL_TREE)
+ return tem;
+ }
+
+ if (TREE_CODE (arg1) == COND_EXPR || COMPARISON_CLASS_P (arg1))
+ {
+ tem = fold_binary_op_with_conditional_arg (t, code, arg1, arg0,
+ /*cond_first_p=*/0);
+ if (tem != NULL_TREE)
+ return tem;
+ }
+ }
+
+ switch (code)
+ {
+ case RANGE_EXPR:
+ if (TREE_CONSTANT (t) != wins)
+ {
+ tem = copy_node (t);
+ TREE_CONSTANT (tem) = wins;
+ TREE_INVARIANT (tem) = wins;
+ return tem;
+ }
+ return t;
+
+ case PLUS_EXPR:
+ /* A + (-B) -> A - B */
+ if (TREE_CODE (arg1) == NEGATE_EXPR)
+ return fold (build2 (MINUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0)));
+ /* (-A) + B -> B - A */
+ if (TREE_CODE (arg0) == NEGATE_EXPR
+ && reorder_operands_p (TREE_OPERAND (arg0, 0), arg1))
+ return fold (build2 (MINUS_EXPR, type, arg1, TREE_OPERAND (arg0, 0)));
+
+ if (TREE_CODE (type) == COMPLEX_TYPE)
+ {
+ tem = fold_complex_add (type, arg0, arg1, PLUS_EXPR);
+ if (tem)
+ return tem;
+ }
+
+ if (! FLOAT_TYPE_P (type))
+ {
+ if (integer_zerop (arg1))
+ return non_lvalue (fold_convert (type, arg0));
+
+ /* If we are adding 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
+ simplifications. */
+ if (TREE_CODE (arg0) == BIT_AND_EXPR
+ && TREE_CODE (arg1) == BIT_AND_EXPR
+ && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
+ && TREE_CODE (TREE_OPERAND (arg1, 1)) == INTEGER_CST
+ && integer_zerop (const_binop (BIT_AND_EXPR,
+ TREE_OPERAND (arg0, 1),
+ TREE_OPERAND (arg1, 1), 0)))
+ {
+ code = BIT_IOR_EXPR;
+ goto bit_ior;
+ }
+
+ /* Reassociate (plus (plus (mult) (foo)) (mult)) as
+ (plus (plus (mult) (mult)) (foo)) so that we can
+ take advantage of the factoring cases below. */
+ if (((TREE_CODE (arg0) == PLUS_EXPR
+ || TREE_CODE (arg0) == MINUS_EXPR)
+ && TREE_CODE (arg1) == MULT_EXPR)
+ || ((TREE_CODE (arg1) == PLUS_EXPR
+ || TREE_CODE (arg1) == MINUS_EXPR)
+ && TREE_CODE (arg0) == MULT_EXPR))
+ {
+ tree parg0, parg1, parg, marg;
+ enum tree_code pcode;
+
+ if (TREE_CODE (arg1) == MULT_EXPR)
+ parg = arg0, marg = arg1;
+ else
+ parg = arg1, marg = arg0;
+ pcode = TREE_CODE (parg);
+ parg0 = TREE_OPERAND (parg, 0);
+ parg1 = TREE_OPERAND (parg, 1);
+ STRIP_NOPS (parg0);
+ STRIP_NOPS (parg1);
+
+ if (TREE_CODE (parg0) == MULT_EXPR
+ && TREE_CODE (parg1) != MULT_EXPR)
+ return fold (build2 (pcode, type,
+ fold (build2 (PLUS_EXPR, type,
+ fold_convert (type, parg0),
+ fold_convert (type, marg))),
+ fold_convert (type, parg1)));
+ if (TREE_CODE (parg0) != MULT_EXPR
+ && TREE_CODE (parg1) == MULT_EXPR)
+ return fold (build2 (PLUS_EXPR, type,
+ fold_convert (type, parg0),
+ fold (build2 (pcode, type,
+ fold_convert (type, marg),
+ fold_convert (type,
+ parg1)))));
+ }
+
+ if (TREE_CODE (arg0) == MULT_EXPR && TREE_CODE (arg1) == MULT_EXPR)
+ {
+ tree arg00, arg01, arg10, arg11;
+ tree alt0 = NULL_TREE, alt1 = NULL_TREE, same;
+
+ /* (A * C) + (B * C) -> (A+B) * C.
+ We are most concerned about the case where C is a constant,
+ but other combinations show up during loop reduction. Since
+ it is not difficult, try all four possibilities. */
+
+ arg00 = TREE_OPERAND (arg0, 0);
+ arg01 = TREE_OPERAND (arg0, 1);
+ arg10 = TREE_OPERAND (arg1, 0);
+ arg11 = TREE_OPERAND (arg1, 1);
+ same = NULL_TREE;
+
+ if (operand_equal_p (arg01, arg11, 0))
+ same = arg01, alt0 = arg00, alt1 = arg10;
+ else if (operand_equal_p (arg00, arg10, 0))
+ same = arg00, alt0 = arg01, alt1 = arg11;
+ else if (operand_equal_p (arg00, arg11, 0))
+ same = arg00, alt0 = arg01, alt1 = arg10;
+ else if (operand_equal_p (arg01, arg10, 0))
+ same = arg01, alt0 = arg00, alt1 = arg11;
+
+ /* No identical multiplicands; see if we can find a common
+ power-of-two factor in non-power-of-two multiplies. This
+ can help in multi-dimensional array access. */
+ else if (TREE_CODE (arg01) == INTEGER_CST
+ && TREE_CODE (arg11) == INTEGER_CST
+ && TREE_INT_CST_HIGH (arg01) == 0
+ && TREE_INT_CST_HIGH (arg11) == 0)
+ {
+ HOST_WIDE_INT int01, int11, tmp;
+ int01 = TREE_INT_CST_LOW (arg01);
+ int11 = TREE_INT_CST_LOW (arg11);
+
+ /* Move min of absolute values to int11. */
+ if ((int01 >= 0 ? int01 : -int01)
+ < (int11 >= 0 ? int11 : -int11))
+ {
+ tmp = int01, int01 = int11, int11 = tmp;
+ alt0 = arg00, arg00 = arg10, arg10 = alt0;
+ alt0 = arg01, arg01 = arg11, arg11 = alt0;
+ }
+
+ if (exact_log2 (int11) > 0 && int01 % int11 == 0)
+ {
+ alt0 = fold (build2 (MULT_EXPR, type, arg00,
+ build_int_cst (NULL_TREE,
+ int01 / int11)));
+ alt1 = arg10;
+ same = arg11;
+ }
+ }
+
+ if (same)
+ return fold (build2 (MULT_EXPR, type,
+ fold (build2 (PLUS_EXPR, type,
+ fold_convert (type, alt0),
+ fold_convert (type, alt1))),
+ same));
+ }
+
+ /* Try replacing &a[i1] + c * i2 with &a[i1 + i2], if c is step
+ of the array. Loop optimizer sometimes produce this type of
+ expressions. */
+ if (TREE_CODE (arg0) == ADDR_EXPR
+ && TREE_CODE (arg1) == MULT_EXPR)
+ {
+ tem = try_move_mult_to_index (PLUS_EXPR, arg0, arg1);
+ if (tem)
+ return fold_convert (type, fold (tem));
+ }
+ else if (TREE_CODE (arg1) == ADDR_EXPR
+ && TREE_CODE (arg0) == MULT_EXPR)
+ {
+ tem = try_move_mult_to_index (PLUS_EXPR, arg1, arg0);
+ if (tem)
+ return fold_convert (type, fold (tem));
+ }
+ }
+ else
+ {
+ /* See if ARG1 is zero and X + ARG1 reduces to X. */
+ if (fold_real_zero_addition_p (TREE_TYPE (arg0), arg1, 0))
+ return non_lvalue (fold_convert (type, arg0));
+
+ /* Likewise if the operands are reversed. */
+ if (fold_real_zero_addition_p (TREE_TYPE (arg1), arg0, 0))
+ return non_lvalue (fold_convert (type, arg1));
+
+ /* Convert X + -C into X - C. */
+ if (TREE_CODE (arg1) == REAL_CST
+ && REAL_VALUE_NEGATIVE (TREE_REAL_CST (arg1)))
+ {
+ tem = fold_negate_const (arg1, type);
+ if (!TREE_OVERFLOW (arg1) || !flag_trapping_math)
+ return fold (build2 (MINUS_EXPR, type,
+ fold_convert (type, arg0),
+ fold_convert (type, tem)));
+ }
+
+ /* Convert x+x into x*2.0. */
+ if (operand_equal_p (arg0, arg1, 0)
+ && SCALAR_FLOAT_TYPE_P (type))
+ return fold (build2 (MULT_EXPR, type, arg0,
+ build_real (type, dconst2)));
+
+ /* Convert x*c+x into x*(c+1). */
+ if (flag_unsafe_math_optimizations
+ && TREE_CODE (arg0) == MULT_EXPR
+ && TREE_CODE (TREE_OPERAND (arg0, 1)) == REAL_CST
+ && ! TREE_CONSTANT_OVERFLOW (TREE_OPERAND (arg0, 1))
+ && operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0))
+ {
+ REAL_VALUE_TYPE c;
+
+ c = TREE_REAL_CST (TREE_OPERAND (arg0, 1));
+ real_arithmetic (&c, PLUS_EXPR, &c, &dconst1);
+ return fold (build2 (MULT_EXPR, type, arg1,
+ build_real (type, c)));
+ }
+
+ /* Convert x+x*c into x*(c+1). */
+ if (flag_unsafe_math_optimizations
+ && TREE_CODE (arg1) == MULT_EXPR
+ && TREE_CODE (TREE_OPERAND (arg1, 1)) == REAL_CST
+ && ! TREE_CONSTANT_OVERFLOW (TREE_OPERAND (arg1, 1))
+ && operand_equal_p (TREE_OPERAND (arg1, 0), arg0, 0))
+ {
+ REAL_VALUE_TYPE c;
+
+ c = TREE_REAL_CST (TREE_OPERAND (arg1, 1));
+ real_arithmetic (&c, PLUS_EXPR, &c, &dconst1);
+ return fold (build2 (MULT_EXPR, type, arg0,
+ build_real (type, c)));
+ }
+
+ /* Convert x*c1+x*c2 into x*(c1+c2). */
+ if (flag_unsafe_math_optimizations
+ && TREE_CODE (arg0) == MULT_EXPR
+ && TREE_CODE (arg1) == MULT_EXPR
+ && TREE_CODE (TREE_OPERAND (arg0, 1)) == REAL_CST
+ && ! TREE_CONSTANT_OVERFLOW (TREE_OPERAND (arg0, 1))
+ && TREE_CODE (TREE_OPERAND (arg1, 1)) == REAL_CST
+ && ! TREE_CONSTANT_OVERFLOW (TREE_OPERAND (arg1, 1))
+ && operand_equal_p (TREE_OPERAND (arg0, 0),
+ TREE_OPERAND (arg1, 0), 0))
+ {
+ REAL_VALUE_TYPE c1, c2;
+
+ c1 = TREE_REAL_CST (TREE_OPERAND (arg0, 1));
+ c2 = TREE_REAL_CST (TREE_OPERAND (arg1, 1));
+ real_arithmetic (&c1, PLUS_EXPR, &c1, &c2);
+ return fold (build2 (MULT_EXPR, type,
+ TREE_OPERAND (arg0, 0),
+ build_real (type, c1)));
+ }
+ /* Convert a + (b*c + d*e) into (a + b*c) + d*e. */
+ if (flag_unsafe_math_optimizations
+ && TREE_CODE (arg1) == PLUS_EXPR
+ && TREE_CODE (arg0) != MULT_EXPR)
+ {
+ tree tree10 = TREE_OPERAND (arg1, 0);
+ tree tree11 = TREE_OPERAND (arg1, 1);
+ if (TREE_CODE (tree11) == MULT_EXPR
+ && TREE_CODE (tree10) == MULT_EXPR)
+ {
+ tree tree0;
+ tree0 = fold (build2 (PLUS_EXPR, type, arg0, tree10));
+ return fold (build2 (PLUS_EXPR, type, tree0, tree11));
+ }
+ }
+ /* Convert (b*c + d*e) + a into b*c + (d*e +a). */
+ if (flag_unsafe_math_optimizations
+ && TREE_CODE (arg0) == PLUS_EXPR
+ && TREE_CODE (arg1) != MULT_EXPR)
+ {
+ tree tree00 = TREE_OPERAND (arg0, 0);
+ tree tree01 = TREE_OPERAND (arg0, 1);
+ if (TREE_CODE (tree01) == MULT_EXPR
+ && TREE_CODE (tree00) == MULT_EXPR)
+ {
+ tree tree0;
+ tree0 = fold (build2 (PLUS_EXPR, type, tree01, arg1));
+ return fold (build2 (PLUS_EXPR, type, tree00, tree0));
+ }
+ }
+ }
+
+ bit_rotate:
+ /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
+ is a rotate of A by C1 bits. */
+ /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
+ is a rotate of A by B bits. */
+ {
+ enum tree_code code0, code1;
+ code0 = TREE_CODE (arg0);
+ code1 = TREE_CODE (arg1);
+ if (((code0 == RSHIFT_EXPR && code1 == LSHIFT_EXPR)
+ || (code1 == RSHIFT_EXPR && code0 == LSHIFT_EXPR))
+ && operand_equal_p (TREE_OPERAND (arg0, 0),
+ TREE_OPERAND (arg1, 0), 0)
+ && TYPE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0))))
+ {
+ tree tree01, tree11;
+ enum tree_code code01, code11;
+
+ tree01 = TREE_OPERAND (arg0, 1);
+ tree11 = TREE_OPERAND (arg1, 1);
+ STRIP_NOPS (tree01);
+ STRIP_NOPS (tree11);
+ code01 = TREE_CODE (tree01);
+ code11 = TREE_CODE (tree11);
+ if (code01 == INTEGER_CST
+ && code11 == INTEGER_CST
+ && TREE_INT_CST_HIGH (tree01) == 0
+ && TREE_INT_CST_HIGH (tree11) == 0
+ && ((TREE_INT_CST_LOW (tree01) + TREE_INT_CST_LOW (tree11))
+ == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)))))
+ return build2 (LROTATE_EXPR, type, TREE_OPERAND (arg0, 0),
+ code0 == LSHIFT_EXPR ? tree01 : tree11);
+ else if (code11 == MINUS_EXPR)
+ {
+ tree tree110, tree111;
+ tree110 = TREE_OPERAND (tree11, 0);
+ tree111 = TREE_OPERAND (tree11, 1);
+ STRIP_NOPS (tree110);
+ STRIP_NOPS (tree111);
+ if (TREE_CODE (tree110) == INTEGER_CST
+ && 0 == compare_tree_int (tree110,
+ TYPE_PRECISION
+ (TREE_TYPE (TREE_OPERAND
+ (arg0, 0))))
+ && operand_equal_p (tree01, tree111, 0))
+ return build2 ((code0 == LSHIFT_EXPR
+ ? LROTATE_EXPR
+ : RROTATE_EXPR),
+ type, TREE_OPERAND (arg0, 0), tree01);
+ }
+ else if (code01 == MINUS_EXPR)
+ {
+ tree tree010, tree011;
+ tree010 = TREE_OPERAND (tree01, 0);
+ tree011 = TREE_OPERAND (tree01, 1);
+ STRIP_NOPS (tree010);
+ STRIP_NOPS (tree011);
+ if (TREE_CODE (tree010) == INTEGER_CST
+ && 0 == compare_tree_int (tree010,
+ TYPE_PRECISION
+ (TREE_TYPE (TREE_OPERAND
+ (arg0, 0))))
+ && operand_equal_p (tree11, tree011, 0))
+ return build2 ((code0 != LSHIFT_EXPR
+ ? LROTATE_EXPR
+ : RROTATE_EXPR),
+ type, TREE_OPERAND (arg0, 0), tree11);
+ }
+ }
+ }
+
+ associate:
+ /* In most languages, can't associate operations on floats through
+ parentheses. Rather than remember where the parentheses were, we
+ don't associate floats at all, unless the user has specified
+ -funsafe-math-optimizations. */
+
+ if (! wins
+ && (! FLOAT_TYPE_P (type) || flag_unsafe_math_optimizations))
+ {
+ tree var0, con0, lit0, minus_lit0;
+ tree var1, con1, lit1, minus_lit1;
+
+ /* Split both trees into variables, constants, and literals. Then
+ associate each group together, the constants with literals,
+ then the result with variables. This increases the chances of
+ literals being recombined later and of generating relocatable
+ expressions for the sum of a constant and literal. */
+ var0 = split_tree (arg0, code, &con0, &lit0, &minus_lit0, 0);
+ var1 = split_tree (arg1, code, &con1, &lit1, &minus_lit1,
+ code == MINUS_EXPR);
+
+ /* Only do something if we found more than two objects. Otherwise,
+ nothing has changed and we risk infinite recursion. */
+ if (2 < ((var0 != 0) + (var1 != 0)
+ + (con0 != 0) + (con1 != 0)
+ + (lit0 != 0) + (lit1 != 0)
+ + (minus_lit0 != 0) + (minus_lit1 != 0)))
+ {
+ /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
+ if (code == MINUS_EXPR)
+ code = PLUS_EXPR;
+
+ var0 = associate_trees (var0, var1, code, type);
+ con0 = associate_trees (con0, con1, code, type);
+ lit0 = associate_trees (lit0, lit1, code, type);
+ minus_lit0 = associate_trees (minus_lit0, minus_lit1, code, type);
+
+ /* Preserve the MINUS_EXPR if the negative part of the literal is
+ greater than the positive part. Otherwise, the multiplicative
+ folding code (i.e extract_muldiv) may be fooled in case
+ unsigned constants are subtracted, like in the following
+ example: ((X*2 + 4) - 8U)/2. */
+ if (minus_lit0 && lit0)
+ {
+ if (TREE_CODE (lit0) == INTEGER_CST
+ && TREE_CODE (minus_lit0) == INTEGER_CST
+ && tree_int_cst_lt (lit0, minus_lit0))
+ {
+ minus_lit0 = associate_trees (minus_lit0, lit0,
+ MINUS_EXPR, type);
+ lit0 = 0;
+ }
+ else
+ {
+ lit0 = associate_trees (lit0, minus_lit0,
+ MINUS_EXPR, type);
+ minus_lit0 = 0;
+ }
+ }
+ if (minus_lit0)
+ {
+ if (con0 == 0)
+ return fold_convert (type,
+ associate_trees (var0, minus_lit0,
+ MINUS_EXPR, type));
+ else
+ {
+ con0 = associate_trees (con0, minus_lit0,
+ MINUS_EXPR, type);
+ return fold_convert (type,
+ associate_trees (var0, con0,
+ PLUS_EXPR, type));
+ }
+ }
+
+ con0 = associate_trees (con0, lit0, code, type);
+ return fold_convert (type, associate_trees (var0, con0,
+ code, type));
+ }
+ }
+
+ binary:
+ if (wins)
+ t1 = const_binop (code, arg0, arg1, 0);
+ if (t1 != NULL_TREE)
+ {
+ /* The return value should always have
+ the same type as the original expression. */
+ if (TREE_TYPE (t1) != type)
+ t1 = fold_convert (type, t1);
+
+ return t1;
+ }
+ return t;
+
+ case MINUS_EXPR:
+ /* A - (-B) -> A + B */
+ if (TREE_CODE (arg1) == NEGATE_EXPR)
+ return fold (build2 (PLUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0)));
+ /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
+ if (TREE_CODE (arg0) == NEGATE_EXPR
+ && (FLOAT_TYPE_P (type)
+ || (INTEGRAL_TYPE_P (type) && flag_wrapv && !flag_trapv))
+ && negate_expr_p (arg1)
+ && reorder_operands_p (arg0, arg1))
+ return fold (build2 (MINUS_EXPR, type, negate_expr (arg1),
+ TREE_OPERAND (arg0, 0)));
+
+ if (TREE_CODE (type) == COMPLEX_TYPE)
+ {
+ tem = fold_complex_add (type, arg0, arg1, MINUS_EXPR);
+ if (tem)
+ return tem;
+ }
+
+ if (! FLOAT_TYPE_P (type))
+ {
+ if (! wins && integer_zerop (arg0))
+ return negate_expr (fold_convert (type, arg1));
+ if (integer_zerop (arg1))
+ return non_lvalue (fold_convert (type, arg0));
+
+ /* Fold A - (A & B) into ~B & A. */
+ if (!TREE_SIDE_EFFECTS (arg0)
+ && TREE_CODE (arg1) == BIT_AND_EXPR)
+ {
+ if (operand_equal_p (arg0, TREE_OPERAND (arg1, 1), 0))
+ return fold (build2 (BIT_AND_EXPR, type,
+ fold (build1 (BIT_NOT_EXPR, type,
+ TREE_OPERAND (arg1, 0))),
+ arg0));
+ if (operand_equal_p (arg0, TREE_OPERAND (arg1, 0), 0))
+ return fold (build2 (BIT_AND_EXPR, type,
+ fold (build1 (BIT_NOT_EXPR, type,
+ TREE_OPERAND (arg1, 1))),
+ arg0));
+ }
+
+ /* Fold (A & ~B) - (A & B) into (A ^ B) - B, where B is
+ any power of 2 minus 1. */
+ if (TREE_CODE (arg0) == BIT_AND_EXPR
+ && TREE_CODE (arg1) == BIT_AND_EXPR
+ && operand_equal_p (TREE_OPERAND (arg0, 0),
+ TREE_OPERAND (arg1, 0), 0))
+ {
+ tree mask0 = TREE_OPERAND (arg0, 1);
+ tree mask1 = TREE_OPERAND (arg1, 1);
+ tree tem = fold (build1 (BIT_NOT_EXPR, type, mask0));
+
+ if (operand_equal_p (tem, mask1, 0))
+ {
+ tem = fold (build2 (BIT_XOR_EXPR, type,
+ TREE_OPERAND (arg0, 0), mask1));
+ return fold (build2 (MINUS_EXPR, type, tem, mask1));
+ }
+ }
+ }
+
+ /* See if ARG1 is zero and X - ARG1 reduces to X. */
+ else if (fold_real_zero_addition_p (TREE_TYPE (arg0), arg1, 1))
+ return non_lvalue (fold_convert (type, arg0));
+
+ /* (ARG0 - ARG1) is the same as (-ARG1 + ARG0). So check whether
+ ARG0 is zero and X + ARG0 reduces to X, since that would mean
+ (-ARG1 + ARG0) reduces to -ARG1. */
+ else if (!wins && fold_real_zero_addition_p (TREE_TYPE (arg1), arg0, 0))
+ return negate_expr (fold_convert (type, arg1));
+
+ /* Fold &x - &x. This can happen from &x.foo - &x.
+ This is unsafe for certain floats even in non-IEEE formats.
+ In IEEE, it is unsafe because it does wrong for NaNs.
+ Also note that operand_equal_p is always false if an operand
+ is volatile. */
+
+ if ((! FLOAT_TYPE_P (type) || flag_unsafe_math_optimizations)
+ && operand_equal_p (arg0, arg1, 0))
+ return fold_convert (type, integer_zero_node);
+
+ /* A - B -> A + (-B) if B is easily negatable. */
+ if (!wins && negate_expr_p (arg1)
+ && ((FLOAT_TYPE_P (type)
+ /* Avoid this transformation if B is a positive REAL_CST. */
+ && (TREE_CODE (arg1) != REAL_CST
+ || REAL_VALUE_NEGATIVE (TREE_REAL_CST (arg1))))
+ || (INTEGRAL_TYPE_P (type) && flag_wrapv && !flag_trapv)))
+ return fold (build2 (PLUS_EXPR, type, arg0, negate_expr (arg1)));
+
+ /* Try folding difference of addresses. */
+ {
+ HOST_WIDE_INT diff;
+
+ if ((TREE_CODE (arg0) == ADDR_EXPR
+ || TREE_CODE (arg1) == ADDR_EXPR)
+ && ptr_difference_const (arg0, arg1, &diff))
+ return build_int_cst_type (type, diff);
+ }
+
+ /* Try replacing &a[i1] - c * i2 with &a[i1 - i2], if c is step
+ of the array. Loop optimizer sometimes produce this type of
+ expressions. */
+ if (TREE_CODE (arg0) == ADDR_EXPR
+ && TREE_CODE (arg1) == MULT_EXPR)
+ {
+ tem = try_move_mult_to_index (MINUS_EXPR, arg0, arg1);
+ if (tem)
+ return fold_convert (type, fold (tem));
+ }
+
+ if (TREE_CODE (arg0) == MULT_EXPR
+ && TREE_CODE (arg1) == MULT_EXPR
+ && (!FLOAT_TYPE_P (type) || flag_unsafe_math_optimizations))
+ {
+ /* (A * C) - (B * C) -> (A-B) * C. */
+ if (operand_equal_p (TREE_OPERAND (arg0, 1),
+ TREE_OPERAND (arg1, 1), 0))
+ return fold (build2 (MULT_EXPR, type,
+ fold (build2 (MINUS_EXPR, type,
+ TREE_OPERAND (arg0, 0),
+ TREE_OPERAND (arg1, 0))),
+ TREE_OPERAND (arg0, 1)));
+ /* (A * C1) - (A * C2) -> A * (C1-C2). */
+ if (operand_equal_p (TREE_OPERAND (arg0, 0),
+ TREE_OPERAND (arg1, 0), 0))
+ return fold (build2 (MULT_EXPR, type,
+ TREE_OPERAND (arg0, 0),
+ fold (build2 (MINUS_EXPR, type,
+ TREE_OPERAND (arg0, 1),
+ TREE_OPERAND (arg1, 1)))));
+ }
+
+ goto associate;
+
+ case MULT_EXPR:
+ /* (-A) * (-B) -> A * B */
+ if (TREE_CODE (arg0) == NEGATE_EXPR && negate_expr_p (arg1))
+ return fold (build2 (MULT_EXPR, type,
+ TREE_OPERAND (arg0, 0),
+ negate_expr (arg1)));
+ if (TREE_CODE (arg1) == NEGATE_EXPR && negate_expr_p (arg0))
+ return fold (build2 (MULT_EXPR, type,
+ negate_expr (arg0),
+ TREE_OPERAND (arg1, 0)));
+
+ if (TREE_CODE (type) == COMPLEX_TYPE)
+ {
+ tem = fold_complex_mult (type, arg0, arg1);
+ if (tem)
+ return tem;
+ }
+
+ if (! FLOAT_TYPE_P (type))
+ {
+ if (integer_zerop (arg1))
+ return omit_one_operand (type, arg1, arg0);
+ if (integer_onep (arg1))
+ return non_lvalue (fold_convert (type, arg0));
+
+ /* (a * (1 << b)) is (a << b) */
+ if (TREE_CODE (arg1) == LSHIFT_EXPR
+ && integer_onep (TREE_OPERAND (arg1, 0)))
+ return fold (build2 (LSHIFT_EXPR, type, arg0,
+ TREE_OPERAND (arg1, 1)));
+ if (TREE_CODE (arg0) == LSHIFT_EXPR
+ && integer_onep (TREE_OPERAND (arg0, 0)))
+ return fold (build2 (LSHIFT_EXPR, type, arg1,
+ TREE_OPERAND (arg0, 1)));
+
+ if (TREE_CODE (arg1) == INTEGER_CST
+ && 0 != (tem = extract_muldiv (TREE_OPERAND (t, 0),
+ fold_convert (type, arg1),
+ code, NULL_TREE)))
+ return fold_convert (type, tem);
+
+ }
+ else
+ {
+ /* Maybe fold x * 0 to 0. The expressions aren't the same
+ when x is NaN, since x * 0 is also NaN. Nor are they the
+ same in modes with signed zeros, since multiplying a
+ negative value by 0 gives -0, not +0. */
+ if (!HONOR_NANS (TYPE_MODE (TREE_TYPE (arg0)))
+ && !HONOR_SIGNED_ZEROS (TYPE_MODE (TREE_TYPE (arg0)))
+ && real_zerop (arg1))
+ return omit_one_operand (type, arg1, arg0);
+ /* In IEEE floating point, x*1 is not equivalent to x for snans. */
+ if (!HONOR_SNANS (TYPE_MODE (TREE_TYPE (arg0)))
+ && real_onep (arg1))
+ return non_lvalue (fold_convert (type, arg0));
+
+ /* Transform x * -1.0 into -x. */
+ if (!HONOR_SNANS (TYPE_MODE (TREE_TYPE (arg0)))
+ && real_minus_onep (arg1))
+ return fold_convert (type, negate_expr (arg0));
+
+ /* Convert (C1/X)*C2 into (C1*C2)/X. */
+ if (flag_unsafe_math_optimizations
+ && TREE_CODE (arg0) == RDIV_EXPR
+ && TREE_CODE (arg1) == REAL_CST
+ && TREE_CODE (TREE_OPERAND (arg0, 0)) == REAL_CST)
+ {
+ tree tem = const_binop (MULT_EXPR, TREE_OPERAND (arg0, 0),
+ arg1, 0);
+ if (tem)
+ return fold (build2 (RDIV_EXPR, type, tem,
+ TREE_OPERAND (arg0, 1)));
+ }
+
+ /* Strip sign operations from X in X*X, i.e. -Y*-Y -> Y*Y. */
+ if (operand_equal_p (arg0, arg1, 0))
+ {
+ tree tem = fold_strip_sign_ops (arg0);
+ if (tem != NULL_TREE)
+ {
+ tem = fold_convert (type, tem);
+ return fold (build2 (MULT_EXPR, type, tem, tem));
+ }
+ }
+
+ if (flag_unsafe_math_optimizations)
+ {
+ enum built_in_function fcode0 = builtin_mathfn_code (arg0);
+ enum built_in_function fcode1 = builtin_mathfn_code (arg1);
+
+ /* Optimizations of root(...)*root(...). */
+ if (fcode0 == fcode1 && BUILTIN_ROOT_P (fcode0))
+ {
+ tree rootfn, arg, arglist;
+ tree arg00 = TREE_VALUE (TREE_OPERAND (arg0, 1));
+ tree arg10 = TREE_VALUE (TREE_OPERAND (arg1, 1));
+
+ /* Optimize sqrt(x)*sqrt(x) as x. */
+ if (BUILTIN_SQRT_P (fcode0)
+ && operand_equal_p (arg00, arg10, 0)
+ && ! HONOR_SNANS (TYPE_MODE (type)))
+ return arg00;
+
+ /* Optimize root(x)*root(y) as root(x*y). */
+ rootfn = TREE_OPERAND (TREE_OPERAND (arg0, 0), 0);
+ arg = fold (build2 (MULT_EXPR, type, arg00, arg10));
+ arglist = build_tree_list (NULL_TREE, arg);
+ return build_function_call_expr (rootfn, arglist);
+ }
+
+ /* Optimize expN(x)*expN(y) as expN(x+y). */
+ if (fcode0 == fcode1 && BUILTIN_EXPONENT_P (fcode0))
+ {
+ tree expfn = TREE_OPERAND (TREE_OPERAND (arg0, 0), 0);
+ tree arg = build2 (PLUS_EXPR, type,
+ TREE_VALUE (TREE_OPERAND (arg0, 1)),
+ TREE_VALUE (TREE_OPERAND (arg1, 1)));
+ tree arglist = build_tree_list (NULL_TREE, fold (arg));
+ return build_function_call_expr (expfn, arglist);
+ }
+
+ /* Optimizations of pow(...)*pow(...). */
+ if ((fcode0 == BUILT_IN_POW && fcode1 == BUILT_IN_POW)
+ || (fcode0 == BUILT_IN_POWF && fcode1 == BUILT_IN_POWF)
+ || (fcode0 == BUILT_IN_POWL && fcode1 == BUILT_IN_POWL))
+ {
+ tree arg00 = TREE_VALUE (TREE_OPERAND (arg0, 1));
+ tree arg01 = TREE_VALUE (TREE_CHAIN (TREE_OPERAND (arg0,
+ 1)));
+ tree arg10 = TREE_VALUE (TREE_OPERAND (arg1, 1));
+ tree arg11 = TREE_VALUE (TREE_CHAIN (TREE_OPERAND (arg1,
+ 1)));
+
+ /* Optimize pow(x,y)*pow(z,y) as pow(x*z,y). */
+ if (operand_equal_p (arg01, arg11, 0))
+ {
+ tree powfn = TREE_OPERAND (TREE_OPERAND (arg0, 0), 0);
+ tree arg = build2 (MULT_EXPR, type, arg00, arg10);
+ tree arglist = tree_cons (NULL_TREE, fold (arg),
+ build_tree_list (NULL_TREE,
+ arg01));
+ return build_function_call_expr (powfn, arglist);
+ }
+
+ /* Optimize pow(x,y)*pow(x,z) as pow(x,y+z). */
+ if (operand_equal_p (arg00, arg10, 0))
+ {
+ tree powfn = TREE_OPERAND (TREE_OPERAND (arg0, 0), 0);
+ tree arg = fold (build2 (PLUS_EXPR, type, arg01, arg11));
+ tree arglist = tree_cons (NULL_TREE, arg00,
+ build_tree_list (NULL_TREE,
+ arg));
+ return build_function_call_expr (powfn, arglist);
+ }
+ }
+
+ /* Optimize tan(x)*cos(x) as sin(x). */
+ if (((fcode0 == BUILT_IN_TAN && fcode1 == BUILT_IN_COS)
+ || (fcode0 == BUILT_IN_TANF && fcode1 == BUILT_IN_COSF)
+ || (fcode0 == BUILT_IN_TANL && fcode1 == BUILT_IN_COSL)
+ || (fcode0 == BUILT_IN_COS && fcode1 == BUILT_IN_TAN)
+ || (fcode0 == BUILT_IN_COSF && fcode1 == BUILT_IN_TANF)
+ || (fcode0 == BUILT_IN_COSL && fcode1 == BUILT_IN_TANL))
+ && operand_equal_p (TREE_VALUE (TREE_OPERAND (arg0, 1)),
+ TREE_VALUE (TREE_OPERAND (arg1, 1)), 0))
+ {
+ tree sinfn = mathfn_built_in (type, BUILT_IN_SIN);
+
+ if (sinfn != NULL_TREE)
+ return build_function_call_expr (sinfn,
+ TREE_OPERAND (arg0, 1));
+ }
+
+ /* Optimize x*pow(x,c) as pow(x,c+1). */
+ if (fcode1 == BUILT_IN_POW
+ || fcode1 == BUILT_IN_POWF
+ || fcode1 == BUILT_IN_POWL)
+ {
+ tree arg10 = TREE_VALUE (TREE_OPERAND (arg1, 1));
+ tree arg11 = TREE_VALUE (TREE_CHAIN (TREE_OPERAND (arg1,
+ 1)));
+ if (TREE_CODE (arg11) == REAL_CST
+ && ! TREE_CONSTANT_OVERFLOW (arg11)
+ && operand_equal_p (arg0, arg10, 0))
+ {
+ tree powfn = TREE_OPERAND (TREE_OPERAND (arg1, 0), 0);
+ REAL_VALUE_TYPE c;
+ tree arg, arglist;
+
+ c = TREE_REAL_CST (arg11);
+ real_arithmetic (&c, PLUS_EXPR, &c, &dconst1);
+ arg = build_real (type, c);
+ arglist = build_tree_list (NULL_TREE, arg);
+ arglist = tree_cons (NULL_TREE, arg0, arglist);
+ return build_function_call_expr (powfn, arglist);
+ }
+ }
+
+ /* Optimize pow(x,c)*x as pow(x,c+1). */
+ if (fcode0 == BUILT_IN_POW
+ || fcode0 == BUILT_IN_POWF
+ || fcode0 == BUILT_IN_POWL)
+ {
+ tree arg00 = TREE_VALUE (TREE_OPERAND (arg0, 1));
+ tree arg01 = TREE_VALUE (TREE_CHAIN (TREE_OPERAND (arg0,
+ 1)));
+ if (TREE_CODE (arg01) == REAL_CST
+ && ! TREE_CONSTANT_OVERFLOW (arg01)
+ && operand_equal_p (arg1, arg00, 0))
+ {
+ tree powfn = TREE_OPERAND (TREE_OPERAND (arg0, 0), 0);
+ REAL_VALUE_TYPE c;
+ tree arg, arglist;
+
+ c = TREE_REAL_CST (arg01);
+ real_arithmetic (&c, PLUS_EXPR, &c, &dconst1);
+ arg = build_real (type, c);
+ arglist = build_tree_list (NULL_TREE, arg);
+ arglist = tree_cons (NULL_TREE, arg1, arglist);
+ return build_function_call_expr (powfn, arglist);
+ }
+ }
+
+ /* Optimize x*x as pow(x,2.0), which is expanded as x*x. */
+ if (! optimize_size
+ && operand_equal_p (arg0, arg1, 0))
+ {
+ tree powfn = mathfn_built_in (type, BUILT_IN_POW);
+
+ if (powfn)
+ {
+ tree arg = build_real (type, dconst2);
+ tree arglist = build_tree_list (NULL_TREE, arg);
+ arglist = tree_cons (NULL_TREE, arg0, arglist);
+ return build_function_call_expr (powfn, arglist);
+ }
+ }
+ }
+ }
+ goto associate;
+
+ case BIT_IOR_EXPR:
+ bit_ior:
+ if (integer_all_onesp (arg1))
+ 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));
+
+ /* ~X | X is -1. */
+ if (TREE_CODE (arg0) == BIT_NOT_EXPR
+ && operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0))
+ {
+ t1 = build_int_cst (type, -1);
+ t1 = force_fit_type (t1, 0, false, false);
+ 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_cst (type, -1);
+ t1 = force_fit_type (t1, 0, false, false);
+ return omit_one_operand (type, t1, arg0);
+ }
+
+ t1 = distribute_bit_expr (code, type, arg0, arg1);
+ if (t1 != NULL_TREE)
+ return t1;
+
+ /* Convert (or (not arg0) (not arg1)) to (not (and (arg0) (arg1))).
+
+ This results in more efficient code for machines without a NAND
+ instruction. Combine will canonicalize to the first form
+ which will allow use of NAND instructions provided by the
+ backend if they exist. */
+ if (TREE_CODE (arg0) == BIT_NOT_EXPR
+ && TREE_CODE (arg1) == BIT_NOT_EXPR)
+ {
+ return fold (build1 (BIT_NOT_EXPR, type,
+ build2 (BIT_AND_EXPR, type,
+ TREE_OPERAND (arg0, 0),
+ TREE_OPERAND (arg1, 0))));
+ }
+
+ /* See if this can be simplified into a rotate first. If that
+ is unsuccessful continue in the association code. */
+ goto bit_rotate;
+
+ case BIT_XOR_EXPR:
+ if (integer_zerop (arg1))
+ 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);
+
+ /* ~X ^ X is -1. */
+ if (TREE_CODE (arg0) == BIT_NOT_EXPR
+ && operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0))
+ {
+ t1 = build_int_cst (type, -1);
+ t1 = force_fit_type (t1, 0, false, false);
+ 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_cst (type, -1);
+ t1 = force_fit_type (t1, 0, false, false);
+ 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
+ simplifications. */
+ if (TREE_CODE (arg0) == BIT_AND_EXPR
+ && TREE_CODE (arg1) == BIT_AND_EXPR
+ && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
+ && TREE_CODE (TREE_OPERAND (arg1, 1)) == INTEGER_CST
+ && integer_zerop (const_binop (BIT_AND_EXPR,
+ TREE_OPERAND (arg0, 1),
+ TREE_OPERAND (arg1, 1), 0)))
+ {
+ code = BIT_IOR_EXPR;
+ goto bit_ior;
+ }
+
+ /* See if this can be simplified into a rotate first. If that
+ is unsuccessful continue in the association code. */
+ goto bit_rotate;
+
+ case BIT_AND_EXPR:
+ if (integer_all_onesp (arg1))
+ 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));
+
+ /* ~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;
+ /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
+ if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg0) == NOP_EXPR
+ && TYPE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0))))
+ {
+ unsigned int prec
+ = TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)));
+
+ if (prec < BITS_PER_WORD && prec < HOST_BITS_PER_WIDE_INT
+ && (~TREE_INT_CST_LOW (arg1)
+ & (((HOST_WIDE_INT) 1 << prec) - 1)) == 0)
+ return fold_convert (type, TREE_OPERAND (arg0, 0));
+ }
+
+ /* Convert (and (not arg0) (not arg1)) to (not (or (arg0) (arg1))).
+
+ This results in more efficient code for machines without a NOR
+ instruction. Combine will canonicalize to the first form
+ which will allow use of NOR instructions provided by the
+ backend if they exist. */
+ if (TREE_CODE (arg0) == BIT_NOT_EXPR
+ && TREE_CODE (arg1) == BIT_NOT_EXPR)
+ {
+ return fold (build1 (BIT_NOT_EXPR, type,
+ build2 (BIT_IOR_EXPR, type,
+ TREE_OPERAND (arg0, 0),
+ TREE_OPERAND (arg1, 0))));
+ }
+
+ goto associate;
+
+ case RDIV_EXPR:
+ /* Don't touch a floating-point divide by zero unless the mode
+ of the constant can represent infinity. */
+ if (TREE_CODE (arg1) == REAL_CST
+ && !MODE_HAS_INFINITIES (TYPE_MODE (TREE_TYPE (arg1)))
+ && real_zerop (arg1))
+ return t;
+
+ /* (-A) / (-B) -> A / B */
+ if (TREE_CODE (arg0) == NEGATE_EXPR && negate_expr_p (arg1))
+ return fold (build2 (RDIV_EXPR, type,
+ TREE_OPERAND (arg0, 0),
+ negate_expr (arg1)));
+ if (TREE_CODE (arg1) == NEGATE_EXPR && negate_expr_p (arg0))
+ return fold (build2 (RDIV_EXPR, type,
+ negate_expr (arg0),
+ TREE_OPERAND (arg1, 0)));
+
+ /* In IEEE floating point, x/1 is not equivalent to x for snans. */
+ if (!HONOR_SNANS (TYPE_MODE (TREE_TYPE (arg0)))
+ && real_onep (arg1))
+ return non_lvalue (fold_convert (type, arg0));
+
+ /* In IEEE floating point, x/-1 is not equivalent to -x for snans. */
+ if (!HONOR_SNANS (TYPE_MODE (TREE_TYPE (arg0)))
+ && real_minus_onep (arg1))
+ return non_lvalue (fold_convert (type, negate_expr (arg0)));
+
+ /* If ARG1 is a constant, we can convert this to a multiply by the
+ reciprocal. This does not have the same rounding properties,
+ so only do this if -funsafe-math-optimizations. We can actually
+ always safely do it if ARG1 is a power of two, but it's hard to
+ tell if it is or not in a portable manner. */
+ if (TREE_CODE (arg1) == REAL_CST)
+ {
+ if (flag_unsafe_math_optimizations
+ && 0 != (tem = const_binop (code, build_real (type, dconst1),
+ arg1, 0)))
+ return fold (build2 (MULT_EXPR, type, arg0, tem));
+ /* Find the reciprocal if optimizing and the result is exact. */
+ if (optimize)
+ {
+ REAL_VALUE_TYPE r;
+ r = TREE_REAL_CST (arg1);
+ if (exact_real_inverse (TYPE_MODE(TREE_TYPE(arg0)), &r))
+ {
+ tem = build_real (type, r);
+ return fold (build2 (MULT_EXPR, type, arg0, tem));
+ }
+ }
+ }
+ /* Convert A/B/C to A/(B*C). */
+ if (flag_unsafe_math_optimizations
+ && TREE_CODE (arg0) == RDIV_EXPR)
+ return fold (build2 (RDIV_EXPR, type, TREE_OPERAND (arg0, 0),
+ fold (build2 (MULT_EXPR, type,
+ TREE_OPERAND (arg0, 1), arg1))));
+
+ /* Convert A/(B/C) to (A/B)*C. */
+ if (flag_unsafe_math_optimizations
+ && TREE_CODE (arg1) == RDIV_EXPR)
+ return fold (build2 (MULT_EXPR, type,
+ fold (build2 (RDIV_EXPR, type, arg0,
+ TREE_OPERAND (arg1, 0))),
+ TREE_OPERAND (arg1, 1)));
+
+ /* Convert C1/(X*C2) into (C1/C2)/X. */
+ if (flag_unsafe_math_optimizations
+ && TREE_CODE (arg1) == MULT_EXPR
+ && TREE_CODE (arg0) == REAL_CST
+ && TREE_CODE (TREE_OPERAND (arg1, 1)) == REAL_CST)
+ {
+ tree tem = const_binop (RDIV_EXPR, arg0,
+ TREE_OPERAND (arg1, 1), 0);
+ if (tem)
+ return fold (build2 (RDIV_EXPR, type, tem,
+ TREE_OPERAND (arg1, 0)));
+ }
+
+ if (TREE_CODE (type) == COMPLEX_TYPE)
+ {
+ tem = fold_complex_div (type, arg0, arg1, code);
+ if (tem)
+ return tem;
+ }
+
+ if (flag_unsafe_math_optimizations)
+ {
+ enum built_in_function fcode = builtin_mathfn_code (arg1);
+ /* Optimize x/expN(y) into x*expN(-y). */
+ if (BUILTIN_EXPONENT_P (fcode))
+ {
+ tree expfn = TREE_OPERAND (TREE_OPERAND (arg1, 0), 0);
+ tree arg = negate_expr (TREE_VALUE (TREE_OPERAND (arg1, 1)));
+ tree arglist = build_tree_list (NULL_TREE,
+ fold_convert (type, arg));
+ arg1 = build_function_call_expr (expfn, arglist);
+ return fold (build2 (MULT_EXPR, type, arg0, arg1));
+ }
+
+ /* Optimize x/pow(y,z) into x*pow(y,-z). */
+ if (fcode == BUILT_IN_POW
+ || fcode == BUILT_IN_POWF
+ || fcode == BUILT_IN_POWL)
+ {
+ tree powfn = TREE_OPERAND (TREE_OPERAND (arg1, 0), 0);
+ tree arg10 = TREE_VALUE (TREE_OPERAND (arg1, 1));
+ tree arg11 = TREE_VALUE (TREE_CHAIN (TREE_OPERAND (arg1, 1)));
+ tree neg11 = fold_convert (type, negate_expr (arg11));
+ tree arglist = tree_cons(NULL_TREE, arg10,
+ build_tree_list (NULL_TREE, neg11));
+ arg1 = build_function_call_expr (powfn, arglist);
+ return fold (build2 (MULT_EXPR, type, arg0, arg1));
+ }
+ }
+
+ if (flag_unsafe_math_optimizations)
+ {
+ enum built_in_function fcode0 = builtin_mathfn_code (arg0);
+ enum built_in_function fcode1 = builtin_mathfn_code (arg1);
+
+ /* Optimize sin(x)/cos(x) as tan(x). */
+ if (((fcode0 == BUILT_IN_SIN && fcode1 == BUILT_IN_COS)
+ || (fcode0 == BUILT_IN_SINF && fcode1 == BUILT_IN_COSF)
+ || (fcode0 == BUILT_IN_SINL && fcode1 == BUILT_IN_COSL))
+ && operand_equal_p (TREE_VALUE (TREE_OPERAND (arg0, 1)),
+ TREE_VALUE (TREE_OPERAND (arg1, 1)), 0))
+ {
+ tree tanfn = mathfn_built_in (type, BUILT_IN_TAN);
+
+ if (tanfn != NULL_TREE)
+ return build_function_call_expr (tanfn,
+ TREE_OPERAND (arg0, 1));
+ }
+
+ /* Optimize cos(x)/sin(x) as 1.0/tan(x). */
+ if (((fcode0 == BUILT_IN_COS && fcode1 == BUILT_IN_SIN)
+ || (fcode0 == BUILT_IN_COSF && fcode1 == BUILT_IN_SINF)
+ || (fcode0 == BUILT_IN_COSL && fcode1 == BUILT_IN_SINL))
+ && operand_equal_p (TREE_VALUE (TREE_OPERAND (arg0, 1)),
+ TREE_VALUE (TREE_OPERAND (arg1, 1)), 0))
+ {
+ tree tanfn = mathfn_built_in (type, BUILT_IN_TAN);
+
+ if (tanfn != NULL_TREE)
+ {
+ tree tmp = TREE_OPERAND (arg0, 1);
+ tmp = build_function_call_expr (tanfn, tmp);
+ return fold (build2 (RDIV_EXPR, type,
+ build_real (type, dconst1), tmp));
+ }
+ }
+
+ /* Optimize pow(x,c)/x as pow(x,c-1). */
+ if (fcode0 == BUILT_IN_POW
+ || fcode0 == BUILT_IN_POWF
+ || fcode0 == BUILT_IN_POWL)
+ {
+ tree arg00 = TREE_VALUE (TREE_OPERAND (arg0, 1));
+ tree arg01 = TREE_VALUE (TREE_CHAIN (TREE_OPERAND (arg0, 1)));
+ if (TREE_CODE (arg01) == REAL_CST
+ && ! TREE_CONSTANT_OVERFLOW (arg01)
+ && operand_equal_p (arg1, arg00, 0))
+ {
+ tree powfn = TREE_OPERAND (TREE_OPERAND (arg0, 0), 0);
+ REAL_VALUE_TYPE c;
+ tree arg, arglist;
+
+ c = TREE_REAL_CST (arg01);
+ real_arithmetic (&c, MINUS_EXPR, &c, &dconst1);
+ arg = build_real (type, c);
+ arglist = build_tree_list (NULL_TREE, arg);
+ arglist = tree_cons (NULL_TREE, arg1, arglist);
+ return build_function_call_expr (powfn, arglist);
+ }
+ }
+ }
+ goto binary;
+
+ case TRUNC_DIV_EXPR:
+ case ROUND_DIV_EXPR:
+ case FLOOR_DIV_EXPR:
+ case CEIL_DIV_EXPR:
+ case EXACT_DIV_EXPR:
+ if (integer_onep (arg1))
+ return non_lvalue (fold_convert (type, arg0));
+ if (integer_zerop (arg1))
+ return t;
+ /* X / -1 is -X. */
+ if (!TYPE_UNSIGNED (type)
+ && TREE_CODE (arg1) == INTEGER_CST
+ && TREE_INT_CST_LOW (arg1) == (unsigned HOST_WIDE_INT) -1
+ && TREE_INT_CST_HIGH (arg1) == -1)
+ return fold_convert (type, negate_expr (arg0));
+
+ /* If arg0 is a multiple of arg1, then rewrite to the fastest div
+ operation, EXACT_DIV_EXPR.
+
+ Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
+ At one time others generated faster code, it's not clear if they do
+ after the last round to changes to the DIV code in expmed.c. */
+ if ((code == CEIL_DIV_EXPR || code == FLOOR_DIV_EXPR)
+ && multiple_of_p (type, arg0, arg1))
+ return fold (build2 (EXACT_DIV_EXPR, type, arg0, arg1));
+
+ if (TREE_CODE (arg1) == INTEGER_CST
+ && 0 != (tem = extract_muldiv (TREE_OPERAND (t, 0), arg1,
+ code, NULL_TREE)))
+ return fold_convert (type, tem);
+
+ if (TREE_CODE (type) == COMPLEX_TYPE)
+ {
+ tem = fold_complex_div (type, arg0, arg1, code);
+ if (tem)
+ return tem;
+ }
+ goto binary;
+
+ case CEIL_MOD_EXPR:
+ case FLOOR_MOD_EXPR:
+ case ROUND_MOD_EXPR:
+ case TRUNC_MOD_EXPR:
+ /* X % 1 is always zero, but be sure to preserve any side
+ effects in X. */
+ if (integer_onep (arg1))
+ return omit_one_operand (type, integer_zero_node, arg0);
+
+ /* X % 0, return X % 0 unchanged so that we can get the
+ proper warnings and errors. */
+ if (integer_zerop (arg1))
+ return t;
+
+ /* 0 % X is always zero, but be sure to preserve any side
+ effects in X. Place this after checking for X == 0. */
+ if (integer_zerop (arg0))
+ return omit_one_operand (type, integer_zero_node, arg1);
+
+ /* X % -1 is zero. */
+ if (!TYPE_UNSIGNED (type)
+ && TREE_CODE (arg1) == INTEGER_CST
+ && TREE_INT_CST_LOW (arg1) == (unsigned HOST_WIDE_INT) -1
+ && TREE_INT_CST_HIGH (arg1) == -1)
+ return omit_one_operand (type, integer_zero_node, arg0);
+
+ /* Optimize unsigned TRUNC_MOD_EXPR by a power of two into a
+ BIT_AND_EXPR, i.e. "X % C" into "X & C2". */
+ if (code == TRUNC_MOD_EXPR
+ && TYPE_UNSIGNED (type)
+ && integer_pow2p (arg1))
+ {
+ unsigned HOST_WIDE_INT high, low;
+ tree mask;
+ int l;
+
+ l = tree_log2 (arg1);
+ if (l >= HOST_BITS_PER_WIDE_INT)
+ {
+ high = ((unsigned HOST_WIDE_INT) 1
+ << (l - HOST_BITS_PER_WIDE_INT)) - 1;
+ low = -1;
+ }
+ else
+ {
+ high = 0;
+ low = ((unsigned HOST_WIDE_INT) 1 << l) - 1;
+ }
+
+ mask = build_int_cst_wide (type, low, high);
+ return fold (build2 (BIT_AND_EXPR, type,
+ fold_convert (type, arg0), mask));
+ }
+
+ /* X % -C is the same as X % C. */
+ if (code == TRUNC_MOD_EXPR
+ && !TYPE_UNSIGNED (type)
+ && TREE_CODE (arg1) == INTEGER_CST
+ && TREE_INT_CST_HIGH (arg1) < 0
+ && !flag_trapv
+ /* Avoid this transformation if C is INT_MIN, i.e. C == -C. */
+ && !sign_bit_p (arg1, arg1))
+ return fold (build2 (code, type, fold_convert (type, arg0),
+ fold_convert (type, negate_expr (arg1))));
+
+ /* X % -Y is the same as X % Y. */
+ if (code == TRUNC_MOD_EXPR
+ && !TYPE_UNSIGNED (type)
+ && TREE_CODE (arg1) == NEGATE_EXPR
+ && !flag_trapv)
+ return fold (build2 (code, type, fold_convert (type, arg0),
+ fold_convert (type, TREE_OPERAND (arg1, 0))));
+
+ if (TREE_CODE (arg1) == INTEGER_CST
+ && 0 != (tem = extract_muldiv (TREE_OPERAND (t, 0), arg1,
+ code, NULL_TREE)))
+ return fold_convert (type, tem);
+
+ goto binary;
+
+ case LROTATE_EXPR:
+ case RROTATE_EXPR:
+ if (integer_all_onesp (arg0))
+ return omit_one_operand (type, arg0, arg1);
+ goto shift;
+
+ case RSHIFT_EXPR:
+ /* Optimize -1 >> x for arithmetic right shifts. */
+ if (integer_all_onesp (arg0) && !TYPE_UNSIGNED (type))
+ return omit_one_operand (type, arg0, arg1);
+ /* ... fall through ... */
+
+ case LSHIFT_EXPR:
+ shift:
+ if (integer_zerop (arg1))
+ return non_lvalue (fold_convert (type, arg0));
+ if (integer_zerop (arg0))
+ return omit_one_operand (type, arg0, arg1);
+
+ /* Since negative shift count is not well-defined,
+ don't try to compute it in the compiler. */
+ if (TREE_CODE (arg1) == INTEGER_CST && tree_int_cst_sgn (arg1) < 0)
+ return t;
+ /* Rewrite an LROTATE_EXPR by a constant into an
+ RROTATE_EXPR by a new constant. */
+ if (code == LROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST)
+ {
+ tree tem = build_int_cst (NULL_TREE,
+ GET_MODE_BITSIZE (TYPE_MODE (type)));
+ tem = fold_convert (TREE_TYPE (arg1), tem);
+ tem = const_binop (MINUS_EXPR, tem, arg1, 0);
+ return fold (build2 (RROTATE_EXPR, type, arg0, tem));
+ }
+
+ /* If we have a rotate of a bit operation with the rotate count and
+ the second operand of the bit operation both constant,
+ permute the two operations. */
+ if (code == RROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST
+ && (TREE_CODE (arg0) == BIT_AND_EXPR
+ || TREE_CODE (arg0) == BIT_IOR_EXPR
+ || TREE_CODE (arg0) == BIT_XOR_EXPR)
+ && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST)
+ return fold (build2 (TREE_CODE (arg0), type,
+ fold (build2 (code, type,
+ TREE_OPERAND (arg0, 0), arg1)),
+ fold (build2 (code, type,
+ TREE_OPERAND (arg0, 1), arg1))));
+
+ /* Two consecutive rotates adding up to the width of the mode can
+ be ignored. */
+ if (code == RROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST
+ && TREE_CODE (arg0) == RROTATE_EXPR
+ && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
+ && TREE_INT_CST_HIGH (arg1) == 0
+ && TREE_INT_CST_HIGH (TREE_OPERAND (arg0, 1)) == 0
+ && ((TREE_INT_CST_LOW (arg1)
+ + TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1)))
+ == (unsigned int) GET_MODE_BITSIZE (TYPE_MODE (type))))
+ return TREE_OPERAND (arg0, 0);
+
+ goto binary;
+
+ case MIN_EXPR:
+ if (operand_equal_p (arg0, arg1, 0))
+ return omit_one_operand (type, arg0, arg1);
+ if (INTEGRAL_TYPE_P (type)
+ && operand_equal_p (arg1, TYPE_MIN_VALUE (type), OEP_ONLY_CONST))
+ return omit_one_operand (type, arg1, arg0);
+ goto associate;
+
+ case MAX_EXPR:
+ if (operand_equal_p (arg0, arg1, 0))
+ return omit_one_operand (type, arg0, arg1);
+ if (INTEGRAL_TYPE_P (type)
+ && TYPE_MAX_VALUE (type)
+ && operand_equal_p (arg1, TYPE_MAX_VALUE (type), OEP_ONLY_CONST))
+ return omit_one_operand (type, arg1, arg0);
+ goto associate;
+
+ case TRUTH_ANDIF_EXPR:
+ /* Note that the operands of this must be ints
+ and their values must be 0 or 1.
+ ("true" is a fixed value perhaps depending on the language.) */
+ /* If first arg is constant zero, return it. */
+ if (integer_zerop (arg0))
+ return fold_convert (type, arg0);
+ case TRUTH_AND_EXPR:
+ /* If either arg is constant true, drop it. */
+ if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
+ return non_lvalue (fold_convert (type, arg1));
+ if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1)
+ /* Preserve sequence points. */
+ && (code != TRUTH_ANDIF_EXPR || ! TREE_SIDE_EFFECTS (arg0)))
+ return non_lvalue (fold_convert (type, arg0));
+ /* If second arg is constant zero, result is zero, but first arg
+ must be evaluated. */
+ if (integer_zerop (arg1))
+ return omit_one_operand (type, arg1, arg0);
+ /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
+ case will be handled here. */
+ 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);
+
+ /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
+ means A >= Y && A != MAX, but in this case we know that
+ A < X <= MAX. */
+
+ if (!TREE_SIDE_EFFECTS (arg0)
+ && !TREE_SIDE_EFFECTS (arg1))
+ {
+ tem = fold_to_nonsharp_ineq_using_bound (arg0, arg1);
+ if (tem)
+ return fold (build2 (code, type, tem, arg1));
+
+ tem = fold_to_nonsharp_ineq_using_bound (arg1, arg0);
+ if (tem)
+ return fold (build2 (code, type, arg0, tem));
+ }
+
+ truth_andor:
+ /* We only do these simplifications if we are optimizing. */
+ if (!optimize)
+ return t;
+
+ /* Check for things like (A || B) && (A || C). We can convert this
+ to A || (B && C). Note that either operator can be any of the four
+ truth and/or operations and the transformation will still be
+ valid. Also note that we only care about order for the
+ ANDIF and ORIF operators. If B contains side effects, this
+ might change the truth-value of A. */
+ if (TREE_CODE (arg0) == TREE_CODE (arg1)
+ && (TREE_CODE (arg0) == TRUTH_ANDIF_EXPR
+ || TREE_CODE (arg0) == TRUTH_ORIF_EXPR
+ || TREE_CODE (arg0) == TRUTH_AND_EXPR
+ || TREE_CODE (arg0) == TRUTH_OR_EXPR)
+ && ! TREE_SIDE_EFFECTS (TREE_OPERAND (arg0, 1)))
+ {
+ tree a00 = TREE_OPERAND (arg0, 0);
+ tree a01 = TREE_OPERAND (arg0, 1);
+ tree a10 = TREE_OPERAND (arg1, 0);
+ tree a11 = TREE_OPERAND (arg1, 1);
+ int commutative = ((TREE_CODE (arg0) == TRUTH_OR_EXPR
+ || TREE_CODE (arg0) == TRUTH_AND_EXPR)
+ && (code == TRUTH_AND_EXPR
+ || code == TRUTH_OR_EXPR));
+
+ if (operand_equal_p (a00, a10, 0))
+ return fold (build2 (TREE_CODE (arg0), type, a00,
+ fold (build2 (code, type, a01, a11))));
+ else if (commutative && operand_equal_p (a00, a11, 0))
+ return fold (build2 (TREE_CODE (arg0), type, a00,
+ fold (build2 (code, type, a01, a10))));
+ else if (commutative && operand_equal_p (a01, a10, 0))
+ return fold (build2 (TREE_CODE (arg0), type, a01,
+ fold (build2 (code, type, a00, a11))));
+
+ /* This case if tricky because we must either have commutative
+ operators or else A10 must not have side-effects. */
+
+ else if ((commutative || ! TREE_SIDE_EFFECTS (a10))
+ && operand_equal_p (a01, a11, 0))
+ return fold (build2 (TREE_CODE (arg0), type,
+ fold (build2 (code, type, a00, a10)),
+ a01));
+ }
+
+ /* See if we can build a range comparison. */
+ if (0 != (tem = fold_range_test (t)))
+ return tem;
+
+ /* Check for the possibility of merging component references. If our
+ lhs is another similar operation, try to merge its rhs with our
+ rhs. Then try to merge our lhs and rhs. */
+ if (TREE_CODE (arg0) == code
+ && 0 != (tem = fold_truthop (code, type,
+ TREE_OPERAND (arg0, 1), arg1)))
+ return fold (build2 (code, type, TREE_OPERAND (arg0, 0), tem));
+
+ if ((tem = fold_truthop (code, type, arg0, arg1)) != 0)
+ return tem;
+
+ return t;
+
+ case TRUTH_ORIF_EXPR:
+ /* Note that the operands of this must be ints
+ and their values must be 0 or true.
+ ("true" is a fixed value perhaps depending on the language.) */
+ /* If first arg is constant true, return it. */
+ if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
+ return fold_convert (type, arg0);
+ case TRUTH_OR_EXPR:
+ /* If either arg is constant zero, drop it. */
+ if (TREE_CODE (arg0) == INTEGER_CST && integer_zerop (arg0))
+ return non_lvalue (fold_convert (type, arg1));
+ if (TREE_CODE (arg1) == INTEGER_CST && integer_zerop (arg1)
+ /* Preserve sequence points. */
+ && (code != TRUTH_ORIF_EXPR || ! TREE_SIDE_EFFECTS (arg0)))
+ return non_lvalue (fold_convert (type, arg0));
+ /* If second arg is constant true, result is true, but we must
+ evaluate first arg. */
+ if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1))
+ return omit_one_operand (type, arg1, arg0);
+ /* Likewise for first arg, but note this only occurs here for
+ 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 the second arg is constant zero, drop it. */
+ if (integer_zerop (arg1))
+ return non_lvalue (fold_convert (type, arg0));
+ /* 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:
+ case NE_EXPR:
+ case LT_EXPR:
+ case GT_EXPR:
+ case LE_EXPR:
+ case GE_EXPR:
+ /* If one arg is a real or integer constant, put it last. */
+ if (tree_swap_operands_p (arg0, arg1, true))
+ return fold (build2 (swap_tree_comparison (code), type, arg1, arg0));
+
+ /* If this is an equality comparison of the address of a non-weak
+ object against zero, then we know the result. */
+ if ((code == EQ_EXPR || code == NE_EXPR)
+ && TREE_CODE (arg0) == ADDR_EXPR
+ && DECL_P (TREE_OPERAND (arg0, 0))
+ && ! DECL_WEAK (TREE_OPERAND (arg0, 0))
+ && integer_zerop (arg1))
+ return constant_boolean_node (code != EQ_EXPR, type);
+
+ /* If this is an equality comparison of the address of two non-weak,
+ unaliased symbols neither of which are extern (since we do not
+ have access to attributes for externs), then we know the result. */
+ if ((code == EQ_EXPR || code == NE_EXPR)
+ && TREE_CODE (arg0) == ADDR_EXPR
+ && DECL_P (TREE_OPERAND (arg0, 0))
+ && ! DECL_WEAK (TREE_OPERAND (arg0, 0))
+ && ! lookup_attribute ("alias",
+ DECL_ATTRIBUTES (TREE_OPERAND (arg0, 0)))
+ && ! DECL_EXTERNAL (TREE_OPERAND (arg0, 0))
+ && TREE_CODE (arg1) == ADDR_EXPR
+ && DECL_P (TREE_OPERAND (arg1, 0))
+ && ! DECL_WEAK (TREE_OPERAND (arg1, 0))
+ && ! lookup_attribute ("alias",
+ DECL_ATTRIBUTES (TREE_OPERAND (arg1, 0)))
+ && ! DECL_EXTERNAL (TREE_OPERAND (arg1, 0)))
+ return constant_boolean_node (operand_equal_p (arg0, arg1, 0)
+ ? code == EQ_EXPR : code != EQ_EXPR,
+ type);
+
+ /* If this is a comparison of two exprs that look like an
+ ARRAY_REF of the same object, then we can fold this to a
+ comparison of the two offsets. */
+ if (COMPARISON_CLASS_P (t))
+ {
+ tree base0, offset0, base1, offset1;
+
+ if (extract_array_ref (arg0, &base0, &offset0)
+ && extract_array_ref (arg1, &base1, &offset1)
+ && operand_equal_p (base0, base1, 0))
+ {
+ if (offset0 == NULL_TREE
+ && offset1 == NULL_TREE)
+ {
+ offset0 = integer_zero_node;
+ offset1 = integer_zero_node;
+ }
+ else if (offset0 == NULL_TREE)
+ offset0 = build_int_cst (TREE_TYPE (offset1), 0);
+ else if (offset1 == NULL_TREE)
+ offset1 = build_int_cst (TREE_TYPE (offset0), 0);
+
+ if (TREE_TYPE (offset0) == TREE_TYPE (offset1))
+ return fold (build2 (code, type, offset0, offset1));
+ }
+ }
+
+ if (FLOAT_TYPE_P (TREE_TYPE (arg0)))
+ {
+ tree targ0 = strip_float_extensions (arg0);
+ tree targ1 = strip_float_extensions (arg1);
+ tree newtype = TREE_TYPE (targ0);
+
+ if (TYPE_PRECISION (TREE_TYPE (targ1)) > TYPE_PRECISION (newtype))
+ newtype = TREE_TYPE (targ1);
+
+ /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
+ if (TYPE_PRECISION (newtype) < TYPE_PRECISION (TREE_TYPE (arg0)))
+ return fold (build2 (code, type, fold_convert (newtype, targ0),
+ fold_convert (newtype, targ1)));
+
+ /* (-a) CMP (-b) -> b CMP a */
+ if (TREE_CODE (arg0) == NEGATE_EXPR
+ && TREE_CODE (arg1) == NEGATE_EXPR)
+ return fold (build2 (code, type, TREE_OPERAND (arg1, 0),
+ TREE_OPERAND (arg0, 0)));
+
+ if (TREE_CODE (arg1) == REAL_CST)
+ {
+ REAL_VALUE_TYPE cst;
+ cst = TREE_REAL_CST (arg1);
+
+ /* (-a) CMP CST -> a swap(CMP) (-CST) */
+ if (TREE_CODE (arg0) == NEGATE_EXPR)
+ return
+ fold (build2 (swap_tree_comparison (code), type,
+ TREE_OPERAND (arg0, 0),
+ build_real (TREE_TYPE (arg1),
+ REAL_VALUE_NEGATE (cst))));
+
+ /* IEEE doesn't distinguish +0 and -0 in comparisons. */
+ /* a CMP (-0) -> a CMP 0 */
+ if (REAL_VALUE_MINUS_ZERO (cst))
+ return fold (build2 (code, type, arg0,
+ build_real (TREE_TYPE (arg1), dconst0)));
+
+ /* x != NaN is always true, other ops are always false. */
+ if (REAL_VALUE_ISNAN (cst)
+ && ! HONOR_SNANS (TYPE_MODE (TREE_TYPE (arg1))))
+ {
+ tem = (code == NE_EXPR) ? integer_one_node : integer_zero_node;
+ return omit_one_operand (type, tem, arg0);
+ }
+
+ /* Fold comparisons against infinity. */
+ if (REAL_VALUE_ISINF (cst))
+ {
+ tem = fold_inf_compare (code, type, arg0, arg1);
+ if (tem != NULL_TREE)
+ return tem;
+ }
+ }
+
+ /* If this is a comparison of a real constant with a PLUS_EXPR
+ or a MINUS_EXPR of a real constant, we can convert it into a
+ comparison with a revised real constant as long as no overflow
+ occurs when unsafe_math_optimizations are enabled. */
+ if (flag_unsafe_math_optimizations
+ && TREE_CODE (arg1) == REAL_CST
+ && (TREE_CODE (arg0) == PLUS_EXPR
+ || TREE_CODE (arg0) == MINUS_EXPR)
+ && TREE_CODE (TREE_OPERAND (arg0, 1)) == REAL_CST
+ && 0 != (tem = const_binop (TREE_CODE (arg0) == PLUS_EXPR
+ ? MINUS_EXPR : PLUS_EXPR,
+ arg1, TREE_OPERAND (arg0, 1), 0))
+ && ! TREE_CONSTANT_OVERFLOW (tem))
+ return fold (build2 (code, type, TREE_OPERAND (arg0, 0), tem));
+
+ /* Likewise, we can simplify a comparison of a real constant with
+ a MINUS_EXPR whose first operand is also a real constant, i.e.
+ (c1 - x) < c2 becomes x > c1-c2. */
+ if (flag_unsafe_math_optimizations
+ && TREE_CODE (arg1) == REAL_CST
+ && TREE_CODE (arg0) == MINUS_EXPR
+ && TREE_CODE (TREE_OPERAND (arg0, 0)) == REAL_CST
+ && 0 != (tem = const_binop (MINUS_EXPR, TREE_OPERAND (arg0, 0),
+ arg1, 0))
+ && ! TREE_CONSTANT_OVERFLOW (tem))
+ return fold (build2 (swap_tree_comparison (code), type,
+ TREE_OPERAND (arg0, 1), tem));
+
+ /* Fold comparisons against built-in math functions. */
+ if (TREE_CODE (arg1) == REAL_CST
+ && flag_unsafe_math_optimizations
+ && ! flag_errno_math)
+ {
+ enum built_in_function fcode = builtin_mathfn_code (arg0);
+
+ if (fcode != END_BUILTINS)
+ {
+ tem = fold_mathfn_compare (fcode, code, type, arg0, arg1);
+ if (tem != NULL_TREE)
+ return tem;
+ }
+ }
+ }
+
+ /* Convert foo++ == CONST into ++foo == CONST + INCR. */
+ if (TREE_CONSTANT (arg1)
+ && (TREE_CODE (arg0) == POSTINCREMENT_EXPR
+ || TREE_CODE (arg0) == POSTDECREMENT_EXPR)
+ /* This optimization is invalid for ordered comparisons
+ if CONST+INCR overflows or if foo+incr might overflow.
+ This optimization is invalid for floating point due to rounding.
+ For pointer types we assume overflow doesn't happen. */
+ && (POINTER_TYPE_P (TREE_TYPE (arg0))
+ || (INTEGRAL_TYPE_P (TREE_TYPE (arg0))
+ && (code == EQ_EXPR || code == NE_EXPR))))
+ {
+ tree varop, newconst;
+
+ if (TREE_CODE (arg0) == POSTINCREMENT_EXPR)
+ {
+ newconst = fold (build2 (PLUS_EXPR, TREE_TYPE (arg0),
+ arg1, TREE_OPERAND (arg0, 1)));
+ varop = build2 (PREINCREMENT_EXPR, TREE_TYPE (arg0),
+ TREE_OPERAND (arg0, 0),
+ TREE_OPERAND (arg0, 1));
+ }
+ else
+ {
+ newconst = fold (build2 (MINUS_EXPR, TREE_TYPE (arg0),
+ arg1, TREE_OPERAND (arg0, 1)));
+ varop = build2 (PREDECREMENT_EXPR, TREE_TYPE (arg0),
+ TREE_OPERAND (arg0, 0),
+ TREE_OPERAND (arg0, 1));
+ }
+
+
+ /* If VAROP is a reference to a bitfield, we must mask
+ the constant by the width of the field. */
+ if (TREE_CODE (TREE_OPERAND (varop, 0)) == COMPONENT_REF
+ && DECL_BIT_FIELD (TREE_OPERAND (TREE_OPERAND (varop, 0), 1))
+ && host_integerp (DECL_SIZE (TREE_OPERAND
+ (TREE_OPERAND (varop, 0), 1)), 1))
+ {
+ tree fielddecl = TREE_OPERAND (TREE_OPERAND (varop, 0), 1);
+ HOST_WIDE_INT size = tree_low_cst (DECL_SIZE (fielddecl), 1);
+ tree folded_compare, shift;
+
+ /* First check whether the comparison would come out
+ always the same. If we don't do that we would
+ change the meaning with the masking. */
+ folded_compare = fold (build2 (code, type,
+ TREE_OPERAND (varop, 0), arg1));
+ if (integer_zerop (folded_compare)
+ || integer_onep (folded_compare))
+ return omit_one_operand (type, folded_compare, varop);
+
+ shift = build_int_cst (NULL_TREE,
+ TYPE_PRECISION (TREE_TYPE (varop)) - size);
+ shift = fold_convert (TREE_TYPE (varop), shift);
+ newconst = fold (build2 (LSHIFT_EXPR, TREE_TYPE (varop),
+ newconst, shift));
+ newconst = fold (build2 (RSHIFT_EXPR, TREE_TYPE (varop),
+ newconst, shift));
+ }
+
+ return fold (build2 (code, type, varop, newconst));
+ }
+
+ /* Change X >= C to X > (C - 1) and X < C to X <= (C - 1) if C > 0.
+ This transformation affects the cases which are handled in later
+ optimizations involving comparisons with non-negative constants. */
+ if (TREE_CODE (arg1) == INTEGER_CST
+ && TREE_CODE (arg0) != INTEGER_CST
+ && tree_int_cst_sgn (arg1) > 0)
+ {
+ switch (code)
+ {
+ case GE_EXPR:
+ arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0);
+ return fold (build2 (GT_EXPR, type, arg0, arg1));
+
+ case LT_EXPR:
+ arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0);
+ return fold (build2 (LE_EXPR, type, arg0, arg1));
+
+ default:
+ break;
+ }
+ }
+
+ /* Comparisons with the highest or lowest possible integer of
+ the specified size will have known values.
+
+ This is quite similar to fold_relational_hi_lo, however,
+ attempts to share the code have been nothing but trouble. */
+ {
+ int width = GET_MODE_BITSIZE (TYPE_MODE (TREE_TYPE (arg1)));
+
+ if (TREE_CODE (arg1) == INTEGER_CST
+ && ! TREE_CONSTANT_OVERFLOW (arg1)
+ && width <= 2 * HOST_BITS_PER_WIDE_INT
+ && (INTEGRAL_TYPE_P (TREE_TYPE (arg1))
+ || POINTER_TYPE_P (TREE_TYPE (arg1))))
+ {
+ HOST_WIDE_INT signed_max_hi;
+ unsigned HOST_WIDE_INT signed_max_lo;
+ unsigned HOST_WIDE_INT max_hi, max_lo, min_hi, min_lo;
+
+ if (width <= HOST_BITS_PER_WIDE_INT)
+ {
+ signed_max_lo = ((unsigned HOST_WIDE_INT) 1 << (width - 1))
+ - 1;
+ signed_max_hi = 0;
+ max_hi = 0;
+
+ if (TYPE_UNSIGNED (TREE_TYPE (arg1)))
+ {
+ max_lo = ((unsigned HOST_WIDE_INT) 2 << (width - 1)) - 1;
+ min_lo = 0;
+ min_hi = 0;
+ }
+ else
+ {
+ max_lo = signed_max_lo;
+ min_lo = ((unsigned HOST_WIDE_INT) -1 << (width - 1));
+ min_hi = -1;
+ }
+ }
+ else
+ {
+ width -= HOST_BITS_PER_WIDE_INT;
+ signed_max_lo = -1;
+ signed_max_hi = ((unsigned HOST_WIDE_INT) 1 << (width - 1))
+ - 1;
+ max_lo = -1;
+ min_lo = 0;
+
+ if (TYPE_UNSIGNED (TREE_TYPE (arg1)))
+ {
+ max_hi = ((unsigned HOST_WIDE_INT) 2 << (width - 1)) - 1;
+ min_hi = 0;
+ }
+ else
+ {
+ max_hi = signed_max_hi;
+ min_hi = ((unsigned HOST_WIDE_INT) -1 << (width - 1));
+ }
+ }
+
+ if ((unsigned HOST_WIDE_INT) TREE_INT_CST_HIGH (arg1) == max_hi
+ && TREE_INT_CST_LOW (arg1) == max_lo)
+ switch (code)
+ {
+ case GT_EXPR:
+ return omit_one_operand (type, integer_zero_node, arg0);
+
+ case GE_EXPR:
+ return fold (build2 (EQ_EXPR, type, arg0, arg1));
+
+ case LE_EXPR:
+ return omit_one_operand (type, integer_one_node, arg0);
+
+ case LT_EXPR:
+ return fold (build2 (NE_EXPR, type, arg0, arg1));
+
+ /* The GE_EXPR and LT_EXPR cases above are not normally
+ reached because of previous transformations. */
+
+ default:
+ break;
+ }
+ else if ((unsigned HOST_WIDE_INT) TREE_INT_CST_HIGH (arg1)
+ == max_hi
+ && TREE_INT_CST_LOW (arg1) == max_lo - 1)
+ switch (code)
+ {
+ case GT_EXPR:
+ arg1 = const_binop (PLUS_EXPR, arg1, integer_one_node, 0);
+ return fold (build2 (EQ_EXPR, type, arg0, arg1));
+ case LE_EXPR:
+ arg1 = const_binop (PLUS_EXPR, arg1, integer_one_node, 0);
+ return fold (build2 (NE_EXPR, type, arg0, arg1));
+ default:
+ break;
+ }
+ else if ((unsigned HOST_WIDE_INT) TREE_INT_CST_HIGH (arg1)
+ == min_hi
+ && TREE_INT_CST_LOW (arg1) == min_lo)
+ switch (code)
+ {
+ case LT_EXPR:
+ return omit_one_operand (type, integer_zero_node, arg0);
+
+ case LE_EXPR:
+ return fold (build2 (EQ_EXPR, type, arg0, arg1));
+
+ case GE_EXPR:
+ return omit_one_operand (type, integer_one_node, arg0);
+
+ case GT_EXPR:
+ return fold (build2 (NE_EXPR, type, arg0, arg1));
+
+ default:
+ break;
+ }
+ else if ((unsigned HOST_WIDE_INT) TREE_INT_CST_HIGH (arg1)
+ == min_hi
+ && TREE_INT_CST_LOW (arg1) == min_lo + 1)
+ switch (code)
+ {
+ case GE_EXPR:
+ arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0);
+ return fold (build2 (NE_EXPR, type, arg0, arg1));
+ case LT_EXPR:
+ arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0);
+ return fold (build2 (EQ_EXPR, type, arg0, arg1));
+ default:
+ break;
+ }
+
+ else if (!in_gimple_form
+ && TREE_INT_CST_HIGH (arg1) == signed_max_hi
+ && TREE_INT_CST_LOW (arg1) == signed_max_lo
+ && TYPE_UNSIGNED (TREE_TYPE (arg1))
+ /* signed_type does not work on pointer types. */
+ && INTEGRAL_TYPE_P (TREE_TYPE (arg1)))
+ {
+ /* The following case also applies to X < signed_max+1
+ and X >= signed_max+1 because previous transformations. */
+ if (code == LE_EXPR || code == GT_EXPR)
+ {
+ tree st0, st1;
+ st0 = lang_hooks.types.signed_type (TREE_TYPE (arg0));
+ st1 = lang_hooks.types.signed_type (TREE_TYPE (arg1));
+ return fold
+ (build2 (code == LE_EXPR ? GE_EXPR: LT_EXPR,
+ type, fold_convert (st0, arg0),
+ fold_convert (st1, integer_zero_node)));
+ }
+ }
+ }
+ }
+
+ /* If this is an EQ or NE comparison of a constant with a PLUS_EXPR or
+ a MINUS_EXPR of a constant, we can convert it into a comparison with
+ a revised constant as long as no overflow occurs. */
+ if ((code == EQ_EXPR || code == NE_EXPR)
+ && TREE_CODE (arg1) == INTEGER_CST
+ && (TREE_CODE (arg0) == PLUS_EXPR
+ || TREE_CODE (arg0) == MINUS_EXPR)
+ && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
+ && 0 != (tem = const_binop (TREE_CODE (arg0) == PLUS_EXPR
+ ? MINUS_EXPR : PLUS_EXPR,
+ arg1, TREE_OPERAND (arg0, 1), 0))
+ && ! TREE_CONSTANT_OVERFLOW (tem))
+ return fold (build2 (code, type, TREE_OPERAND (arg0, 0), tem));
+
+ /* Similarly for a NEGATE_EXPR. */
+ else if ((code == EQ_EXPR || code == NE_EXPR)
+ && TREE_CODE (arg0) == NEGATE_EXPR
+ && TREE_CODE (arg1) == INTEGER_CST
+ && 0 != (tem = negate_expr (arg1))
+ && TREE_CODE (tem) == INTEGER_CST
+ && ! TREE_CONSTANT_OVERFLOW (tem))
+ return fold (build2 (code, type, TREE_OPERAND (arg0, 0), tem));
+
+ /* If we have X - Y == 0, we can convert that to X == Y and similarly
+ for !=. Don't do this for ordered comparisons due to overflow. */
+ else if ((code == NE_EXPR || code == EQ_EXPR)
+ && integer_zerop (arg1) && TREE_CODE (arg0) == MINUS_EXPR)
+ return fold (build2 (code, type,
+ TREE_OPERAND (arg0, 0), TREE_OPERAND (arg0, 1)));
+
+ else if (TREE_CODE (TREE_TYPE (arg0)) == INTEGER_TYPE
+ && TREE_CODE (arg0) == NOP_EXPR)
+ {
+ /* If we are widening one operand of an integer comparison,
+ see if the other operand is similarly being widened. Perhaps we
+ can do the comparison in the narrower type. */
+ tem = fold_widened_comparison (code, type, arg0, arg1);
+ if (tem)
+ return tem;
+
+ /* Or if we are changing signedness. */
+ tem = fold_sign_changed_comparison (code, type, arg0, arg1);
+ if (tem)
+ return tem;
+ }
+
+ /* If this is comparing a constant with a MIN_EXPR or a MAX_EXPR of a
+ constant, we can simplify it. */
+ else if (TREE_CODE (arg1) == INTEGER_CST
+ && (TREE_CODE (arg0) == MIN_EXPR
+ || TREE_CODE (arg0) == MAX_EXPR)
+ && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST)
+ return optimize_minmax_comparison (t);
+
+ /* If we are comparing an ABS_EXPR with a constant, we can
+ convert all the cases into explicit comparisons, but they may
+ well not be faster than doing the ABS and one comparison.
+ But ABS (X) <= C is a range comparison, which becomes a subtraction
+ and a comparison, and is probably faster. */
+ else if (code == LE_EXPR && TREE_CODE (arg1) == INTEGER_CST
+ && TREE_CODE (arg0) == ABS_EXPR
+ && ! TREE_SIDE_EFFECTS (arg0)
+ && (0 != (tem = negate_expr (arg1)))
+ && TREE_CODE (tem) == INTEGER_CST
+ && ! TREE_CONSTANT_OVERFLOW (tem))
+ return fold (build2 (TRUTH_ANDIF_EXPR, type,
+ build2 (GE_EXPR, type,
+ TREE_OPERAND (arg0, 0), tem),
+ 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)
+ && (integer_zerop (arg1)
+ || (! HONOR_NANS (TYPE_MODE (TREE_TYPE (arg0)))
+ && real_zerop (arg1))))
+ return omit_one_operand (type, integer_one_node, arg0);
+
+ /* Convert ABS_EXPR<x> < 0 to false. */
+ else if (code == LT_EXPR
+ && tree_expr_nonnegative_p (arg0)
+ && (integer_zerop (arg1) || real_zerop (arg1)))
+ return omit_one_operand (type, integer_zero_node, arg0);
+
+ /* 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
+ && (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
+ on machines that have only two-operand insns or on which a
+ constant cannot be the first operand. */
+ if (integer_zerop (arg1) && (code == EQ_EXPR || code == NE_EXPR)
+ && TREE_CODE (arg0) == BIT_AND_EXPR)
+ {
+ tree arg00 = TREE_OPERAND (arg0, 0);
+ tree arg01 = TREE_OPERAND (arg0, 1);
+ if (TREE_CODE (arg00) == LSHIFT_EXPR
+ && integer_onep (TREE_OPERAND (arg00, 0)))
+ return
+ fold (build2 (code, type,
+ build2 (BIT_AND_EXPR, TREE_TYPE (arg0),
+ build2 (RSHIFT_EXPR, TREE_TYPE (arg00),
+ arg01, TREE_OPERAND (arg00, 1)),
+ fold_convert (TREE_TYPE (arg0),
+ integer_one_node)),
+ arg1));
+ else if (TREE_CODE (TREE_OPERAND (arg0, 1)) == LSHIFT_EXPR
+ && integer_onep (TREE_OPERAND (TREE_OPERAND (arg0, 1), 0)))
+ return
+ fold (build2 (code, type,
+ build2 (BIT_AND_EXPR, TREE_TYPE (arg0),
+ build2 (RSHIFT_EXPR, TREE_TYPE (arg01),
+ arg00, TREE_OPERAND (arg01, 1)),
+ fold_convert (TREE_TYPE (arg0),
+ integer_one_node)),
+ arg1));
+ }
+
+ /* If this is an NE or EQ comparison of zero against the result of a
+ signed MOD operation whose second operand is a power of 2, make
+ the MOD operation unsigned since it is simpler and equivalent. */
+ if ((code == NE_EXPR || code == EQ_EXPR)
+ && integer_zerop (arg1)
+ && !TYPE_UNSIGNED (TREE_TYPE (arg0))
+ && (TREE_CODE (arg0) == TRUNC_MOD_EXPR
+ || TREE_CODE (arg0) == CEIL_MOD_EXPR
+ || TREE_CODE (arg0) == FLOOR_MOD_EXPR
+ || TREE_CODE (arg0) == ROUND_MOD_EXPR)
+ && integer_pow2p (TREE_OPERAND (arg0, 1)))
+ {
+ tree newtype = lang_hooks.types.unsigned_type (TREE_TYPE (arg0));
+ tree newmod = fold (build2 (TREE_CODE (arg0), newtype,
+ fold_convert (newtype,
+ TREE_OPERAND (arg0, 0)),
+ fold_convert (newtype,
+ TREE_OPERAND (arg0, 1))));
+
+ return fold (build2 (code, type, newmod,
+ fold_convert (newtype, arg1)));
+ }
+
+ /* If this is an NE comparison of zero with an AND of one, remove the
+ comparison since the AND will give the correct value. */
+ if (code == NE_EXPR && integer_zerop (arg1)
+ && TREE_CODE (arg0) == BIT_AND_EXPR
+ && integer_onep (TREE_OPERAND (arg0, 1)))
+ return fold_convert (type, arg0);
+
+ /* If we have (A & C) == C where C is a power of 2, convert this into
+ (A & C) != 0. Similarly for NE_EXPR. */
+ if ((code == EQ_EXPR || code == NE_EXPR)
+ && TREE_CODE (arg0) == BIT_AND_EXPR
+ && integer_pow2p (TREE_OPERAND (arg0, 1))
+ && operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0))
+ return fold (build2 (code == EQ_EXPR ? NE_EXPR : EQ_EXPR, type,
+ arg0, fold_convert (TREE_TYPE (arg0),
+ integer_zero_node)));
+
+ /* If we have (A & C) != 0 or (A & C) == 0 and C is a power of
+ 2, then fold the expression into shifts and logical operations. */
+ tem = fold_single_bit_test (code, arg0, arg1, type);
+ if (tem)
+ return tem;
+
+ /* If we have (A & C) == D where D & ~C != 0, convert this into 0.
+ Similarly for NE_EXPR. */
+ if ((code == EQ_EXPR || code == NE_EXPR)
+ && TREE_CODE (arg0) == BIT_AND_EXPR
+ && TREE_CODE (arg1) == INTEGER_CST
+ && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST)
+ {
+ tree notc = fold (build1 (BIT_NOT_EXPR,
+ TREE_TYPE (TREE_OPERAND (arg0, 1)),
+ TREE_OPERAND (arg0, 1)));
+ tree dandnotc = fold (build2 (BIT_AND_EXPR, TREE_TYPE (arg0),
+ arg1, notc));
+ tree rslt = code == EQ_EXPR ? integer_zero_node : integer_one_node;
+ if (integer_nonzerop (dandnotc))
+ return omit_one_operand (type, rslt, arg0);
+ }
+
+ /* If we have (A | C) == D where C & ~D != 0, convert this into 0.
+ Similarly for NE_EXPR. */
+ if ((code == EQ_EXPR || code == NE_EXPR)
+ && TREE_CODE (arg0) == BIT_IOR_EXPR
+ && TREE_CODE (arg1) == INTEGER_CST
+ && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST)
+ {
+ tree notd = fold (build1 (BIT_NOT_EXPR, TREE_TYPE (arg1), arg1));
+ tree candnotd = fold (build2 (BIT_AND_EXPR, TREE_TYPE (arg0),
+ TREE_OPERAND (arg0, 1), notd));
+ tree rslt = code == EQ_EXPR ? integer_zero_node : integer_one_node;
+ if (integer_nonzerop (candnotd))
+ return omit_one_operand (type, rslt, arg0);
+ }
+
+ /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
+ and similarly for >= into !=. */
+ if ((code == LT_EXPR || code == GE_EXPR)
+ && TYPE_UNSIGNED (TREE_TYPE (arg0))
+ && TREE_CODE (arg1) == LSHIFT_EXPR
+ && integer_onep (TREE_OPERAND (arg1, 0)))
+ return build2 (code == LT_EXPR ? EQ_EXPR : NE_EXPR, type,
+ build2 (RSHIFT_EXPR, TREE_TYPE (arg0), arg0,
+ TREE_OPERAND (arg1, 1)),
+ fold_convert (TREE_TYPE (arg0), integer_zero_node));
+
+ else if ((code == LT_EXPR || code == GE_EXPR)
+ && TYPE_UNSIGNED (TREE_TYPE (arg0))
+ && (TREE_CODE (arg1) == NOP_EXPR
+ || TREE_CODE (arg1) == CONVERT_EXPR)
+ && TREE_CODE (TREE_OPERAND (arg1, 0)) == LSHIFT_EXPR
+ && integer_onep (TREE_OPERAND (TREE_OPERAND (arg1, 0), 0)))
+ return
+ build2 (code == LT_EXPR ? EQ_EXPR : NE_EXPR, type,
+ fold_convert (TREE_TYPE (arg0),
+ build2 (RSHIFT_EXPR, TREE_TYPE (arg0), arg0,
+ TREE_OPERAND (TREE_OPERAND (arg1, 0),
+ 1))),
+ fold_convert (TREE_TYPE (arg0), integer_zero_node));
+
+ /* Simplify comparison of something with itself. (For IEEE
+ floating-point, we can only do some of these simplifications.) */
+ if (operand_equal_p (arg0, arg1, 0))
+ {
+ switch (code)
+ {
+ case EQ_EXPR:
+ if (! FLOAT_TYPE_P (TREE_TYPE (arg0))
+ || ! HONOR_NANS (TYPE_MODE (TREE_TYPE (arg0))))
+ return constant_boolean_node (1, type);
+ break;
+
+ case GE_EXPR:
+ case LE_EXPR:
+ if (! FLOAT_TYPE_P (TREE_TYPE (arg0))
+ || ! HONOR_NANS (TYPE_MODE (TREE_TYPE (arg0))))
+ return constant_boolean_node (1, type);
+ return fold (build2 (EQ_EXPR, type, arg0, arg1));
+
+ case NE_EXPR:
+ /* For NE, we can only do this simplification if integer
+ or we don't honor IEEE floating point NaNs. */
+ if (FLOAT_TYPE_P (TREE_TYPE (arg0))
+ && HONOR_NANS (TYPE_MODE (TREE_TYPE (arg0))))
+ break;
+ /* ... fall through ... */
+ case GT_EXPR:
+ case LT_EXPR:
+ return constant_boolean_node (0, type);
+ default:
+ gcc_unreachable ();
+ }
+ }
+
+ /* If we are comparing an expression that just has comparisons
+ of two integer values, arithmetic expressions of those comparisons,
+ and constants, we can simplify it. There are only three cases
+ to check: the two values can either be equal, the first can be
+ greater, or the second can be greater. Fold the expression for
+ those three values. Since each value must be 0 or 1, we have
+ eight possibilities, each of which corresponds to the constant 0
+ or 1 or one of the six possible comparisons.
+
+ This handles common cases like (a > b) == 0 but also handles
+ expressions like ((x > y) - (y > x)) > 0, which supposedly
+ occur in macroized code. */
+
+ if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg0) != INTEGER_CST)
+ {
+ tree cval1 = 0, cval2 = 0;
+ int save_p = 0;
+
+ if (twoval_comparison_p (arg0, &cval1, &cval2, &save_p)
+ /* Don't handle degenerate cases here; they should already
+ have been handled anyway. */
+ && cval1 != 0 && cval2 != 0
+ && ! (TREE_CONSTANT (cval1) && TREE_CONSTANT (cval2))
+ && TREE_TYPE (cval1) == TREE_TYPE (cval2)
+ && INTEGRAL_TYPE_P (TREE_TYPE (cval1))
+ && TYPE_MAX_VALUE (TREE_TYPE (cval1))
+ && TYPE_MAX_VALUE (TREE_TYPE (cval2))
+ && ! operand_equal_p (TYPE_MIN_VALUE (TREE_TYPE (cval1)),
+ TYPE_MAX_VALUE (TREE_TYPE (cval2)), 0))
+ {
+ tree maxval = TYPE_MAX_VALUE (TREE_TYPE (cval1));
+ tree minval = TYPE_MIN_VALUE (TREE_TYPE (cval1));
+
+ /* We can't just pass T to eval_subst in case cval1 or cval2
+ was the same as ARG1. */
+
+ tree high_result
+ = fold (build2 (code, type,
+ eval_subst (arg0, cval1, maxval,
+ cval2, minval),
+ arg1));
+ tree equal_result
+ = fold (build2 (code, type,
+ eval_subst (arg0, cval1, maxval,
+ cval2, maxval),
+ arg1));
+ tree low_result
+ = fold (build2 (code, type,
+ eval_subst (arg0, cval1, minval,
+ cval2, maxval),
+ arg1));
+
+ /* All three of these results should be 0 or 1. Confirm they
+ are. Then use those values to select the proper code
+ to use. */
+
+ if ((integer_zerop (high_result)
+ || integer_onep (high_result))
+ && (integer_zerop (equal_result)
+ || integer_onep (equal_result))
+ && (integer_zerop (low_result)
+ || integer_onep (low_result)))
+ {
+ /* Make a 3-bit mask with the high-order bit being the
+ value for `>', the next for '=', and the low for '<'. */
+ switch ((integer_onep (high_result) * 4)
+ + (integer_onep (equal_result) * 2)
+ + integer_onep (low_result))
+ {
+ case 0:
+ /* Always false. */
+ return omit_one_operand (type, integer_zero_node, arg0);
+ case 1:
+ code = LT_EXPR;
+ break;
+ case 2:
+ code = EQ_EXPR;
+ break;
+ case 3:
+ code = LE_EXPR;
+ break;
+ case 4:
+ code = GT_EXPR;
+ break;
+ case 5:
+ code = NE_EXPR;
+ break;
+ case 6:
+ code = GE_EXPR;
+ break;
+ case 7:
+ /* Always true. */
+ return omit_one_operand (type, integer_one_node, arg0);
+ }
+
+ tem = build2 (code, type, cval1, cval2);
+ if (save_p)
+ return save_expr (tem);
+ else
+ return fold (tem);
+ }
+ }
+ }
+
+ /* If this is a comparison of a field, we may be able to simplify it. */
+ if (((TREE_CODE (arg0) == COMPONENT_REF
+ && lang_hooks.can_use_bit_fields_p ())
+ || TREE_CODE (arg0) == BIT_FIELD_REF)
+ && (code == EQ_EXPR || code == NE_EXPR)
+ /* Handle the constant case even without -O
+ to make sure the warnings are given. */
+ && (optimize || TREE_CODE (arg1) == INTEGER_CST))
+ {
+ t1 = optimize_bit_field_compare (code, type, arg0, arg1);
+ if (t1)
+ return t1;
+ }
+
+ /* If this is a comparison of complex values and either or both sides
+ are a COMPLEX_EXPR or COMPLEX_CST, it is best to split up the
+ comparisons and join them with a TRUTH_ANDIF_EXPR or TRUTH_ORIF_EXPR.
+ This may prevent needless evaluations. */
+ if ((code == EQ_EXPR || code == NE_EXPR)
+ && TREE_CODE (TREE_TYPE (arg0)) == COMPLEX_TYPE
+ && (TREE_CODE (arg0) == COMPLEX_EXPR
+ || TREE_CODE (arg1) == COMPLEX_EXPR
+ || TREE_CODE (arg0) == COMPLEX_CST
+ || TREE_CODE (arg1) == COMPLEX_CST))
+ {
+ tree subtype = TREE_TYPE (TREE_TYPE (arg0));
+ tree real0, imag0, real1, imag1;
+
+ arg0 = save_expr (arg0);
+ arg1 = save_expr (arg1);
+ real0 = fold (build1 (REALPART_EXPR, subtype, arg0));
+ imag0 = fold (build1 (IMAGPART_EXPR, subtype, arg0));
+ real1 = fold (build1 (REALPART_EXPR, subtype, arg1));
+ imag1 = fold (build1 (IMAGPART_EXPR, subtype, arg1));
+
+ return fold (build2 ((code == EQ_EXPR ? TRUTH_ANDIF_EXPR
+ : TRUTH_ORIF_EXPR),
+ type,
+ fold (build2 (code, type, real0, real1)),
+ fold (build2 (code, type, imag0, imag1))));
+ }
+
+ /* Optimize comparisons of strlen vs zero to a compare of the
+ first character of the string vs zero. To wit,
+ strlen(ptr) == 0 => *ptr == 0
+ strlen(ptr) != 0 => *ptr != 0
+ Other cases should reduce to one of these two (or a constant)
+ due to the return value of strlen being unsigned. */
+ if ((code == EQ_EXPR || code == NE_EXPR)
+ && integer_zerop (arg1)
+ && TREE_CODE (arg0) == CALL_EXPR)
+ {
+ tree fndecl = get_callee_fndecl (arg0);
+ tree arglist;
+
+ if (fndecl
+ && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL
+ && DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STRLEN
+ && (arglist = TREE_OPERAND (arg0, 1))
+ && TREE_CODE (TREE_TYPE (TREE_VALUE (arglist))) == POINTER_TYPE
+ && ! TREE_CHAIN (arglist))
+ return fold (build2 (code, type,
+ build1 (INDIRECT_REF, char_type_node,
+ TREE_VALUE (arglist)),
+ fold_convert (char_type_node,
+ integer_zero_node)));
+ }
+
+ /* We can fold X/C1 op C2 where C1 and C2 are integer constants
+ into a single range test. */
+ if ((TREE_CODE (arg0) == TRUNC_DIV_EXPR
+ || TREE_CODE (arg0) == EXACT_DIV_EXPR)
+ && TREE_CODE (arg1) == INTEGER_CST
+ && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
+ && !integer_zerop (TREE_OPERAND (arg0, 1))
+ && !TREE_OVERFLOW (TREE_OPERAND (arg0, 1))
+ && !TREE_OVERFLOW (arg1))
+ {
+ t1 = fold_div_compare (code, type, arg0, arg1);
+ if (t1 != NULL_TREE)
+ return t1;
+ }
+
+ if ((code == EQ_EXPR || code == NE_EXPR)
+ && !TREE_SIDE_EFFECTS (arg0)
+ && integer_zerop (arg1)
+ && tree_expr_nonzero_p (arg0))
+ return constant_boolean_node (code==NE_EXPR, type);
+
+ t1 = fold_relational_const (code, type, arg0, arg1);
+ return t1 == NULL_TREE ? t : t1;
+
+ case UNORDERED_EXPR:
+ case ORDERED_EXPR:
+ case UNLT_EXPR:
+ case UNLE_EXPR:
+ case UNGT_EXPR:
+ case UNGE_EXPR:
+ case UNEQ_EXPR:
+ case LTGT_EXPR:
+ if (TREE_CODE (arg0) == REAL_CST && TREE_CODE (arg1) == REAL_CST)
+ {
+ t1 = fold_relational_const (code, type, arg0, arg1);
+ if (t1 != NULL_TREE)
+ return t1;
+ }
+
+ /* If the first operand is NaN, the result is constant. */
+ if (TREE_CODE (arg0) == REAL_CST
+ && REAL_VALUE_ISNAN (TREE_REAL_CST (arg0))
+ && (code != LTGT_EXPR || ! flag_trapping_math))
+ {
+ t1 = (code == ORDERED_EXPR || code == LTGT_EXPR)
+ ? integer_zero_node
+ : integer_one_node;
+ return omit_one_operand (type, t1, arg1);
+ }
+
+ /* If the second operand is NaN, the result is constant. */
+ if (TREE_CODE (arg1) == REAL_CST
+ && REAL_VALUE_ISNAN (TREE_REAL_CST (arg1))
+ && (code != LTGT_EXPR || ! flag_trapping_math))
+ {
+ t1 = (code == ORDERED_EXPR || code == LTGT_EXPR)
+ ? integer_zero_node
+ : integer_one_node;
+ return omit_one_operand (type, t1, arg0);
+ }
+
+ /* Simplify unordered comparison of something with itself. */
+ if ((code == UNLE_EXPR || code == UNGE_EXPR || code == UNEQ_EXPR)
+ && operand_equal_p (arg0, arg1, 0))
+ return constant_boolean_node (1, type);
+
+ if (code == LTGT_EXPR
+ && !flag_trapping_math
+ && operand_equal_p (arg0, arg1, 0))
+ return constant_boolean_node (0, type);
+
+ /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
+ {
+ tree targ0 = strip_float_extensions (arg0);
+ tree targ1 = strip_float_extensions (arg1);
+ tree newtype = TREE_TYPE (targ0);
+
+ if (TYPE_PRECISION (TREE_TYPE (targ1)) > TYPE_PRECISION (newtype))
+ newtype = TREE_TYPE (targ1);
+
+ if (TYPE_PRECISION (newtype) < TYPE_PRECISION (TREE_TYPE (arg0)))
+ return fold (build2 (code, type, fold_convert (newtype, targ0),
+ fold_convert (newtype, targ1)));
+ }
+
+ return t;
+
+ case COMPOUND_EXPR:
+ /* When pedantic, a compound expression can be neither an lvalue
+ nor an integer constant expression. */
+ if (TREE_SIDE_EFFECTS (arg0) || TREE_CONSTANT (arg1))
+ return t;
+ /* Don't let (0, 0) be null pointer constant. */
+ tem = integer_zerop (arg1) ? build1 (NOP_EXPR, type, arg1)
+ : fold_convert (type, arg1);
+ return pedantic_non_lvalue (tem);
+
+ case COMPLEX_EXPR:
+ if (wins)
+ return build_complex (type, arg0, arg1);
+ return t;
+
+ default:
+ return t;
+ } /* switch (code) */
+}
+
/* Fold a ternary expression EXPR. Return the folded expression if
folding is successful. Otherwise, return the original
expression. */
@@ -7279,6 +9894,8 @@ fold (tree expr)
{
case 1:
return fold_unary (expr);
+ case 2:
+ return fold_binary (expr);
case 3:
return fold_ternary (expr);
default: