Add HTM fastpath and use Intel RTM for it on x86.

	* beginend.cc (htm_fastpath): New.
	(gtm_thread::begin_transaction, _ITM_commitTransaction,
	_ITM_commitTransactionEH): Add HTM fastpath handling.
	* config/linux/rwlock.h (gtm_rwlock.is_write_locked): New.
	* config/posix/rwlock.h (gtm_rwlock.is_write_locked): New.
	* config/x86/target.h (htm_available, htm_init, htm_begin_success,
	htm_begin, htm_commit, htm_abort, htm_abort_should_retry): New.
	* configure.tgt: Add -mrtm to XCFLAGS.
	* method-serial.cc (htm_mg, o_htm_mg, htm_dispatch, dispatch_htm): New.
	(gtm_thread::serialirr_mode): Add HTM fastpath handling.
	* libitm_i.h (htm_fastpath, dispatch_htm): Declare.
	* retry.cc (parse_default_method): Add HTM method parsing.
	(gtm_thread::number_of_threads_changed): Use HTM by default if
	available.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@193369 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 15 insertions, 2 deletions

diff --git a/libitm/retry.cc b/libitm/retry.cc
index 172419bb803..bb7a1f574a1 100644
--- a/libitm/retry.cc
+++ b/libitm/retry.cc
@@ -1,4 +1,4 @@
-/* Copyright (C) 2008, 2009, 2011 Free Software Foundation, Inc.
+/* Copyright (C) 2008, 2009, 2011, 2012 Free Software Foundation, Inc.
    Contributed by Richard Henderson <rth@redhat.com>.
 
    This file is part of the GNU Transactional Memory Library (libitm).
@@ -254,6 +254,11 @@ parse_default_method()
       disp = GTM::dispatch_ml_wt();
       env += 5;
     }
+  else if (strncmp(env, "htm", 3) == 0)
+    {
+      disp = GTM::dispatch_htm();
+      env += 3;
+    }
   else
     goto unknown;
 
@@ -311,7 +316,15 @@ GTM::gtm_thread::number_of_threads_changed(unsigned previous, unsigned now)
 	set_default_dispatch(default_dispatch_user);
       else
 	{
-	  abi_dispatch* a = dispatch_ml_wt();
+	  // If HTM is available, use it by default with serial mode as
+	  // fallback.  Otherwise, use ml_wt because it probably scales best.
+	  abi_dispatch* a;
+#ifdef USE_HTM_FASTPATH
+	  if (htm_available())
+	    a = dispatch_htm();
+	  else
+#endif
+	    a = dispatch_ml_wt();
 	  if (a->supports(now))
 	    set_default_dispatch(a);
 	  else