Detect whether target can use -fprofile-update=atomic

	PR gcov-profile/77378
	PR gcov-profile/77466
	* libgcov-profiler.c: Use __GCC_HAVE_SYNC_COMPARE_AND_SWAP_{4,8} to
	conditionaly enable/disable *_atomic functions.
	PR gcov-profile/77378
	PR gcov-profile/77466
	* tree-profile.c (tree_profiling): Detect whether target can use
	-fprofile-update=atomic.
	PR gcov-profile/77378
	PR gcov-profile/77466
	* gcc.dg/profile-update-warning.c: New test.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@240008 138bc75d-0d04-0410-961f-82ee72b054a4

2 files changed, 25 insertions, 5 deletions

diff --git a/libgcc/ChangeLog b/libgcc/ChangeLog
index d5ecf7776a7..8ad8ef5802d 100644
--- a/libgcc/ChangeLog
+++ b/libgcc/ChangeLog
@@ -1,3 +1,10 @@
+2016-09-06  Martin Liska  <mliska@suse.cz>
+
+	PR gcov-profile/77378
+	PR gcov-profile/77466
+	* libgcov-profiler.c: Use __GCC_HAVE_SYNC_COMPARE_AND_SWAP_{4,8} to
+	conditionaly enable/disable *_atomic functions.
+
 2016-08-26  Joseph Myers  <joseph@codesourcery.com>
 
 	* config.host (i[34567]86-*-* | x86_64-*-*): Enable TFmode soft-fp
diff --git a/libgcc/libgcov-profiler.c b/libgcc/libgcov-profiler.c
index 70a821dc625..d9217b9885b 100644
--- a/libgcc/libgcov-profiler.c
+++ b/libgcc/libgcov-profiler.c
@@ -26,6 +26,17 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #include "libgcov.h"
 #if !defined(inhibit_libc)
 
+/* Detect whether target can support atomic update of profilers.  */
+#if __SIZEOF_LONG_LONG__ == 4 && __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4
+#define GCOV_SUPPORTS_ATOMIC 1
+#else
+#if __SIZEOF_LONG_LONG__ == 8 && __GCC_HAVE_SYNC_COMPARE_AND_SWAP_8
+#define GCOV_SUPPORTS_ATOMIC 1
+#else
+#define GCOV_SUPPORTS_ATOMIC 0
+#endif
+#endif
+
 #ifdef L_gcov_interval_profiler
 /* If VALUE is in interval <START, START + STEPS - 1>, then increases the
    corresponding counter in COUNTERS.  If the VALUE is above or below
@@ -46,7 +57,7 @@ __gcov_interval_profiler (gcov_type *counters, gcov_type value,
 }
 #endif
 
-#ifdef L_gcov_interval_profiler_atomic
+#if defined(L_gcov_interval_profiler_atomic) && GCOV_SUPPORTS_ATOMIC
 /* If VALUE is in interval <START, START + STEPS - 1>, then increases the
    corresponding counter in COUNTERS.  If the VALUE is above or below
    the interval, COUNTERS[STEPS] or COUNTERS[STEPS + 1] is increased
@@ -80,7 +91,7 @@ __gcov_pow2_profiler (gcov_type *counters, gcov_type value)
 }
 #endif
 
-#ifdef L_gcov_pow2_profiler_atomic
+#if defined(L_gcov_pow2_profiler_atomic) && GCOV_SUPPORTS_ATOMIC
 /* If VALUE is a power of two, COUNTERS[1] is incremented.  Otherwise
    COUNTERS[0] is incremented.  Function is thread-safe.  */
 
@@ -134,7 +145,7 @@ __gcov_one_value_profiler (gcov_type *counters, gcov_type value)
 }
 #endif
 
-#ifdef L_gcov_one_value_profiler_atomic
+#if defined(L_gcov_one_value_profiler_atomic) && GCOV_SUPPORTS_ATOMIC
 
 /* Update one value profilers (COUNTERS) for a given VALUE.
 
@@ -342,6 +353,7 @@ __gcov_time_profiler (gcov_type* counters)
     counters[0] = ++function_counter;
 }
 
+#if GCOV_SUPPORTS_ATOMIC
 /* Sets corresponding COUNTERS if there is no value.
    Function is thread-safe.  */
 
@@ -352,6 +364,7 @@ __gcov_time_profiler_atomic (gcov_type* counters)
     counters[0] = __atomic_add_fetch (&function_counter, 1, MEMMODEL_RELAXED);
 }
 #endif
+#endif
 
 
 #ifdef L_gcov_average_profiler
@@ -366,7 +379,7 @@ __gcov_average_profiler (gcov_type *counters, gcov_type value)
 }
 #endif
 
-#ifdef L_gcov_average_profiler_atomic
+#if defined(L_gcov_average_profiler_atomic) && GCOV_SUPPORTS_ATOMIC
 /* Increase corresponding COUNTER by VALUE.  FIXME: Perhaps we want
    to saturate up.  Function is thread-safe.  */
 
@@ -388,7 +401,7 @@ __gcov_ior_profiler (gcov_type *counters, gcov_type value)
 }
 #endif
 
-#ifdef L_gcov_ior_profiler_atomic
+#if defined(L_gcov_ior_profiler_atomic) && GCOV_SUPPORTS_ATOMIC
 /* Bitwise-OR VALUE into COUNTER.  Function is thread-safe.  */
 
 void