From: Ju-Zhe Zhong <juzhe.zh...@rivai.ai>
Hi, Richard and Richi.
This patch add support live vectorization by VEC_EXTRACT for LEN loop control.
Consider this following case:
#include <stdint.h>
#define EXTRACT_LAST(TYPE) \
TYPE __attribute__ ((noinline, noclone)) \
test_##TYPE (TYPE *x, int n, TYPE value) \
{ \
TYPE last; \
for (int j = 0; j < n; ++j) \
{ \
last = x[j]; \
x[j] = last * value; \
} \
return last; \
}
#define TEST_ALL(T) \
T (uint8_t) \
TEST_ALL (EXTRACT_LAST)
ARM SVE IR:
Preheader:
max_mask_34 = .WHILE_ULT (0, bnd.5_6, { 0, ... });
Loop:
...
# loop_mask_22 = PHI <next_mask_35(4), max_mask_34(3)>
...
vect_last_12.8_23 = .MASK_LOAD (_7, 8B, loop_mask_22);
vect__4.9_27 = vect_last_12.8_23 * vect_cst__26;
.MASK_STORE (_7, 8B, loop_mask_22, vect__4.9_27);
...
next_mask_35 = .WHILE_ULT (_1, bnd.5_6, { 0, ... });
...
Epilogue:
_25 = .EXTRACT_LAST (loop_mask_22, vect_last_12.8_23);
For RVV since we prefer len in loop control, after this patch for RVV:
Loop:
...
loop_len_22 = SELECT_VL;
vect_last_12.8_23 = .MASK_LOAD (_7, 8B, loop_len_22);
vect__4.9_27 = vect_last_12.8_23 * vect_cst__26;
.MASK_STORE (_7, 8B, loop_len_22, vect__4.9_27);
...
Epilogue:
_25 = .VEC_EXTRACT (loop_len_22 + bias - 1, vect_last_12.8_23);
Details of this approach:
1. Step 1 - Add 'vect_can_vectorize_extract_last_with_len_p' to enable live
vectorization
for LEN loop control.
This function we check whether target support:
- Use LEN as the loop control.
- Support VEC_EXTRACT optab.
2. Step 2 - Record LEN for loop control if
'vect_can_vectorize_extract_last_with_len_p' is true.
3. Step 3 - Gerenate VEC_EXTRACT (v, LEN + BIAS - 1).
The only difference between mask and len is that len is using length generated
by SELECT_VL and
use VEC_EXTRACT pattern. The rest of the live vectorization is totally the same
ARM SVE.
gcc/ChangeLog:
* tree-vect-loop.cc (vectorizable_live_operation): Add loop len control.
---
gcc/tree-vect-loop.cc | 78 ++++++++++++++++++++++++++++++++++---------
1 file changed, 62 insertions(+), 16 deletions(-)
diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
index bf8d677b584..a011e2dacb2 100644
--- a/gcc/tree-vect-loop.cc
+++ b/gcc/tree-vect-loop.cc
@@ -10278,17 +10278,7 @@ vectorizable_live_operation (vec_info *vinfo,
stmt_vec_info stmt_info,
/* No transformation required. */
if (loop_vinfo && LOOP_VINFO_CAN_USE_PARTIAL_VECTORS_P (loop_vinfo))
{
- if (!direct_internal_fn_supported_p (IFN_EXTRACT_LAST, vectype,
- OPTIMIZE_FOR_SPEED))
- {
- if (dump_enabled_p ())
- dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
- "can't operate on partial vectors "
- "because the target doesn't support extract "
- "last reduction.\n");
- LOOP_VINFO_CAN_USE_PARTIAL_VECTORS_P (loop_vinfo) = false;
- }
- else if (slp_node)
+ if (slp_node)
{
if (dump_enabled_p ())
dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
@@ -10308,9 +10298,28 @@ vectorizable_live_operation (vec_info *vinfo,
stmt_vec_info stmt_info,
else
{
gcc_assert (ncopies == 1 && !slp_node);
- vect_record_loop_mask (loop_vinfo,
- &LOOP_VINFO_MASKS (loop_vinfo),
- 1, vectype, NULL);
+ if (direct_internal_fn_supported_p (IFN_EXTRACT_LAST, vectype,
+ OPTIMIZE_FOR_SPEED))
+ vect_record_loop_mask (loop_vinfo,
+ &LOOP_VINFO_MASKS (loop_vinfo),
+ 1, vectype, NULL);
+ else if (convert_optab_handler (vec_extract_optab,
+ TYPE_MODE (vectype),
+ TYPE_MODE (TREE_TYPE (vectype)))
+ != CODE_FOR_nothing)
+ vect_record_loop_len (loop_vinfo,
+ &LOOP_VINFO_LENS (loop_vinfo),
+ 1, vectype, 1);
+ else
+ {
+ if (dump_enabled_p ())
+ dump_printf_loc (
+ MSG_MISSED_OPTIMIZATION, vect_location,
+ "can't operate on partial vectors "
+ "because the target doesn't support extract "
+ "last reduction.\n");
+ LOOP_VINFO_CAN_USE_PARTIAL_VECTORS_P (loop_vinfo) = false;
+ }
}
}
/* ??? Enable for loop costing as well. */
@@ -10336,7 +10345,9 @@ vectorizable_live_operation (vec_info *vinfo,
stmt_vec_info stmt_info,
gimple *vec_stmt;
if (slp_node)
{
- gcc_assert (!loop_vinfo || !LOOP_VINFO_FULLY_MASKED_P (loop_vinfo));
+ gcc_assert (!loop_vinfo
+ || (!LOOP_VINFO_FULLY_MASKED_P (loop_vinfo)
+ && !LOOP_VINFO_FULLY_WITH_LENGTH_P (loop_vinfo)));
/* Get the correct slp vectorized stmt. */
vec_lhs = SLP_TREE_VEC_DEFS (slp_node)[vec_entry];
@@ -10380,7 +10391,42 @@ vectorizable_live_operation (vec_info *vinfo,
stmt_vec_info stmt_info,
gimple_seq stmts = NULL;
tree new_tree;
- if (LOOP_VINFO_FULLY_MASKED_P (loop_vinfo))
+ if (LOOP_VINFO_FULLY_WITH_LENGTH_P (loop_vinfo))
+ {
+ /* Emit:
+
+ SCALAR_RES = VEC_EXTRACT <VEC_LHS, LEN + BIAS - 1>
+
+ where VEC_LHS is the vectorized live-out result and MASK is
+ the loop mask for the final iteration. */
+ gcc_assert (ncopies == 1 && !slp_node);
+ gimple_seq tem = NULL;
+ gimple_stmt_iterator gsi = gsi_last (tem);
+ tree len
+ = vect_get_loop_len (loop_vinfo, &gsi,
+ &LOOP_VINFO_LENS (loop_vinfo),
+ 1, vectype, 0, 0);
+
+ /* BIAS - 1. */
+ signed char biasval = LOOP_VINFO_PARTIAL_LOAD_STORE_BIAS (loop_vinfo);
+ tree bias_minus_one
+ = int_const_binop (MINUS_EXPR,
+ build_int_cst (TREE_TYPE (len), biasval),
+ build_one_cst (TREE_TYPE (len)));
+
+ /* LAST_INDEX = LEN + (BIAS - 1). */
+ tree last_index = gimple_build (&stmts, PLUS_EXPR, TREE_TYPE (len),
+ len, bias_minus_one);
+
+ /* SCALAR_RES = VEC_EXTRACT <VEC_LHS, LEN + BIAS - 1>. */
+ tree scalar_res
+ = gimple_build (&stmts, CFN_VEC_EXTRACT, TREE_TYPE (vectype),
+ vec_lhs_phi, last_index);
+
+ /* Convert the extracted vector element to the scalar type. */
+ new_tree = gimple_convert (&stmts, lhs_type, scalar_res);
+ }
+ else if (LOOP_VINFO_FULLY_MASKED_P (loop_vinfo))
{
/* Emit:
--
2.36.3
