2005-05-25 Adrian Straetling <straetling@de.ibm.com>

	* loop-doloop.c: Include "target.h".
	  (doloop_valid_p): Move tests to function in targhooks.c.
	* target.h (struct gcc_target): New target hook
	  "insn_valid_within_doloop".
	* target-def.h: Define default value for "insn_valid_within_doloop".
	  (TARGET_INITIALIZER): Insert new target hook into initializer.
	* targhooks.c (default_insn_valid_within_doloop): New function.
	* targhooks.h (default_insn_valid_within_doloop): Declare.
	* hooks.c (hook_bool_rtx_true): New function.
	* hooks.h (hook_bool_rtx_true): Declare.
	* doc/tm.texi: Add documentation for new target hook.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@100143 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 11 insertions, 0 deletions

diff --git a/gcc/doc/tm.texi b/gcc/doc/tm.texi
index 9e755aaf8af..e541a20d2a9 100644
--- a/gcc/doc/tm.texi
+++ b/gcc/doc/tm.texi
@@ -9511,6 +9511,17 @@ simplified expression for the call's result.  If @var{ignore} is true
 the value will be ignored.
 @end deftypefn
 
+@deftypefn {Target Hook} bool TARGET_INSN_VALID_WITHIN_DOLOOP (rtx @var{insn})
+
+Take an instruction in @var{insn} and return true if it is valid within a
+low-overhead loop.
+
+Many targets use special registers for low-overhead looping. This function
+should return false for any instruction that clobbers these. 
+By default, the RTL loop optimizer does not use a present doloop pattern for
+loops containing function calls or brach on table instructions.  
+@end deftypefn
+
 @defmac MD_CAN_REDIRECT_BRANCH (@var{branch1}, @var{branch2})
 
 Take a branch insn in @var{branch1} and another in @var{branch2}.