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fold-const.c (fold): Prefer fold_convert (negate_expr (...)) to fold (build1 (NEGATE_EXPR, ...)).

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* fold-const.c (fold): Prefer fold_convert (negate_expr (...)) to
	fold (build1 (NEGATE_EXPR, ...)).  Optimize X / -1 as -X and
	X % -1 as 0.

From-SVN: r81177
This commit is contained in:
Roger Sayle 2004-04-26 03:43:17 +00:00 committed by Roger Sayle
parent 29c246a7a7
commit 7c95f621b3
2 changed files with 23 additions and 5 deletions
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6
gcc/ChangeLog
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@ -1,3 +1,9 @@
2004-04-25 Roger Sayle <roger@eyesopen.com>
* fold-const.c (fold): Prefer fold_convert (negate_expr (...)) to
fold (build1 (NEGATE_EXPR, ...)). Optimize X / -1 as -X and
X % -1 as 0.
2004-04-26 Hans-Peter Nilsson <hp@bitrange.com>
PR bootstrap/15141

22
gcc/fold-const.c
View File

@ -6412,7 +6412,7 @@ fold (tree expr)
/* Transform x * -1.0 into -x. */
if (!HONOR_SNANS (TYPE_MODE (TREE_TYPE (arg0)))
&& real_minus_onep (arg1))
return fold (build1 (NEGATE_EXPR, type, arg0));
return fold_convert (type, negate_expr (arg0));
/* Convert (C1/X)*C2 into (C1*C2)/X. */
if (flag_unsafe_math_optimizations
@ -6768,9 +6768,9 @@ fold (tree expr)
if (BUILTIN_EXPONENT_P (fcode))
{
tree expfn = TREE_OPERAND (TREE_OPERAND (arg1, 0), 0);
tree arg = build1 (NEGATE_EXPR, type,
TREE_VALUE (TREE_OPERAND (arg1, 1)));
tree arglist = build_tree_list (NULL_TREE, fold (arg));
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 (build (MULT_EXPR, type, arg0, arg1));
}
@ -6783,7 +6783,7 @@ fold (tree expr)
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 (build1 (NEGATE_EXPR, type, arg11));
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);
@ -6864,6 +6864,12 @@ fold (tree expr)
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.
@ -6890,6 +6896,12 @@ fold (tree expr)
return omit_one_operand (type, integer_zero_node, arg0);
if (integer_zerop (arg1))
return t;
/* 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);
if (TREE_CODE (arg1) == INTEGER_CST
&& 0 != (tem = extract_muldiv (TREE_OPERAND (t, 0), arg1,