invoke.texi: Document new MIPS -mllsc and -mno-llsc options.

	* doc/invoke.texi: Document new MIPS -mllsc and -mno-llsc options.
	* doc/install.texi: Document new --with-llsc and --without-llsc
	options.
	* config.gcc: Handle --with-llsc and --without-llsc configure options.
	* config/mips/mips.md (sync, memory_barrier): Wrap sync instrunction
	in %| and %- operand codes.  Depend on GENERATE_SYNC instead of
	ISA_HAS_SYNC.
	(sync_compare_and_swap<mode>, sync_add<mode>, sync_sub<mode>,
	sync_old_add<mode>, sync_old_sub<mode>, sync_new_add<mode>,
	sync_new_sub<mode>, sync_<optab><mode>, sync_old_<optab><mode>,
	sync_new_<optab><mode>, sync_nand<mode>, sync_old_nand<mode>,
	sync_new_nand<mode>, sync_lock_test_and_set<mode>): Depend on
	GENERATE_LL_SC instead of ISA_HAS_LL_SC.
	* config/mips/mips.opt (mllsc): New option.
	* config/mips/mips.c (mips_llsc): Define variable.
	(mips_handle_option): Handle mllsc option.
	(override_options): Set mips_print_operand_punct for '|' and '-'.
	(print_operand): Add new %| and %- operand codes.
	* config/mips/mips.h (mips_llsc_setting): New enum type.
	(mips_llsc): Declare.
	(OPTION_DEFAULT_SPECS): Add llsc handling.
	(GENERATE_SYNC): New macro.
	(GENERATE_LL_SC): New macro.
	(MIPS_COMPARE_AND_SWAP, MIPS_SYNC_OP, MIPS_SYNC_OLD_OP,
	MIPS_SYNC_NEW_OP, MIPS_SYNC_NAND, MIPS_SYNC_OLD_NAND,
	MIPS_SYNC_NEW_NAND, MIPS_SYNC_EXCHANGE): Wrap instructions
	in %| and %- operand codes.

From-SVN: r128392

2 files changed, 44 insertions, 1 deletions

diff --git a/gcc/doc/install.texi b/gcc/doc/install.texi
index bac3bb2..2517303 100644
--- a/gcc/doc/install.texi
+++ b/gcc/doc/install.texi
@@ -1062,6 +1062,19 @@ systems that support conditional traps).
 Division by zero checks use the break instruction.
 @end table
 
+@c If you make --with-llsc the default for additional targets,
+@c update the --with-llsc description in the MIPS section below.
+
+@item --with-llsc
+On MIPS targets, make @option{-mllsc} the default when no
+@option{-mno-lsc} option is passed.  This is the default for
+Linux-based targets, as the kernel will emulate them if the ISA does
+not provide them.
+
+@item --without-llsc
+On MIPS targets, make @option{-mno-llsc} the default when no
+@option{-mllsc} option is passed.
+
 @item --enable-__cxa_atexit
 Define if you want to use __cxa_atexit, rather than atexit, to
 register C++ destructors for local statics and global objects.
@@ -3610,6 +3623,20 @@ configure for @samp{mipsel-elf} as a workaround.  The
 @samp{mips*-*-linux*} target continues to use the MIPS II routines.  More
 work on this is expected in future releases.
 
+@c If you make --with-llsc the default for another target, please also
+@c update the description of the --with-llsc option.
+
+The built-in @code{__sync_*} functions are available on MIPS II and
+later systems and others that support the @samp{ll}, @samp{sc} and
+@samp{sync} instructions.  This can be overridden by passing
+@option{--with-llsc} or @option{--without-llsc} when configuring GCC.
+Since the Linux kernel emulates these instructions if they are
+missing, the default for @samp{mips*-*-linux*} targets is
+@option{--with-llsc}.  The @option{--with-llsc} and
+@option{--without-llsc} configure options may be overridden at compile
+time by passing the @option{-mllsc} or @option{-mno-llsc} options to
+the compiler.
+
 MIPS systems check for division by zero (unless
 @option{-mno-check-zero-division} is passed to the compiler) by
 generating either a conditional trap or a break instruction.  Using
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 7413abd..f916b50 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -627,7 +627,7 @@ Objective-C and Objective-C++ Dialects}.
 -msingle-float  -mdouble-float  -mdsp  -mno-dsp  -mdspr2  -mno-dspr2 @gol
 -msmartmips  -mno-smartmips @gol
 -mpaired-single  -mno-paired-single  -mdmx  -mno-mdmx @gol
--mips3d  -mno-mips3d  -mmt  -mno-mt @gol
+-mips3d  -mno-mips3d  -mmt  -mno-mt  -mllsc  -mno-llsc @gol
 -mlong64  -mlong32  -msym32  -mno-sym32 @gol
 -G@var{num}  -mlocal-sdata  -mno-local-sdata @gol
 -mextern-sdata  -mno-extern-sdata  -mgpopt  -mno-gopt @gol
@@ -11772,6 +11772,22 @@ operations.
 Assume that the floating-point coprocessor supports double-precision
 operations.  This is the default.
 
+@item -mllsc
+@itemx -mno-llsc
+@opindex mllsc
+@opindex mno-llsc
+Use (do not use) @samp{ll}, @samp{sc}, and @samp{sync} instructions to
+implement atomic memory built-in functions.  When neither option is
+specified, GCC will use the instructions if the target architecture
+supports them.
+
+@option{-mllsc} is useful if the runtime environment can emulate the
+instructions and @option{-mno-llsc} can be useful when compiling for
+nonstandard ISAs.  You can make either option the default by
+configuring GCC with @option{--with-llsc} and @option{--without-llsc}
+respectively.  @option{--with-llsc} is the default for some
+configurations; see the installation documentation for details.
+
 @item -mdsp
 @itemx -mno-dsp
 @opindex mdsp