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| author | Richard Biener <rguenther@suse.de> | 2015-06-03 08:02:10 +0000 |
|---|---|---|
| committer | Richard Biener <rguenth@gcc.gnu.org> | 2015-06-03 08:02:10 +0000 |
| commit | 4da60082232bc3dbf5782687e9f0ff25d733de10 (patch) | |
| tree | 4a730c210522915db4aab6f110f5afa8c3aa58b7 /gcc/tree-ssa-sccvn.c | |
| parent | b9b79ba4264cf635fbd3cc66530c5eb83d3ce568 (diff) | |
| download | gcc-4da60082232bc3dbf5782687e9f0ff25d733de10.zip gcc-4da60082232bc3dbf5782687e9f0ff25d733de10.tar.gz gcc-4da60082232bc3dbf5782687e9f0ff25d733de10.tar.bz2 | |
re PR tree-optimization/63916 (value-numbering fails to forward variable addresses)
2015-06-03 Richard Biener <rguenther@suse.de>
PR tree-optimization/63916
* tree-ssa-sccvn.c (vn_reference_maybe_forwprop_address):
Forward-propagate non-invariant addresses by splicing their
reference ops if the result isn't going to be used by PRE.
(vn_reference_lookup_3): Remove pointless assert.
* gcc.dg/tree-ssa/ssa-fre-45.c: New testcase.
From-SVN: r224061
Diffstat (limited to 'gcc/tree-ssa-sccvn.c')
| -rw-r--r-- | gcc/tree-ssa-sccvn.c | 30 |
1 files changed, 23 insertions, 7 deletions
diff --git a/gcc/tree-ssa-sccvn.c b/gcc/tree-ssa-sccvn.c index 19fb604..e7838ed 100644 --- a/gcc/tree-ssa-sccvn.c +++ b/gcc/tree-ssa-sccvn.c @@ -144,6 +144,10 @@ along with GCC; see the file COPYING3. If not see */ +static tree *last_vuse_ptr; +static vn_lookup_kind vn_walk_kind; +static vn_lookup_kind default_vn_walk_kind; + /* vn_nary_op hashtable helpers. */ struct vn_nary_op_hasher : typed_noop_remove <vn_nary_op_s> @@ -1259,6 +1263,25 @@ vn_reference_maybe_forwprop_address (vec<vn_reference_op_s> *ops, addr = gimple_assign_rhs1 (def_stmt); addr_base = get_addr_base_and_unit_offset (TREE_OPERAND (addr, 0), &addr_offset); + /* If that didn't work because the address isn't invariant propagate + the reference tree from the address operation in case the current + dereference isn't offsetted. */ + if (!addr_base + && *i_p == ops->length () - 1 + && off == 0 + /* This makes us disable this transform for PRE where the + reference ops might be also used for code insertion which + is invalid. */ + && default_vn_walk_kind == VN_WALKREWRITE) + { + auto_vec<vn_reference_op_s, 32> tem; + copy_reference_ops_from_ref (TREE_OPERAND (addr, 0), &tem); + ops->pop (); + ops->pop (); + ops->safe_splice (tem); + --*i_p; + return; + } if (!addr_base || TREE_CODE (addr_base) != MEM_REF) return; @@ -1557,10 +1580,6 @@ vn_reference_lookup_1 (vn_reference_t vr, vn_reference_t *vnresult) return NULL_TREE; } -static tree *last_vuse_ptr; -static vn_lookup_kind vn_walk_kind; -static vn_lookup_kind default_vn_walk_kind; - /* Callback for walk_non_aliased_vuses. Adjusts the vn_reference_t VR_ with the current VUSE and performs the expression lookup. */ @@ -1649,15 +1668,12 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *vr_, /* First try to disambiguate after value-replacing in the definitions LHS. */ if (is_gimple_assign (def_stmt)) { - vec<vn_reference_op_s> tem; tree lhs = gimple_assign_lhs (def_stmt); bool valueized_anything = false; /* Avoid re-allocation overhead. */ lhs_ops.truncate (0); copy_reference_ops_from_ref (lhs, &lhs_ops); - tem = lhs_ops; lhs_ops = valueize_refs_1 (lhs_ops, &valueized_anything); - gcc_assert (lhs_ops == tem); if (valueized_anything) { lhs_ref_ok = ao_ref_init_from_vn_reference (&lhs_ref, |