invoke.texi (sched-pressure-algorithm): Document new --param.

gcc/
	* doc/invoke.texi (sched-pressure-algorithm): Document new --param.
	* common.opt (fsched-pressure-algorithm=): Remove.
	* flag-types.h (sched_pressure_algorithm): Move to...
	* sched-int.h (sched_pressure_algorithm): ...here.
	* params.def (sched-pressure-algorithm): New param.
	* haifa-sched.c (sched_init): Use it to initialize sched_pressure.
	* common/config/s390/s390-common.c (s390_option_optimization_table):
	Remove OPT_fsched_pressure_algorithm_ entry.
	* config/s390/s390.c (s390_option_override): Set a default value for
	PARAM_SCHED_PRESSURE_ALGORITHM.

From-SVN: r188258

gcc/ChangeLog

+2012-06-06  Richard Sandiford  <r.sandiford@uk.ibm.com>
+
+	* doc/invoke.texi (sched-pressure-algorithm): Document new --param.
+	* common.opt (fsched-pressure-algorithm=): Remove.
+	* flag-types.h (sched_pressure_algorithm): Move to...
+	* sched-int.h (sched_pressure_algorithm): ...here.
+	* params.def (sched-pressure-algorithm): New param.
+	* haifa-sched.c (sched_init): Use it to initialize sched_pressure.
+	* common/config/s390/s390-common.c (s390_option_optimization_table):
+	Remove OPT_fsched_pressure_algorithm_ entry.
+	* config/s390/s390.c (s390_option_override): Set a default value for
+	PARAM_SCHED_PRESSURE_ALGORITHM.
+
 2012-06-05  Michael Meissner  <meissner@linux.vnet.ibm.com>
 
 	PR target/53487

gcc/common.opt

@@ -1664,19 +1664,6 @@ fsched-pressure
 Common Report Var(flag_sched_pressure) Init(0) Optimization
 Enable register pressure sensitive insn scheduling
 
-fsched-pressure-algorithm=
-Common Joined RejectNegative Enum(sched_pressure_algorithm) Var(flag_sched_pressure_algorithm) Init(SCHED_PRESSURE_WEIGHTED)
--fsched-pressure-algorithm=[weighted|model] Set the pressure-scheduling algorithm
-
-Enum
-Name(sched_pressure_algorithm) Type(enum sched_pressure_algorithm) UnknownError(unknown %<fsched-pressure%> algorithm %qs)
-
-EnumValue
-Enum(sched_pressure_algorithm) String(weighted) Value(SCHED_PRESSURE_WEIGHTED)
-
-EnumValue
-Enum(sched_pressure_algorithm) String(model) Value(SCHED_PRESSURE_MODEL)
-
 fsched-spec
 Common Report Var(flag_schedule_speculative) Init(1) Optimization
 Allow speculative motion of non-loads

gcc/common/config/s390/s390-common.c

@@ -51,11 +51,8 @@ static const struct default_options s390_option_optimization_table[] =
   {
     { OPT_LEVELS_1_PLUS, OPT_fomit_frame_pointer, NULL, 1 },
 
-    /* Enable -fsched-pressure using -fsched-pressure-algorithm=model
-       by default when optimizing.  */
+    /* Enable -fsched-pressure by default when optimizing.  */
     { OPT_LEVELS_1_PLUS, OPT_fsched_pressure, NULL, 1 },
-    { OPT_LEVELS_1_PLUS, OPT_fsched_pressure_algorithm_,
-      NULL, SCHED_PRESSURE_MODEL },
 
     /* ??? There are apparently still problems with -fcaller-saves.  */
     { OPT_LEVELS_ALL, OPT_fcaller_saves, NULL, 0 },

gcc/config/s390/s390.c

@@ -1649,6 +1649,11 @@ s390_option_override (void)
      is beneficial on s390, we enable it if available.  */
   if (flag_prefetch_loop_arrays < 0 && HAVE_prefetch && optimize >= 3)
     flag_prefetch_loop_arrays = 1;
+
+  /* Use the alternative scheduling-pressure algorithm by default.  */
+  maybe_set_param_value (PARAM_SCHED_PRESSURE_ALGORITHM, 2,
+                         global_options.x_param_values,
+                         global_options_set.x_param_values);
 }
 
 /* Map for smallest class containing reg regno.  */

gcc/doc/invoke.texi

@@ -9350,6 +9350,17 @@ Set the maximum number of instructions executed in parallel in
 reassociated tree. This parameter overrides target dependent
 heuristics used by default if has non zero value.
 
+@item sched-pressure-algorithm
+Choose between the two available implementations of
+@option{-fsched-pressure}.  Algorithm 1 is the original implementation
+and is the more likely to prevent instructions from being reordered.
+Algorithm 2 was designed to be a compromise between the relatively
+conservative approach taken by algorithm 1 and the rather aggressive
+approach taken by the default scheduler.  It relies more heavily on
+having a regular register file and accurate register pressure classes.
+See @file{haifa-sched.c} in the GCC sources for more details.
+
+The default choice depends on the target.
 @end table
 @end table
 

gcc/flag-types.h

@@ -106,14 +106,6 @@ enum symbol_visibility
 };
 #endif
 
-/* The algorithm used to implement -fsched-pressure.  */
-enum sched_pressure_algorithm
-{
-  SCHED_PRESSURE_NONE,
-  SCHED_PRESSURE_WEIGHTED,
-  SCHED_PRESSURE_MODEL
-};
-
 /* The algorithm used for the integrated register allocator (IRA).  */
 enum ira_algorithm
 {

gcc/haifa-sched.c

@@ -6229,7 +6229,8 @@ sched_init (void)
   if (flag_sched_pressure
       && !reload_completed
       && common_sched_info->sched_pass_id == SCHED_RGN_PASS)
-    sched_pressure = flag_sched_pressure_algorithm;
+    sched_pressure = ((enum sched_pressure_algorithm)
+		      PARAM_VALUE (PARAM_SCHED_PRESSURE_ALGORITHM));
   else
     sched_pressure = SCHED_PRESSURE_NONE;
 

gcc/params.def

@@ -979,6 +979,12 @@ DEFPARAM (PARAM_MAX_TRACKED_STRLENS,
 	  "track string lengths",
 	  1000, 0, 0)
 
+/* Keep this in sync with the sched_pressure_algorithm enum.  */
+DEFPARAM (PARAM_SCHED_PRESSURE_ALGORITHM,
+	  "sched-pressure-algorithm",
+	  "Which -fsched-pressure algorithm to apply",
+	  1, 1, 2)
+
 /*
 Local variables:
 mode:c

gcc/sched-int.h

@@ -37,6 +37,14 @@ along with GCC; see the file COPYING3.  If not see
 enum sched_pass_id_t { SCHED_PASS_UNKNOWN, SCHED_RGN_PASS, SCHED_EBB_PASS,
 		       SCHED_SMS_PASS, SCHED_SEL_PASS };
 
+/* The algorithm used to implement -fsched-pressure.  */
+enum sched_pressure_algorithm
+{
+  SCHED_PRESSURE_NONE,
+  SCHED_PRESSURE_WEIGHTED,
+  SCHED_PRESSURE_MODEL
+};
+
 typedef VEC (basic_block, heap) *bb_vec_t;
 typedef VEC (rtx, heap) *insn_vec_t;
 typedef VEC (rtx, heap) *rtx_vec_t;