libfuncs.h (LTI_synchronize): New libfunc_index.

gcc/
	* libfuncs.h (LTI_synchronize): New libfunc_index.
	(synchronize_libfunc): Declare.
	* builtins.c (expand_builtin_synchronize): Consider using
	synchronize_libfunc before falling back on an asm blockage.
	* config/mips/mips.c: Include libfuncs.h
	(mips_init_libfuncs): Initialize synchronize_libfunc for TARGET_MIPS16.

From-SVN: r137162

gcc/ChangeLog

+2008-06-26  Richard Sandiford  <rdsandiford@googlemail.com>
+
+	* libfuncs.h (LTI_synchronize): New libfunc_index.
+	(synchronize_libfunc): Declare.
+	* builtins.c (expand_builtin_synchronize): Consider using
+	synchronize_libfunc before falling back on an asm blockage.
+	* config/mips/mips.c: Include libfuncs.h
+	(mips_init_libfuncs): Initialize synchronize_libfunc for TARGET_MIPS16.
+
 2008-06-26  Nathan Froyd  <froydnj@codesourcery.com>
 
 	* config/rs6000/rs6000.c (emit_allocate_stack): Add copy_r11

gcc/builtins.c

@@ -5999,6 +5999,12 @@ expand_builtin_synchronize (void)
     }
 #endif
 
+  if (synchronize_libfunc != NULL_RTX)
+    {
+      emit_library_call (synchronize_libfunc, LCT_NORMAL, VOIDmode, 0);
+      return;
+    }
+
   /* If no explicit memory barrier instruction is available, create an
      empty asm stmt with a memory clobber.  */
   x = build4 (ASM_EXPR, void_type_node, build_string (0, ""), NULL, NULL,

gcc/config/mips/mips.c

@@ -42,6 +42,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "function.h"
 #include "expr.h"
 #include "optabs.h"
+#include "libfuncs.h"
 #include "flags.h"
 #include "reload.h"
 #include "tm_p.h"
@@ -9424,6 +9425,11 @@ mips_init_libfuncs (void)
   else
     /* Register the gofast functions if selected using --enable-gofast.  */
     gofast_maybe_init_libfuncs ();
+
+  /* The MIPS16 ISA does not have an encoding for "sync", so we rely
+     on an external non-MIPS16 routine to implement __sync_synchronize.  */
+  if (TARGET_MIPS16)
+    synchronize_libfunc = init_one_libfunc ("__sync_synchronize");
 }
 
 /* Return the length of INSN.  LENGTH is the initial length computed by

gcc/libfuncs.h

@@ -40,6 +40,8 @@ enum libfunc_index
   LTI_profile_function_entry,
   LTI_profile_function_exit,
 
+  LTI_synchronize,
+
   LTI_gcov_flush,
 
   LTI_MAX
@@ -69,6 +71,8 @@ extern GTY(()) rtx libfunc_table[LTI_MAX];
 #define profile_function_entry_libfunc	(libfunc_table[LTI_profile_function_entry])
 #define profile_function_exit_libfunc	(libfunc_table[LTI_profile_function_exit])
 
+#define synchronize_libfunc	(libfunc_table[LTI_synchronize])
+
 #define gcov_flush_libfunc	(libfunc_table[LTI_gcov_flush])
 
 #endif /* GCC_LIBFUNCS_H */