Hi!
While hacking on the gomp4 simd clauses stuff, I've noticed that
we don't vectorize IVs with non-constant step. The following patch
implements it, basically we just can't rely that the step or VF * step
is a constant and instead for VF * step need to emit a temporary with
scalar VF * step value before adding a vector temporary.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
I wasn't sure about nested loop vectorization, so I've disabled it for that
case, perhaps with a testcase that exhibits it could be replaced just with a
test that the step, if SSA_NAME, doesn't have definition even in the outer
loop, because we still put the vector constants before the outer loop.
2013-06-25 Jakub Jelinek <ja...@redhat.com>
PR tree-optimization/57705
* tree-vect-loop.c (vect_is_simple_iv_evolution): Allow
SSA_NAME step, provided that it is not defined inside the loop.
(vect_analyze_scalar_cycles_1): Disallow SSA_NAME step in nested
loop.
(get_initial_def_for_induction): Handle SSA_NAME IV step.
* gcc.dg/vect/pr57705.c: New test.
* gcc.dg/vect/vect-iv-7.c: Add noclone attribute, remove xfail.
--- gcc/tree-vect-loop.c.jj 2013-06-06 08:39:24.000000000 +0200
+++ gcc/tree-vect-loop.c 2013-06-25 11:17:02.947602981 +0200
@@ -500,7 +500,7 @@ vect_determine_vectorization_factor (loo
/* Function vect_is_simple_iv_evolution.
FORNOW: A simple evolution of an induction variables in the loop is
- considered a polynomial evolution with constant step. */
+ considered a polynomial evolution. */
static bool
vect_is_simple_iv_evolution (unsigned loop_nb, tree access_fn, tree * init,
@@ -509,6 +509,7 @@ vect_is_simple_iv_evolution (unsigned lo
tree init_expr;
tree step_expr;
tree evolution_part = evolution_part_in_loop_num (access_fn, loop_nb);
+ basic_block bb;
/* When there is no evolution in this loop, the evolution function
is not "simple". */
@@ -534,7 +535,10 @@ vect_is_simple_iv_evolution (unsigned lo
*init = init_expr;
*step = step_expr;
- if (TREE_CODE (step_expr) != INTEGER_CST)
+ if (TREE_CODE (step_expr) != INTEGER_CST
+ && (TREE_CODE (step_expr) != SSA_NAME
+ || ((bb = gimple_bb (SSA_NAME_DEF_STMT (step_expr)))
+ && flow_bb_inside_loop_p (get_loop (cfun, loop_nb), bb))))
{
if (dump_enabled_p ())
dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
@@ -556,7 +560,7 @@ static void
vect_analyze_scalar_cycles_1 (loop_vec_info loop_vinfo, struct loop *loop)
{
basic_block bb = loop->header;
- tree dumy;
+ tree init, step;
vec<gimple> worklist;
worklist.create (64);
gimple_stmt_iterator gsi;
@@ -605,7 +609,9 @@ vect_analyze_scalar_cycles_1 (loop_vec_i
}
if (!access_fn
- || !vect_is_simple_iv_evolution (loop->num, access_fn, &dumy, &dumy))
+ || !vect_is_simple_iv_evolution (loop->num, access_fn, &init, &step)
+ || (LOOP_VINFO_LOOP (loop_vinfo) != loop
+ && TREE_CODE (step) != INTEGER_CST))
{
worklist.safe_push (phi);
continue;
@@ -3273,10 +3279,14 @@ get_initial_def_for_induction (gimple iv
expr = build_int_cst (TREE_TYPE (step_expr), vf);
new_name = fold_build2 (MULT_EXPR, TREE_TYPE (step_expr),
expr, step_expr);
+ if (TREE_CODE (step_expr) == SSA_NAME)
+ new_name = vect_init_vector (iv_phi, new_name,
+ TREE_TYPE (step_expr), NULL);
}
t = unshare_expr (new_name);
- gcc_assert (CONSTANT_CLASS_P (new_name));
+ gcc_assert (CONSTANT_CLASS_P (new_name)
+ || TREE_CODE (new_name) == SSA_NAME);
stepvectype = get_vectype_for_scalar_type (TREE_TYPE (new_name));
gcc_assert (stepvectype);
new_vec = build_vector_from_val (stepvectype, t);
@@ -3332,8 +3342,12 @@ get_initial_def_for_induction (gimple iv
expr = build_int_cst (TREE_TYPE (step_expr), nunits);
new_name = fold_build2 (MULT_EXPR, TREE_TYPE (step_expr),
expr, step_expr);
+ if (TREE_CODE (step_expr) == SSA_NAME)
+ new_name = vect_init_vector (iv_phi, new_name,
+ TREE_TYPE (step_expr), NULL);
t = unshare_expr (new_name);
- gcc_assert (CONSTANT_CLASS_P (new_name));
+ gcc_assert (CONSTANT_CLASS_P (new_name)
+ || TREE_CODE (new_name) == SSA_NAME);
new_vec = build_vector_from_val (stepvectype, t);
vec_step = vect_init_vector (iv_phi, new_vec, stepvectype, NULL);
--- gcc/testsuite/gcc.dg/vect/pr57705.c.jj 2013-06-25 10:15:21.037092153
+0200
+++ gcc/testsuite/gcc.dg/vect/pr57705.c 2013-06-25 10:15:02.239733689 +0200
@@ -0,0 +1,65 @@
+/* { dg-do run } */
+
+#include "tree-vect.h"
+
+int a[1024];
+unsigned char b[1024];
+
+extern void abort (void);
+
+__attribute__((noinline, noclone)) void
+foo (int k, int m)
+{
+ int i, k2 = k;
+ for (i = 0; i < 1024; i++)
+ {
+ a[i] = k2;
+ k2 += m + 1;
+ }
+}
+
+__attribute__((noinline, noclone)) void
+bar (int k, int m)
+{
+ int i, k2 = k;
+ for (i = 0; i < 1024; i++)
+ {
+ k2 += m + 1;
+ a[i] = k2;
+ }
+}
+
+__attribute__((noinline, noclone)) void
+baz (int k, int m)
+{
+ int i, k2 = k;
+ for (i = 0; i < 1024; i++)
+ {
+ a[i] = k2;
+ b[i] = i;
+ k2 += m + 1;
+ }
+}
+
+int
+main ()
+{
+ int i;
+ check_vect ();
+ foo (5, 3);
+ for (i = 0; i < 1024; i++)
+ if (a[i] != 5 + 4 * i)
+ abort ();
+ bar (5, 3);
+ for (i = 0; i < 1024; i++)
+ if (a[i] != 9 + 4 * i)
+ abort ();
+ baz (5, 3);
+ for (i = 0; i < 1024; i++)
+ if (a[i] != 5 + 4 * i || b[i] != (unsigned char) i)
+ abort ();
+ return 0;
+}
+
+/* { dg-final { scan-tree-dump-times "vectorized 1 loop" 3 "vect" } } */
+/* { dg-final { cleanup-tree-dump "vect" } } */
--- gcc/testsuite/gcc.dg/vect/vect-iv-7.c.jj 2008-09-05 12:54:35.000000000
+0200
+++ gcc/testsuite/gcc.dg/vect/vect-iv-7.c 2013-06-25 10:37:35.864287369
+0200
@@ -6,7 +6,7 @@
#define N 16
int result[N] = {8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36,
38};
-__attribute__ ((noinline)) int main1 (int X)
+__attribute__ ((noinline, noclone)) int main1 (int X)
{
int arr[N];
int k = 3;
@@ -38,5 +38,5 @@ int main (void)
return main1 (2);
}
-/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" { xfail
*-*-* } } } */
+/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" } } */
/* { dg-final { cleanup-tree-dump "vect" } } */
Jakub
