diff options
Diffstat (limited to 'gcc/expr.c')
| -rw-r--r-- | gcc/expr.c | 76 |
1 files changed, 8 insertions, 68 deletions
@@ -7283,74 +7283,14 @@ safe_from_p (const_rtx x, tree exp, int top_p) unsigned HOST_WIDE_INT highest_pow2_factor (const_tree exp) { - unsigned HOST_WIDE_INT c0, c1; - - switch (TREE_CODE (exp)) - { - case INTEGER_CST: - /* We can find the lowest bit that's a one. If the low - HOST_BITS_PER_WIDE_INT bits are zero, return BIGGEST_ALIGNMENT. - We need to handle this case since we can find it in a COND_EXPR, - a MIN_EXPR, or a MAX_EXPR. If the constant overflows, we have an - erroneous program, so return BIGGEST_ALIGNMENT to avoid any - later ICE. */ - if (TREE_OVERFLOW (exp)) - return BIGGEST_ALIGNMENT; - else - { - /* Note: tree_low_cst is intentionally not used here, - we don't care about the upper bits. */ - c0 = TREE_INT_CST_LOW (exp); - c0 &= -c0; - return c0 ? c0 : BIGGEST_ALIGNMENT; - } - break; - - case PLUS_EXPR: case MINUS_EXPR: case MIN_EXPR: case MAX_EXPR: - c0 = highest_pow2_factor (TREE_OPERAND (exp, 0)); - c1 = highest_pow2_factor (TREE_OPERAND (exp, 1)); - return MIN (c0, c1); - - case MULT_EXPR: - c0 = highest_pow2_factor (TREE_OPERAND (exp, 0)); - c1 = highest_pow2_factor (TREE_OPERAND (exp, 1)); - return c0 * c1; - - case ROUND_DIV_EXPR: case TRUNC_DIV_EXPR: case FLOOR_DIV_EXPR: - case CEIL_DIV_EXPR: - if (integer_pow2p (TREE_OPERAND (exp, 1)) - && host_integerp (TREE_OPERAND (exp, 1), 1)) - { - c0 = highest_pow2_factor (TREE_OPERAND (exp, 0)); - c1 = tree_low_cst (TREE_OPERAND (exp, 1), 1); - return MAX (1, c0 / c1); - } - break; - - case BIT_AND_EXPR: - /* The highest power of two of a bit-and expression is the maximum of - that of its operands. We typically get here for a complex LHS and - a constant negative power of two on the RHS to force an explicit - alignment, so don't bother looking at the LHS. */ - return highest_pow2_factor (TREE_OPERAND (exp, 1)); - - CASE_CONVERT: - case SAVE_EXPR: - return highest_pow2_factor (TREE_OPERAND (exp, 0)); - - case COMPOUND_EXPR: - return highest_pow2_factor (TREE_OPERAND (exp, 1)); - - case COND_EXPR: - c0 = highest_pow2_factor (TREE_OPERAND (exp, 1)); - c1 = highest_pow2_factor (TREE_OPERAND (exp, 2)); - return MIN (c0, c1); - - default: - break; - } - - return 1; + unsigned HOST_WIDE_INT ret; + int trailing_zeros = tree_ctz (exp); + if (trailing_zeros >= HOST_BITS_PER_WIDE_INT) + return BIGGEST_ALIGNMENT; + ret = (unsigned HOST_WIDE_INT) 1 << trailing_zeros; + if (ret > BIGGEST_ALIGNMENT) + return BIGGEST_ALIGNMENT; + return ret; } /* Similar, except that the alignment requirements of TARGET are |