diff options
Diffstat (limited to 'gcc/tree-dfa.c')
| -rw-r--r-- | gcc/tree-dfa.c | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/gcc/tree-dfa.c b/gcc/tree-dfa.c index a121b88..00aa75f 100644 --- a/gcc/tree-dfa.c +++ b/gcc/tree-dfa.c @@ -529,6 +529,49 @@ get_ref_base_and_extent (tree exp, poly_int64_pod *poffset, /* Remember that we have seen an array ref with a variable index. */ seen_variable_array_ref = true; + + wide_int min, max; + if (TREE_CODE (index) == SSA_NAME + && (low_bound = array_ref_low_bound (exp), + poly_int_tree_p (low_bound)) + && (unit_size = array_ref_element_size (exp), + TREE_CODE (unit_size) == INTEGER_CST) + && get_range_info (index, &min, &max) == VR_RANGE) + { + poly_offset_int lbound = wi::to_poly_offset (low_bound); + /* Try to constrain maxsize with range information. */ + offset_int omax + = offset_int::from (max, TYPE_SIGN (TREE_TYPE (index))); + if (known_lt (lbound, omax)) + { + poly_offset_int rmaxsize; + rmaxsize = (omax - lbound + 1) + * wi::to_offset (unit_size) << LOG2_BITS_PER_UNIT; + if (!known_size_p (maxsize) + || known_lt (rmaxsize, maxsize)) + { + /* If we know an upper bound below the declared + one this is no longer variable. */ + if (known_size_p (maxsize)) + seen_variable_array_ref = false; + maxsize = rmaxsize; + } + } + /* Try to adjust bit_offset with range information. */ + offset_int omin + = offset_int::from (min, TYPE_SIGN (TREE_TYPE (index))); + if (known_le (lbound, omin)) + { + poly_offset_int woffset + = wi::sext (omin - lbound, + TYPE_PRECISION (TREE_TYPE (index))); + woffset *= wi::to_offset (unit_size); + woffset <<= LOG2_BITS_PER_UNIT; + bit_offset += woffset; + if (known_size_p (maxsize)) + maxsize -= woffset; + } + } } } break; |