Bootstrap / regtest running on x86_64-unknown-linux-gnu.
Richard.
2019-12-04 Richard Biener <rguent...@suse.de>
* tree-ssa-sccvn.c (vn_reference_lookup_3): Properly guard
empty CTOR and memset partial-def registering. Take advantage
of fancy offset analysis in memset handling.
Index: gcc/tree-ssa-sccvn.c
===================================================================
--- gcc/tree-ssa-sccvn.c (revision 278955)
+++ gcc/tree-ssa-sccvn.c (working copy)
@@ -2432,6 +2432,12 @@ vn_reference_lookup_3 (ao_ref *ref, tree
}
else
return (void *)-1;
+ /* Sometimes the above trickery is smarter than alias analysis. Take
+ advantage of that. */
+ if (!ranges_maybe_overlap_p (offset, maxsize, offset2,
+ (wi::to_poly_offset (len)
+ << LOG2_BITS_PER_UNIT)))
+ return NULL;
tree len = gimple_call_arg (def_stmt, 2);
HOST_WIDE_INT leni, offset2i, offseti;
if (data->partial_defs.is_empty ()
@@ -2471,7 +2477,8 @@ vn_reference_lookup_3 (ao_ref *ref, tree
&& tree_to_poly_int64 (len).is_constant (&leni)
&& offset.is_constant (&offseti)
&& offset2.is_constant (&offset2i)
- && maxsize.is_constant (&maxsizei))
+ && maxsize.is_constant (&maxsizei)
+ && ranges_known_overlap_p (offseti, maxsizei, offset2i, leni))
{
pd_data pd;
pd.rhs = build_constructor (NULL_TREE, NULL);
@@ -2527,7 +2534,9 @@ vn_reference_lookup_3 (ao_ref *ref, tree
&& offset2.is_constant (&offset2i)
&& offset2i % BITS_PER_UNIT == 0
&& size2.is_constant (&size2i)
- && size2i % BITS_PER_UNIT == 0)
+ && size2i % BITS_PER_UNIT == 0
+ && ranges_known_overlap_p (offseti, maxsizei,
+ offset2i, size2i))
{
/* Let clobbers be consumed by the partial-def tracker
which can choose to ignore them if they are shadowed
