PR libgomp/49490

	* omp-low.c (expand_omp_for_static_nochunk): Only
	use n ceil/ nthreads size for the first
	n % nthreads threads in the team instead of
	all threads except for the last few ones which
	get less work or none at all.

	* iter.c (gomp_iter_static_next): For chunk size 0
	only use n ceil/ nthreads size for the first
	n % nthreads threads in the team instead of
	all threads except for the last few ones which
	get less work or none at all.
	* iter_ull.c (gomp_iter_ull_static_next): Likewise.
	* env.c (parse_schedule): If OMP_SCHEDULE doesn't have
	chunk argument, set run_sched_modifier to 0 for static
	resp. 1 for other kinds.  If chunk argument is 0
	and not static, set value to 1.


git-svn-id: https://gcc.gnu.org/svn/gcc/trunk@175315 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 49 insertions, 15 deletions

diff --git a/gcc/omp-low.c b/gcc/omp-low.c
index 944a40bce97..05646bf8833 100644
--- a/gcc/omp-low.c
+++ b/gcc/omp-low.c
@@ -3,7 +3,7 @@
    marshalling to implement data sharing and copying clauses.
    Contributed by Diego Novillo <dnovillo@redhat.com>
 
-   Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010
+   Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011
    Free Software Foundation, Inc.
 
 This file is part of GCC.
@@ -4108,9 +4108,14 @@ expand_omp_for_generic (struct omp_region *region,
 	else
 	  n = (adj + N2 - N1) / STEP;
 	q = n / nthreads;
-	q += (q * nthreads != n);
-	s0 = q * threadid;
-	e0 = min(s0 + q, n);
+	tt = n % nthreads;
+	if (threadid < tt) goto L3; else goto L4;
+    L3:
+	tt = 0;
+	q = q + 1;
+    L4:
+	s0 = q * threadid + tt;
+	e0 = s0 + q;
 	V = s0 * STEP + N1;
 	if (s0 >= e0) goto L2; else goto L0;
     L0:
@@ -4126,12 +4131,14 @@ static void
 expand_omp_for_static_nochunk (struct omp_region *region,
 			       struct omp_for_data *fd)
 {
-  tree n, q, s0, e0, e, t, nthreads, threadid;
+  tree n, q, s0, e0, e, t, tt, nthreads, threadid;
   tree type, itype, vmain, vback;
-  basic_block entry_bb, exit_bb, seq_start_bb, body_bb, cont_bb;
+  basic_block entry_bb, second_bb, third_bb, exit_bb, seq_start_bb;
+  basic_block body_bb, cont_bb;
   basic_block fin_bb;
   gimple_stmt_iterator gsi;
   gimple stmt;
+  edge ep;
 
   itype = type = TREE_TYPE (fd->loop.v);
   if (POINTER_TYPE_P (type))
@@ -4185,19 +4192,39 @@ expand_omp_for_static_nochunk (struct omp_region *region,
   t = fold_convert (itype, t);
   n = force_gimple_operand_gsi (&gsi, t, true, NULL_TREE, true, GSI_SAME_STMT);
 
+  q = create_tmp_var (itype, "q");
   t = fold_build2 (TRUNC_DIV_EXPR, itype, n, nthreads);
-  q = force_gimple_operand_gsi (&gsi, t, true, NULL_TREE, true, GSI_SAME_STMT);
+  t = force_gimple_operand_gsi (&gsi, t, false, NULL_TREE, true, GSI_SAME_STMT);
+  gsi_insert_before (&gsi, gimple_build_assign (q, t), GSI_SAME_STMT);
+
+  tt = create_tmp_var (itype, "tt");
+  t = fold_build2 (TRUNC_MOD_EXPR, itype, n, nthreads);
+  t = force_gimple_operand_gsi (&gsi, t, false, NULL_TREE, true, GSI_SAME_STMT);
+  gsi_insert_before (&gsi, gimple_build_assign (tt, t), GSI_SAME_STMT);
 
-  t = fold_build2 (MULT_EXPR, itype, q, nthreads);
-  t = fold_build2 (NE_EXPR, itype, t, n);
-  t = fold_build2 (PLUS_EXPR, itype, q, t);
-  q = force_gimple_operand_gsi (&gsi, t, true, NULL_TREE, true, GSI_SAME_STMT);
+  t = build2 (LT_EXPR, boolean_type_node, threadid, tt);
+  stmt = gimple_build_cond_empty (t);
+  gsi_insert_before (&gsi, stmt, GSI_SAME_STMT);
+
+  second_bb = split_block (entry_bb, stmt)->dest;
+  gsi = gsi_last_bb (second_bb);
+  gcc_assert (gimple_code (gsi_stmt (gsi)) == GIMPLE_OMP_FOR);
+
+  gsi_insert_before (&gsi, gimple_build_assign (tt, build_int_cst (itype, 0)),
+		     GSI_SAME_STMT);
+  stmt = gimple_build_assign_with_ops (PLUS_EXPR, q, q,
+				       build_int_cst (itype, 1));
+  gsi_insert_before (&gsi, stmt, GSI_SAME_STMT);
+
+  third_bb = split_block (second_bb, stmt)->dest;
+  gsi = gsi_last_bb (third_bb);
+  gcc_assert (gimple_code (gsi_stmt (gsi)) == GIMPLE_OMP_FOR);
 
   t = build2 (MULT_EXPR, itype, q, threadid);
+  t = build2 (PLUS_EXPR, itype, t, tt);
   s0 = force_gimple_operand_gsi (&gsi, t, true, NULL_TREE, true, GSI_SAME_STMT);
 
   t = fold_build2 (PLUS_EXPR, itype, s0, q);
-  t = fold_build2 (MIN_EXPR, itype, t, n);
   e0 = force_gimple_operand_gsi (&gsi, t, true, NULL_TREE, true, GSI_SAME_STMT);
 
   t = build2 (GE_EXPR, boolean_type_node, s0, e0);
@@ -4263,13 +4290,20 @@ expand_omp_for_static_nochunk (struct omp_region *region,
   gsi_remove (&gsi, true);
 
   /* Connect all the blocks.  */
-  find_edge (entry_bb, seq_start_bb)->flags = EDGE_FALSE_VALUE;
-  find_edge (entry_bb, fin_bb)->flags = EDGE_TRUE_VALUE;
+  ep = make_edge (entry_bb, third_bb, EDGE_FALSE_VALUE);
+  ep->probability = REG_BR_PROB_BASE / 4 * 3;
+  ep = find_edge (entry_bb, second_bb);
+  ep->flags = EDGE_TRUE_VALUE;
+  ep->probability = REG_BR_PROB_BASE / 4;
+  find_edge (third_bb, seq_start_bb)->flags = EDGE_FALSE_VALUE;
+  find_edge (third_bb, fin_bb)->flags = EDGE_TRUE_VALUE;
 
   find_edge (cont_bb, body_bb)->flags = EDGE_TRUE_VALUE;
   find_edge (cont_bb, fin_bb)->flags = EDGE_FALSE_VALUE;
 
-  set_immediate_dominator (CDI_DOMINATORS, seq_start_bb, entry_bb);
+  set_immediate_dominator (CDI_DOMINATORS, second_bb, entry_bb);
+  set_immediate_dominator (CDI_DOMINATORS, third_bb, entry_bb);
+  set_immediate_dominator (CDI_DOMINATORS, seq_start_bb, third_bb);
   set_immediate_dominator (CDI_DOMINATORS, body_bb,
 			   recompute_dominator (CDI_DOMINATORS, body_bb));
   set_immediate_dominator (CDI_DOMINATORS, fin_bb,