tm.texi (defmac SMALL_REGISTER_CLASSES): Remove.

	* doc/tm.texi (defmac SMALL_REGISTER_CLASSES): Remove.
	(TARGET_SMALL_REGISTER_CLASSES_FOR_MODE_P): Add documentation,
	based on the above, for new target hook.

	* hooks.c (hook_bool_mode_true): New generic hook.
	* hooks.h (hook_bool_mode_true): Add prototype.

	* target.h (struct gcc_target): Add small_register_classes_for_mode_p
	target hook.
	* target-def.h (TARGET_SMALL_REGISTER_CLASSES_FOR_MODE_P): New default
	target hook, set to hook_bool_mode_false.
	* regs.h: Remove default definition of SMALL_REGISTER_CLASSES.
	* reload.c (push_secondary_reload): Replace SMALL_REGISTER_CLASSES
	with targetm.small_register_classes_for_mode_p.
	(find_reusable_reload): Likewise.
	(combine_reloads): Likewise.
	* reload1.c (reload_as_needed): Likewise.
	* cse.c (approx_reg_cost_1, hash_rtx_cb): Likewise.
	* ifcvt.c (noce_process_if_block, check_cond_move_block,
	dead_or_predicable): Likewise.
	* regmove.c (optimize_reg_copy_1): Likewise.
	* calls.c (prepare_call_address): Likewise.
	(precompute_register_parameters): Likewise.

	* config/sh/sh.h: Replace SMALL_REGISTER_CLASSES with new target
	hook definition.
	* config/sh/sh.c (sh_small_register_classes_for_mode_p): Add
	implementation of the hook that considers all register classes
	small except for SH64.
	(sh_override_options): Use the new hook.
	* config/sh/sh-protos.h (sh_small_register_classes_for_mode_p):
	Add prototype.

	* config/arm/arm.h: Replace SMALL_REGISTER_CLASSES with new target
	hook definition.
	* config/arm/arm.c (arm_small_register_classes_for_mode_p): Add
	implementation of the hook that considers all register classes
	small for THUMB1.
	* config/arm/arm-protos.h (arm_small_register_classes_for_mode_p):
	Add prototype.

	* config/mips/mips.h: Replace SMALL_REGISTER_CLASSES with new target
	hook definition.
	* config/mips/mips.c (mips_small_register_classes_for_mode_p): Add
	implementation of the hook that considers all register classes
	small for MIPS16.
	* config/mips/mips-protos.h (mips_small_register_classes_for_mode_p):
	Add prototype.

	* config/i386/i386.h: Replace SMALL_REGISTER_CLASSES with new target
	hook definition.
	* config/m32c/m32c.h: Likewise.
	* config/pdp11/pdp11.h: Likewise.
	* config/avr/avr.h: Likewise.
	* config/xtensa/xtensa.h: Likewise.
	* config/m68hc11/m68hc11.h: Likewise.
	* config/mn10300/mn10300.h: Likewise.
	* config/mcore/mcore.h: Likewise.
	* config/h8300/h8300.h: Likewise.
	* config/bfin/bfin.h: Likewise.

	* config/iq2000/iq2000.h: Remove SMALL_REGISTER_CLASSES definition.
	* config/rx/rx.h: Remove SMALL_REGISTER_CLASSES definition.

From-SVN: r158997

1 files changed, 32 insertions, 19 deletions

diff --git a/gcc/doc/tm.texi b/gcc/doc/tm.texi
index a20d48c..3a36314 100644
--- a/gcc/doc/tm.texi
+++ b/gcc/doc/tm.texi
@@ -2868,25 +2868,6 @@ Do not define this macro if you do not define
 is @code{BITS_PER_WORD} bits wide is correct for your machine.
 @end defmac
 
-@defmac SMALL_REGISTER_CLASSES
-On some machines, it is risky to let hard registers live across arbitrary
-insns.  Typically, these machines have instructions that require values
-to be in specific registers (like an accumulator), and reload will fail
-if the required hard register is used for another purpose across such an
-insn.
-
-Define @code{SMALL_REGISTER_CLASSES} to be an expression with a nonzero
-value on these machines.  When this macro has a nonzero value, the
-compiler will try to minimize the lifetime of hard registers.
-
-It is always safe to define this macro with a nonzero value, but if you
-unnecessarily define it, you will reduce the amount of optimizations
-that can be performed in some cases.  If you do not define this macro
-with a nonzero value when it is required, the compiler will run out of
-spill registers and print a fatal error message.  For most machines, you
-should not define this macro at all.
-@end defmac
-
 @defmac CLASS_LIKELY_SPILLED_P (@var{class})
 A C expression whose value is nonzero if pseudos that have been assigned
 to registers of class @var{class} would likely be spilled because
@@ -4360,6 +4341,38 @@ insns involving vector mode @var{mode}.  At the very least, it
 must have move patterns for this mode.
 @end deftypefn
 
+@deftypefn {Target Hook} bool TARGET_SMALL_REGISTER_CLASSES_FOR_MODE_P (enum machine_mode @var{mode})
+Define this to return nonzero for machine modes for which the port has
+small register classes.  If this target hook returns nonzero for a given
+@var{mode}, the compiler will try to minimize the lifetime of registers
+in @var{mode}.  The hook may be called with @code{VOIDmode} as argument.
+In this case, the hook is expected to return nonzero if it returns nonzero
+for any mode.
+
+On some machines, it is risky to let hard registers live across arbitrary
+insns.  Typically, these machines have instructions that require values
+to be in specific registers (like an accumulator), and reload will fail
+if the required hard register is used for another purpose across such an
+insn.
+
+Passes before reload do not know which hard registers will be used
+in an instruction, but the machine modes of the registers set or used in
+the instruction are already known.  And for some machines, register
+classes are small for, say, integer registers but not for floating point
+registers.  For example, the AMD x86-64 architecture requires specific
+registers for the legacy x86 integer instructions, but there are many
+SSE registers for floating point operations.  On such targets, a good
+strategy may be to return nonzero from this hook for @code{INTEGRAL_MODE_P}
+machine modes but zero for the SSE register classes.
+
+The default version of this hook retuns false for any mode.  It is always
+safe to redefine this hook to return with a nonzero value.  But if you
+unnecessarily define it, you will reduce the amount of optimizations
+that can be performed in some cases.  If you do not define this hook
+to return a nonzero value when it is required, the compiler will run out
+of spill registers and print a fatal error message.
+@end deftypefn
+
 @node Scalar Return
 @subsection How Scalar Function Values Are Returned
 @cindex return values in registers