diff --git a/gcc/c/c-parser.cc b/gcc/c/c-parser.cc
index 84deac04c44..dc834158d1c 100644
--- a/gcc/c/c-parser.cc
+++ b/gcc/c/c-parser.cc
@@ -22542,7 +22542,16 @@ c_parser_omp_requires (c_parser *parser)
 	  if (!strcmp (p, "unified_address"))
 	    this_req = OMP_REQUIRES_UNIFIED_ADDRESS;
 	  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;
+	  }
 	  else if (!strcmp (p, "dynamic_allocators"))
 	    this_req = OMP_REQUIRES_DYNAMIC_ALLOCATORS;
 	  else if (!strcmp (p, "reverse_offload"))
@@ -22609,7 +22618,9 @@ c_parser_omp_requires (c_parser *parser)
 	      c_parser_skip_to_pragma_eol (parser, false);
 	      return;
 	    }
-	  if (p && this_req != OMP_REQUIRES_DYNAMIC_ALLOCATORS)
+	  if (p
+	      && this_req != OMP_REQUIRES_DYNAMIC_ALLOCATORS
+	      && this_req != OMP_REQUIRES_UNIFIED_SHARED_MEMORY)
 	    sorry_at (cloc, "%qs clause on %<requires%> directive not "
 			    "supported yet", p);
 	  if (p)
diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
index 03d99aba13e..ba263152aaf 100644
--- a/gcc/cp/parser.cc
+++ b/gcc/cp/parser.cc
@@ -46464,7 +46464,16 @@ cp_parser_omp_requires (cp_parser *parser, cp_token *pragma_tok)
 	  if (!strcmp (p, "unified_address"))
 	    this_req = OMP_REQUIRES_UNIFIED_ADDRESS;
 	  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;
+	  }
 	  else if (!strcmp (p, "dynamic_allocators"))
 	    this_req = OMP_REQUIRES_DYNAMIC_ALLOCATORS;
 	  else if (!strcmp (p, "reverse_offload"))
@@ -46537,7 +46546,9 @@ cp_parser_omp_requires (cp_parser *parser, cp_token *pragma_tok)
 	      cp_parser_skip_to_pragma_eol (parser, pragma_tok);
 	      return false;
 	    }
-	  if (p && this_req != OMP_REQUIRES_DYNAMIC_ALLOCATORS)
+	  if (p
+	      && this_req != OMP_REQUIRES_DYNAMIC_ALLOCATORS
+	      && this_req != OMP_REQUIRES_UNIFIED_SHARED_MEMORY)
 	    sorry_at (cloc, "%qs clause on %<requires%> directive not "
 			    "supported yet", p);
 	  if (p)
diff --git a/gcc/fortran/openmp.cc b/gcc/fortran/openmp.cc
index 16cd03a3d67..1f434857719 100644
--- a/gcc/fortran/openmp.cc
+++ b/gcc/fortran/openmp.cc
@@ -29,6 +29,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "diagnostic.h"
 #include "gomp-constants.h"
 #include "target-memory.h"  /* For gfc_encode_character.  */
+#include "options.h"
 
 /* Match an end of OpenMP directive.  End of OpenMP directive is optional
    whitespace, followed by '\n' or comment '!'.  */
@@ -5373,6 +5374,12 @@ gfc_match_omp_requires (void)
 	  requires_clause = OMP_REQ_UNIFIED_SHARED_MEMORY;
 	  if (requires_clauses & OMP_REQ_UNIFIED_SHARED_MEMORY)
 	    goto duplicate_clause;
+
+	  if (flag_offload_memory != OFFLOAD_MEMORY_UNIFIED
+	      && flag_offload_memory != OFFLOAD_MEMORY_NONE)
+	    gfc_error_now ("unified_shared_memory at %C is incompatible with "
+			   "the selected -foffload-memory option");
+	  flag_offload_memory = OFFLOAD_MEMORY_UNIFIED;
 	}
       else if (gfc_match (clauses[3]) == MATCH_YES)
 	{
@@ -5412,7 +5419,8 @@ gfc_match_omp_requires (void)
 	goto error;
 
       if (requires_clause & ~(OMP_REQ_ATOMIC_MEM_ORDER_MASK
-			      | OMP_REQ_DYNAMIC_ALLOCATORS))
+			      | OMP_REQ_DYNAMIC_ALLOCATORS
+			      | OMP_REQ_UNIFIED_SHARED_MEMORY))
 	gfc_error_now ("Sorry, %qs clause at %L on REQUIRES directive is not "
 		       "yet supported", clause, &old_loc);
       if (!gfc_omp_requires_add_clause (requires_clause, clause, &old_loc, NULL))
diff --git a/gcc/testsuite/c-c++-common/gomp/usm-1.c b/gcc/testsuite/c-c++-common/gomp/usm-1.c
new file mode 100644
index 00000000000..619c21a83f4
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/gomp/usm-1.c
@@ -0,0 +1,4 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-foffload-memory=pinned" } */
+
+#pragma omp requires unified_shared_memory  /* { dg-error "unified_shared_memory is incompatible with the selected -foffload-memory option" } */
diff --git a/gcc/testsuite/gfortran.dg/gomp/usm-1.f90 b/gcc/testsuite/gfortran.dg/gomp/usm-1.f90
new file mode 100644
index 00000000000..340f6bb50a5
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/gomp/usm-1.f90
@@ -0,0 +1,6 @@
+! { dg-do compile }
+! { dg-additional-options "-foffload-memory=pinned" }
+
+!$omp requires unified_shared_memory  ! { dg-error "unified_shared_memory at .* is incompatible with the selected -foffload-memory option" }
+
+end
