tree-parloops.c: New file.

	* tree-parloops.c: New file.
	* tree-ssa-operands.h (free_stmt_operands): Declare.
	* tree-ssa-loop-manip.c (split_loop_exit_edge): Return the new basic
	block.
	* tree-pass.h (pass_parallelize_loops): Declare.
	* omp-low.c (expand_omp_parallel, expand_omp_for): Update SSA form for
	virtual operands.
	(build_omp_regions_1): Allow analysing just a single OMP region and
	its subregions.
	( build_omp_regions_root, omp_expand_local): New functions.
	(build_omp_regions): Add argument to build_omp_regions_1 call.
	* builtins.def (DEF_GOMP_BUILTIN): Initialize OMP builtins when
	autoparallelization is run.
	* timevar.def (TV_TREE_PARALLELIZE_LOOPS): New.
	* tree-ssa-loop.c (gate_tree_parallelize_loops, tree_parallelize_loops,
	pass_parallelize_loops): New.
	* common.opt (ftree-parallelize-loops): New.
	* tree-flow.h (omp_expand_local, tree_duplicate_sese_tail,
	parallelize_loops): Declare.
	(add_phi_args_after_copy, split_loop_exit_edge): Declaration changed.
	* Makefile.in (tree-parloops.o): Added.
	* tree-cfg.c (add_phi_args_after_copy_edge, tree_duplicate_sese_tail):
	New functions.
	(add_phi_args_after_copy_bb): Use add_phi_args_after_copy_edge.
	(add_phi_args_after_copy): Call add_phi_args_after_copy_edge for
	one extra edge as well.
	(tree_duplicate_sese_region): Add argument to add_phi_args_after_copy.
	Use VEC_free to free doms vector.
	(move_block_to_fn): Update loop info. Remove phi nodes for virtual
	operands.  Recompute operand caches in the new function.
	(move_sese_region_to_fn): Update loop info.
	* passes.c (init_optimization_passes): Add pass_parallelize_loops.
	* tree-ssa-operands.c (free_stmt_operands): New function.

	* doc/passes.texi: Document autoparallelization.
	* doc/invoke.texi (-ftree-parallelize-loops): New option.

	* gcc.dg/tree-ssa/parallelization-1.c: New test.

From-SVN: r128517

gcc/ChangeLog

+2007-09-15  Zdenek Dvorak  <ook@ucw.cz>
+
+	* tree-parloops.c: New file.
+	* tree-ssa-operands.h (free_stmt_operands): Declare.
+	* tree-ssa-loop-manip.c (split_loop_exit_edge): Return the new basic
+	block.
+	* tree-pass.h (pass_parallelize_loops): Declare.
+	* omp-low.c (expand_omp_parallel, expand_omp_for): Update SSA form for
+	virtual operands.
+	(build_omp_regions_1): Allow analysing just a single OMP region and
+	its subregions.
+	( build_omp_regions_root, omp_expand_local): New functions.
+	(build_omp_regions): Add argument to build_omp_regions_1 call.
+	* builtins.def (DEF_GOMP_BUILTIN): Initialize OMP builtins when
+	autoparallelization is run.
+	* timevar.def (TV_TREE_PARALLELIZE_LOOPS): New.
+	* tree-ssa-loop.c (gate_tree_parallelize_loops, tree_parallelize_loops,
+	pass_parallelize_loops): New.
+	* common.opt (ftree-parallelize-loops): New.
+	* tree-flow.h (omp_expand_local, tree_duplicate_sese_tail,
+	parallelize_loops): Declare.
+	(add_phi_args_after_copy, split_loop_exit_edge): Declaration changed.
+	* Makefile.in (tree-parloops.o): Added.
+	* tree-cfg.c (add_phi_args_after_copy_edge, tree_duplicate_sese_tail):
+	New functions.
+	(add_phi_args_after_copy_bb): Use add_phi_args_after_copy_edge.
+	(add_phi_args_after_copy): Call add_phi_args_after_copy_edge for
+	one extra edge as well.
+	(tree_duplicate_sese_region): Add argument to add_phi_args_after_copy.
+	Use VEC_free to free doms vector.
+	(move_block_to_fn): Update loop info. Remove phi nodes for virtual
+	operands.  Recompute operand caches in the new function.
+	(move_sese_region_to_fn): Update loop info.
+	* passes.c (init_optimization_passes): Add pass_parallelize_loops.
+	* tree-ssa-operands.c (free_stmt_operands): New function.
+
+	* doc/passes.texi: Document autoparallelization.
+	* doc/invoke.texi (-ftree-parallelize-loops): New option.
+
 2007-09-15  John David Anglin  <dave.anglin@nrc-cnrc.gc.ca>
 
 	PR target/33062

gcc/Makefile.in

@@ -1153,6 +1153,7 @@ OBJS-common = \
 	tree-object-size.o \
 	tree-optimize.o \
 	tree-outof-ssa.o \
+	tree-parloops.o \
 	tree-phinodes.o \
 	tree-predcom.o \
 	tree-pretty-print.o \
@@ -2270,6 +2271,9 @@ tree-loop-linear.o: tree-loop-linear.c $(CONFIG_H) $(SYSTEM_H) coretypes.h \
    $(DIAGNOSTIC_H) $(TREE_FLOW_H) $(TREE_DUMP_H) $(TIMEVAR_H) $(CFGLOOP_H) \
    tree-pass.h $(TREE_DATA_REF_H) $(SCEV_H) $(EXPR_H) $(LAMBDA_H) \
    $(TARGET_H) tree-chrec.h $(OBSTACK_H)
+tree-parloops.o: tree-parloops.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) \
+   $(TREE_FLOW_H) $(TREE_H) $(RTL_H) $(CFGLOOP_H) $(TREE_DATA_REF_H) $(GGC_H) \
+   $(DIAGNOSTIC_H) tree-pass.h $(SCEV_H) langhooks.h gt-tree-parloops.h
 tree-stdarg.o: tree-stdarg.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) \
    $(TREE_H) $(FUNCTION_H) $(DIAGNOSTIC_H) $(TREE_FLOW_H) tree-pass.h \
    tree-stdarg.h $(TARGET_H) langhooks.h
@@ -3091,7 +3095,7 @@ GTFILES = $(srcdir)/input.h $(srcdir)/coretypes.h \
   $(srcdir)/tree-ssa-operands.h \
   $(srcdir)/tree-profile.c $(srcdir)/tree-nested.c \
   $(srcdir)/ipa-reference.c $(srcdir)/tree-ssa-structalias.h \
-  $(srcdir)/tree-ssa-structalias.c \
+  $(srcdir)/tree-ssa-structalias.c $(srcdir)/tree-parloops.c \
   $(srcdir)/omp-low.c $(srcdir)/varpool.c \
   $(srcdir)/targhooks.c $(out_file) $(srcdir)/passes.c $(srcdir)/cgraphunit.c \
   @all_gtfiles@

gcc/builtins.def

@@ -139,7 +139,8 @@ along with GCC; see the file COPYING3.  If not see
 #undef DEF_GOMP_BUILTIN
 #define DEF_GOMP_BUILTIN(ENUM, NAME, TYPE, ATTRS) \
   DEF_BUILTIN (ENUM, "__builtin_" NAME, BUILT_IN_NORMAL, TYPE, TYPE,    \
-               false, true, true, ATTRS, false, flag_openmp)
+               false, true, true, ATTRS, false, \
+	       (flag_openmp || flag_tree_parallelize_loops))
 
 /* Define an attribute list for math functions that are normally
    "impure" because some of them may write into global memory for

gcc/common.opt

@@ -1088,6 +1088,10 @@ ftree-loop-optimize
 Common Report Var(flag_tree_loop_optimize) Init(1) Optimization
 Enable loop optimizations on tree level
 
+ftree-parallelize-loops=
+Common Report Joined UInteger Var(flag_tree_parallelize_loops) Init(1)
+Enable automatic parallelization of loops
+
 ftree-pre
 Common Report Var(flag_tree_pre) Optimization
 Enable SSA-PRE optimization on trees

gcc/doc/invoke.texi

@@ -358,7 +358,7 @@ Objective-C and Objective-C++ Dialects}.
 -fvariable-expansion-in-unroller -ftree-reassoc @gol
 -ftree-pre  -ftree-ccp  -ftree-dce -ftree-loop-optimize @gol
 -ftree-loop-linear -ftree-loop-im -ftree-loop-ivcanon -fivopts @gol
--fcheck-data-deps @gol
+-fcheck-data-deps -ftree-parallelize-loops @gol
 -ftree-dominator-opts -ftree-dse -ftree-copyrename -ftree-sink @gol
 -ftree-ch -ftree-sra -ftree-ter -ftree-fre -ftree-vectorize @gol
 -ftree-vect-loop-version -fvect-cost-model -ftree-salias -fipa-pta -fweb @gol
@@ -5744,6 +5744,14 @@ in connection with unrolling.
 Perform induction variable optimizations (strength reduction, induction
 variable merging and induction variable elimination) on trees.
 
+@item -ftree-parallelize-loops=n
+@opindex ftree-parallelize-loops=n
+Parallelize loops, i.e., split their iteration space to run in n threads.
+This is only possible for loops whose iterations are independent
+and can be arbitrarily reordered.  The optimization is only
+profitable on multiprocessor machines, for loops that are CPU-intensive,
+rather than constrained e.g. by memory bandwidth.
+
 @item -ftree-sra
 Perform scalar replacement of aggregates.  This pass replaces structure
 references with scalars to prevent committing structures to memory too

gcc/doc/passes.texi

@@ -438,6 +438,9 @@ The pass is implemented in @file{tree-vectorizer.c} (the main driver and general
 utilities), @file{tree-vect-analyze.c} and @file{tree-vect-transform.c}.
 Analysis of data references is in @file{tree-data-ref.c}.
 
+Autoparallelization.  This pass splits the loop iteration space to run
+into several threads.  The pass is implemented in @file{tree-parloops.c}.
+
 @item Tree level if-conversion for vectorizer
 
 This pass applies if-conversion to simple loops to help vectorizer.

gcc/omp-low.c

@@ -2600,6 +2600,7 @@ expand_omp_parallel (struct omp_region *region)
 
   /* Emit a library call to launch the children threads.  */
   expand_parallel_call (region, new_bb, entry_stmt, ws_args);
+  update_ssa (TODO_update_ssa_only_virtuals);
 }
 
 
@@ -3282,6 +3283,8 @@ expand_omp_for (struct omp_region *region)
       int next_ix = BUILT_IN_GOMP_LOOP_STATIC_NEXT + fn_index;
       expand_omp_for_generic (region, &fd, start_ix, next_ix);
     }
+
+  update_ssa (TODO_update_ssa_only_virtuals);
 }
 
 
@@ -3591,10 +3594,13 @@ expand_omp (struct omp_region *region)
 
 
 /* Helper for build_omp_regions.  Scan the dominator tree starting at
-   block BB.  PARENT is the region that contains BB.  */
+   block BB.  PARENT is the region that contains BB.  If SINGLE_TREE is
+   true, the function ends once a single tree is built (otherwise, whole
+   forest of OMP constructs may be built).  */
 
 static void
-build_omp_regions_1 (basic_block bb, struct omp_region *parent)
+build_omp_regions_1 (basic_block bb, struct omp_region *parent,
+		     bool single_tree)
 {
   block_stmt_iterator si;
   tree stmt;
@@ -3643,12 +3649,44 @@ build_omp_regions_1 (basic_block bb, struct omp_region *parent)
 	}
     }
 
+  if (single_tree && !parent)
+    return;
+
   for (son = first_dom_son (CDI_DOMINATORS, bb);
        son;
        son = next_dom_son (CDI_DOMINATORS, son))
-    build_omp_regions_1 (son, parent);
+    build_omp_regions_1 (son, parent, single_tree);
+}
+
+/* Builds the tree of OMP regions rooted at ROOT, storing it to
+   root_omp_region.  */
+
+static void
+build_omp_regions_root (basic_block root)
+{
+  gcc_assert (root_omp_region == NULL);
+  build_omp_regions_1 (root, NULL, true);
+  gcc_assert (root_omp_region != NULL);
 }
 
+/* Expands omp construct (and its subconstructs) starting in HEAD.  */
+
+void
+omp_expand_local (basic_block head)
+{
+  build_omp_regions_root (head);
+  if (dump_file && (dump_flags & TDF_DETAILS))
+    {
+      fprintf (dump_file, "\nOMP region tree\n\n");
+      dump_omp_region (dump_file, root_omp_region, 0);
+      fprintf (dump_file, "\n");
+    }
+
+  remove_exit_barriers (root_omp_region);
+  expand_omp (root_omp_region);
+
+  free_omp_regions ();
+}
 
 /* Scan the CFG and build a tree of OMP regions.  Return the root of
    the OMP region tree.  */
@@ -3658,7 +3696,7 @@ build_omp_regions (void)
 {
   gcc_assert (root_omp_region == NULL);
   calculate_dominance_info (CDI_DOMINATORS);
-  build_omp_regions_1 (ENTRY_BLOCK_PTR, NULL);
+  build_omp_regions_1 (ENTRY_BLOCK_PTR, NULL, false);
 }
 
 

gcc/passes.c

@@ -629,6 +629,7 @@ init_optimization_passes (void)
 	      NEXT_PASS (pass_dce_loop);
 	    }
 	  NEXT_PASS (pass_complete_unroll);
+	  NEXT_PASS (pass_parallelize_loops);
 	  NEXT_PASS (pass_loop_prefetch);
 	  NEXT_PASS (pass_iv_optimize);
 	  NEXT_PASS (pass_tree_loop_done);

gcc/testsuite/ChangeLog

+2007-09-15  Zdenek Dvorak  <ook@ucw.cz>
+
+	* gcc.dg/tree-ssa/parallelization-1.c: New test.
+
 2007-09-15  Dorit Nuzman  <dorit@il.ibm.com>
 
 	* gcc.dg/vect/pr33373b.c: New test.

gcc/testsuite/gcc.dg/tree-ssa/parallelization-1.c

+/* { dg-do compile } */
+/* { dg-options "-O2 -ftree-parallelize-loops=4 -fdump-tree-parloops-details -fdump-tree-final_cleanup" } */
+
+void abort (void);
+
+void parloop (int N)
+{
+  int i;
+  int x[10000000];
+
+  for (i = 0; i < N; i++)
+    x[i] = i + 3;
+
+  for (i = 0; i < N; i++)
+    {
+      if (x[i] != i + 3)
+	abort ();
+    }
+}
+
+int main(void)
+{
+  parloop(10000000);
+
+  return 0;
+}
+
+/* Check that the first loop in parloop got parallelized.  */
+
+/* { dg-final { scan-tree-dump-times "SUCCESS: may be parallelized" 1 "parloops" } } */
+/* { dg-final { scan-tree-dump-times "loopfn" 5 "final_cleanup" } } */
+/* { dg-final { cleanup-tree-dump "parloops" } } */
+/* { dg-final { cleanup-tree-dump "final_cleanup" } } */

gcc/timevar.def

@@ -120,6 +120,7 @@ DEFTIMEVAR (TV_TREE_LOOP_IVCANON     , "tree canonical iv")
 DEFTIMEVAR (TV_SCEV_CONST            , "scev constant prop")
 DEFTIMEVAR (TV_TREE_LOOP_UNSWITCH    , "tree loop unswitching")
 DEFTIMEVAR (TV_COMPLETE_UNROLL       , "complete unrolling")
+DEFTIMEVAR (TV_TREE_PARALLELIZE_LOOPS, "tree parallelize loops")
 DEFTIMEVAR (TV_TREE_VECTORIZATION    , "tree vectorization")
 DEFTIMEVAR (TV_TREE_LINEAR_TRANSFORM , "tree loop linear")
 DEFTIMEVAR (TV_CHECK_DATA_DEPS       , "tree check data dependences")

gcc/tracer.c

@@ -310,7 +310,7 @@ tail_duplicate (void)
 	      copy = duplicate_block (bb2, e, bb);
 	      flush_pending_stmts (e);
 
-	      add_phi_args_after_copy (&copy, 1);
+	      add_phi_args_after_copy (&copy, 1, NULL);
 
 	      /* Reconsider the original copy of block we've duplicated.
 	         Removing the most common predecessor may make it to be

gcc/tree-flow.h

@@ -704,6 +704,7 @@ extern struct omp_region *root_omp_region;
 extern struct omp_region *new_omp_region (basic_block, enum tree_code,
 					  struct omp_region *);
 extern void free_omp_regions (void);
+void omp_expand_local (basic_block);
 extern tree find_omp_clause (tree, enum tree_code);
 tree copy_var_decl (tree, tree, tree);
 
@@ -753,8 +754,10 @@ extern tree tree_block_label (basic_block);
 extern void extract_true_false_edges_from_block (basic_block, edge *, edge *);
 extern bool tree_duplicate_sese_region (edge, edge, basic_block *, unsigned,
 					basic_block *);
+extern bool tree_duplicate_sese_tail (edge, edge, basic_block *, unsigned,
+				      basic_block *);
 extern void add_phi_args_after_copy_bb (basic_block);
-extern void add_phi_args_after_copy (basic_block *, unsigned);
+extern void add_phi_args_after_copy (basic_block *, unsigned, edge);
 extern bool tree_purge_dead_abnormal_call_edges (basic_block);
 extern bool tree_purge_dead_eh_edges (basic_block);
 extern bool tree_purge_all_dead_eh_edges (const_bitmap);
@@ -971,6 +974,7 @@ unsigned int tree_ssa_prefetch_arrays (void);
 unsigned int remove_empty_loops (void);
 void tree_ssa_iv_optimize (void);
 unsigned tree_predictive_commoning (void);
+bool parallelize_loops (void);
 
 bool number_of_iterations_exit (struct loop *, edge,
 				struct tree_niter_desc *niter, bool);
@@ -992,7 +996,7 @@ void verify_loop_closed_ssa (void);
 bool for_each_index (tree *, bool (*) (tree, tree *, void *), void *);
 void create_iv (tree, tree, tree, struct loop *, block_stmt_iterator *, bool,
 		tree *, tree *);
-void split_loop_exit_edge (edge);
+basic_block split_loop_exit_edge (edge);
 unsigned force_expr_to_var_cost (tree);
 void standard_iv_increment_position (struct loop *, block_stmt_iterator *,
 				     bool *);

gcc/tree-pass.h

@@ -268,6 +268,7 @@ extern struct tree_opt_pass pass_record_bounds;
 extern struct tree_opt_pass pass_if_conversion;
 extern struct tree_opt_pass pass_vectorize;
 extern struct tree_opt_pass pass_complete_unroll;
+extern struct tree_opt_pass pass_parallelize_loops;
 extern struct tree_opt_pass pass_loop_prefetch;
 extern struct tree_opt_pass pass_iv_optimize;
 extern struct tree_opt_pass pass_tree_loop_done;

gcc/tree-ssa-loop-manip.c

@@ -454,9 +454,9 @@ verify_loop_closed_ssa (void)
 }
 
 /* Split loop exit edge EXIT.  The things are a bit complicated by a need to
-   preserve the loop closed ssa form.  */
+   preserve the loop closed ssa form.  The newly created block is returned.  */
 
-void
+basic_block
 split_loop_exit_edge (edge exit)
 {
   basic_block dest = exit->dest;
@@ -483,6 +483,8 @@ split_loop_exit_edge (edge exit)
       add_phi_arg (new_phi, name, exit);
       SET_USE (op_p, new_name);
     }
+
+  return bb;
 }
 
 /* Returns the basic block in that statements should be emitted for induction

gcc/tree-ssa-loop.c

@@ -468,6 +468,42 @@ struct tree_opt_pass pass_complete_unroll =
   0					/* letter */
 };
 
+/* Parallelization.  */
+
+static bool
+gate_tree_parallelize_loops (void)
+{
+  return flag_tree_parallelize_loops != 1;
+}
+
+static unsigned
+tree_parallelize_loops (void)
+{
+  if (number_of_loops () <= 1)
+    return 0;
+
+  if (parallelize_loops ())
+    return TODO_cleanup_cfg | TODO_rebuild_alias;
+  return 0;
+}
+
+struct tree_opt_pass pass_parallelize_loops =
+{
+  "parloops",				/* name */
+  gate_tree_parallelize_loops,		/* gate */
+  tree_parallelize_loops,      		/* execute */
+  NULL,					/* sub */
+  NULL,					/* next */
+  0,					/* static_pass_number */
+  TV_TREE_PARALLELIZE_LOOPS,  		/* tv_id */
+  PROP_cfg | PROP_ssa,			/* properties_required */
+  0,					/* properties_provided */
+  0,					/* properties_destroyed */
+  0,					/* todo_flags_start */
+  TODO_dump_func | TODO_verify_loops,	/* todo_flags_finish */
+  0				        /* letter */	
+};
+
 /* Prefetching.  */
 
 static unsigned int

gcc/tree-ssa-operands.c

@@ -2450,6 +2450,56 @@ build_ssa_operands (tree stmt)
     ann->references_memory = true;
 }
 
+/* Releases the operands of STMT back to their freelists, and clears
+   the stmt operand lists.  */
+
+void
+free_stmt_operands (tree stmt)
+{
+  def_optype_p defs = DEF_OPS (stmt), last_def;
+  use_optype_p uses = USE_OPS (stmt), last_use;
+  voptype_p vuses = VUSE_OPS (stmt);
+  voptype_p vdefs = VDEF_OPS (stmt), vdef, next_vdef;
+  unsigned i;
+
+  if (defs)
+    {
+      for (last_def = defs; last_def->next; last_def = last_def->next)
+	continue;
+      last_def->next = gimple_ssa_operands (cfun)->free_defs;
+      gimple_ssa_operands (cfun)->free_defs = defs;
+      DEF_OPS (stmt) = NULL;
+    }
+
+  if (uses)
+    {
+      for (last_use = uses; last_use->next; last_use = last_use->next)
+	delink_imm_use (USE_OP_PTR (last_use));
+      delink_imm_use (USE_OP_PTR (last_use));
+      last_use->next = gimple_ssa_operands (cfun)->free_uses;
+      gimple_ssa_operands (cfun)->free_uses = uses;
+      USE_OPS (stmt) = NULL;
+    }
+
+  if (vuses)
+    {
+      for (i = 0; i < VUSE_NUM (vuses); i++)
+	delink_imm_use (VUSE_OP_PTR (vuses, i));
+      add_vop_to_freelist (vuses);
+      VUSE_OPS (stmt) = NULL;
+    }
+
+  if (vdefs)
+    {
+      for (vdef = vdefs; vdef; vdef = next_vdef)
+	{
+	  next_vdef = vdef->next;
+	  delink_imm_use (VDEF_OP_PTR (vdef, 0));
+	  add_vop_to_freelist (vdef);
+	}
+      VDEF_OPS (stmt) = NULL;
+    }
+}
 
 /* Free any operands vectors in OPS.  */
 

gcc/tree-ssa-operands.h

@@ -206,6 +206,7 @@ extern void init_ssa_operands (void);
 extern void fini_ssa_operands (void);
 extern void free_ssa_operands (stmt_operands_p);
 extern void update_stmt_operands (tree);
+extern void free_stmt_operands (tree);
 extern bool verify_imm_links (FILE *f, tree var);
 
 extern void copy_virtual_operands (tree, tree);