common.opt (flag_ira_hoist_pressure): New.

	gcc/ChangeLog
	* common.opt (flag_ira_hoist_pressure): New.
	* doc/invoke.texi (-fira-hoist-pressure): Describe.
	* ira-costs.c (ira_set_pseudo_classes): New parameter.
	* ira.h: Update copyright dates.
	(ira_set_pseudo_classes): Update prototype.
	* haifa-sched.c (sched_init): Update call.
	* ira.c (ira): Update call.
	* regmove.c: Update copyright dates.
	(regmove_optimize): Update call.
	* loop-invariant.c: Update copyright dates.
	(move_loop_invariants): Update call.
	* gcse.c: (struct bb_data): New structure.
	(BB_DATA): New macro.
	(curr_bb, curr_reg_pressure): New static variables.
	(should_hoist_expr_to_dom): Rename from hoist_expr_reaches_here_p.
	Change parameter expr_index to expr.
	New parameters pressure_class, nregs and hoisted_bbs.
	Use reg pressure to determine the distance expr can be hoisted.
	(hoist_code): Use reg pressure to direct the hoist process.
	(get_regno_pressure_class, get_pressure_class_and_nregs)
	(change_pressure, calculate_bb_reg_pressure): New.
	(one_code_hoisting_pass): Calculate register pressure. Allocate
	and free data.

	gcc/testsuite/ChangeLog
	* testsuite/gcc.dg/hoist-register-pressure.c: New test.

From-SVN: r192604

gcc/ChangeLog

 2012-10-19  Bin Cheng  <bin.cheng@arm.com>
 
+	* common.opt (flag_ira_hoist_pressure): New.
+	* doc/invoke.texi (-fira-hoist-pressure): Describe.
+	* ira-costs.c (ira_set_pseudo_classes): New parameter.
+	* ira.h: Update copyright dates.
+	(ira_set_pseudo_classes): Update prototype.
+	* haifa-sched.c (sched_init): Update call.
+	* ira.c (ira): Update call.
+	* regmove.c: Update copyright dates.
+	(regmove_optimize): Update call.
+	* loop-invariant.c: Update copyright dates.
+	(move_loop_invariants): Update call.
+	* gcse.c: (struct bb_data): New structure.
+	(BB_DATA): New macro.
+	(curr_bb, curr_reg_pressure): New static variables.
+	(should_hoist_expr_to_dom): Rename from hoist_expr_reaches_here_p.
+	Change parameter expr_index to expr.
+	New parameters pressure_class, nregs and hoisted_bbs.
+	Use reg pressure to determine the distance expr can be hoisted.
+	(hoist_code): Use reg pressure to direct the hoist process.
+	(get_regno_pressure_class, get_pressure_class_and_nregs)
+	(change_pressure, calculate_bb_reg_pressure): New.
+	(one_code_hoisting_pass): Calculate register pressure. Allocate
+	and free data.
+
+2012-10-19  Bin Cheng  <bin.cheng@arm.com>
+
 	* gcse.c: Update copyright dates.
 	(hoist_expr_reaches_here_p): Change parameter type from char *
 	to sbitmap.

gcc/common.opt

@@ -1392,6 +1392,11 @@ Enum(ira_region) String(all) Value(IRA_REGION_ALL)
 EnumValue
 Enum(ira_region) String(mixed) Value(IRA_REGION_MIXED)
 
+fira-hoist-pressure
+Common Report Var(flag_ira_hoist_pressure) Init(1) Optimization
+Use IRA based register pressure calculation
+in RTL hoist optimizations.
+
 fira-loop-pressure
 Common Report Var(flag_ira_loop_pressure)
 Use IRA based register pressure calculation

gcc/doc/invoke.texi

@@ -372,7 +372,7 @@ Objective-C and Objective-C++ Dialects}.
 -finline-small-functions -fipa-cp -fipa-cp-clone @gol
 -fipa-pta -fipa-profile -fipa-pure-const -fipa-reference @gol
 -fira-algorithm=@var{algorithm} @gol
--fira-region=@var{region} @gol
+-fira-region=@var{region} -fira-hoist-pressure @gol
 -fira-loop-pressure -fno-ira-share-save-slots @gol
 -fno-ira-share-spill-slots -fira-verbose=@var{n} @gol
 -fivopts -fkeep-inline-functions -fkeep-static-consts @gol
@@ -6996,6 +6996,14 @@ This typically results in the smallest code size, and is enabled by default for
 
 @end table
 
+@item -fira-hoist-pressure
+@opindex fira-hoist-pressure
+Use IRA to evaluate register pressure in the code hoisting pass for
+decisions to hoist expressions.  This option usually results in smaller
+code, but it can slow the compiler down.
+
+This option is enabled at level @option{-Os} for all targets.
+
 @item -fira-loop-pressure
 @opindex fira-loop-pressure
 Use IRA to evaluate register pressure in loops for decisions to move

gcc/haifa-sched.c

@@ -6633,7 +6633,7 @@ sched_init (void)
 	/* We need info about pseudos for rtl dumps about pseudo
 	   classes and costs.  */
 	regstat_init_n_sets_and_refs ();
-      ira_set_pseudo_classes (sched_verbose ? sched_dump : NULL);
+      ira_set_pseudo_classes (true, sched_verbose ? sched_dump : NULL);
       sched_regno_pressure_class
 	= (enum reg_class *) xmalloc (max_regno * sizeof (enum reg_class));
       for (i = 0; i < max_regno; i++)

gcc/ira-costs.c

@@ -2048,9 +2048,10 @@ ira_costs (void)
   ira_free (total_allocno_costs);
 }
 
-/* Entry function which defines classes for pseudos.  */
+/* Entry function which defines classes for pseudos.
+   Set pseudo_classes_defined_p only if DEFINE_PSEUDO_CLASSES is true.  */
 void
-ira_set_pseudo_classes (FILE *dump_file)
+ira_set_pseudo_classes (bool define_pseudo_classes, FILE *dump_file)
 {
   allocno_p = false;
   internal_flag_ira_verbose = flag_ira_verbose;
@@ -2059,7 +2060,9 @@ ira_set_pseudo_classes (FILE *dump_file)
   initiate_regno_cost_classes ();
   find_costs_and_classes (dump_file);
   finish_regno_cost_classes ();
-  pseudo_classes_defined_p = true;
+  if (define_pseudo_classes)
+    pseudo_classes_defined_p = true;
+
   finish_costs ();
 }
 

gcc/ira.c

@@ -4186,7 +4186,7 @@ ira (FILE *f)
   crtl->is_leaf = leaf_function_p ();
 
   if (resize_reg_info () && flag_ira_loop_pressure)
-    ira_set_pseudo_classes (ira_dump_file);
+    ira_set_pseudo_classes (true, ira_dump_file);
 
   rebuild_p = update_equiv_regs ();
 

gcc/ira.h

 /* Communication between the Integrated Register Allocator (IRA) and
    the rest of the compiler.
-   Copyright (C) 2006, 2007, 2008, 2009, 2010
+   Copyright (C) 2006, 2007, 2008, 2009, 2010, 2012
    Free Software Foundation, Inc.
    Contributed by Vladimir Makarov <vmakarov@redhat.com>.
 
@@ -131,7 +131,7 @@ extern void ira_init (void);
 extern void ira_finish_once (void);
 extern void ira_setup_eliminable_regset (void);
 extern rtx ira_eliminate_regs (rtx, enum machine_mode);
-extern void ira_set_pseudo_classes (FILE *);
+extern void ira_set_pseudo_classes (bool, FILE *);
 extern void ira_implicitly_set_insn_hard_regs (HARD_REG_SET *);
 
 extern void ira_sort_regnos_for_alter_reg (int *, int, unsigned int *);

gcc/loop-invariant.c

 /* RTL-level loop invariant motion.
-   Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010
+   Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012
    Free Software Foundation, Inc.
 
 This file is part of GCC.
@@ -1939,7 +1939,7 @@ move_loop_invariants (void)
     {
       df_analyze ();
       regstat_init_n_sets_and_refs ();
-      ira_set_pseudo_classes (dump_file);
+      ira_set_pseudo_classes (true, dump_file);
       calculate_loop_reg_pressure ();
       regstat_free_n_sets_and_refs ();
     }

gcc/regmove.c

 /* Move registers around to reduce number of move instructions needed.
    Copyright (C) 1987, 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
-   1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
+   1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
+   2012
    Free Software Foundation, Inc.
 
 This file is part of GCC.
@@ -1237,7 +1238,7 @@ regmove_optimize (void)
   regstat_compute_ri ();
 
   if (flag_ira_loop_pressure)
-    ira_set_pseudo_classes (dump_file);
+    ira_set_pseudo_classes (true, dump_file);
 
   regno_src_regno = XNEWVEC (int, nregs);
   for (i = nregs; --i >= 0; )

gcc/testsuite/ChangeLog

+2012-10-19  Bin Cheng  <bin.cheng@arm.com>
+
+	* testsuite/gcc.dg/hoist-register-pressure.c: New test.
+
 2012-10-18  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	PR c++/54501

gcc/testsuite/gcc.dg/hoist-register-pressure.c

+/* { dg-options "-Os -fdump-rtl-hoist" }  */
+/* { dg-final { scan-rtl-dump "PRE/HOIST: end of bb .* copying expression" "hoist" } } */
+
+#define BUF 100
+int a[BUF];
+
+void com (int);
+void bar (int);
+
+int foo (int x, int y, int z)
+{
+  /* "x+y" won't be hoisted if "-fira-hoist-pressure" is disabled,
+     because its rtx_cost is too small.  */
+  if (z)
+    {
+      a[1] = a[0] + a[2];
+      a[2] = a[1] + a[3];
+      a[3] = a[2] + a[4];
+      a[4] = a[3] + a[5];
+      a[5] = a[4] + a[6];
+      a[6] = a[5] + a[7];
+      a[7] = a[6] + a[8];
+      com (x+y);
+    }
+  else
+    {
+      bar (x+y);
+    }
+
+  return 0;
+}