PR gcc/1532

	* cse.c (cse_change_cc_mode): New static function.
	(cse_change_cc_mode_insns, cse_cc_succs): Likewise.
	(cse_condition_code_reg): New function.
	* rtl.h (cse_condition_code_reg): Declare.
	* toplev.c (rest_of_handle_cse2): Call cse_condition_code_reg.
	* target.h (struct gcc_target): Add fixed_condition_code_regs and
	cc_modes_compatible.
	* target-def.h (TARGET_FIXED_CONDITION_CODE_REGS): Define.
	(TARGET_CC_MODES_COMPATIBLE): Define.
	(TARGET_INITIALIZER): Add new initializers.
	* targhooks.c (default_cc_modes_compatible): New function.
	* targhooks.c (default_cc_modes_compatible): Declare.
	* hooks.c (hook_bool_intp_intp_false): New function.
	* hooks.h (hook_bool_intp_intp_false): Declare.
	* config/i386/i386.c (TARGET_FIXED_CONDITION_CODE_REGS): Define.
	(TARGET_CC_MODES_COMPATIBLE): Define.
	(ix86_fixed_condition_code_regs): New static function.
	(ix86_cc_modes_compatible): Likewise.
	* doc/tm.texi (Condition Code): Document new hooks.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@76454 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 28 insertions, 0 deletions

diff --git a/gcc/doc/tm.texi b/gcc/doc/tm.texi
index 41f1fcb6732..8f1dfa7233d 100644
--- a/gcc/doc/tm.texi
+++ b/gcc/doc/tm.texi
@@ -5177,6 +5177,34 @@ follows:
 @end smallexample
 @end defmac
 
+@deftypefn {Target Hook} bool TARGET_FIXED_CONDITION_CODE_REGS (unsigned int *, unsigned int *)
+On targets which do not use @code{(cc0)}, and which use a hard
+register rather than a pseudo-register to hold condition codes, the
+regular CSE passes are often not able to identify cases in which the
+hard register is set to a common value.  Use this hook to enable a
+small pass which optimizes such cases.  This hook should return true
+to enable this pass, and it should set the integers to which its
+arguments point to the hard register numbers used for condition codes.
+When there is only one such register, as is true on most systems, the
+integer pointed to by the second argument should be set to
+@code{INVALID_REGNUM}.
+
+The default version of this hook returns false.
+@end deftypefn
+
+@deftypefn {Target Hook} enum machine_mode TARGET_CC_MODES_COMPATIBLE (enum machine_mode, enum machine_mode)
+On targets which use multiple condition code modes in class
+@code{MODE_CC}, it is sometimes the case that a comparison can be
+validly done in more than one mode.  On such a system, define this
+target hook to take two mode arguments and to return a mode in which
+both comparisons may be validly done.  If there is no such mode,
+return @code{VOIDmode}.
+
+The default version of this hook checks whether the modes are the
+same.  If they are, it returns that mode.  If they are different, it
+returns @code{VOIDmode}.
+@end deftypefn
+
 @node Costs
 @section Describing Relative Costs of Operations
 @cindex costs of instructions