Hi,
the attached testcase exhibits a corruption of the SSA form:
t.c: In function 'foo':
t.c:9:10: error: definition in block 2 follows the use
for SSA_NAME: vect_p.7_12 in statement:
# VUSE <.MEM_6(D)>
vect_var_.8_13 = MEM[(struct R *)vect_p.7_12];
t.c:9:10: internal compiler error: verify_ssa failed
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.
introduced by SLP on x86-64 at -O2 -ftree-vectorize -fno-vect-cost-model.
This is a wrong statement rewriting in vectorizable_load. Before SLP we have:
D.2687_1 = arg.d2;
D.2688_2 = arg.d1;
D.2689_3 = 0.0 - D.2688_2;
D.2690_4 = D.2687_1 * D.2689_3;
D.2692.d1 = D.2690_4;
vect_check_interleaving computes that field d1 is accessed before field d2
because the structure is defined as
struct R {
double d1;
double d2;
};
but it's the opposite in the code. So, in vectorizable_load, first_stmt is the
load of d1 and new statements are wrongly inserted _after_ the load of d2.
Note that, on release branches (4.5 and 4.6 at least), you get wrong code.
Proposed fix attached. It adds a GSI parameter to vect_create_data_ref_ptr.
Tested on {i586,x86_64}-suse-linux, OK for the mainline? And the branches?
2011-03-27 Eric Botcazou <ebotca...@adacore.com>
* tree-vectorizer.h (vect_create_data_ref_ptr): Adjust prototype.
* tree-vect-data-refs.c (vect_create_data_ref_ptr): Add GSI parameter.
Insert new statements at it in lieu of STMT.
(vect_setup_realignment): Adjust call to vect_create_data_ref_ptr.
* tree-vect-stmts.c (vectorizable_store): Likewise.
(vectorizable_load): Likewise.
2011-03-27 Eric Botcazou <ebotca...@adacore.com>
* gcc.dg/slp-1.c: New test.
--
Eric Botcazou
Index: tree-vectorizer.h
===================================================================
--- tree-vectorizer.h (revision 171572)
+++ tree-vectorizer.h (working copy)
@@ -824,7 +824,8 @@ extern bool vect_analyze_data_ref_access
extern bool vect_prune_runtime_alias_test_list (loop_vec_info);
extern bool vect_analyze_data_refs (loop_vec_info, bb_vec_info, int *);
extern tree vect_create_data_ref_ptr (gimple, struct loop *, tree, tree *,
- gimple *, bool, bool *);
+ gimple_stmt_iterator *, gimple *,
+ bool, bool *);
extern tree bump_vector_ptr (tree, gimple, gimple_stmt_iterator *, gimple, tree);
extern tree vect_create_destination_var (tree, tree);
extern bool vect_strided_store_supported (tree);
Index: tree-vect-data-refs.c
===================================================================
--- tree-vect-data-refs.c (revision 171572)
+++ tree-vect-data-refs.c (working copy)
@@ -2922,9 +2922,10 @@ vect_create_addr_base_for_vector_ref (gi
2. AT_LOOP: the loop where the vector memref is to be created.
3. OFFSET (optional): an offset to be added to the initial address accessed
by the data-ref in STMT.
- 4. ONLY_INIT: indicate if vp is to be updated in the loop, or remain
+ 4. BSI: location where the new stmts are to be placed if there is no loop
+ 5. ONLY_INIT: indicate if vp is to be updated in the loop, or remain
pointing to the initial address.
- 5. TYPE: if not NULL indicates the required type of the data-ref.
+ 6. TYPE: if not NULL indicates the required type of the data-ref.
Output:
1. Declare a new ptr to vector_type, and have it point to the base of the
@@ -2952,9 +2953,9 @@ vect_create_addr_base_for_vector_ref (gi
4. Return the pointer. */
tree
-vect_create_data_ref_ptr (gimple stmt, struct loop *at_loop,
- tree offset, tree *initial_address, gimple *ptr_incr,
- bool only_init, bool *inv_p)
+vect_create_data_ref_ptr (gimple stmt, struct loop *at_loop, tree offset,
+ tree *initial_address, gimple_stmt_iterator *gsi,
+ gimple *ptr_incr, bool only_init, bool *inv_p)
{
tree base_name;
stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
@@ -2980,7 +2981,6 @@ vect_create_data_ref_ptr (gimple stmt, s
gimple incr;
tree step;
bb_vec_info bb_vinfo = STMT_VINFO_BB_VINFO (stmt_info);
- gimple_stmt_iterator gsi = gsi_for_stmt (stmt);
tree base;
if (loop_vinfo)
@@ -3125,7 +3125,7 @@ vect_create_data_ref_ptr (gimple stmt, s
gcc_assert (!new_bb);
}
else
- gsi_insert_seq_before (&gsi, new_stmt_list, GSI_SAME_STMT);
+ gsi_insert_seq_before (gsi, new_stmt_list, GSI_SAME_STMT);
}
*initial_address = new_temp;
@@ -3147,7 +3147,7 @@ vect_create_data_ref_ptr (gimple stmt, s
gcc_assert (!new_bb);
}
else
- gsi_insert_before (&gsi, vec_stmt, GSI_SAME_STMT);
+ gsi_insert_before (gsi, vec_stmt, GSI_SAME_STMT);
}
else
vect_ptr_init = new_temp;
@@ -3672,7 +3672,7 @@ vect_setup_realignment (gimple stmt, gim
gcc_assert (!compute_in_loop);
vec_dest = vect_create_destination_var (scalar_dest, vectype);
ptr = vect_create_data_ref_ptr (stmt, loop_for_initial_load, NULL_TREE,
- &init_addr, &inc, true, &inv_p);
+ &init_addr, NULL, &inc, true, &inv_p);
new_stmt = gimple_build_assign_with_ops
(BIT_AND_EXPR, NULL_TREE, ptr,
build_int_cst (TREE_TYPE (ptr),
Index: tree-vect-stmts.c
===================================================================
--- tree-vect-stmts.c (revision 171572)
+++ tree-vect-stmts.c (working copy)
@@ -3582,7 +3582,7 @@ vectorizable_store (gimple stmt, gimple_
gcc_assert (useless_type_conversion_p (vectype,
TREE_TYPE (vec_oprnd)));
dataref_ptr = vect_create_data_ref_ptr (first_stmt, NULL, NULL_TREE,
- &dummy, &ptr_incr, false,
+ &dummy, gsi, &ptr_incr, false,
&inv_p);
gcc_assert (bb_vinfo || !inv_p);
}
@@ -4109,9 +4109,8 @@ vectorizable_load (gimple stmt, gimple_s
{
/* 1. Create the vector pointer update chain. */
if (j == 0)
- dataref_ptr = vect_create_data_ref_ptr (first_stmt,
- at_loop, offset,
- &dummy, &ptr_incr, false,
+ dataref_ptr = vect_create_data_ref_ptr (first_stmt, at_loop, offset,
+ &dummy, gsi, &ptr_incr, false,
&inv_p);
else
dataref_ptr =
/* { dg-do compile } */
/* { dg-options "-O2 -ftree-vectorize -fno-vect-cost-model" } */
struct R {
double d1;
double d2;
};
struct R foo (struct R arg)
{
struct R ret;
ret.d1 = arg.d2 * (0.0 - arg.d1);
ret.d2 = ret.d1;
return ret;
}
