diff options
Diffstat (limited to 'gcc/fold-const.cc')
| -rw-r--r-- | gcc/fold-const.cc | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/gcc/fold-const.cc b/gcc/fold-const.cc index 3b397ae..7d2352d 100644 --- a/gcc/fold-const.cc +++ b/gcc/fold-const.cc @@ -150,6 +150,50 @@ static tree fold_convert_const (enum tree_code, tree, tree); static tree fold_view_convert_expr (tree, tree); static tree fold_negate_expr (location_t, tree); +/* This is a helper function to detect min/max for some operands of COND_EXPR. + The form is "(EXP0 CMP EXP1) ? EXP2 : EXP3". */ +tree_code +minmax_from_comparison (tree_code cmp, tree exp0, tree exp1, tree exp2, tree exp3) +{ + enum tree_code code = ERROR_MARK; + + if (HONOR_NANS (exp0) || HONOR_SIGNED_ZEROS (exp0)) + return ERROR_MARK; + + if (!operand_equal_p (exp0, exp2)) + return ERROR_MARK; + + if (TREE_CODE (exp3) == INTEGER_CST && TREE_CODE (exp1) == INTEGER_CST) + { + if (wi::to_widest (exp1) == (wi::to_widest (exp3) - 1)) + { + /* X <= Y - 1 equals to X < Y. */ + if (cmp == LE_EXPR) + code = LT_EXPR; + /* X > Y - 1 equals to X >= Y. */ + if (cmp == GT_EXPR) + code = GE_EXPR; + } + if (wi::to_widest (exp1) == (wi::to_widest (exp3) + 1)) + { + /* X < Y + 1 equals to X <= Y. */ + if (cmp == LT_EXPR) + code = LE_EXPR; + /* X >= Y + 1 equals to X > Y. */ + if (cmp == GE_EXPR) + code = GT_EXPR; + } + } + if (code != ERROR_MARK + || operand_equal_p (exp1, exp3)) + { + if (cmp == LT_EXPR || cmp == LE_EXPR) + code = MIN_EXPR; + if (cmp == GT_EXPR || cmp == GE_EXPR) + code = MAX_EXPR; + } + return code; +} /* Return EXPR_LOCATION of T if it is not UNKNOWN_LOCATION. Otherwise, return LOC. */ |