re PR fortran/83017 (DO CONCURRENT not parallelizing)

2017-11-17  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/83017
	* tree-parloops.c (MIN_PER_THREAD): Use --param parloops-min-per-thread.
	(gen_parallel_loop): Properly count iterations.
	(parallelize_loops): Handle loop->can_be_parallel independent
	of flag_loop_parallelize_all.  Make static profitability test match
	the runtime one.
	* params.def (PARAM_PARLOOPS_MIN_PER_THREAD): New.
	* invoke.texi (parloops-min-per-thread): Document.

	* gcc.dg/autopar/pr49960.c: Adjust.

From-SVN: r254867

6 files changed, 46 insertions, 21 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 07f2aa9..030a13c 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,14 @@
+2017-11-17  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/83017
+	* tree-parloops.c (MIN_PER_THREAD): Use --param parloops-min-per-thread.
+	(gen_parallel_loop): Properly count iterations.
+	(parallelize_loops): Handle loop->can_be_parallel independent
+	of flag_loop_parallelize_all.  Make static profitability test match
+	the runtime one.
+	* params.def (PARAM_PARLOOPS_MIN_PER_THREAD): New.
+	* invoke.texi (parloops-min-per-thread): Document.
+
 2017-11-17  Vineet Gupta  <vgupta@synopsys.com>
 
 	* config/arc/linux.h: GLIBC_DYNAMIC_LINKER update per glibc
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 1e2b869..e18fa54 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -10816,6 +10816,12 @@ is 0.
 Schedule type of omp schedule for loops parallelized by parloops (static,
 dynamic, guided, auto, runtime).  The default is static.
 
+@item parloops-min-per-thread
+The minimum number of iterations per thread of an innermost parallelized
+loop for which the parallelized variant is prefered over the single threaded
+one.  The default is 100.  Note that for a parallelized loop nest the
+minimum number of iterations of the outermost loop per thread is two.
+
 @item max-ssa-name-query-depth
 Maximum depth of recursion when querying properties of SSA names in things
 like fold routines.  One level of recursion corresponds to following a
diff --git a/gcc/params.def b/gcc/params.def
index 8881f4c..89915d4 100644
--- a/gcc/params.def
+++ b/gcc/params.def
@@ -1240,6 +1240,12 @@ DEFPARAMENUM5 (PARAM_PARLOOPS_SCHEDULE,
 	       static,
 	       static, dynamic, guided, auto, runtime)
 
+DEFPARAM (PARAM_PARLOOPS_MIN_PER_THREAD,
+	  "parloops-min-per-thread",
+	  "Minimum number of iterations per thread of an innermost "
+	  "parallelized loop.",
+	  100, 2, 0)
+
 DEFPARAM (PARAM_MAX_SSA_NAME_QUERY_DEPTH,
 	  "max-ssa-name-query-depth",
 	  "Maximum recursion depth allowed when querying a property of an"
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 1699033..2238dae 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2017-11-17  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/83017
+	* gcc.dg/autopar/pr49960.c: Adjust.
+
 2017-11-17  Sudakshina Das  <sudi.das@arm.com>
 
 	* gcc.target/arm/armv8_2-fp16-move-1.c: Edit vmov scan-assembler
diff --git a/gcc/testsuite/gcc.dg/autopar/pr49960.c b/gcc/testsuite/gcc.dg/autopar/pr49960.c
index e3fb04d..447169d 100644
--- a/gcc/testsuite/gcc.dg/autopar/pr49960.c
+++ b/gcc/testsuite/gcc.dg/autopar/pr49960.c
@@ -7,7 +7,8 @@
 #define MA 400
 
 int T[MA][MB],A[MA][NA],B[MB][NA];
-void MRTRBR(int MA_1, int NA_1, int MB_1)
+void __attribute__((noinline))
+MRTRBR(int MA_1, int NA_1, int MB_1)
 {
   int i,j, t,k;
 
@@ -21,7 +22,7 @@ void MRTRBR(int MA_1, int NA_1, int MB_1)
   /* The outer most loop is not parallel because for different k's there
      is write-write dependency for T[i][j].  */
   
-  /* The two inner loops don't get parallelized due to low number of 
+  /* The innermost loop doesn't get parallelized due to low number of 
      iterations.  */
 
   for (k = 3; k < NA_1; k++)
@@ -38,7 +39,10 @@ void main ()
   
   for (i = 3; i < MA; i++)
     for (j = 3; j < MB; j++)
-      T[i][j] = (i>j?i:j);
+      {
+	__asm__ volatile ("" : : : "memory");
+	T[i][j] = (i>j?i:j);
+      }
   
   MRTRBR (MA,NA,MB);
   
@@ -48,7 +52,7 @@ void main ()
 }
 
 
-/* Check that the outer most loop doesn't get parallelized (thus no loop gets parallelized)  */
+/* Check that the outer most loop doesn't get parallelized.  */
 
-/* { dg-final { scan-tree-dump-times "SUCCESS: may be parallelized" 0 "parloops2" } } */
-/* { dg-final { scan-tree-dump-times "loopfn" 0 "optimized" } } */
+/* { dg-final { scan-tree-dump-times "SUCCESS: may be parallelized" 1 "parloops2" } } */
+/* { dg-final { scan-tree-dump-times "__builtin_GOMP_parallel" 1 "optimized" } } */
diff --git a/gcc/tree-parloops.c b/gcc/tree-parloops.c
index cfc143f..643ab57 100644
--- a/gcc/tree-parloops.c
+++ b/gcc/tree-parloops.c
@@ -184,7 +184,7 @@ parloop
 
 /* Minimal number of iterations of a loop that should be executed in each
    thread.  */
-#define MIN_PER_THREAD 100
+#define MIN_PER_THREAD PARAM_VALUE (PARAM_PARLOOPS_MIN_PER_THREAD)
 
 /* Element of the hashtable, representing a
    reduction in the current loop.  */
@@ -2336,7 +2336,7 @@ gen_parallel_loop (struct loop *loop,
       gcc_checking_assert (n_threads != 0);
       many_iterations_cond =
 	fold_build2 (GE_EXPR, boolean_type_node,
-		     nit, build_int_cst (type, m_p_thread * n_threads));
+		     nit, build_int_cst (type, m_p_thread * n_threads - 1));
 
       many_iterations_cond
 	= fold_build2 (TRUTH_AND_EXPR, boolean_type_node,
@@ -3299,15 +3299,6 @@ parallelize_loops (bool oacc_kernels_p)
 	  fprintf (dump_file, "loop %d is innermost\n",loop->num);
       }
 
-      /* If we use autopar in graphite pass, we use its marked dependency
-      checking results.  */
-      if (flag_loop_parallelize_all && !loop->can_be_parallel)
-      {
-        if (dump_file && (dump_flags & TDF_DETAILS))
-	   fprintf (dump_file, "loop is not parallel according to graphite\n");
-	continue;
-      }
-
       if (!single_dom_exit (loop))
       {
 
@@ -3325,15 +3316,17 @@ parallelize_loops (bool oacc_kernels_p)
 	  || loop_has_vector_phi_nodes (loop))
 	continue;
 
-      estimated = estimated_stmt_executions_int (loop);
+      estimated = estimated_loop_iterations_int (loop);
       if (estimated == -1)
-	estimated = likely_max_stmt_executions_int (loop);
+	estimated = get_likely_max_loop_iterations_int (loop);
       /* FIXME: Bypass this check as graphite doesn't update the
 	 count and frequency correctly now.  */
       if (!flag_loop_parallelize_all
 	  && !oacc_kernels_p
 	  && ((estimated != -1
-	       && estimated <= (HOST_WIDE_INT) n_threads * MIN_PER_THREAD)
+	       && (estimated
+		   < ((HOST_WIDE_INT) n_threads
+		      * (loop->inner ? 2 : MIN_PER_THREAD) - 1)))
 	      /* Do not bother with loops in cold areas.  */
 	      || optimize_loop_nest_for_size_p (loop)))
 	continue;
@@ -3347,7 +3340,7 @@ parallelize_loops (bool oacc_kernels_p)
       if (loop_has_phi_with_address_arg (loop))
 	continue;
 
-      if (!flag_loop_parallelize_all
+      if (!loop->can_be_parallel
 	  && !loop_parallel_p (loop, &parloop_obstack))
 	continue;