openmp: unified_address support

This makes "requires unified_address" work by making it eqivalent to
"requires unified_shared_memory".  This is more than is strictly necessary,
but should be standard compliant.

gcc/c/ChangeLog:

	* c-parser.c (c_parser_omp_requires): Check requires unified_address
	for conflict with -foffload-memory=shared.

gcc/cp/ChangeLog:

	* parser.c (cp_parser_omp_requires): Check requires unified_address
	for conflict with -foffload-memory=shared.

gcc/fortran/ChangeLog:

	* openmp.c (gfc_match_omp_requires): Check requires unified_address
	for conflict with -foffload-memory=shared.

gcc/ChangeLog:

	* omp-low.c: Do USM transformations for "unified_address".

gcc/testsuite/ChangeLog:

	* c-c++-common/gomp/usm-4.c: New test.
	* gfortran.dg/gomp/usm-4.f90: New test.

diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c
index 12408770193..9a3d0cb8cea 100644
--- a/gcc/c/c-parser.c
+++ b/gcc/c/c-parser.c
@@ -22531,18 +22531,27 @@ c_parser_omp_requires (c_parser *parser)
 	  enum omp_requires this_req = (enum omp_requires) 0;
 
 	  if (!strcmp (p, "unified_address"))
-	    this_req = OMP_REQUIRES_UNIFIED_ADDRESS;
+	    {
+	      this_req = OMP_REQUIRES_UNIFIED_ADDRESS;
+
+	      if (flag_offload_memory != OFFLOAD_MEMORY_UNIFIED
+		  && flag_offload_memory != OFFLOAD_MEMORY_NONE)
+		error_at (cloc,
+			  "unified_address is incompatible with the "
+			  "selected -foffload-memory option");
+	      flag_offload_memory = OFFLOAD_MEMORY_UNIFIED;
+	    }
 	  else if (!strcmp (p, "unified_shared_memory"))
-	  {
-	    this_req = OMP_REQUIRES_UNIFIED_SHARED_MEMORY;
-
-	    if (flag_offload_memory != OFFLOAD_MEMORY_UNIFIED
-		&& flag_offload_memory != OFFLOAD_MEMORY_NONE)
-	      error_at (cloc,
-			"unified_shared_memory is incompatible with the "
-			"selected -foffload-memory option");
-	    flag_offload_memory = OFFLOAD_MEMORY_UNIFIED;
-	  }
+	    {
+	      this_req = OMP_REQUIRES_UNIFIED_SHARED_MEMORY;
+
+	      if (flag_offload_memory != OFFLOAD_MEMORY_UNIFIED
+		  && flag_offload_memory != OFFLOAD_MEMORY_NONE)
+		error_at (cloc,
+			  "unified_shared_memory is incompatible with the "
+			  "selected -foffload-memory option");
+	      flag_offload_memory = OFFLOAD_MEMORY_UNIFIED;
+	    }
 	  else if (!strcmp (p, "dynamic_allocators"))
 	    this_req = OMP_REQUIRES_DYNAMIC_ALLOCATORS;
 	  else if (!strcmp (p, "reverse_offload"))
diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index fd9f62f4543..3a9ea272f10 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -46406,18 +46406,27 @@ cp_parser_omp_requires (cp_parser *parser, cp_token *pragma_tok)
 	  enum omp_requires this_req = (enum omp_requires) 0;
 
 	  if (!strcmp (p, "unified_address"))
-	    this_req = OMP_REQUIRES_UNIFIED_ADDRESS;
+	    {
+	      this_req = OMP_REQUIRES_UNIFIED_ADDRESS;
+
+	      if (flag_offload_memory != OFFLOAD_MEMORY_UNIFIED
+		  && flag_offload_memory != OFFLOAD_MEMORY_NONE)
+		error_at (cloc,
+			  "unified_address is incompatible with the "
+			  "selected -foffload-memory option");
+	      flag_offload_memory = OFFLOAD_MEMORY_UNIFIED;
+	    }
 	  else if (!strcmp (p, "unified_shared_memory"))
-	  {
-	    this_req = OMP_REQUIRES_UNIFIED_SHARED_MEMORY;
-
-	    if (flag_offload_memory != OFFLOAD_MEMORY_UNIFIED
-		&& flag_offload_memory != OFFLOAD_MEMORY_NONE)
-	      error_at (cloc,
-			"unified_shared_memory is incompatible with the "
-			"selected -foffload-memory option");
-	    flag_offload_memory = OFFLOAD_MEMORY_UNIFIED;
-	  }
+	    {
+	      this_req = OMP_REQUIRES_UNIFIED_SHARED_MEMORY;
+
+	      if (flag_offload_memory != OFFLOAD_MEMORY_UNIFIED
+		  && flag_offload_memory != OFFLOAD_MEMORY_NONE)
+		error_at (cloc,
+			  "unified_shared_memory is incompatible with the "
+			  "selected -foffload-memory option");
+	      flag_offload_memory = OFFLOAD_MEMORY_UNIFIED;
+	    }
 	  else if (!strcmp (p, "dynamic_allocators"))
 	    this_req = OMP_REQUIRES_DYNAMIC_ALLOCATORS;
 	  else if (!strcmp (p, "reverse_offload"))
diff --git a/gcc/fortran/openmp.c b/gcc/fortran/openmp.c
index ac4126bd7ea..ece04c03a68 100644
--- a/gcc/fortran/openmp.c
+++ b/gcc/fortran/openmp.c
@@ -5546,6 +5546,12 @@ gfc_match_omp_requires (void)
 	  requires_clause = OMP_REQ_UNIFIED_ADDRESS;
 	  if (requires_clauses & OMP_REQ_UNIFIED_ADDRESS)
 	    goto duplicate_clause;
+
+	  if (flag_offload_memory != OFFLOAD_MEMORY_UNIFIED
+	      && flag_offload_memory != OFFLOAD_MEMORY_NONE)
+	    gfc_error_now ("unified_address at %C is incompatible with "
+			   "the selected -foffload-memory option");
+	  flag_offload_memory = OFFLOAD_MEMORY_UNIFIED;
 	}
       else if (gfc_match (clauses[2]) == MATCH_YES)
 	{
diff --git a/gcc/omp-low.c b/gcc/omp-low.c
index 4653370aa41..ce30f53dbb5 100644
--- a/gcc/omp-low.c
+++ b/gcc/omp-low.c
@@ -16008,7 +16008,8 @@ public:
   {
     return (flag_openmp || flag_openmp_simd)
 	    && (flag_offload_memory == OFFLOAD_MEMORY_UNIFIED
-		|| omp_requires_mask & OMP_REQUIRES_UNIFIED_SHARED_MEMORY);
+		|| omp_requires_mask & OMP_REQUIRES_UNIFIED_SHARED_MEMORY
+		|| omp_requires_mask & OMP_REQUIRES_UNIFIED_ADDRESS);
   }
   virtual unsigned int execute (function *)
   {
diff --git a/gcc/testsuite/c-c++-common/gomp/usm-4.c b/gcc/testsuite/c-c++-common/gomp/usm-4.c
new file mode 100644
index 00000000000..b19664e9b66
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/gomp/usm-4.c
@@ -0,0 +1,4 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-foffload-memory=pinned" } */
+
+#pragma omp requires unified_address        /* { dg-error "unified_address is incompatible with the selected -foffload-memory option" } */
diff --git a/gcc/testsuite/gfortran.dg/gomp/usm-4.f90 b/gcc/testsuite/gfortran.dg/gomp/usm-4.f90
new file mode 100644
index 00000000000..725b07f2f88
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/gomp/usm-4.f90
@@ -0,0 +1,6 @@
+! { dg-do compile }
+! { dg-additional-options "-foffload-memory=pinned" }
+
+!$omp requires unified_address  ! { dg-error "unified_address at .* is incompatible with the selected -foffload-memory option" }
+
+end