The fix for PR49651 was too conservative as I noticed when trying
to backport it to the 4.5 branch. The following adjusts it to
preserve the optimization cases we have in the tree-ssa testsuite.
Bootstrap / regtest pending on x86_64-unknown-linux-gnu.
Richard.
2012-01-03 Richard Guenther <rguent...@suse.de>
PR tree-optimization/49651
* tree-ssa-structalias.c (type_can_have_subvars): New function.
(var_can_have_subvars): Use it.
(get_constraint_for_1): Only consider subfields if there
can be any.
* gcc.dg/tree-ssa/pta-ptrarith-1.c: Adjust.
* gcc.dg/tree-ssa/pta-ptrarith-2.c: Likewise.
Index: gcc/tree-ssa-structalias.c
===================================================================
--- gcc/tree-ssa-structalias.c (revision 182838)
+++ gcc/tree-ssa-structalias.c (working copy)
@@ -303,6 +303,7 @@ static varinfo_t first_vi_for_offset (va
static varinfo_t first_or_preceding_vi_for_offset (varinfo_t,
unsigned HOST_WIDE_INT);
static varinfo_t lookup_vi_for_tree (tree);
+static inline bool type_can_have_subvars (const_tree);
/* Pool of variable info structures. */
static alloc_pool variable_info_pool;
@@ -3275,7 +3276,8 @@ get_constraint_for_1 (tree t, VEC (ce_s,
return;
cs = *VEC_last (ce_s, *results);
- if (cs.type == DEREF)
+ if (cs.type == DEREF
+ && type_can_have_subvars (TREE_TYPE (t)))
{
/* For dereferences this means we have to defer it
to solving time. */
@@ -5043,6 +5045,15 @@ sort_fieldstack (VEC(fieldoff_s,heap) *f
VEC_qsort (fieldoff_s, fieldstack, fieldoff_compare);
}
+/* Return true if T is a type that can have subvars. */
+
+static inline bool
+type_can_have_subvars (const_tree t)
+{
+ /* Aggregates without overlapping fields can have subvars. */
+ return TREE_CODE (t) == RECORD_TYPE;
+}
+
/* Return true if V is a tree that we can have subvars for.
Normally, this is any aggregate type. Also complex
types which are not gimple registers can have subvars. */
@@ -5058,11 +5069,7 @@ var_can_have_subvars (const_tree v)
if (!DECL_P (v))
return false;
- /* Aggregates without overlapping fields can have subvars. */
- if (TREE_CODE (TREE_TYPE (v)) == RECORD_TYPE)
- return true;
-
- return false;
+ return type_can_have_subvars (TREE_TYPE (v));
}
/* Return true if T is a type that does contain pointers. */
Index: gcc/testsuite/gcc.dg/tree-ssa/pta-ptrarith-1.c
===================================================================
--- gcc/testsuite/gcc.dg/tree-ssa/pta-ptrarith-1.c (revision 182838)
+++ gcc/testsuite/gcc.dg/tree-ssa/pta-ptrarith-1.c (working copy)
@@ -1,5 +1,5 @@
/* { dg-do compile } */
-/* { dg-options "-O2 -fno-tree-ccp -fdump-tree-ealias" } */
+/* { dg-options "-O2 -fno-tree-forwprop -fno-tree-ccp -fdump-tree-ealias" } */
extern void abort (void);
struct X {
Index: gcc/testsuite/gcc.dg/tree-ssa/pta-ptrarith-2.c
===================================================================
--- gcc/testsuite/gcc.dg/tree-ssa/pta-ptrarith-2.c (revision 182838)
+++ gcc/testsuite/gcc.dg/tree-ssa/pta-ptrarith-2.c (working copy)
@@ -1,5 +1,5 @@
/* { dg-do compile } */
-/* { dg-options "-O2 -fno-tree-ccp -fdump-tree-ealias" } */
+/* { dg-options "-O2 -fno-tree-forwprop -fno-tree-ccp -fdump-tree-ealias" } */
extern void abort (void);
struct X {
