On 31/01/12 22:07, Tom de Vries wrote:
> On 31/01/12 22:05, Tom de Vries wrote:
>> Richard,
>>
>
> Sorry, with patch this time.
>
>> this patch fixes PR52009.
>>
>> Consider this test-case:
>> ...
>> int z;
>>
>> void
>> foo (int y)
>> {
>> if (y == 6)
>> z = 5;
>> else
>> z = 5;
>> }
>> ...
>>
>> Currently, compiling with -O2 gives us this representation at
>> pr51879-7.c.094t.pre:
>> ...
>> # BLOCK 3 freq:1991
>> # PRED: 2 [19.9%] (true,exec)
>> # .MEMD.1710_4 = VDEF <.MEMD.1710_3(D)>
>> zD.1702 = 5;
>> goto <bb 5>;
>> # SUCC: 5 [100.0%] (fallthru,exec)
>>
>> # BLOCK 4 freq:8009
>> # PRED: 2 [80.1%] (false,exec)
>> # .MEMD.1710_5 = VDEF <.MEMD.1710_3(D)>
>> zD.1702 = 5;
>> # SUCC: 5 [100.0%] (fallthru,exec)
>>
>> # BLOCK 5 freq:10000
>> # PRED: 3 [100.0%] (fallthru,exec) 4 [100.0%] (fallthru,exec)
>> # .MEMD.1710_2 = PHI <.MEMD.1710_4(3), .MEMD.1710_5(4)>
>> # VUSE <.MEMD.1710_2>
>> return;
>> ...
>>
>> Blocks 3 and 4 are not tail-merged.
>>
>> The patch allows the example to be tail-merged by:
>> - value numbering .MEMD.1710_4 and .MEMD.1710_5 equal
>> - comparing gimple_vdef value numbers for assignments during tail-merge
>>
>> Bootstrapped and reg-tested on x86_64.
>>
>> OK for stage1?
>>
Richard,
I did some trivial changes such that the patch is applicable again to trunk, and
added a test-case, which you suggested in
http://gcc.gnu.org/ml/gcc-patches/2012-05/msg00220.html.
The test-case handles the case of 2 identical calls assigning to different
deferenced pointers, where the pointers are value-numbered the same:
...
void bar (int c, int *p)
{
int *q = p;
if (c)
*p = foo ();
else
*q = foo ();
}
...
The representation before pre looks like this:
...
# BLOCK 3 freq:3900
# PRED: 2 [39.0%] (true,exec)
# .MEMD.1724_8 = VDEF <.MEMD.1724_7(D)>
# USE = nonlocal
# CLB = nonlocal
D.1721_4 = fooD.1712 ();
# .MEMD.1724_9 = VDEF <.MEMD.1724_8>
*pD.1714_1(D) = D.1721_4;
goto <bb 5>;
# SUCC: 5 [100.0%] (fallthru,exec)
# BLOCK 4 freq:6100
# PRED: 2 [61.0%] (false,exec)
# .MEMD.1724_10 = VDEF <.MEMD.1724_7(D)>
# USE = nonlocal
# CLB = nonlocal
D.1723_5 = fooD.1712 ();
# .MEMD.1724_11 = VDEF <.MEMD.1724_10>
*qD.1717_2 = D.1723_5;
# SUCC: 5 [100.0%] (fallthru,exec)
...
In pre, we're already value numbering the result and vdef of the calls the same,
and the pointers the same:
...
Value numbers:
q_2 = p_1(D)
D.1723_5 = D.1721_4
.MEM_10 = .MEM_8
...
But not the vdefs of the stores. This patch implements that, and allows the
blocks to be merged.
ok for trunk?
Thanks,
- Tom
2012-07-04 Tom de Vries <t...@codesourcery.com>
PR tree-optimization/52009
* tree-ssa-tail-merge.c (gimple_equal_p): For GIMPLE_ASSIGN, compare
value numbers of gimple_vdef.
* tree-ssa-sccvn.h (vn_reference_insert): Add vdef parameter to
prototype.
* tree-ssa-sccvn.c (copy_reference_ops_from_ref): Handle MODIFY_EXPR.
(vn_reference_insert): Add and handle vdef parameter.
(visit_reference_op_load): Add argument to vn_reference_insert call.
(visit_reference_op_store): Find value number of vdef of store. Insert
value number of vdef of store.
* gcc.dg/pr51879-7.c: New test.
* gcc.dg/pr51879-18.c: New test.
Index: gcc/tree-ssa-tail-merge.c
===================================================================
--- gcc/tree-ssa-tail-merge.c (revision 189007)
+++ gcc/tree-ssa-tail-merge.c (working copy)
@@ -1119,6 +1119,14 @@ gimple_equal_p (same_succ same_succ, gim
case GIMPLE_ASSIGN:
lhs1 = gimple_get_lhs (s1);
lhs2 = gimple_get_lhs (s2);
+ if (gimple_vdef (s1))
+ {
+ if (vn_valueize (gimple_vdef (s1)) != vn_valueize (gimple_vdef (s2)))
+ return false;
+ if (TREE_CODE (lhs1) != SSA_NAME
+ && TREE_CODE (lhs2) != SSA_NAME)
+ return true;
+ }
return (TREE_CODE (lhs1) == SSA_NAME
&& TREE_CODE (lhs2) == SSA_NAME
&& vn_valueize (lhs1) == vn_valueize (lhs2));
Index: gcc/tree-ssa-sccvn.c
===================================================================
--- gcc/tree-ssa-sccvn.c (revision 189007)
+++ gcc/tree-ssa-sccvn.c (working copy)
@@ -628,6 +628,9 @@ copy_reference_ops_from_ref (tree ref, V
switch (temp.opcode)
{
+ case MODIFY_EXPR:
+ temp.op0 = TREE_OPERAND (ref, 1);
+ break;
case WITH_SIZE_EXPR:
temp.op0 = TREE_OPERAND (ref, 1);
temp.off = 0;
@@ -748,6 +751,7 @@ copy_reference_ops_from_ref (tree ref, V
VEC_safe_push (vn_reference_op_s, heap, *result, &temp);
if (REFERENCE_CLASS_P (ref)
+ || TREE_CODE (ref) == MODIFY_EXPR
|| TREE_CODE (ref) == WITH_SIZE_EXPR
|| (TREE_CODE (ref) == ADDR_EXPR
&& !is_gimple_min_invariant (ref)))
@@ -1941,7 +1945,7 @@ vn_reference_lookup (tree op, tree vuse,
RESULT, and return the resulting reference structure we created. */
vn_reference_t
-vn_reference_insert (tree op, tree result, tree vuse)
+vn_reference_insert (tree op, tree result, tree vuse, tree vdef)
{
void **slot;
vn_reference_t vr1;
@@ -1957,6 +1961,7 @@ vn_reference_insert (tree op, tree resul
vr1->set = get_alias_set (op);
vr1->hashcode = vn_reference_compute_hash (vr1);
vr1->result = TREE_CODE (result) == SSA_NAME ? SSA_VAL (result) : result;
+ vr1->result_vdef = vdef;
slot = htab_find_slot_with_hash (current_info->references, vr1, vr1->hashcode,
INSERT);
@@ -2775,7 +2780,7 @@ visit_reference_op_load (tree lhs, tree
else
{
changed = set_ssa_val_to (lhs, lhs);
- vn_reference_insert (op, lhs, last_vuse);
+ vn_reference_insert (op, lhs, last_vuse, NULL_TREE);
}
return changed;
@@ -2789,8 +2794,11 @@ static bool
visit_reference_op_store (tree lhs, tree op, gimple stmt)
{
bool changed = false;
- tree result;
+ vn_reference_t vnresult = NULL;
+ tree result, assign;
bool resultsame = false;
+ tree vuse = gimple_vuse (stmt);
+ tree vdef = gimple_vdef (stmt);
/* First we want to lookup using the *vuses* from the store and see
if there the last store to this location with the same address
@@ -2808,7 +2816,7 @@ visit_reference_op_store (tree lhs, tree
Otherwise, the vdefs for the store are used when inserting into
the table, since the store generates a new memory state. */
- result = vn_reference_lookup (lhs, gimple_vuse (stmt), VN_NOWALK, NULL);
+ result = vn_reference_lookup (lhs, vuse, VN_NOWALK, NULL);
if (result)
{
@@ -2821,8 +2829,17 @@ visit_reference_op_store (tree lhs, tree
if (!result || !resultsame)
{
- tree vdef;
+ assign = build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, op);
+ vn_reference_lookup (assign, vuse, VN_NOWALK, &vnresult);
+ if (vnresult)
+ {
+ VN_INFO (vdef)->use_processed = true;
+ return set_ssa_val_to (vdef, vnresult->result_vdef);
+ }
+ }
+ if (!result || !resultsame)
+ {
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "No store match\n");
@@ -2834,7 +2851,7 @@ visit_reference_op_store (tree lhs, tree
}
/* Have to set value numbers before insert, since insert is
going to valueize the references in-place. */
- if ((vdef = gimple_vdef (stmt)))
+ if (vdef)
{
changed |= set_ssa_val_to (vdef, vdef);
}
@@ -2842,22 +2859,21 @@ visit_reference_op_store (tree lhs, tree
/* Do not insert structure copies into the tables. */
if (is_gimple_min_invariant (op)
|| is_gimple_reg (op))
- vn_reference_insert (lhs, op, vdef);
+ vn_reference_insert (lhs, op, vdef, NULL);
+
+ assign = build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, op);
+ vn_reference_insert (assign, lhs, vuse, vdef);
}
else
{
/* We had a match, so value number the vdef to have the value
number of the vuse it came from. */
- tree def, use;
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "Store matched earlier value,"
"value numbering store vdefs to matching vuses.\n");
- def = gimple_vdef (stmt);
- use = gimple_vuse (stmt);
-
- changed |= set_ssa_val_to (def, SSA_VAL (use));
+ changed |= set_ssa_val_to (vdef, SSA_VAL (vuse));
}
return changed;
Index: gcc/tree-ssa-sccvn.h
===================================================================
--- gcc/tree-ssa-sccvn.h (revision 189007)
+++ gcc/tree-ssa-sccvn.h (working copy)
@@ -200,7 +200,7 @@ tree vn_reference_lookup_pieces (tree, a
VEC (vn_reference_op_s, heap) *,
vn_reference_t *, vn_lookup_kind);
tree vn_reference_lookup (tree, tree, vn_lookup_kind, vn_reference_t *);
-vn_reference_t vn_reference_insert (tree, tree, tree);
+vn_reference_t vn_reference_insert (tree, tree, tree, tree);
vn_reference_t vn_reference_insert_pieces (tree, alias_set_type, tree,
VEC (vn_reference_op_s, heap) *,
tree, unsigned int);
Index: gcc/testsuite/gcc.dg/pr51879-7.c
===================================================================
--- /dev/null (new file)
+++ gcc/testsuite/gcc.dg/pr51879-7.c (revision 0)
@@ -0,0 +1,18 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-pre" } */
+
+int bar (int);
+
+int z;
+
+void
+foo (int y)
+{
+ if (y == 6)
+ z = 5;
+ else
+ z = 5;
+}
+
+/* { dg-final { scan-tree-dump-times "z = 5" 1 "pre"} } */
+/* { dg-final { cleanup-tree-dump "pre" } } */
Index: gcc/testsuite/gcc.dg/pr51879-18.c
===================================================================
--- /dev/null (new file)
+++ gcc/testsuite/gcc.dg/pr51879-18.c (revision 0)
@@ -0,0 +1,17 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-pre -fno-tree-copy-prop -fno-tree-dominator-opts -fno-tree-copyrename" } */
+
+extern int foo (void);
+
+void bar (int c, int *p)
+{
+ int *q = p;
+
+ if (c)
+ *p = foo ();
+ else
+ *q = foo ();
+}
+
+/* { dg-final { scan-tree-dump-times "foo \\(" 1 "pre"} } */
+/* { dg-final { cleanup-tree-dump "pre" } } */
