[PATCH v2 1/2] IFN: Implement IFN_VEC_SET for ARRAY_REF with VIEW_CONVERT_EXPR

[Xiong Hu Luo <luoxhu@linux.ibm.com>]

This patch enables transformation from ARRAY_REF(VIEW_CONVERT_EXPR) to
VEC_SET internal function in gimple-isel pass if target supports
vec_set with variable index by checking can_vec_set_var_idx_p.

gcc/ChangeLog:

2020-09-18  Xionghu Luo  <luoxhu@linux.ibm.com>

	* gimple-isel.cc (gimple_expand_vec_set_expr): New function.
	(gimple_expand_vec_cond_exprs): Call gimple_expand_vec_set_expr.
	* internal-fn.c (vec_set_direct): New define.
	(expand_vec_set_optab_fn): New function.
	(direct_vec_set_optab_supported_p): New define.
	* internal-fn.def (VEC_SET): New DEF_INTERNAL_OPTAB_FN.
	* optabs.c (can_vec_set_var_idx_p): New function.
	* optabs.h (can_vec_set_var_idx_p): New declare.
---
 gcc/gimple-isel.cc  | 116 +++++++++++++++++++++++++++++++++++++++++++-
 gcc/internal-fn.c   |  36 ++++++++++++++
 gcc/internal-fn.def |   2 +
 gcc/optabs.c        |  17 +++++++
 gcc/optabs.h        |   3 ++
 5 files changed, 172 insertions(+), 2 deletions(-)

diff --git a/gcc/gimple-isel.cc b/gcc/gimple-isel.cc
index b330cf4c20e..bc61e2895be 100644
--- a/gcc/gimple-isel.cc
+++ b/gcc/gimple-isel.cc
@@ -35,6 +35,80 @@ along with GCC; see the file COPYING3.  If not see
 #include "tree-cfg.h"
 #include "bitmap.h"
 #include "tree-ssa-dce.h"
+#include "fold-const.h"
+#include "gimple-fold.h"
+#include "memmodel.h"
+#include "optabs.h"
+
+/* Expand all ARRAY_REF(VIEW_CONVERT_EXPR) gimple assignments into calls to
+   internal function based on vector type of selected expansion.
+   i.e.:
+     VIEW_CONVERT_EXPR<int[4]>(u)[_1] =  = i_4(D);
+   =>
+     _7 = u;
+     _8 = .VEC_SET (_7, i_4(D), _1);
+     u = _8;  */
+
+static gimple *
+gimple_expand_vec_set_expr (gimple_stmt_iterator *gsi)
+{
+  enum tree_code code;
+  gcall *new_stmt = NULL;
+  gassign *ass_stmt = NULL;
+
+  /* Only consider code == GIMPLE_ASSIGN.  */
+  gassign *stmt = dyn_cast<gassign *> (gsi_stmt (*gsi));
+  if (!stmt)
+    return NULL;
+
+  code = TREE_CODE (gimple_assign_lhs (stmt));
+  if (code != ARRAY_REF)
+    return NULL;
+
+  tree lhs = gimple_assign_lhs (stmt);
+  tree val = gimple_assign_rhs1 (stmt);
+
+  tree type = TREE_TYPE (lhs);
+  tree op0 = TREE_OPERAND (lhs, 0);
+  if (TREE_CODE (op0) == VIEW_CONVERT_EXPR
+      && tree_fits_uhwi_p (TYPE_SIZE (type)))
+    {
+      tree pos = TREE_OPERAND (lhs, 1);
+      tree view_op0 = TREE_OPERAND (op0, 0);
+      machine_mode outermode = TYPE_MODE (TREE_TYPE (view_op0));
+      scalar_mode innermode = GET_MODE_INNER (outermode);
+      tree_code code = TREE_CODE (TREE_TYPE(view_op0));
+      if (!is_global_var (view_op0) && code == VECTOR_TYPE
+	  && tree_fits_uhwi_p (TYPE_SIZE (TREE_TYPE (view_op0)))
+	  && can_vec_set_var_idx_p (code, outermode, innermode,
+				    TYPE_MODE (TREE_TYPE (pos))))
+	{
+	  location_t loc = gimple_location (stmt);
+	  tree var_src = make_ssa_name (TREE_TYPE (view_op0));
+	  tree var_dst = make_ssa_name (TREE_TYPE (view_op0));
+
+	  ass_stmt = gimple_build_assign (var_src, view_op0);
+	  gimple_set_vuse (ass_stmt, gimple_vuse (stmt));
+	  gimple_set_location (ass_stmt, loc);
+	  gsi_insert_before (gsi, ass_stmt, GSI_SAME_STMT);
+
+	  new_stmt
+	    = gimple_build_call_internal (IFN_VEC_SET, 3, var_src, val, pos);
+	  gimple_call_set_lhs (new_stmt, var_dst);
+	  gimple_set_location (new_stmt, loc);
+	  gsi_insert_before (gsi, new_stmt, GSI_SAME_STMT);
+
+	  ass_stmt = gimple_build_assign (view_op0, var_dst);
+	  gimple_set_location (ass_stmt, loc);
+	  gsi_insert_before (gsi, ass_stmt, GSI_SAME_STMT);
+
+	  gimple_move_vops (ass_stmt, stmt);
+	  gsi_remove (gsi, true);
+	}
+    }
+
+  return ass_stmt;
+}
 
 /* Expand all VEC_COND_EXPR gimple assignments into calls to internal
    function based on type of selected expansion.  */
@@ -187,8 +261,25 @@ gimple_expand_vec_cond_exprs (void)
     {
       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 	{
-	  gimple *g = gimple_expand_vec_cond_expr (&gsi,
-						   &vec_cond_ssa_name_uses);
+	  gassign *stmt = dyn_cast<gassign *> (gsi_stmt (gsi));
+	  if (!stmt)
+	    continue;
+
+	  enum tree_code code;
+	  gimple *g = NULL;
+	  code = gimple_assign_rhs_code (stmt);
+	  switch (code)
+	    {
+	    case VEC_COND_EXPR:
+	      g = gimple_expand_vec_cond_expr (&gsi, &vec_cond_ssa_name_uses);
+	      break;
+	    case ARRAY_REF:
+	      /*  TODO: generate IFN for vec_extract with variable index.  */
+	      break;
+	    default:
+	      break;
+	    }
+
 	  if (g != NULL)
 	    {
 	      tree lhs = gimple_assign_lhs (gsi_stmt (gsi));
@@ -204,6 +295,27 @@ gimple_expand_vec_cond_exprs (void)
 
   simple_dce_from_worklist (dce_ssa_names);
 
+  FOR_EACH_BB_FN (bb, cfun)
+    {
+      for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+	{
+	  gassign *stmt = dyn_cast<gassign *> (gsi_stmt (gsi));
+	  if (!stmt)
+	    continue;
+
+	  enum tree_code code;
+	  code = TREE_CODE (gimple_assign_lhs (stmt));
+	  switch (code)
+	    {
+	    case ARRAY_REF:
+	      gimple_expand_vec_set_expr (&gsi);
+	      break;
+	    default:
+	      break;
+	    }
+	}
+    }
+
   return 0;
 }
 
diff --git a/gcc/internal-fn.c b/gcc/internal-fn.c
index 8efc77d986b..36837381c04 100644
--- a/gcc/internal-fn.c
+++ b/gcc/internal-fn.c
@@ -115,6 +115,7 @@ init_internal_fns ()
 #define vec_condeq_direct { 0, 0, false }
 #define scatter_store_direct { 3, 1, false }
 #define len_store_direct { 3, 3, false }
+#define vec_set_direct { 3, 3, false }
 #define unary_direct { 0, 0, true }
 #define binary_direct { 0, 0, true }
 #define ternary_direct { 0, 0, true }
@@ -2658,6 +2659,40 @@ expand_vect_cond_mask_optab_fn (internal_fn, gcall *stmt, convert_optab optab)
 
 #define expand_vec_cond_mask_optab_fn expand_vect_cond_mask_optab_fn
 
+static void
+expand_vec_set_optab_fn (internal_fn, gcall *stmt, convert_optab optab)
+{
+  tree lhs = gimple_call_lhs (stmt);
+  tree op0 = gimple_call_arg (stmt, 0);
+  tree op1 = gimple_call_arg (stmt, 1);
+  tree op2 = gimple_call_arg (stmt, 2);
+  rtx target = expand_expr (lhs, NULL_RTX, VOIDmode, EXPAND_WRITE);
+  rtx src = expand_expr (op0, NULL_RTX, VOIDmode, EXPAND_WRITE);
+
+  machine_mode outermode = TYPE_MODE (TREE_TYPE (op0));
+  scalar_mode innermode = GET_MODE_INNER (outermode);
+
+  rtx value = expand_expr (op1, NULL_RTX, VOIDmode, EXPAND_NORMAL);
+  rtx pos = expand_expr (op2, NULL_RTX, VOIDmode, EXPAND_NORMAL);
+
+  class expand_operand ops[3];
+  enum insn_code icode = optab_handler (optab, outermode);
+
+  if (icode != CODE_FOR_nothing)
+    {
+      pos = convert_to_mode (E_SImode, pos, 0);
+
+      create_fixed_operand (&ops[0], src);
+      create_input_operand (&ops[1], value, innermode);
+      create_input_operand (&ops[2], pos, GET_MODE (pos));
+      if (maybe_expand_insn (icode, 3, ops))
+	{
+	  emit_move_insn (target, src);
+	  return;
+	}
+    }
+}
+
 static void
 expand_ABNORMAL_DISPATCHER (internal_fn, gcall *)
 {
@@ -3253,6 +3288,7 @@ multi_vector_optab_supported_p (convert_optab optab, tree_pair types,
 #define direct_fold_left_optab_supported_p direct_optab_supported_p
 #define direct_mask_fold_left_optab_supported_p direct_optab_supported_p
 #define direct_check_ptrs_optab_supported_p direct_optab_supported_p
+#define direct_vec_set_optab_supported_p direct_optab_supported_p
 
 /* Return the optab used by internal function FN.  */
 
diff --git a/gcc/internal-fn.def b/gcc/internal-fn.def
index 13e60828fcf..e6cfe1b6159 100644
--- a/gcc/internal-fn.def
+++ b/gcc/internal-fn.def
@@ -145,6 +145,8 @@ DEF_INTERNAL_OPTAB_FN (VCONDU, 0, vcondu, vec_condu)
 DEF_INTERNAL_OPTAB_FN (VCONDEQ, 0, vcondeq, vec_condeq)
 DEF_INTERNAL_OPTAB_FN (VCOND_MASK, 0, vcond_mask, vec_cond_mask)
 
+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)
diff --git a/gcc/optabs.c b/gcc/optabs.c
index 184827fdf4e..c8125670d2d 100644
--- a/gcc/optabs.c
+++ b/gcc/optabs.c
@@ -3841,6 +3841,23 @@ can_vcond_compare_p (enum rtx_code code, machine_mode value_mode,
 	 && insn_operand_matches (icode, 3, test);
 }
 
+bool
+can_vec_set_var_idx_p (enum tree_code code, machine_mode vec_mode,
+		       machine_mode value_mode, machine_mode idx_mode)
+{
+  gcc_assert (code == VECTOR_TYPE);
+
+  rtx reg1 = alloca_raw_REG (vec_mode, LAST_VIRTUAL_REGISTER + 1);
+  rtx reg2 = alloca_raw_REG (value_mode, LAST_VIRTUAL_REGISTER + 2);
+  rtx reg3 = alloca_raw_REG (idx_mode, LAST_VIRTUAL_REGISTER + 3);
+
+  enum insn_code icode = optab_handler (vec_set_optab, vec_mode);
+
+  return icode != CODE_FOR_nothing && insn_operand_matches (icode, 0, reg1)
+	 && insn_operand_matches (icode, 1, reg2)
+	 && insn_operand_matches (icode, 2, reg3);
+}
+
 /* This function is called when we are going to emit a compare instruction that
    compares the values found in X and Y, using the rtl operator COMPARISON.
 
diff --git a/gcc/optabs.h b/gcc/optabs.h
index 7c2ec257cb0..c018d127756 100644
--- a/gcc/optabs.h
+++ b/gcc/optabs.h
@@ -249,6 +249,9 @@ extern int can_compare_p (enum rtx_code, machine_mode,
    VALUE_MODE.  */
 extern bool can_vcond_compare_p (enum rtx_code, machine_mode, machine_mode);
 
+extern bool can_vec_set_var_idx_p (enum tree_code, machine_mode, machine_mode,
+				   machine_mode);
+
 extern rtx prepare_operand (enum insn_code, rtx, int, machine_mode,
 			    machine_mode, int);
 /* Emit a pair of rtl insns to compare two rtx's and to jump
-- 
2.27.0.90.geebb51ba8c