2007-08-24 Sandra Loosemore <sandra@codesourcery.com>

            Nigel Stephens <nigel@mips.com>

	PR target/11787

	gcc/

	* doc/tm.texi (SET_RATIO, SET_BY_PIECES_P): Document new macros.
	(STORE_BY_PIECES_P): No longer applies to __builtin_memset.
	* expr.c (SET_BY_PIECES_P): Define.
	(can_store_by_pieces, store_by_pieces): Add MEMSETP argument; use
	it to decide whether to use SET_BY_PIECES_P or STORE_BY_PIECES_P.
	(store_expr):  Pass MEMSETP argument to can_store_by_pieces and
	store_by_pieces.
	* expr.h (SET_RATIO): Define.
	(can_store_by_pieces, store_by_pieces):	Update prototypes.
	* builtins.c (expand_builtin_memcpy): Pass MEMSETP argument to
	can_store_by_pieces/store_by_pieces.
	(expand_builtin_memcpy_args): Likewise.
	(expand_builtin_strncpy): Likewise.
	(expand_builtin_memset_args): Likewise.  Also remove special case
	for optimize_size so that can_store_by_pieces/SET_BY_PIECES_P can
	decide what to do instead.
	* value-prof.c (tree_stringops_transform): Pass MEMSETP argument
	to can_store_by_pieces.

	* config/sh/sh.h (SET_BY_PIECES_P): Clone from STORE_BY_PIECES_P.
	* config/s390/s390.h (SET_BY_PIECES_P): Likewise.

	* config/mips/mips.opt (mmemcpy): Change from Var to Mask.
	* config/mips/mips.c (override_options): Make -Os default to -mmemcpy.
	* config/mips/mips.h (MIPS_CALL_RATIO): Define.
	(MOVE_RATIO, CLEAR_RATIO, SET_RATIO): Define.
	(STORE_BY_PIECES_P): Define.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@127790 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 22 insertions, 4 deletions

diff --git a/gcc/doc/tm.texi b/gcc/doc/tm.texi
index 0ec10c5949d..a913b8058c6 100644
--- a/gcc/doc/tm.texi
+++ b/gcc/doc/tm.texi
@@ -5897,12 +5897,30 @@ will be used.  Defaults to 1 if @code{move_by_pieces_ninsns} returns less
 than @code{CLEAR_RATIO}.
 @end defmac
 
+@defmac SET_RATIO
+The threshold of number of scalar move insns, @emph{below} which a sequence
+of insns should be generated to set memory to a constant value, instead of
+a block set insn or a library call.  
+Increasing the value will always make code faster, but
+eventually incurs high cost in increased code size.
+
+If you don't define this, it defaults to the value of @code{MOVE_RATIO}.
+@end defmac
+
+@defmac SET_BY_PIECES_P (@var{size}, @var{alignment})
+A C expression used to determine whether @code{store_by_pieces} will be
+used to set a chunk of memory to a constant value, or whether some 
+other mechanism will be used.  Used by @code{__builtin_memset} when 
+storing values other than constant zero.
+Defaults to 1 if @code{move_by_pieces_ninsns} returns less
+than @code{SET_RATIO}.
+@end defmac
+
 @defmac STORE_BY_PIECES_P (@var{size}, @var{alignment})
 A C expression used to determine whether @code{store_by_pieces} will be
-used to set a chunk of memory to a constant value, or whether some other
-mechanism will be used.  Used by @code{__builtin_memset} when storing
-values other than constant zero and by @code{__builtin_strcpy} when
-when called with a constant source string.
+used to set a chunk of memory to a constant string value, or whether some 
+other mechanism will be used.  Used by @code{__builtin_strcpy} when
+called with a constant source string.
 Defaults to 1 if @code{move_by_pieces_ninsns} returns less
 than @code{MOVE_RATIO}.
 @end defmac