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-rw-r--r--gcc/fold-const.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index 9d0a9f0..3fdfb92 100644
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -7198,6 +7198,11 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1)
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)));
+ /* Convert ~A + 1 to -A. */
+ if (INTEGRAL_TYPE_P (type)
+ && TREE_CODE (arg0) == BIT_NOT_EXPR
+ && integer_onep (arg1))
+ return fold (build1 (NEGATE_EXPR, type, TREE_OPERAND (arg0, 0)));
if (TREE_CODE (type) == COMPLEX_TYPE)
{
@@ -7636,6 +7641,16 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1)
&& reorder_operands_p (arg0, arg1))
return fold (build2 (MINUS_EXPR, type, negate_expr (arg1),
TREE_OPERAND (arg0, 0)));
+ /* Convert -A - 1 to ~A. */
+ if (INTEGRAL_TYPE_P (type)
+ && TREE_CODE (arg0) == NEGATE_EXPR
+ && integer_onep (arg1))
+ return fold (build1 (BIT_NOT_EXPR, type, TREE_OPERAND (arg0, 0)));
+
+ /* Convert -1 - A to ~A. */
+ if (INTEGRAL_TYPE_P (type)
+ && integer_all_onesp (arg0))
+ return fold (build1 (BIT_NOT_EXPR, type, arg1));
if (TREE_CODE (type) == COMPLEX_TYPE)
{