Makefile.in: Add $(TARGET_H) to the regrename.o rule.

        * Makefile.in: Add $(TARGET_H) to the regrename.o rule.
        * regrename.c (struct du_head): Add new element length.
        (sort_du_head, get_element, merge, merge_sort_comparison):
        New functions of merge sort implementation to du_head list.
        (regrename_optimize): Sort du_head linked list by length.
        Iterate registers in a preferred-register-first order.
        Move some code to ...
        (check_new_reg_p): here.  New function.
        (create_new_chain):  Initialize length.
        (scan_rtx_reg): Increase length for non-debug insns.
        * target.def: New hook preferred_rename_class.
        * targhook.c (default_preferred_rename_class): New.
        * targhook.h: Declare it.
        * doc/tm.texi.in: New hook TARGET_PREFERRED_RENAME_CLASS.
        * doc/tm.texi: Regenerate.

From-SVN: r167534

gcc/ChangeLog

+2010-12-07  Yao Qi  <yao@codesourcery.com>
+
+	* Makefile.in: Add $(TARGET_H) to the regrename.o rule.
+	* regrename.c (struct du_head): Add new element length.
+	(sort_du_head, get_element, merge, merge_sort_comparison):
+	New functions of merge sort implementation to du_head list.
+	(regrename_optimize): Sort du_head linked list by length.
+	Iterate registers in a preferred-register-first order.
+	Move some code to ...
+	(check_new_reg_p): here.  New function.
+	(create_new_chain):  Initialize length.
+	(scan_rtx_reg): Increase length for non-debug insns.
+	* target.def: New hook preferred_rename_class.
+	* targhook.c (default_preferred_rename_class): New.
+	* targhook.h: Declare it.
+	* doc/tm.texi.in: New hook TARGET_PREFERRED_RENAME_CLASS.
+	* doc/tm.texi: Regenerate.
+	
 2010-12-07  Jakub Jelinek  <jakub@redhat.com>
 
 	PR debug/46799

gcc/Makefile.in

@@ -3493,7 +3493,7 @@ regcprop.o : regcprop.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) \
 regrename.o : regrename.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) \
    $(RTL_ERROR_H) insn-config.h $(BASIC_BLOCK_H) $(REGS_H) hard-reg-set.h \
    output.h $(RECOG_H) $(FUNCTION_H) $(OBSTACK_H) $(FLAGS_H) $(TM_P_H) \
-   addresses.h reload.h $(TIMEVAR_H) $(TREE_PASS_H) $(DF_H)
+   addresses.h reload.h $(TIMEVAR_H) $(TREE_PASS_H) $(DF_H) $(TARGET_H)
 ifcvt.o : ifcvt.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(RTL_H) \
    $(REGS_H) $(DIAGNOSTIC_CORE_H) $(FLAGS_H) insn-config.h $(FUNCTION_H) $(RECOG_H) \
    $(TARGET_H) $(BASIC_BLOCK_H) $(EXPR_H) output.h $(EXCEPT_H) $(TM_P_H) \

gcc/doc/tm.texi

@@ -2504,6 +2504,10 @@ looking for one that is valid, and will reload one or both registers
 only if neither labeling works.
 @end defmac
 
+@deftypefn {Target Hook} reg_class_t TARGET_PREFERRED_RENAME_CLASS (reg_class_t @var{rclass})
+A target hook that places additional preference on the register class to use when it is necessary to rename a register in class @var{class} to another class, or perhaps @var{NO_REGS}, if no prefered register class is found or hook @code{preferred_rename_class} is not implemented. Sometimes returning a more restrictive class makes better code.  For example, on ARM, thumb-2 instructions using @code{LO_REGS} may be smaller than instructions using @code{GENERIC_REGS}.  By returning @code{LO_REGS} from @code{preferred_rename_class}, code size can be reduced.
+@end deftypefn
+
 @deftypefn {Target Hook} reg_class_t TARGET_PREFERRED_RELOAD_CLASS (rtx @var{x}, reg_class_t @var{rclass})
 A target hook that places additional restrictions on the register class
 to use when it is necessary to copy value @var{x} into a register in class

gcc/doc/tm.texi.in

@@ -2494,6 +2494,8 @@ looking for one that is valid, and will reload one or both registers
 only if neither labeling works.
 @end defmac
 
+@hook TARGET_PREFERRED_RENAME_CLASS
+
 @hook TARGET_PREFERRED_RELOAD_CLASS
 A target hook that places additional restrictions on the register class
 to use when it is necessary to copy value @var{x} into a register in class

gcc/target.def

@@ -2224,6 +2224,21 @@ DEFHOOK
  bool, (reg_class_t rclass),
  default_class_likely_spilled_p)
 
+DEFHOOK
+(preferred_rename_class,
+ "A target hook that places additional preference on the register\
+ class to use when it is necessary to rename a register in class\
+ @var{class} to another class, or perhaps @var{NO_REGS}, if no\
+ prefered register class is found or hook @code{preferred_rename_class}\
+ is not implemented.\
+ Sometimes returning a more restrictive class makes better code.  For\
+ example, on ARM, thumb-2 instructions using @code{LO_REGS} may be\
+ smaller than instructions using @code{GENERIC_REGS}.  By returning\
+ @code{LO_REGS} from @code{preferred_rename_class}, code size can\
+ be reduced.",
+ reg_class_t, (reg_class_t rclass),
+ default_preferred_rename_class)
+
 /* This target hook allows the backend to perform additional
    processing while initializing for variable expansion.  */
 DEFHOOK

gcc/targhooks.c

@@ -1278,6 +1278,13 @@ default_preferred_output_reload_class (rtx x ATTRIBUTE_UNUSED,
 #endif
 }
 
+/* The default implementation of TARGET_PREFERRED_RENAME_CLASS.  */
+reg_class_t
+default_preferred_rename_class (reg_class_t rclass ATTRIBUTE_UNUSED)
+{
+  return NO_REGS;
+}
+
 /* The default implementation of TARGET_CLASS_LIKELY_SPILLED_P.  */
 
 bool

gcc/targhooks.h

@@ -160,6 +160,7 @@ extern int default_register_move_cost (enum machine_mode, reg_class_t,
 extern bool default_profile_before_prologue (void);
 extern reg_class_t default_preferred_reload_class (rtx, reg_class_t);
 extern reg_class_t default_preferred_output_reload_class (rtx, reg_class_t);
+extern reg_class_t default_preferred_rename_class (reg_class_t rclass);
 extern bool default_class_likely_spilled_p (reg_class_t);
 
 extern enum unwind_info_type default_debug_unwind_info (void);