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| author | Jakub Jelinek <jakub@redhat.com> | 2017-12-19 08:44:07 +0100 |
|---|---|---|
| committer | Jakub Jelinek <jakub@gcc.gnu.org> | 2017-12-19 08:44:07 +0100 |
| commit | f744bfec7ffb92b476da82bc62a81eaf087b2391 (patch) | |
| tree | 14829559d70dd7a4530537fb45f37839eba9b180 /gcc/tree-ssa-strlen.c | |
| parent | d6ea70a0dcf7ca69321c6fa7c583bc9a2ca3dfd0 (diff) | |
| download | gcc-f744bfec7ffb92b476da82bc62a81eaf087b2391.zip gcc-f744bfec7ffb92b476da82bc62a81eaf087b2391.tar.gz gcc-f744bfec7ffb92b476da82bc62a81eaf087b2391.tar.bz2 | |
re PR tree-optimization/83444 (missing strlen optimization on a member array of a local struct)
PR tree-optimization/83444
* tree-ssa-strlen.c (strlen_check_and_optimize_stmt): Optimize
character loads.
* gcc.dg/strlenopt-38.c: New test.
From-SVN: r255806
Diffstat (limited to 'gcc/tree-ssa-strlen.c')
| -rw-r--r-- | gcc/tree-ssa-strlen.c | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/gcc/tree-ssa-strlen.c b/gcc/tree-ssa-strlen.c index 0386883..a2d514c 100644 --- a/gcc/tree-ssa-strlen.c +++ b/gcc/tree-ssa-strlen.c @@ -3146,6 +3146,64 @@ strlen_check_and_optimize_stmt (gimple_stmt_iterator *gsi) else if (code == EQ_EXPR || code == NE_EXPR) fold_strstr_to_strncmp (gimple_assign_rhs1 (stmt), gimple_assign_rhs2 (stmt), stmt); + else if (gimple_assign_load_p (stmt) + && TREE_CODE (TREE_TYPE (lhs)) == INTEGER_TYPE + && TYPE_MODE (TREE_TYPE (lhs)) == TYPE_MODE (char_type_node) + && (TYPE_PRECISION (TREE_TYPE (lhs)) + == TYPE_PRECISION (char_type_node)) + && !gimple_has_volatile_ops (stmt)) + { + tree off = integer_zero_node; + unsigned HOST_WIDE_INT coff = 0; + int idx = -1; + tree rhs1 = gimple_assign_rhs1 (stmt); + if (code == MEM_REF) + { + idx = get_stridx (TREE_OPERAND (rhs1, 0)); + off = TREE_OPERAND (rhs1, 1); + } + else + idx = get_addr_stridx (rhs1, NULL_TREE, &coff); + if (idx > 0) + { + strinfo *si = get_strinfo (idx); + if (si + && si->nonzero_chars + && TREE_CODE (si->nonzero_chars) == INTEGER_CST) + { + widest_int w1 = wi::to_widest (si->nonzero_chars); + widest_int w2 = wi::to_widest (off) + coff; + if (w1 == w2 + && si->full_string_p) + { + /* Reading the final '\0' character. */ + tree zero = build_int_cst (TREE_TYPE (lhs), 0); + gimple_set_vuse (stmt, NULL_TREE); + gimple_assign_set_rhs_from_tree (gsi, zero); + update_stmt (gsi_stmt (*gsi)); + } + else if (w1 > w2) + { + /* Reading a character before the final '\0' + character. Just set the value range to ~[0, 0] + if we don't have anything better. */ + wide_int min, max; + tree type = TREE_TYPE (lhs); + enum value_range_type vr + = get_range_info (lhs, &min, &max); + if (vr == VR_VARYING + || (vr == VR_RANGE + && min == wi::min_value (TYPE_PRECISION (type), + TYPE_SIGN (type)) + && max == wi::max_value (TYPE_PRECISION (type), + TYPE_SIGN (type)))) + set_range_info (lhs, VR_ANTI_RANGE, + wi::zero (TYPE_PRECISION (type)), + wi::zero (TYPE_PRECISION (type))); + } + } + } + } if (strlen_to_stridx) { |