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* [PATCH] VECT: Add decrement IV iteration loop control by variable amount support
@ 2023-04-25 13:42 juzhe.zhong
  2023-04-25 16:58 ` Richard Sandiford
  0 siblings, 1 reply; 12+ messages in thread
From: juzhe.zhong @ 2023-04-25 13:42 UTC (permalink / raw)
  To: gcc-patches; +Cc: richard.sandiford, rguenther, Juzhe-Zhong

From: Juzhe-Zhong <juzhe.zhong@rivai.ai>

Hi, this is the most important patch for RVV auto-vectorization support.
It supports WHILE_LEN pattern to not only decrement Loop control IV counter,
but also adjust data reference address pointer by WHILE_LEN.

1. Single control loop (vec_num == 1 && ncopies == 1):
int A[1024], B[1024];
void foo(int n)
{
  for (int i = 0; i < n; i++) 
    A[i] = B[i];
}

-fno-vect-cost-model -fno-tree-loop-distribute-patterns:
Gimple IR:
  # vectp_B.6_8 = PHI <vectp_B.6_13(6), &B(5)>
  # vectp_B.8_16 = PHI <vectp_B.8_17(6), &B(5)>
  # vectp_A.11_19 = PHI <vectp_A.11_20(6), &A(5)>
  # vectp_A.13_22 = PHI <vectp_A.13_23(6), &A(5)>
  # ivtmp_26 = PHI <ivtmp_27(6), _25(5)>
  _28 = .WHILE_LEN (ivtmp_26, POLY_INT_CST [4, 4]);
  ivtmp_15 = _28 * 4;
  vect__1.10_18 = .LEN_LOAD (vectp_B.8_16, 128B, _28, 0);
  _1 = B[i_10];
  .LEN_STORE (vectp_A.13_22, 128B, _28, vect__1.10_18, 0);
  i_7 = i_10 + 1;
  vectp_B.8_17 = vectp_B.8_16 + ivtmp_15;
  vectp_A.13_23 = vectp_A.13_22 + ivtmp_15;
  ivtmp_27 = ivtmp_26 - _28;
  if (ivtmp_27 != 0)
    goto <bb 6>; [83.33%]
  else
    goto <bb 7>; [16.67%]

The WHILE_LEN:
_28 = .WHILE_LEN (ivtmp_26, POLY_INT_CST [4, 4]);

Data address pointer IVs:
ivtmp_15 = _28 * 4;
vectp_B.8_17 = vectp_B.8_16 + ivtmp_15;
vectp_A.13_23 = vectp_A.13_22 + ivtmp_15;

Loop control IVs:
ivtmp_27 = ivtmp_26 - _28;
  if (ivtmp_27 != 0)
    goto <bb 6>; [83.33%]
  else
    goto <bb 7>; [16.67%]

So, in this case, we can have non-VF elements to be processed 
in non-final iteration. 
Some target like RVV(according to vsetvli instruction in RVV ISA), 
we can allow from iteration 0 to n - 2 update VF elements, and
iteration n - 1 and n update the remain elements / 2.
Such situation will make RVV CPU even distribute workload in the last
2 iterations.

So, we define WHILE_LEN as any iteration can process any number (<=VF) elements
in any iteration.


2. Multi control loop (SLP, vec_num != 1 && ncopies != 1):
void
foo0 (int16_t *__restrict f, int32_t *__restrict d, int n)
{
  for (int i = 0; i < n; ++i)
    {
      f[i * 2 + 0] = 1;
      f[i * 2 + 1] = 2;
      d[i] = 3;
    }
}

Gimple IR:
  # i_23 = PHI <i_20(6), 0(11)>
  # vectp_f.8_51 = PHI <vectp_f.8_52(6), f_15(D)(11)>
  # vectp_d.10_59 = PHI <vectp_d.10_60(6), d_18(D)(11)>
  # ivtmp_70 = PHI <ivtmp_71(6), _69(11)>
  # ivtmp_73 = PHI <ivtmp_74(6), _67(11)>
  _72 = MIN_EXPR <ivtmp_70, 16>; Force VF elements to be processed in SLP
  _75 = MIN_EXPR <ivtmp_73, 16>;
  _1 = i_23 * 2;
  _2 = (long unsigned int) _1;
  _3 = _2 * 2;
  _4 = f_15(D) + _3;
  _5 = _2 + 1;
  _6 = _5 * 2;
  _7 = f_15(D) + _6;
  .LEN_STORE (vectp_f.8_51, 128B, _75, { 1, 2, 1, 2, 1, 2, 1, 2 }, 0);
  vectp_f.8_56 = vectp_f.8_51 + 16;
  .LEN_STORE (vectp_f.8_56, 128B, _72, { 1, 2, 1, 2, 1, 2, 1, 2 }, 0);
  _8 = (long unsigned int) i_23;
  _9 = _8 * 4;
  _10 = d_18(D) + _9;
  _61 = _75 / 2;
  .LEN_STORE (vectp_d.10_59, 128B, _61, { 3, 3, 3, 3 }, 0);
  vectp_d.10_63 = vectp_d.10_59 + 16;
  _64 = _72 / 2;
  .LEN_STORE (vectp_d.10_63, 128B, _64, { 3, 3, 3, 3 }, 0);
  i_20 = i_23 + 1;
  vectp_f.8_52 = vectp_f.8_56 + 16;
  vectp_d.10_60 = vectp_d.10_63 + 16;
  ivtmp_74 = ivtmp_73 - _75;
  ivtmp_71 = ivtmp_70 - _72;
  if (ivtmp_74 != 0)
    goto <bb 6>; [83.33%]
  else
    goto <bb 13>; [16.67%]


For SLP auto-vectorization, we don't use WHILE_LEN to do the variable adjustment
for loop control counter and data reference pointer IVs. We make them still use VF
for the IVs iterations.

Here is the reason:

.LEN_STORE (vectp_f.8_51, 128B, _75, { 1, 2, 1, 2, 1, 2, 1, 2 }, 0);
vectp_f.8_56 = vectp_f.8_51 + 16;
.LEN_STORE (vectp_f.8_56, 128B, _72, { 1, 2, 1, 2, 1, 2, 1, 2 }, 0);

The sequence listed above, we still force compiler SLP auto-vectorization using VF
elements to be processed. Since if we use WHILE_LEN to iterate IVs in SLP we will
have problems:

Since WHILE_ELN pattern allows us update any number of elements of any iteration
which is not suitable for SLP auto-vectorization:

...
_76 = WHILE_LEN (AVL)
.LEN_STORE (vectp_f.8_51, 128B, _76, { 1, 2, 1, 2, 1, 2, 1, 2 }, 0);
...
.LEN_STORE (vectp_f.8_56, 128B, _72, { 1, 2, 1, 2, 1, 2, 1, 2 }, 0);

If AVL is 6 (n * 2), and VF is 4, then if we flexible allow _76 to be 3 which is AVL / 2,
then the second store will be a problem, it can not store { 1, 2, 1, 2, 1, 2, 1, 2 },
It should store { 2, 1, 2, 1, 2, 1, 2, 1 }

gcc/ChangeLog:

        * doc/md.texi: Add WHILE_LEN pattern support.
        * internal-fn.cc (while_len_direct): New function.
        (expand_while_len_optab_fn): Ditto.
        (direct_while_len_optab_supported_p): Ditto.
        * internal-fn.def (WHILE_LEN): New pattern.
        * optabs.def (OPTAB_D): New pattern.
        * tree-ssa-loop-manip.cc (create_iv): Add decrement IV support.
        * tree-ssa-loop-manip.h (create_iv): Ditto.
        * tree-vect-loop-manip.cc (vect_set_loop_controls_by_while_len): New function.
        (vect_set_loop_condition_partial_vectors): Add WHILE_LEN support.
        * tree-vect-loop.cc (vect_get_loop_len): Ditto.
        * tree-vect-stmts.cc (get_while_len_data_ref_ptr): New function.
        (vectorizable_store): Adjust data pointer by WHILE_LEN.
        (vectorizable_load): Ditto.
        * tree-vectorizer.h (vect_get_loop_len): Adjust for SLP vectorizer.

---
 gcc/doc/md.texi             |  34 ++++++
 gcc/internal-fn.cc          |  29 +++++
 gcc/internal-fn.def         |   1 +
 gcc/optabs.def              |   1 +
 gcc/tree-ssa-loop-manip.cc  |   4 +-
 gcc/tree-ssa-loop-manip.h   |   2 +-
 gcc/tree-vect-loop-manip.cc | 223 +++++++++++++++++++++++++++++++++++-
 gcc/tree-vect-loop.cc       |  27 ++++-
 gcc/tree-vect-stmts.cc      |  91 ++++++++++++++-
 gcc/tree-vectorizer.h       |   4 +-
 10 files changed, 399 insertions(+), 17 deletions(-)

diff --git a/gcc/doc/md.texi b/gcc/doc/md.texi
index 07bf8bdebff..307d3c407d8 100644
--- a/gcc/doc/md.texi
+++ b/gcc/doc/md.texi
@@ -4965,6 +4965,40 @@ for (i = 1; i < operand3; i++)
   operand0[i] = operand0[i - 1] && (operand1 + i < operand2);
 @end smallexample
 
+@cindex @code{while_len@var{m}@var{n}} instruction pattern
+@item @code{while_len@var{m}@var{n}}
+Set operand 0 to the number of active elements in vector will be updated value.
+operand 1 is the total elements need to be updated value.
+operand 2 is the vectorization factor.
+The value of operand 0 is target dependent and flexible in each iteration.
+The operation of this pattern can be:
+
+@smallexample
+Case 1:
+operand0 = MIN (operand1, operand2);
+operand2 can be const_poly_int or poly_int related to vector mode size.
+Some target like RISC-V has a standalone instruction to get MIN (n, MODE SIZE) so
+that we can reduce a use of general purpose register.
+
+In this case, only the last iteration of the loop is partial iteration.
+@end smallexample
+
+@smallexample
+Case 2:
+if (operand1 <= operand2)
+  operand0 = operand1;
+else if (operand1 < 2 * operand2)
+  operand0 = IN_RANGE (ceil (operand1 / 2), operand2);
+else
+  operand0 = operand2;
+
+This case will evenly distribute work over the last 2 iterations of a stripmine loop.
+@end smallexample
+
+The output of this pattern is not only used as IV of loop control counter, but also
+is used as the IV of address calculation with multiply/shift operation. This allow
+us dynamic adjust the number of elements is processed in each iteration of the loop.
+
 @cindex @code{check_raw_ptrs@var{m}} instruction pattern
 @item @samp{check_raw_ptrs@var{m}}
 Check whether, given two pointers @var{a} and @var{b} and a length @var{len},
diff --git a/gcc/internal-fn.cc b/gcc/internal-fn.cc
index 6e81dc05e0e..5f44def90d3 100644
--- a/gcc/internal-fn.cc
+++ b/gcc/internal-fn.cc
@@ -127,6 +127,7 @@ init_internal_fns ()
 #define cond_binary_direct { 1, 1, true }
 #define cond_ternary_direct { 1, 1, true }
 #define while_direct { 0, 2, false }
+#define while_len_direct { 0, 0, false }
 #define fold_extract_direct { 2, 2, false }
 #define fold_left_direct { 1, 1, false }
 #define mask_fold_left_direct { 1, 1, false }
@@ -3702,6 +3703,33 @@ expand_while_optab_fn (internal_fn, gcall *stmt, convert_optab optab)
     emit_move_insn (lhs_rtx, ops[0].value);
 }
 
+/* Expand WHILE_LEN call STMT using optab OPTAB.  */
+static void
+expand_while_len_optab_fn (internal_fn, gcall *stmt, convert_optab optab)
+{
+  expand_operand ops[3];
+  tree rhs_type[2];
+
+  tree lhs = gimple_call_lhs (stmt);
+  tree lhs_type = TREE_TYPE (lhs);
+  rtx lhs_rtx = expand_expr (lhs, NULL_RTX, VOIDmode, EXPAND_WRITE);
+  create_output_operand (&ops[0], lhs_rtx, TYPE_MODE (lhs_type));
+
+  for (unsigned int i = 0; i < gimple_call_num_args (stmt); ++i)
+    {
+      tree rhs = gimple_call_arg (stmt, i);
+      rhs_type[i] = TREE_TYPE (rhs);
+      rtx rhs_rtx = expand_normal (rhs);
+      create_input_operand (&ops[i + 1], rhs_rtx, TYPE_MODE (rhs_type[i]));
+    }
+
+  insn_code icode = direct_optab_handler (optab, TYPE_MODE (rhs_type[0]));
+
+  expand_insn (icode, 3, ops);
+  if (!rtx_equal_p (lhs_rtx, ops[0].value))
+    emit_move_insn (lhs_rtx, ops[0].value);
+}
+
 /* Expand a call to a convert-like optab using the operands in STMT.
    FN has a single output operand and NARGS input operands.  */
 
@@ -3843,6 +3871,7 @@ multi_vector_optab_supported_p (convert_optab optab, tree_pair types,
 #define direct_scatter_store_optab_supported_p convert_optab_supported_p
 #define direct_len_store_optab_supported_p direct_optab_supported_p
 #define direct_while_optab_supported_p convert_optab_supported_p
+#define direct_while_len_optab_supported_p direct_optab_supported_p
 #define direct_fold_extract_optab_supported_p direct_optab_supported_p
 #define direct_fold_left_optab_supported_p direct_optab_supported_p
 #define direct_mask_fold_left_optab_supported_p direct_optab_supported_p
diff --git a/gcc/internal-fn.def b/gcc/internal-fn.def
index 7fe742c2ae7..3a933abff5d 100644
--- a/gcc/internal-fn.def
+++ b/gcc/internal-fn.def
@@ -153,6 +153,7 @@ DEF_INTERNAL_OPTAB_FN (VEC_SET, 0, vec_set, vec_set)
 DEF_INTERNAL_OPTAB_FN (LEN_STORE, 0, len_store, len_store)
 
 DEF_INTERNAL_OPTAB_FN (WHILE_ULT, ECF_CONST | ECF_NOTHROW, while_ult, while)
+DEF_INTERNAL_OPTAB_FN (WHILE_LEN, ECF_CONST | ECF_NOTHROW, while_len, while_len)
 DEF_INTERNAL_OPTAB_FN (CHECK_RAW_PTRS, ECF_CONST | ECF_NOTHROW,
 		       check_raw_ptrs, check_ptrs)
 DEF_INTERNAL_OPTAB_FN (CHECK_WAR_PTRS, ECF_CONST | ECF_NOTHROW,
diff --git a/gcc/optabs.def b/gcc/optabs.def
index 695f5911b30..f5938bd2c24 100644
--- a/gcc/optabs.def
+++ b/gcc/optabs.def
@@ -476,3 +476,4 @@ OPTAB_DC (vec_series_optab, "vec_series$a", VEC_SERIES)
 OPTAB_D (vec_shl_insert_optab, "vec_shl_insert_$a")
 OPTAB_D (len_load_optab, "len_load_$a")
 OPTAB_D (len_store_optab, "len_store_$a")
+OPTAB_D (while_len_optab, "while_len$a")
diff --git a/gcc/tree-ssa-loop-manip.cc b/gcc/tree-ssa-loop-manip.cc
index a52277abdbf..54845a62298 100644
--- a/gcc/tree-ssa-loop-manip.cc
+++ b/gcc/tree-ssa-loop-manip.cc
@@ -59,14 +59,14 @@ static bitmap_obstack loop_renamer_obstack;
 void
 create_iv (tree base, tree step, tree var, class loop *loop,
 	   gimple_stmt_iterator *incr_pos, bool after,
-	   tree *var_before, tree *var_after)
+	   tree *var_before, tree *var_after, enum tree_code code)
 {
   gassign *stmt;
   gphi *phi;
   tree initial, step1;
   gimple_seq stmts;
   tree vb, va;
-  enum tree_code incr_op = PLUS_EXPR;
+  enum tree_code incr_op = code;
   edge pe = loop_preheader_edge (loop);
 
   if (var != NULL_TREE)
diff --git a/gcc/tree-ssa-loop-manip.h b/gcc/tree-ssa-loop-manip.h
index d49273a3987..da755320a3a 100644
--- a/gcc/tree-ssa-loop-manip.h
+++ b/gcc/tree-ssa-loop-manip.h
@@ -23,7 +23,7 @@ along with GCC; see the file COPYING3.  If not see
 typedef void (*transform_callback)(class loop *, void *);
 
 extern void create_iv (tree, tree, tree, class loop *, gimple_stmt_iterator *,
-		       bool, tree *, tree *);
+		       bool, tree *, tree *, enum tree_code = PLUS_EXPR);
 extern void rewrite_into_loop_closed_ssa (bitmap, unsigned);
 extern void verify_loop_closed_ssa (bool, class loop * = NULL);
 
diff --git a/gcc/tree-vect-loop-manip.cc b/gcc/tree-vect-loop-manip.cc
index f60fa50e8f4..a1c892f285a 100644
--- a/gcc/tree-vect-loop-manip.cc
+++ b/gcc/tree-vect-loop-manip.cc
@@ -682,6 +682,210 @@ vect_set_loop_controls_directly (class loop *loop, loop_vec_info loop_vinfo,
   return next_ctrl;
 }
 
+/* Helper for vect_set_loop_condition_partial_vectors.  Generate definitions
+   for all the rgroup controls in RGC and return a control that is nonzero
+   when the loop needs to iterate.  Add any new preheader statements to
+   PREHEADER_SEQ.  Use LOOP_COND_GSI to insert code before the exit gcond.
+
+   RGC belongs to loop LOOP.  The loop originally iterated NITERS
+   times and has been vectorized according to LOOP_VINFO.
+
+   Unlike vect_set_loop_controls_directly which is iterating from 0-based IV
+   to TEST_LIMIT - bias.
+
+   In vect_set_loop_controls_by_while_len, we are iterating from start at
+   IV = TEST_LIMIT - bias and keep subtract IV by the length calculated by
+   IFN_WHILE_LEN pattern.
+
+   Note: the cost of the code generated by this function is modeled
+   by vect_estimate_min_profitable_iters, so changes here may need
+   corresponding changes there.
+
+   1. Single rgroup, the Gimple IR should be:
+
+	<bb 3>
+	_19 = (unsigned long) n_5(D);
+	...
+
+	<bb 4>:
+	...
+	# ivtmp_20 = PHI <ivtmp_21(4), _19(3)>
+	...
+	_22 = .WHILE_LEN (ivtmp_20, vf);
+	...
+	vector statement (use _22);
+	...
+	ivtmp_21 = ivtmp_20 - _22;
+	...
+	if (ivtmp_21 != 0)
+	  goto <bb 4>; [75.00%]
+	else
+	  goto <bb 5>; [25.00%]
+
+	<bb 5>
+	return;
+
+   Note: IFN_WHILE_LEN will guarantee "ivtmp_21 = ivtmp_20 - _22" never
+   underflow 0.
+
+   2. Multiple rgroup, the Gimple IR should be:
+
+	<bb 3>
+	_70 = (unsigned long) bnd.7_52;
+	_71 = _70 * 2;
+	_72 = MAX_EXPR <_71, 4>;
+	_73 = _72 + 18446744073709551612;
+	...
+
+	<bb 4>:
+	...
+	# ivtmp_74 = PHI <ivtmp_75(6), _73(12)>
+	# ivtmp_77 = PHI <ivtmp_78(6), _71(12)>
+	_76 = .WHILE_LEN (ivtmp_74, vf * nitems_per_ctrl);
+	_79 = .WHILE_LEN (ivtmp_77, vf * nitems_per_ctrl);
+	...
+	vector statement (use _79);
+	...
+	vector statement (use _76);
+	...
+	_65 = _79 / 2;
+	vector statement (use _65);
+	...
+	_68 = _76 / 2;
+	vector statement (use _68);
+	...
+	ivtmp_78 = ivtmp_77 - _79;
+	ivtmp_75 = ivtmp_74 - _76;
+	...
+	if (ivtmp_78 != 0)
+	  goto <bb 4>; [75.00%]
+	else
+	  goto <bb 5>; [25.00%]
+
+	<bb 5>
+	return;
+
+*/
+
+static tree
+vect_set_loop_controls_by_while_len (class loop *loop, loop_vec_info loop_vinfo,
+				     gimple_seq *preheader_seq,
+				     gimple_seq *header_seq,
+				     rgroup_controls *rgc, tree niters)
+{
+  tree compare_type = LOOP_VINFO_RGROUP_COMPARE_TYPE (loop_vinfo);
+  tree iv_type = LOOP_VINFO_RGROUP_IV_TYPE (loop_vinfo);
+  /* We are not allowing masked approach in WHILE_LEN.  */
+  gcc_assert (!LOOP_VINFO_FULLY_MASKED_P (loop_vinfo));
+
+  tree ctrl_type = rgc->type;
+  unsigned int nitems_per_iter = rgc->max_nscalars_per_iter * rgc->factor;
+  poly_uint64 nitems_per_ctrl = TYPE_VECTOR_SUBPARTS (ctrl_type) * rgc->factor;
+  poly_uint64 vf = LOOP_VINFO_VECT_FACTOR (loop_vinfo);
+
+  /* Calculate the maximum number of item values that the rgroup
+     handles in total, the number that it handles for each iteration
+     of the vector loop.  */
+  tree nitems_total = niters;
+  if (nitems_per_iter != 1)
+    {
+      /* We checked before setting LOOP_VINFO_USING_PARTIAL_VECTORS_P that
+	 these multiplications don't overflow.  */
+      tree compare_factor = build_int_cst (compare_type, nitems_per_iter);
+      nitems_total = gimple_build (preheader_seq, MULT_EXPR, compare_type,
+				   nitems_total, compare_factor);
+    }
+
+  /* Convert the comparison value to the IV type (either a no-op or
+     a promotion).  */
+  nitems_total = gimple_convert (preheader_seq, iv_type, nitems_total);
+
+  /* Create an induction variable that counts the number of items
+     processed.  */
+  tree index_before_incr, index_after_incr;
+  gimple_stmt_iterator incr_gsi;
+  bool insert_after;
+  standard_iv_increment_position (loop, &incr_gsi, &insert_after);
+
+  /* Test the decremented IV, which will never underflow 0 since we have
+     IFN_WHILE_LEN to gurantee that.  */
+  tree test_limit = nitems_total;
+
+  /* Provide a definition of each control in the group.  */
+  tree ctrl;
+  unsigned int i;
+  FOR_EACH_VEC_ELT_REVERSE (rgc->controls, i, ctrl)
+    {
+      /* Previous controls will cover BIAS items.  This control covers the
+	 next batch.  */
+      poly_uint64 bias = nitems_per_ctrl * i;
+      tree bias_tree = build_int_cst (iv_type, bias);
+
+      /* Rather than have a new IV that starts at TEST_LIMIT and goes down to
+	 BIAS, prefer to use the same TEST_LIMIT - BIAS based IV for each
+	 control and adjust the bound down by BIAS.  */
+      tree this_test_limit = test_limit;
+      if (i != 0)
+	{
+	  this_test_limit = gimple_build (preheader_seq, MAX_EXPR, iv_type,
+					  this_test_limit, bias_tree);
+	  this_test_limit = gimple_build (preheader_seq, MINUS_EXPR, iv_type,
+					  this_test_limit, bias_tree);
+	}
+
+      /* Create decrement IV.  */
+      create_iv (this_test_limit, ctrl, NULL_TREE, loop, &incr_gsi,
+		 insert_after, &index_before_incr, &index_after_incr,
+		 MINUS_EXPR);
+
+      poly_uint64 final_vf = vf * nitems_per_iter;
+      tree vf_step = build_int_cst (iv_type, final_vf);
+      tree res_len;
+      if (nitems_per_iter != 1)
+	{
+	  /* For SLP, we can't allow non-VF number of elements to be processed
+	     in non-final iteration. We force the number of elements to be
+	   processed in each non-final iteration is VF elements. If we allow
+	   non-VF elements processing in non-final iteration will make SLP too
+	   complicated and produce inferior codegen.
+
+	       For example:
+
+		If non-final iteration process VF elements.
+
+		  ...
+		  .LEN_STORE (vectp_f.8_51, 128B, _71, { 1, 2, 1, 2 }, 0);
+		  .LEN_STORE (vectp_f.8_56, 128B, _72, { 1, 2, 1, 2 }, 0);
+		  ...
+
+		If non-final iteration process non-VF elements.
+
+		  ...
+		  .LEN_STORE (vectp_f.8_51, 128B, _71, { 1, 2, 1, 2 }, 0);
+		  if (_71 % 2 == 0)
+		   .LEN_STORE (vectp_f.8_56, 128B, _72, { 1, 2, 1, 2 }, 0);
+		  else
+		   .LEN_STORE (vectp_f.8_56, 128B, _72, { 2, 1, 2, 1 }, 0);
+		  ...
+
+	   This is the simple case of 2-elements interleaved vector SLP. We
+	   consider other interleave vector, the situation will become more
+	   complicated.  */
+	  res_len = gimple_build (header_seq, MIN_EXPR, iv_type,
+				  index_before_incr, vf_step);
+	}
+      else
+	{
+	  res_len = gimple_build (header_seq, IFN_WHILE_LEN, iv_type,
+				  index_before_incr, vf_step);
+	}
+      gassign *assign = gimple_build_assign (ctrl, res_len);
+      gimple_seq_add_stmt (header_seq, assign);
+    }
+
+  return index_after_incr;
+}
+
 /* Set up the iteration condition and rgroup controls for LOOP, given
    that LOOP_VINFO_USING_PARTIAL_VECTORS_P is true for the vectorized
    loop.  LOOP_VINFO describes the vectorization of LOOP.  NITERS is
@@ -703,6 +907,7 @@ vect_set_loop_condition_partial_vectors (class loop *loop,
 
   bool use_masks_p = LOOP_VINFO_FULLY_MASKED_P (loop_vinfo);
   tree compare_type = LOOP_VINFO_RGROUP_COMPARE_TYPE (loop_vinfo);
+  tree iv_type = LOOP_VINFO_RGROUP_IV_TYPE (loop_vinfo);
   unsigned int compare_precision = TYPE_PRECISION (compare_type);
   tree orig_niters = niters;
 
@@ -757,12 +962,18 @@ vect_set_loop_condition_partial_vectors (class loop *loop,
 	bool might_wrap_p = vect_rgroup_iv_might_wrap_p (loop_vinfo, rgc);
 
 	/* Set up all controls for this group.  */
-	test_ctrl = vect_set_loop_controls_directly (loop, loop_vinfo,
-						     &preheader_seq,
-						     &header_seq,
-						     loop_cond_gsi, rgc,
-						     niters, niters_skip,
-						     might_wrap_p);
+	if (direct_internal_fn_supported_p (IFN_WHILE_LEN, iv_type,
+					    OPTIMIZE_FOR_SPEED))
+	  test_ctrl
+	    = vect_set_loop_controls_by_while_len (loop, loop_vinfo,
+						   &preheader_seq, &header_seq,
+						   rgc, niters);
+	else
+	  test_ctrl
+	    = vect_set_loop_controls_directly (loop, loop_vinfo, &preheader_seq,
+					       &header_seq, loop_cond_gsi, rgc,
+					       niters, niters_skip,
+					       might_wrap_p);
       }
 
   /* Emit all accumulated statements.  */
diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
index 6ea0f21fd13..c44b91bface 100644
--- a/gcc/tree-vect-loop.cc
+++ b/gcc/tree-vect-loop.cc
@@ -10364,12 +10364,14 @@ vect_record_loop_len (loop_vec_info loop_vinfo, vec_loop_lens *lens,
    rgroup that operates on NVECTORS vectors, where 0 <= INDEX < NVECTORS.  */
 
 tree
-vect_get_loop_len (loop_vec_info loop_vinfo, vec_loop_lens *lens,
-		   unsigned int nvectors, unsigned int index)
+vect_get_loop_len (gimple_stmt_iterator *gsi, loop_vec_info loop_vinfo,
+		   vec_loop_lens *lens, unsigned int nvectors, tree vectype,
+		   unsigned int index)
 {
   rgroup_controls *rgl = &(*lens)[nvectors - 1];
   bool use_bias_adjusted_len =
     LOOP_VINFO_PARTIAL_LOAD_STORE_BIAS (loop_vinfo) != 0;
+  tree iv_type = LOOP_VINFO_RGROUP_IV_TYPE (loop_vinfo);
 
   /* Populate the rgroup's len array, if this is the first time we've
      used it.  */
@@ -10400,6 +10402,27 @@ vect_get_loop_len (loop_vec_info loop_vinfo, vec_loop_lens *lens,
 
   if (use_bias_adjusted_len)
     return rgl->bias_adjusted_ctrl;
+  else if (direct_internal_fn_supported_p (IFN_WHILE_LEN, iv_type,
+					   OPTIMIZE_FOR_SPEED))
+    {
+      tree loop_len = rgl->controls[index];
+      poly_int64 nunits1 = TYPE_VECTOR_SUBPARTS (rgl->type);
+      poly_int64 nunits2 = TYPE_VECTOR_SUBPARTS (vectype);
+      if (maybe_ne (nunits1, nunits2))
+	{
+	  /* A loop len for data type X can be reused for data type Y
+	     if X has N times more elements than Y and if Y's elements
+	     are N times bigger than X's.  */
+	  gcc_assert (multiple_p (nunits1, nunits2));
+	  unsigned int factor = exact_div (nunits1, nunits2).to_constant ();
+	  gimple_seq seq = NULL;
+	  loop_len = gimple_build (&seq, RDIV_EXPR, iv_type, loop_len,
+				   build_int_cst (iv_type, factor));
+	  if (seq)
+	    gsi_insert_seq_before (gsi, seq, GSI_SAME_STMT);
+	}
+      return loop_len;
+    }
   else
     return rgl->controls[index];
 }
diff --git a/gcc/tree-vect-stmts.cc b/gcc/tree-vect-stmts.cc
index 6b7dbfd4a23..0b2fb8eef0a 100644
--- a/gcc/tree-vect-stmts.cc
+++ b/gcc/tree-vect-stmts.cc
@@ -3144,6 +3144,70 @@ vect_get_data_ptr_increment (vec_info *vinfo,
   return iv_step;
 }
 
+/* Prepare the pointer IVs which needs to be updated by a variable amount.
+   Such variable amount is the outcome of .WHILE_LEN. In this case, we can
+   allow each iteration process the flexible number of elements as long as
+   the number <= vf elments.
+
+   Return data reference according to WHILE_LEN.
+   If new statements are needed, insert them before GSI.  */
+
+static tree
+get_while_len_data_ref_ptr (vec_info *vinfo, stmt_vec_info stmt_info,
+			    tree aggr_type, class loop *at_loop, tree offset,
+			    tree *dummy, gimple_stmt_iterator *gsi,
+			    bool simd_lane_access_p, vec_loop_lens *loop_lens,
+			    dr_vec_info *dr_info,
+			    vect_memory_access_type memory_access_type)
+{
+  if (!loop_lens || loop_lens->length () != 1)
+    return NULL_TREE;
+  loop_vec_info loop_vinfo = dyn_cast<loop_vec_info> (vinfo);
+  tree iv_type = LOOP_VINFO_RGROUP_IV_TYPE (loop_vinfo);
+  tree step = vect_dr_behavior (vinfo, dr_info)->step;
+  if (!direct_internal_fn_supported_p (IFN_WHILE_LEN, iv_type,
+				       OPTIMIZE_FOR_SPEED))
+    return NULL_TREE;
+
+  if (memory_access_type == VMAT_INVARIANT)
+    return NULL_TREE;
+
+  /* TODO: We don't support gather/scatter or load_lanes/store_lanes for pointer
+     IVs are updated by variable amount but we will support them in the future.
+   */
+  gcc_assert (memory_access_type != VMAT_GATHER_SCATTER
+	      && memory_access_type != VMAT_LOAD_STORE_LANES);
+
+  /* When we support WHILE_LEN pattern, we dynamic adjust
+     the memory address by .WHILE_LEN result.
+
+     The result of .WHILE_LEN is the number of elements to
+     be processed of each iteration. So the memory address
+     adjustment operation should be:
+
+     bytesize = GET_MODE_SIZE (element_mode (aggr_type));
+     addr = addr + .WHILE_LEN (ARG..) * bytesize;
+  */
+  gimple *ptr_incr;
+  tree loop_len
+    = vect_get_loop_len (gsi, loop_vinfo, loop_lens, 1, aggr_type, 0);
+  tree len_type = TREE_TYPE (loop_len);
+  poly_uint64 bytesize = GET_MODE_SIZE (element_mode (aggr_type));
+  /* Since the outcome of .WHILE_LEN is element size, we should adjust
+     it into bytesize so that it can be used in address pointer variable
+     amount IVs adjustment.  */
+  tree tmp = fold_build2 (MULT_EXPR, len_type, loop_len,
+			  build_int_cst (len_type, bytesize));
+  if (tree_int_cst_sgn (step) == -1)
+    tmp = fold_build1 (NEGATE_EXPR, len_type, tmp);
+  tree bump = make_temp_ssa_name (len_type, NULL, "ivtmp");
+  gassign *assign = gimple_build_assign (bump, tmp);
+  gsi_insert_before (gsi, assign, GSI_SAME_STMT);
+  return vect_create_data_ref_ptr (vinfo, stmt_info, aggr_type, at_loop, offset,
+				   dummy, gsi, &ptr_incr, simd_lane_access_p,
+				   bump);
+}
+
 /* Check and perform vectorization of BUILT_IN_BSWAP{16,32,64,128}.  */
 
 static bool
@@ -8465,6 +8529,15 @@ vectorizable_store (vec_info *vinfo,
 					  simd_lane_access_p ? loop : NULL,
 					  offset, &dummy, gsi, &ptr_incr,
 					  simd_lane_access_p, bump);
+
+	  tree while_len_data_ref_ptr
+	    = get_while_len_data_ref_ptr (vinfo, stmt_info, aggr_type,
+					  simd_lane_access_p ? loop : NULL,
+					  offset, &dummy, gsi,
+					  simd_lane_access_p, loop_lens,
+					  dr_info, memory_access_type);
+	  if (while_len_data_ref_ptr)
+	    dataref_ptr = while_len_data_ref_ptr;
 	}
       else
 	{
@@ -8652,8 +8725,9 @@ vectorizable_store (vec_info *vinfo,
 	      else if (loop_lens)
 		{
 		  tree final_len
-		    = vect_get_loop_len (loop_vinfo, loop_lens,
-					 vec_num * ncopies, vec_num * j + i);
+		    = vect_get_loop_len (gsi, loop_vinfo, loop_lens,
+					 vec_num * ncopies, vectype,
+					 vec_num * j + i);
 		  tree ptr = build_int_cst (ref_type, align * BITS_PER_UNIT);
 		  machine_mode vmode = TYPE_MODE (vectype);
 		  opt_machine_mode new_ovmode
@@ -9798,6 +9872,15 @@ vectorizable_load (vec_info *vinfo,
 					  at_loop,
 					  offset, &dummy, gsi, &ptr_incr,
 					  simd_lane_access_p, bump);
+
+	  tree while_len_data_ref_ptr
+	    = get_while_len_data_ref_ptr (vinfo, stmt_info, aggr_type, at_loop,
+					  offset, &dummy, gsi,
+					  simd_lane_access_p, loop_lens,
+					  dr_info, memory_access_type);
+	  if (while_len_data_ref_ptr)
+	    dataref_ptr = while_len_data_ref_ptr;
+
 	  if (mask)
 	    vec_mask = vec_masks[0];
 	}
@@ -10008,8 +10091,8 @@ vectorizable_load (vec_info *vinfo,
 		    else if (loop_lens && memory_access_type != VMAT_INVARIANT)
 		      {
 			tree final_len
-			  = vect_get_loop_len (loop_vinfo, loop_lens,
-					       vec_num * ncopies,
+			  = vect_get_loop_len (gsi, loop_vinfo, loop_lens,
+					       vec_num * ncopies, vectype,
 					       vec_num * j + i);
 			tree ptr = build_int_cst (ref_type,
 						  align * BITS_PER_UNIT);
diff --git a/gcc/tree-vectorizer.h b/gcc/tree-vectorizer.h
index 9cf2fb23fe3..811c17e1d3d 100644
--- a/gcc/tree-vectorizer.h
+++ b/gcc/tree-vectorizer.h
@@ -2293,8 +2293,8 @@ extern tree vect_get_loop_mask (gimple_stmt_iterator *, vec_loop_masks *,
 				unsigned int, tree, unsigned int);
 extern void vect_record_loop_len (loop_vec_info, vec_loop_lens *, unsigned int,
 				  tree, unsigned int);
-extern tree vect_get_loop_len (loop_vec_info, vec_loop_lens *, unsigned int,
-			       unsigned int);
+extern tree vect_get_loop_len (gimple_stmt_iterator *, loop_vec_info, vec_loop_lens *,
+			       unsigned int, tree, unsigned int);
 extern gimple_seq vect_gen_len (tree, tree, tree, tree);
 extern stmt_vec_info info_for_reduction (vec_info *, stmt_vec_info);
 extern bool reduction_fn_for_scalar_code (code_helper, internal_fn *);
-- 
2.36.1


^ permalink raw reply	[flat|nested] 12+ messages in thread
end of thread, other threads:[~2023-04-26 11:49 UTC | newest]

Thread overview: 12+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-04-25 13:42 [PATCH] VECT: Add decrement IV iteration loop control by variable amount support juzhe.zhong
2023-04-25 16:58 ` Richard Sandiford
2023-04-25 18:30   ` Bernhard Reutner-Fischer
2023-04-26  4:15   ` juzhe.zhong
2023-04-26  8:06     ` Richard Sandiford
2023-04-26  8:55       ` juzhe.zhong
2023-04-26  9:06         ` Richard Sandiford
2023-04-26 10:03           ` juzhe.zhong
2023-04-26 11:49             ` Richard Sandiford
     [not found]       ` <20230426165504066654201@rivai.ai>
2023-04-26  9:05         ` juzhe.zhong
2023-04-26  7:43   ` Richard Biener
2023-04-26  7:46     ` Richard Sandiford

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