omp-low.c (lower_rec_input_clauses): For if (0) or simdlen (1) set max_vf to 1.

	* omp-low.c (lower_rec_input_clauses): For if (0) or simdlen (1) set
	max_vf to 1.
	* omp-expand.c (expand_omp_simd): For if (0) or simdlen (1) clear
	safelen_int and set loop->dont_vectorize.

	* c-c++-common/gomp/simd8.c: New test.

From-SVN: r271270

gcc/ChangeLog

+2019-05-15  Jakub Jelinek  <jakub@redhat.com>
+
+	* omp-low.c (lower_rec_input_clauses): For if (0) or simdlen (1) set
+	max_vf to 1.
+	* omp-expand.c (expand_omp_simd): For if (0) or simdlen (1) clear
+	safelen_int and set loop->dont_vectorize.
+
 2019-05-15  H.J. Lu  <hongjiu.lu@intel.com>
 
 	PR target/89021

gcc/omp-expand.c

@@ -4664,10 +4664,15 @@ expand_omp_simd (struct omp_region *region, struct omp_for_data *fd)
   tree *counts = NULL;
   int i;
   int safelen_int = INT_MAX;
+  bool dont_vectorize = false;
   tree safelen = omp_find_clause (gimple_omp_for_clauses (fd->for_stmt),
 				  OMP_CLAUSE_SAFELEN);
   tree simduid = omp_find_clause (gimple_omp_for_clauses (fd->for_stmt),
 				  OMP_CLAUSE__SIMDUID_);
+  tree ifc = omp_find_clause (gimple_omp_for_clauses (fd->for_stmt),
+			      OMP_CLAUSE_IF);
+  tree simdlen = omp_find_clause (gimple_omp_for_clauses (fd->for_stmt),
+				  OMP_CLAUSE_SIMDLEN);
   tree n1, n2;
 
   if (safelen)
@@ -4681,6 +4686,12 @@ expand_omp_simd (struct omp_region *region, struct omp_for_data *fd)
       if (safelen_int == 1)
 	safelen_int = 0;
     }
+  if ((ifc && integer_zerop (OMP_CLAUSE_IF_EXPR (ifc)))
+      || (simdlen && integer_onep (OMP_CLAUSE_SIMDLEN_EXPR (simdlen))))
+    {
+      safelen_int = 0;
+      dont_vectorize = true;
+    }
   type = TREE_TYPE (fd->loop.v);
   entry_bb = region->entry;
   cont_bb = region->cont;
@@ -4965,6 +4976,8 @@ expand_omp_simd (struct omp_region *region, struct omp_for_data *fd)
 	  loop->force_vectorize = true;
 	  cfun->has_force_vectorize_loops = true;
 	}
+      else if (dont_vectorize)
+	loop->dont_vectorize = true;
     }
   else if (simduid)
     cfun->has_simduid_loops = true;

gcc/omp-low.c

@@ -3811,6 +3811,14 @@ lower_rec_input_clauses (tree clauses, gimple_seq *ilist, gimple_seq *dlist,
 	      || is_variable_sized (OMP_CLAUSE_DECL (c)))
 	    sctx.max_vf = 1;
 	  break;
+	case OMP_CLAUSE_IF:
+	  if (integer_zerop (OMP_CLAUSE_IF_EXPR (c)))
+	    sctx.max_vf = 1;
+	  break;
+        case OMP_CLAUSE_SIMDLEN:
+	  if (integer_onep (OMP_CLAUSE_SIMDLEN_EXPR (c)))
+	    sctx.max_vf = 1;
+	  break;
 	default:
 	  continue;
 	}

gcc/testsuite/ChangeLog

+2019-05-15  Jakub Jelinek  <jakub@redhat.com>
+
+	* c-c++-common/gomp/simd8.c: New test.
+
 2019-05-15  Marek Polacek  <polacek@redhat.com>
 
 	CWG 2096 - constraints on literal unions.

gcc/testsuite/c-c++-common/gomp/simd8.c

+/* { dg-do compile } */
+/* { dg-options "-fopenmp -O3 -fdump-tree-vect-details" } */
+/* { dg-final { scan-tree-dump-times "vectorized 0 loops in function" 4 "vect" } } */
+
+int a[1024];
+
+void
+foo (void)
+{
+  #pragma omp simd if (0)
+  for (int i = 0; i < 1024; ++i)
+    a[i] = a[i] + 1;
+}
+
+void
+bar (void)
+{
+  #pragma omp simd if (0) safelen (256) simdlen (8)
+  for (int i = 0; i < 512; ++i)
+    a[i] = a[i] + 1;
+}
+
+void
+baz (void)
+{
+  #pragma omp simd safelen (256) simdlen (1)
+  for (int i = 0; i < 512; ++i)
+    a[i] = a[i] + 1;
+}
+
+void
+qux (void)
+{
+  #pragma omp simd simdlen (1) if (1)
+  for (int i = 0; i < 512; ++i)
+    a[i] = a[i] + 1;
+}