[gomp4] ptx reduction simplification

[gomp4] ptx reduction simplification

[Nathan Sidwell]

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I've committed this patch to rework and simplify the ptx backend's 
implementation of the reduction lowering hooks.

The current implementation had a number of bugs (multiple 
gimplify_push_contexts, for instance), and overcomplicated in a number of ways.

Most of the changes are straightforwards.  The vector initializer didn't need to 
create 2 new BBs -- just one for the intialization path.

nathan

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2015-09-18  Nathan Sidwell  <nathan@codesourcery.com>

	* omp-low.h (omp_reduction_init_op): Declare.
	* omp-low.c (omp_reduction_init_op): New, broken out of ...
	(omp_reduction_init): ... here.  Call it.
	* tree-parloops.c (initialize_reductions): Use
	omp_redutction_init_op.
	* config/nvptx/nvptx.c (nvptx_shuffle_reduction): Fold into only
	caller.
	(nvptx_goacc_reduction_setup, nvptx_goacc_reduction_init,
	nvptx_goacc_reduction_fini, goacc_reduction_teardown): Reimplement
	& simplify.

Index: tree-parloops.c
===================================================================
--- tree-parloops.c	(revision 227903)
+++ tree-parloops.c	(working copy)
@@ -566,7 +566,7 @@ reduc_stmt_res (gimple stmt)
 int
 initialize_reductions (reduction_info **slot, struct loop *loop)
 {
-  tree init, c;
+  tree init;
   tree bvar, type, arg;
   edge e;
 
@@ -582,12 +582,8 @@ initialize_reductions (reduction_info **
   type = TREE_TYPE (PHI_RESULT (reduc->reduc_phi));
   bvar = create_tmp_var (type, "reduction");
 
-  c = build_omp_clause (gimple_location (reduc->reduc_stmt),
-			OMP_CLAUSE_REDUCTION);
-  OMP_CLAUSE_REDUCTION_CODE (c) = reduc->reduction_code;
-  OMP_CLAUSE_DECL (c) = SSA_NAME_VAR (reduc_stmt_res (reduc->reduc_stmt));
-
-  init = omp_reduction_init (c, TREE_TYPE (bvar));
+  init = omp_reduction_init_op (gimple_location (reduc->reduc_stmt),
+				reduc->reduction_code, type);
   reduc->init = init;
 
   /* Replace the argument representing the initialization value
Index: config/nvptx/nvptx.c
===================================================================
--- config/nvptx/nvptx.c	(revision 227903)
+++ config/nvptx/nvptx.c	(working copy)
@@ -4542,49 +4542,6 @@ nvptx_generate_vector_shuffle (tree dest
   gimple_call_set_lhs (call, casted_dest);
 }
 
-/* Fold an OpenACC vector reduction using shuffle down instructions.  */
-
-static void
-nvptx_shuffle_reduction (tree lhs, tree var, enum tree_code code,
-			 gimple_seq *seq)
-{
-  /* Generate a sequence of instructions to preform a tree reduction using
-     shfl.down as an intermediate step.  */
-
-  tree type = TREE_TYPE (var);
-  tree t, t2;
-  gassign *g;
-
-  if (code == TRUTH_ANDIF_EXPR)
-    code = BIT_AND_EXPR;
-  else if (code == TRUTH_ORIF_EXPR)
-    code = BIT_IOR_EXPR;
-
-  for (int shfl = PTX_VECTOR_LENGTH / 2; shfl > 0; shfl = shfl >> 1)
-    {
-      t = make_ssa_name (type);
-      nvptx_generate_vector_shuffle (t, var, shfl, seq);
-      t2 = make_ssa_name (create_tmp_var (type));
-      g = gimple_build_assign (t2, fold_build2 (code, type, var, t));
-      gimple_seq_add_stmt (seq, g);
-      var = t2;
-    }
-
-  /* Restore the type of the comparison operand.  */
-  if (code == EQ_EXPR || code == NE_EXPR)
-    {
-      type = TREE_TYPE (lhs);
-      t = make_ssa_name (type);
-      t2 = fold_build1 (NOP_EXPR, type, var);
-      g = gimple_build_assign (t, t2);
-      gimple_seq_add_stmt (seq, g);
-      var = t;
-    }
-
-  g = gimple_build_assign (lhs, var);
-  gimple_seq_add_stmt (seq, g);
-}
-
 /* NVPTX implementation of GOACC_REDUCTION_SETUP.  Reserve shared
    memory for worker reductions.
 
@@ -4614,41 +4571,35 @@ static bool
 nvptx_goacc_reduction_setup (gimple call)
 {
   gimple_stmt_iterator gsi = gsi_for_stmt (call);
-  tree v = gimple_call_lhs (call);
-  tree local_var = gimple_call_arg (call, 1);
-  int loop_dim = tree_to_shwi (gimple_call_arg (call, 2));
+  tree lhs = gimple_call_lhs (call);
+  tree var = gimple_call_arg (call, 1);
+  int level = TREE_INT_CST_LOW (gimple_call_arg (call, 2));
   tree lid = gimple_call_arg (call, 4);
   tree rid = gimple_call_arg (call, 5);
   gimple_seq seq = NULL;
+  tree r = NULL_TREE;
 
   push_gimplify_context (true);
 
-  switch (loop_dim)
+  if (level == GOMP_DIM_WORKER)
     {
-    case GOMP_DIM_GANG:
-    case GOMP_DIM_VECTOR:
-      gimplify_assign (v, local_var, &seq);
-      break;
-    case GOMP_DIM_WORKER:
-      {
-	tree ptr = make_ssa_name (build_pointer_type (TREE_TYPE (local_var)));
-	tree call = nvptx_get_worker_red_addr_fn (local_var, rid, lid);
-	tree ref;
-
-	gimplify_assign (ptr, call, &seq);
-	ref = build_simple_mem_ref (ptr);
-	TREE_THIS_VOLATILE (ref) = 1;
-	gimplify_assign (ref, local_var, &seq);
-	if (v)
-	  gimplify_assign (v, local_var, &seq);
-      }
-      break;
-    default:
-      gcc_unreachable ();
+      tree ptr = make_ssa_name (build_pointer_type (TREE_TYPE (var)));
+      tree call = nvptx_get_worker_red_addr_fn (var, rid, lid);
+      tree ref;
+
+      gimplify_assign (ptr, call, &seq);
+      ref = build_simple_mem_ref (ptr);
+      TREE_THIS_VOLATILE (ref) = 1;
+      gimplify_assign (ref, var, &seq);
+      r = var;
     }
+  else
+    r = var;
+  
+  if (lhs)
+    gimplify_assign (lhs, r, &seq);
 
   pop_gimplify_context (NULL);
-
   gsi_replace_with_seq (&gsi, seq, true);
 
   return false;
@@ -4681,104 +4632,67 @@ static bool
 nvptx_goacc_reduction_init (gimple call)
 {
   gimple_stmt_iterator gsi = gsi_for_stmt (call);
-  tree v = gimple_call_lhs (call);
-  tree local_var = gimple_call_arg (call, 1);
-  tree clause = build_omp_clause (UNKNOWN_LOCATION, OMP_CLAUSE_REDUCTION);
-  int loop_dim = tree_to_shwi (gimple_call_arg (call, 2));
-  tree local_vartype = TREE_TYPE (local_var);
-  enum tree_code op;
+  tree lhs = gimple_call_lhs (call);
+  tree var = gimple_call_arg (call, 1);
+  int level = TREE_INT_CST_LOW (gimple_call_arg (call, 2));
+  tree init = omp_reduction_init_op
+    (gimple_location (call),
+     (enum tree_code)TREE_INT_CST_LOW (gimple_call_arg (call, 3)),
+     TREE_TYPE (var));
   gimple_seq seq = NULL;
-  bool retval = false;
-
-  op = (enum tree_code) tree_to_shwi (gimple_call_arg (call, 3));
-  OMP_CLAUSE_REDUCTION_CODE (clause) = op;
+  
+  push_gimplify_context (true);
 
-  switch (loop_dim)
+  if (level == GOMP_DIM_VECTOR)
     {
-    case GOMP_DIM_GANG:
-    case GOMP_DIM_WORKER:
-      push_gimplify_context (true);
-      gimplify_assign(v, omp_reduction_init (clause, local_vartype), &seq);
-      pop_gimplify_context (NULL);
-      gsi_replace_with_seq (&gsi, seq, true);
-      break;
-    case GOMP_DIM_VECTOR:
-      {
-	tree tid = make_ssa_name (unsigned_type_node);
-	tree dim_vector = build_int_cst (unsigned_type_node, GOMP_DIM_VECTOR);
-	gimple tid_call = gimple_build_call_internal (IFN_GOACC_DIM_POS, 1,
-						      dim_vector);
-
-	gimple_call_set_lhs (tid_call, tid);
-	gsi_insert_before (&gsi, tid_call, GSI_SAME_STMT);
-
-	tree zero = build_int_cst (unsigned_type_node, 0);
-	gimple cond_stmt = gimple_build_cond (NE_EXPR, tid, zero,
-					      NULL_TREE, NULL_TREE);
-
-	gsi_insert_before (&gsi, cond_stmt, GSI_SAME_STMT);
-
-	basic_block cond_bb = gsi_bb (gsi);
-	edge e = split_block (cond_bb, cond_stmt);
-	basic_block fallthru_bb = e->dest;
-	basic_block true_bb = create_empty_bb (cond_bb);
-	basic_block false_bb = create_empty_bb (cond_bb);
-	gimple_stmt_iterator true_gsi = gsi_start_bb (true_bb);
-	gimple_stmt_iterator false_gsi = gsi_start_bb (false_bb);
-
-	/* True case: v = gomp_init_reduction () */
-
-	make_edge (cond_bb, true_bb, EDGE_TRUE_VALUE);
-	edge etrue = make_edge (true_bb, fallthru_bb, EDGE_FALLTHRU);
-	remove_edge (e);
-
-	add_bb_to_loop (true_bb, cond_bb->loop_father);
-	set_immediate_dominator (CDI_DOMINATORS, true_bb, cond_bb);
-
-	tree true_v = make_ssa_name (local_vartype);
-	seq = NULL;
-
-	push_gimplify_context (true);
-	gimplify_assign (true_v, omp_reduction_init (clause, local_vartype),
-			 &seq);
-	pop_gimplify_context (NULL);
-	gsi_insert_seq_after (&true_gsi, seq, GSI_CONTINUE_LINKING);
-	gsi = gsi_start_bb (fallthru_bb);
-
-	/* False case: v = local_var  */
-
-	make_edge (cond_bb, false_bb, EDGE_FALSE_VALUE);
-	edge efalse = make_edge (false_bb, fallthru_bb, EDGE_FALLTHRU);
-
-	tree false_v = make_ssa_name (local_vartype);
-	seq = NULL;
-
-	push_gimplify_context (true);
-	gimplify_assign (false_v, local_var, &seq);
-	pop_gimplify_context (NULL);
-	gsi_insert_seq_after (&false_gsi, seq, GSI_CONTINUE_LINKING);
-
-	gsi = gsi_for_stmt (call);
-
-	add_bb_to_loop (false_bb, cond_bb->loop_father);
-	set_immediate_dominator (CDI_DOMINATORS, false_bb, cond_bb);
-
-	gsi_remove (&gsi, true);
-
-	/* Update phi.  */
-
-	gphi *phi = create_phi_node (v, fallthru_bb);
-	add_phi_arg (phi, true_v, etrue, UNKNOWN_LOCATION);
-	add_phi_arg (phi, false_v, efalse, UNKNOWN_LOCATION);
-
-	retval = true;
-      }
-      break;
-    default:
-      gcc_unreachable ();
+      tree tid = make_ssa_name (integer_type_node);
+      tree dim_vector = gimple_call_arg (call, 2);
+      gimple tid_call = gimple_build_call_internal (IFN_GOACC_DIM_POS, 1,
+						    dim_vector);
+      gimple cond_stmt = gimple_build_cond (NE_EXPR, tid, integer_zero_node,
+					    NULL_TREE, NULL_TREE);
+
+      gimple_call_set_lhs (tid_call, tid);
+      gimple_seq_add_stmt (&seq, tid_call);
+      gimple_seq_add_stmt (&seq, cond_stmt);
+
+      /* Split the block just after the call.  */
+      basic_block call_bb = gsi_bb (gsi);
+      edge nop_edge = split_block (call_bb, call);
+      basic_block dst_bb = nop_edge->dest;
+
+      /* Create the initialization block.  */
+      gimple_seq init_seq = NULL;
+      tree init_var = make_ssa_name (TREE_TYPE (var));
+      gimplify_assign (init_var, init, &init_seq);
+      /* One would think create_basic_block is the right thing to use
+	 here to create a new BB and set its gimple sequence.  Sadly
+	 that doesn't set the stmts' bb field :(  */
+      basic_block init_bb = create_empty_bb (call_bb);
+      gimple_stmt_iterator init_gsi = gsi_start_bb (init_bb);
+      gsi_insert_seq_after (&init_gsi, init_seq, GSI_CONTINUE_LINKING);
+
+      /* Link the init block in between the call and dst blocks.  */
+      make_edge (call_bb, init_bb, EDGE_TRUE_VALUE);
+      edge init_edge = make_edge (init_bb, dst_bb, EDGE_FALLTHRU);
+      add_bb_to_loop (init_bb, call_bb->loop_father);
+      set_immediate_dominator (CDI_DOMINATORS, init_bb, call_bb);
+
+      /* Mark the edge linking call to dst to non-fallthrough false edge.  */
+      nop_edge->flags ^= EDGE_FALLTHRU | EDGE_FALSE_VALUE;
+      
+      /* Create phi node in dst block.  */
+      gphi *phi = create_phi_node (lhs, dst_bb);
+      add_phi_arg (phi, init_var, init_edge, gimple_location (call));
+      add_phi_arg (phi, var, nop_edge, gimple_location (call));
     }
+  else
+    gimplify_assign (lhs, init, &seq);
 
-  return retval;
+  pop_gimplify_context (NULL);
+  gsi_replace_with_seq (&gsi, seq, true);
+
+  return false;
 }
 
 /* NVPTX implementation of GOACC_REDUCTION_FINI. For vectors, preform
@@ -4816,15 +4730,16 @@ static bool
 nvptx_goacc_reduction_fini (gimple call)
 {
   gimple_stmt_iterator gsi = gsi_for_stmt (call);
-  tree v = gimple_call_lhs (call);
+  tree lhs = gimple_call_lhs (call);
   tree ref_to_res = gimple_call_arg (call, 0);
-  tree local_var = gimple_call_arg (call, 1);
-  int loop_dim = tree_to_shwi (gimple_call_arg (call, 2));
-  enum tree_code op = (enum tree_code)tree_to_shwi (gimple_call_arg (call, 3));
+  tree var = gimple_call_arg (call, 1);
+  int level = TREE_INT_CST_LOW (gimple_call_arg (call, 2));
+  enum tree_code op
+    = (enum tree_code)TREE_INT_CST_LOW (gimple_call_arg (call, 3));
   tree lid = gimple_call_arg (call, 4);
   tree rid = gimple_call_arg (call, 5);
-  tree local_vartype = TREE_TYPE (local_var);
   gimple_seq seq = NULL;
+  tree r = NULL_TREE;;
 
   if (op == TRUTH_ANDIF_EXPR)
     op = BIT_AND_EXPR;
@@ -4833,54 +4748,45 @@ nvptx_goacc_reduction_fini (gimple call)
 
   push_gimplify_context (true);
 
-  switch (loop_dim)
+  if (level == GOMP_DIM_VECTOR)
     {
-    case GOMP_DIM_GANG:
-      {
-	tree ref = build_simple_mem_ref (ref_to_res);
-	tree t = make_ssa_name (local_vartype);
-
-	gimplify_assign (t, fold_build2 (op, local_vartype, ref, local_var),
-			 &seq);
-	gimplify_assign (ref, t, &seq);
-
-	if (v != NULL)
-	  {
-	    push_gimplify_context (true);
-	    gimplify_assign (v, t, &seq);
-	  }
-      }
-      break;
-    case GOMP_DIM_WORKER:
-      {
-	tree ptr = make_ssa_name (build_pointer_type (local_vartype));
-	tree call = nvptx_get_worker_red_addr_fn (local_var, rid, lid);
-	tree t1 = make_ssa_name (local_vartype);
-	tree t2 = make_ssa_name (local_vartype);
-	tree ref;
-
-	gimplify_assign (ptr, call, &seq);
-	ref = build_simple_mem_ref (ptr);
-	TREE_THIS_VOLATILE (ref) = 1;
-	gimplify_assign (t1, ref, &seq);
-	gimplify_assign (t2, fold_build2 (op, local_vartype, t1, local_var),
-			 &seq);
-	ref = build_simple_mem_ref (ptr);
-	gimplify_assign (ref, t2, &seq);
-	TREE_THIS_VOLATILE (ref) = 1;
-
-	if (v != NULL)
-	  gimplify_assign (v, t2, &seq);
-      }
-      break;
-    case GOMP_DIM_VECTOR:
-      nvptx_shuffle_reduction (v, local_var, op, &seq);
-      break;
-    default:
-      gcc_unreachable ();
+      for (int shfl = PTX_VECTOR_LENGTH / 2; shfl > 0; shfl = shfl >> 1)
+	{
+	  tree other_var = make_ssa_name (TREE_TYPE (var));
+	  nvptx_generate_vector_shuffle (other_var, var, shfl, &seq);
+
+	  r = make_ssa_name (TREE_TYPE (var));
+	  gimplify_assign (r, fold_build2 (op, TREE_TYPE (var),
+					     var, other_var), &seq);
+	  var = r;
+	}
     }
+  else
+    {
+      tree accum;
 
-  push_gimplify_context (true);
+      if (level == GOMP_DIM_GANG)
+	accum = build_simple_mem_ref (ref_to_res);
+      else if (level == GOMP_DIM_WORKER)
+	{
+	  tree ptr = make_ssa_name (build_pointer_type (TREE_TYPE (var)));
+	  tree call = nvptx_get_worker_red_addr_fn (var, rid, lid);
+
+	  gimplify_assign (ptr, call, &seq);
+	  accum = build_simple_mem_ref (ptr);
+	}
+      else
+	gcc_unreachable ();
+
+      TREE_THIS_VOLATILE (accum) = 1;
+      r = make_ssa_name (TREE_TYPE (var));
+      gimplify_assign (r, fold_build2 (op, TREE_TYPE (var), accum, var), &seq);
+      gimplify_assign (accum, r, &seq);
+    }
+
+  if (lhs)
+    gimple_seq_add_stmt (&seq, gimple_build_assign (lhs, r));
+  pop_gimplify_context (NULL);
 
   gsi_replace_with_seq (&gsi, seq, true);
 
@@ -4916,43 +4822,30 @@ static bool
 nvptx_goacc_reduction_teardown (gimple call)
 {
   gimple_stmt_iterator gsi = gsi_for_stmt (call);
-  tree v = gimple_call_lhs (call);
-  tree local_var = gimple_call_arg (call, 1);
-  int loop_dim = tree_to_shwi (gimple_call_arg (call, 2));
+  tree lhs = gimple_call_lhs (call);
+  tree var = gimple_call_arg (call, 1);
+  int level = TREE_INT_CST_LOW (gimple_call_arg (call, 2));
   tree lid = gimple_call_arg (call, 4);
   tree rid = gimple_call_arg (call, 5);
   gimple_seq seq = NULL;
-
-  if (v == NULL)
-    {
-      gsi_remove (&gsi, true);
-      return false;
-    }
-
+  tree r = NULL_TREE;
+  
   push_gimplify_context (true);
-
-  switch (loop_dim)
+  if (level == GOMP_DIM_WORKER)
     {
-    case GOMP_DIM_GANG:
-    case GOMP_DIM_VECTOR:
-      gimplify_assign (v, local_var, &seq);
-      break;
-    case GOMP_DIM_WORKER:
-      {
-	tree ptr = make_ssa_name (build_pointer_type (TREE_TYPE (local_var)));
-	tree call = nvptx_get_worker_red_addr_fn (local_var, rid, lid);
-	tree ref;
-
-	gimplify_assign (ptr, call, &seq);
-	ref = build_simple_mem_ref (ptr);
-	TREE_THIS_VOLATILE (ref) = 1;
-	gimplify_assign (v, ref, &seq);
-      }
-      break;
-    default:
-      gcc_unreachable ();
+      tree ptr = make_ssa_name (build_pointer_type (TREE_TYPE (var)));
+      tree call = nvptx_get_worker_red_addr_fn (var, rid, lid);
+
+      gimplify_assign (ptr, call, &seq);
+      r = build_simple_mem_ref (ptr);
+      TREE_THIS_VOLATILE (r) = 1;
     }
+  else
+    r = var;
 
+  if (lhs)
+    gimplify_assign (lhs, r, &seq);
+  
   pop_gimplify_context (NULL);
 
   gsi_replace_with_seq (&gsi, seq, true);
Index: omp-low.c
===================================================================
--- omp-low.c	(revision 227903)
+++ omp-low.c	(working copy)
@@ -3541,13 +3541,12 @@ maybe_lookup_decl_in_outer_ctx (tree dec
 }
 
 
-/* Construct the initialization value for reduction CLAUSE.  */
+/* Construct the initialization value for reduction operation OP.  */
 
 tree
-omp_reduction_init (tree clause, tree type)
+omp_reduction_init_op (location_t loc, enum tree_code op, tree type)
 {
-  location_t loc = OMP_CLAUSE_LOCATION (clause);
-  switch (OMP_CLAUSE_REDUCTION_CODE (clause))
+  switch (op)
     {
     case PLUS_EXPR:
     case MINUS_EXPR:
@@ -3612,6 +3611,15 @@ omp_reduction_init (tree clause, tree ty
     }
 }
 
+/* Construct the initialization value for reduction CLAUSE.  */
+
+tree
+omp_reduction_init (tree clause, tree type)
+{
+  return omp_reduction_init_op (OMP_CLAUSE_LOCATION (clause),
+				OMP_CLAUSE_REDUCTION_CODE (clause), type);
+}
+
 /* Return alignment to be assumed for var in CLAUSE, which should be
    OMP_CLAUSE_ALIGNED.  */
 
Index: omp-low.h
===================================================================
--- omp-low.h	(revision 227903)
+++ omp-low.h	(working copy)
@@ -25,6 +25,7 @@ struct omp_region;
 extern tree find_omp_clause (tree, enum omp_clause_code);
 extern void omp_expand_local (basic_block);
 extern void free_omp_regions (void);
+extern tree omp_reduction_init_op (location_t, enum tree_code, tree);
 extern tree omp_reduction_init (tree, tree);
 extern bool make_gimple_omp_edges (basic_block, struct omp_region **, int *);
 extern void omp_finish_file (void);

Re: [gomp4] ptx reduction simplification

[Thomas Schwinge]

[-- Attachment #1: Type: text/plain, Size: 3780 bytes --]

Hi!

On Fri, 18 Sep 2015 20:05:48 -0400, Nathan Sidwell <nathan@acm.org> wrote:
> I've committed this patch to rework and simplify [...]
> the reduction lowering hooks.
> 
> The current implementation [...]
> [was] overcomplicated in a number of ways.

> 	* omp-low.h (omp_reduction_init_op): Declare.
> 	* omp-low.c (omp_reduction_init_op): New, broken out of ...
> 	(omp_reduction_init): ... here.  Call it.
> 	* tree-parloops.c (initialize_reductions): Use
> 	omp_redutction_init_op.

Should this go into trunk already?  (I can test it, if you'd like me to.)

> --- tree-parloops.c	(revision 227903)
> +++ tree-parloops.c	(working copy)
> @@ -566,7 +566,7 @@ reduc_stmt_res (gimple stmt)
>  int
>  initialize_reductions (reduction_info **slot, struct loop *loop)
>  {
> -  tree init, c;
> +  tree init;
>    tree bvar, type, arg;
>    edge e;
>  
> @@ -582,12 +582,8 @@ initialize_reductions (reduction_info **
>    type = TREE_TYPE (PHI_RESULT (reduc->reduc_phi));
>    bvar = create_tmp_var (type, "reduction");
>  
> -  c = build_omp_clause (gimple_location (reduc->reduc_stmt),
> -			OMP_CLAUSE_REDUCTION);
> -  OMP_CLAUSE_REDUCTION_CODE (c) = reduc->reduction_code;
> -  OMP_CLAUSE_DECL (c) = SSA_NAME_VAR (reduc_stmt_res (reduc->reduc_stmt));
> -
> -  init = omp_reduction_init (c, TREE_TYPE (bvar));
> +  init = omp_reduction_init_op (gimple_location (reduc->reduc_stmt),
> +				reduc->reduction_code, type);
>    reduc->init = init;
>  
>    /* Replace the argument representing the initialization value

    [...]/source-gcc/gcc/tree-parloops.c: In function 'int initialize_reductions(reduction_info**, loop*)':
    [...]/source-gcc/gcc/tree-parloops.c:570:8: error: variable 'bvar' set but not used [-Werror=unused-but-set-variable]
       tree bvar, type, arg;
            ^

Committed to gomp-4_0-branch in r228016:

commit f858a76ae899a95b712beaaa8c110f708fd06a7a
Author: tschwinge <tschwinge@138bc75d-0d04-0410-961f-82ee72b054a4>
Date:   Tue Sep 22 15:07:23 2015 +0000

    Address -Werror=unused-but-set-variable diagnostic
    
    	gcc/
    	* tree-parloops.c (initialize_reductions): Remove local variable
    	bvar.
    
    git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/branches/gomp-4_0-branch@228016 138bc75d-0d04-0410-961f-82ee72b054a4
---
 gcc/ChangeLog.gomp  |    5 +++++
 gcc/tree-parloops.c |    6 ++----
 2 files changed, 7 insertions(+), 4 deletions(-)

diff --git gcc/ChangeLog.gomp gcc/ChangeLog.gomp
index e70d6cb..b7dbba0 100644
--- gcc/ChangeLog.gomp
+++ gcc/ChangeLog.gomp
@@ -1,3 +1,8 @@
+2015-09-22  Thomas Schwinge  <thomas@codesourcery.com>
+
+	* tree-parloops.c (initialize_reductions): Remove local variable
+	bvar.
+
 2015-09-18  Nathan Sidwell  <nathan@codesourcery.com>
 
 	* omp-low.h (omp_reduction_init_op): Declare.
diff --git gcc/tree-parloops.c gcc/tree-parloops.c
index 5062732..04ec254 100644
--- gcc/tree-parloops.c
+++ gcc/tree-parloops.c
@@ -567,7 +567,7 @@ int
 initialize_reductions (reduction_info **slot, struct loop *loop)
 {
   tree init;
-  tree bvar, type, arg;
+  tree type, arg;
   edge e;
 
   struct reduction_info *const reduc = *slot;
@@ -578,10 +578,8 @@ initialize_reductions (reduction_info **slot, struct loop *loop)
   /* In the phi node at the header, replace the argument coming
      from the preheader with the reduction initialization value.  */
 
-  /* Create a new variable to initialize the reduction.  */
+  /* Initialize the reduction.  */
   type = TREE_TYPE (PHI_RESULT (reduc->reduc_phi));
-  bvar = create_tmp_var (type, "reduction");
-
   init = omp_reduction_init_op (gimple_location (reduc->reduc_stmt),
 				reduc->reduction_code, type);
   reduc->init = init;


Grüße,
 Thomas

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Re: [gomp4] ptx reduction simplification

[Nathan Sidwell]

On 09/22/15 11:10, Thomas Schwinge wrote:
> Hi!
>
> On Fri, 18 Sep 2015 20:05:48 -0400, Nathan Sidwell <nathan@acm.org> wrote:
>> I've committed this patch to rework and simplify [...]
>> the reduction lowering hooks.
>>
>> The current implementation [...]
>> [was] overcomplicated in a number of ways.
>
>> 	* omp-low.h (omp_reduction_init_op): Declare.
>> 	* omp-low.c (omp_reduction_init_op): New, broken out of ...
>> 	(omp_reduction_init): ... here.  Call it.
>> 	* tree-parloops.c (initialize_reductions): Use
>> 	omp_redutction_init_op.
>
> Should this go into trunk already?  (I can test it, if you'd like me to.)

go  for it!

nathan

-- 
Nathan Sidwell

Refactor omp_reduction_init: omp_reduction_init_op (was: [gomp4] ptx reduction simplification)

[Thomas Schwinge]

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Hi!

On Tue, 22 Sep 2015 11:11:59 -0400, Nathan Sidwell <nathan@codesourcery.com> wrote:
> On 09/22/15 11:10, Thomas Schwinge wrote:
> > On Fri, 18 Sep 2015 20:05:48 -0400, Nathan Sidwell <nathan@acm.org> wrote:
> >> I've committed this patch to rework and simplify [...]
> >> the reduction lowering hooks.
> >>
> >> The current implementation [...]
> >> [was] overcomplicated in a number of ways.
> >
> >> 	* omp-low.h (omp_reduction_init_op): Declare.
> >> 	* omp-low.c (omp_reduction_init_op): New, broken out of ...
> >> 	(omp_reduction_init): ... here.  Call it.
> >> 	* tree-parloops.c (initialize_reductions): Use
> >> 	omp_redutction_init_op.
> >
> > Should this go into trunk already?  (I can test it, if you'd like me to.)
> 
> go  for it!

Tested on x86_64-pc-linux-gnu; no changes.  OK for trunk?

commit de2726ef46b8d875239ccb445c784c56e1a716dc
Author: Thomas Schwinge <thomas@codesourcery.com>
Date:   Tue Sep 22 17:30:40 2015 +0200

    Refactor omp_reduction_init: omp_reduction_init_op
    
    2015-09-23  Thomas Schwinge  <thomas@codesourcery.com>
    	    Nathan Sidwell  <nathan@codesourcery.com>
    
    	gcc/
    	* omp-low.h (omp_reduction_init_op): Declare.
    	* omp-low.c (omp_reduction_init_op): New, broken out of ...
    	(omp_reduction_init): ... here.  Call it.
    	* tree-parloops.c (initialize_reductions): Use
    	omp_reduction_init_op.
---
 gcc/omp-low.c       |   16 ++++++++++++----
 gcc/omp-low.h       |    1 +
 gcc/tree-parloops.c |   16 +++++-----------
 3 files changed, 18 insertions(+), 15 deletions(-)

diff --git gcc/omp-low.c gcc/omp-low.c
index 88a5149..fae407d 100644
--- gcc/omp-low.c
+++ gcc/omp-low.c
@@ -3372,13 +3372,12 @@ maybe_lookup_decl_in_outer_ctx (tree decl, omp_context *ctx)
 }
 
 
-/* Construct the initialization value for reduction CLAUSE.  */
+/* Construct the initialization value for reduction operation OP.  */
 
 tree
-omp_reduction_init (tree clause, tree type)
+omp_reduction_init_op (location_t loc, enum tree_code op, tree type)
 {
-  location_t loc = OMP_CLAUSE_LOCATION (clause);
-  switch (OMP_CLAUSE_REDUCTION_CODE (clause))
+  switch (op)
     {
     case PLUS_EXPR:
     case MINUS_EXPR:
@@ -3451,6 +3450,15 @@ omp_reduction_init (tree clause, tree type)
     }
 }
 
+/* Construct the initialization value for reduction CLAUSE.  */
+
+tree
+omp_reduction_init (tree clause, tree type)
+{
+  return omp_reduction_init_op (OMP_CLAUSE_LOCATION (clause),
+				OMP_CLAUSE_REDUCTION_CODE (clause), type);
+}
+
 /* Return alignment to be assumed for var in CLAUSE, which should be
    OMP_CLAUSE_ALIGNED.  */
 
diff --git gcc/omp-low.h gcc/omp-low.h
index 8a4052e..44e35a3 100644
--- gcc/omp-low.h
+++ gcc/omp-low.h
@@ -25,6 +25,7 @@ struct omp_region;
 extern tree find_omp_clause (tree, enum omp_clause_code);
 extern void omp_expand_local (basic_block);
 extern void free_omp_regions (void);
+extern tree omp_reduction_init_op (location_t, enum tree_code, tree);
 extern tree omp_reduction_init (tree, tree);
 extern bool make_gimple_omp_edges (basic_block, struct omp_region **, int *);
 extern void omp_finish_file (void);
diff --git gcc/tree-parloops.c gcc/tree-parloops.c
index c164121..94cacb6 100644
--- gcc/tree-parloops.c
+++ gcc/tree-parloops.c
@@ -565,8 +565,8 @@ reduc_stmt_res (gimple stmt)
 int
 initialize_reductions (reduction_info **slot, struct loop *loop)
 {
-  tree init, c;
-  tree bvar, type, arg;
+  tree init;
+  tree type, arg;
   edge e;
 
   struct reduction_info *const reduc = *slot;
@@ -577,16 +577,10 @@ initialize_reductions (reduction_info **slot, struct loop *loop)
   /* In the phi node at the header, replace the argument coming
      from the preheader with the reduction initialization value.  */
 
-  /* Create a new variable to initialize the reduction.  */
+  /* Initialize the reduction.  */
   type = TREE_TYPE (PHI_RESULT (reduc->reduc_phi));
-  bvar = create_tmp_var (type, "reduction");
-
-  c = build_omp_clause (gimple_location (reduc->reduc_stmt),
-			OMP_CLAUSE_REDUCTION);
-  OMP_CLAUSE_REDUCTION_CODE (c) = reduc->reduction_code;
-  OMP_CLAUSE_DECL (c) = SSA_NAME_VAR (reduc_stmt_res (reduc->reduc_stmt));
-
-  init = omp_reduction_init (c, TREE_TYPE (bvar));
+  init = omp_reduction_init_op (gimple_location (reduc->reduc_stmt),
+				reduc->reduction_code, type);
   reduc->init = init;
 
   /* Replace the argument representing the initialization value


Grüße,
 Thomas

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Re: Refactor omp_reduction_init: omp_reduction_init_op

[Bernd Schmidt]

>      	gcc/
>      	* omp-low.h (omp_reduction_init_op): Declare.
>      	* omp-low.c (omp_reduction_init_op): New, broken out of ...
>      	(omp_reduction_init): ... here.  Call it.
>      	* tree-parloops.c (initialize_reductions): Use
>      	omp_reduction_init_op.

That looks ok.


Bernd