diff options
Diffstat (limited to 'gcc/tree.c')
-rw-r--r-- | gcc/tree.c | 27 |
1 files changed, 27 insertions, 0 deletions
@@ -5035,6 +5035,33 @@ tree_int_cst_sgn (const_tree t) return 1; } +/* Return the minimum number of bits needed to represent VALUE in a + signed or unsigned type, UNSIGNEDP says which. */ + +unsigned int +tree_int_cst_min_precision (tree value, bool unsignedp) +{ + int log; + + /* If the value is negative, compute its negative minus 1. The latter + adjustment is because the absolute value of the largest negative value + is one larger than the largest positive value. This is equivalent to + a bit-wise negation, so use that operation instead. */ + + if (tree_int_cst_sgn (value) < 0) + value = fold_build1 (BIT_NOT_EXPR, TREE_TYPE (value), value); + + /* Return the number of bits needed, taking into account the fact + that we need one more bit for a signed than unsigned type. */ + + if (integer_zerop (value)) + log = 0; + else + log = tree_floor_log2 (value); + + return log + 1 + !unsignedp; +} + /* Compare two constructor-element-type constants. Return 1 if the lists are known to be equal; otherwise return 0. */ |