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.

From-SVN: r240008

gcc/ChangeLog

+2016-09-06  Martin Liska  <mliska@suse.cz>
+
+	PR gcov-profile/77378
+	PR gcov-profile/77466
+	* tree-profile.c (tree_profiling): Detect whether target can use
+	-fprofile-update=atomic.
+
 2016-09-06  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/77479

gcc/testsuite/ChangeLog

+2016-09-06  Martin Liska  <mliska@suse.cz>
+
+	PR gcov-profile/77378
+	PR gcov-profile/77466
+	* gcc.dg/profile-update-warning.c: New test.
+
 2016-09-06  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/77479

gcc/testsuite/gcc.dg/profile-update-warning.c

+/* { dg-do compile { target { i?86-*-* x86_64-*-* } } } */
+/* { dg-options "-fprofile-update=atomic -fprofile-generate -march=i386 -m32" } */
+
+int main(int argc, char *argv[])
+{
+  return 0;
+} /* { dg-warning "target does not support atomic profile update, single mode is selected" } */

gcc/tree-profile.c

@@ -528,6 +528,20 @@ gimple_gen_ior_profiler (histogram_value value, unsigned tag, unsigned base)
   gsi_insert_before (&gsi, call, GSI_NEW_STMT);
 }
 
+#ifndef HAVE_sync_compare_and_swapsi
+#define HAVE_sync_compare_and_swapsi 0
+#endif
+#ifndef HAVE_atomic_compare_and_swapsi
+#define HAVE_atomic_compare_and_swapsi 0
+#endif
+
+#ifndef HAVE_sync_compare_and_swapdi
+#define HAVE_sync_compare_and_swapdi 0
+#endif
+#ifndef HAVE_atomic_compare_and_swapdi
+#define HAVE_atomic_compare_and_swapdi 0
+#endif
+
 /* Profile all functions in the callgraph.  */
 
 static unsigned int
@@ -535,6 +549,27 @@ tree_profiling (void)
 {
   struct cgraph_node *node;
 
+  /* Verify whether we can utilize atomic update operations.  */
+  if (flag_profile_update == PROFILE_UPDATE_ATOMIC)
+    {
+      bool can_support = false;
+      unsigned HOST_WIDE_INT gcov_type_size
+	= tree_to_uhwi (TYPE_SIZE_UNIT (get_gcov_type ()));
+      if (gcov_type_size == 4)
+	can_support
+	  = HAVE_sync_compare_and_swapsi || HAVE_atomic_compare_and_swapsi;
+      else if (gcov_type_size == 8)
+	can_support
+	  = HAVE_sync_compare_and_swapdi || HAVE_atomic_compare_and_swapdi;
+
+      if (!can_support)
+      {
+	warning (0, "target does not support atomic profile update, "
+		 "single mode is selected");
+	flag_profile_update = PROFILE_UPDATE_SINGLE;
+      }
+    }
+
   /* This is a small-ipa pass that gets called only once, from
      cgraphunit.c:ipa_passes().  */
   gcc_assert (symtab->state == IPA_SSA);

libgcc/ChangeLog

+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

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