diff --git a/gcc/config/rs6000/rs6000-cpus.def b/gcc/config/rs6000/rs6000-cpus.def
index 5337382bdcf..101efd54183 100644
--- a/gcc/config/rs6000/rs6000-cpus.def
+++ b/gcc/config/rs6000/rs6000-cpus.def
@@ -56,29 +56,35 @@
 				 | OPTION_MASK_QUAD_MEMORY		\
 				 | OPTION_MASK_QUAD_MEMORY_ATOMIC)
 
+/* ISA masks setting fusion options.  */
+#define OTHER_FUSION_MASKS	(OPTION_MASK_P8_FUSION			\
+				 | OPTION_MASK_P8_FUSION_SIGN)
+
 /* Add ISEL back into ISA 3.0, since it is supposed to be a win.  Do not add
    FLOAT128_HW here until we are ready to make -mfloat128 on by default.  */
-#define ISA_3_0_MASKS_SERVER	(ISA_2_7_MASKS_SERVER			\
-				 | OPTION_MASK_ISEL			\
-				 | OPTION_MASK_MODULO			\
-				 | OPTION_MASK_P9_MINMAX		\
-				 | OPTION_MASK_P9_MISC			\
-				 | OPTION_MASK_P9_VECTOR)
+#define ISA_3_0_MASKS_SERVER	((ISA_2_7_MASKS_SERVER			\
+				  | OPTION_MASK_ISEL			\
+				  | OPTION_MASK_MODULO			\
+				  | OPTION_MASK_P9_MINMAX		\
+				  | OPTION_MASK_P9_MISC			\
+				  | OPTION_MASK_P9_VECTOR)		\
+				 & ~OTHER_FUSION_MASKS)
 
 /* Support for the IEEE 128-bit floating point hardware requires a lot of the
    VSX instructions that are part of ISA 3.0.  */
 #define ISA_3_0_MASKS_IEEE	(OPTION_MASK_VSX			\
 				 | OPTION_MASK_P8_VECTOR		\
-				 | OPTION_MASK_P9_VECTOR		\
-				 | OPTION_MASK_DIRECT_MOVE)
+				 | OPTION_MASK_P9_VECTOR)
 
 /* Support for a future processor's features.  */
 #define ISA_FUTURE_MASKS_SERVER	(ISA_3_0_MASKS_SERVER			\
 				 | OPTION_MASK_FUTURE			\
-				 | OPTION_MASK_PCREL)
+				 | OPTION_MASK_PCREL			\
+				 | OPTION_MASK_PREFIXED_ADDR)
 
 /* Flags that need to be turned off if -mno-future.  */
-#define OTHER_FUTURE_MASKS	(OPTION_MASK_PCREL)
+#define OTHER_FUTURE_MASKS	(OPTION_MASK_PCREL			\
+				 | OPTION_MASK_PREFIXED_ADDR)
 
 /* Flags that need to be turned off if -mno-power9-vector.  */
 #define OTHER_P9_VECTOR_MASKS	(OPTION_MASK_FLOAT128_HW		\
@@ -139,6 +145,7 @@
 				 | OPTION_MASK_POWERPC64		\
 				 | OPTION_MASK_PPC_GFXOPT		\
 				 | OPTION_MASK_PPC_GPOPT		\
+				 | OPTION_MASK_PREFIXED_ADDR		\
 				 | OPTION_MASK_QUAD_MEMORY		\
 				 | OPTION_MASK_QUAD_MEMORY_ATOMIC	\
 				 | OPTION_MASK_RECIP_PRECISION		\
diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index b9fd89837a6..f9ef8e38314 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -4296,15 +4296,24 @@ rs6000_option_override_internal (bool global_init_p)
       rs6000_isa_flags &= ~OPTION_MASK_FLOAT128_HW;
     }
 
-  /* -mpcrel requires the prefixed load/store support on FUTURE systems.  */
-  if (!TARGET_FUTURE && TARGET_PCREL)
+  /* -mpcrel requires prefixed load/store addressing.  */
+  if (TARGET_PCREL && !TARGET_PREFIXED_ADDR)
     {
       if ((rs6000_isa_flags_explicit & OPTION_MASK_PCREL) != 0)
-	error ("%qs requires %qs", "-mpcrel", "-mcpu=future");
+	error ("%qs requires %qs", "-mpcrel", "-mprefixed-addr");
 
       rs6000_isa_flags &= ~OPTION_MASK_PCREL;
     }
 
+  /* -mprefixed-addr (and hence -mpcrel) requires -mcpu=future.  */
+  if (TARGET_PREFIXED_ADDR && !TARGET_FUTURE)
+    {
+      if ((rs6000_isa_flags_explicit & OPTION_MASK_PCREL) != 0)
+	error ("%qs requires %qs", "-mprefixed-addr", "-mcpu=future");
+
+      rs6000_isa_flags &= ~(OPTION_MASK_PCREL | OPTION_MASK_PREFIXED_ADDR);
+    }
+
   /* Print the options after updating the defaults.  */
   if (TARGET_DEBUG_REG || TARGET_DEBUG_TARGET)
     rs6000_print_isa_options (stderr, 0, "after defaults", rs6000_isa_flags);
@@ -36376,6 +36385,7 @@ static struct rs6000_opt_mask const rs6000_opt_masks[] =
   { "power9-vector",		OPTION_MASK_P9_VECTOR,		false, true  },
   { "powerpc-gfxopt",		OPTION_MASK_PPC_GFXOPT,		false, true  },
   { "powerpc-gpopt",		OPTION_MASK_PPC_GPOPT,		false, true  },
+  { "prefixed-addr",		OPTION_MASK_PREFIXED_ADDR,	false, true  },
   { "quad-memory",		OPTION_MASK_QUAD_MEMORY,	false, true  },
   { "quad-memory-atomic",	OPTION_MASK_QUAD_MEMORY_ATOMIC,	false, true  },
   { "recip-precision",		OPTION_MASK_RECIP_PRECISION,	false, true  },
diff --git a/gcc/config/rs6000/rs6000.opt b/gcc/config/rs6000/rs6000.opt
index 43b04834746..3a4353674b8 100644
--- a/gcc/config/rs6000/rs6000.opt
+++ b/gcc/config/rs6000/rs6000.opt
@@ -574,6 +574,10 @@ mfuture
 Target Report Mask(FUTURE) Var(rs6000_isa_flags)
 Use instructions for a future architecture.
 
+mprefixed-addr
+Target Undocumented Mask(PREFIXED_ADDR) Var(rs6000_isa_flags)
+Generate (do not generate) prefixed memory instructions.
+
 mpcrel
 Target Report Mask(PCREL) Var(rs6000_isa_flags)
 Generate (do not generate) pc-relative memory addressing.
