diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index eddd2adbab5..019bb7ccc38 100644
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -3830,32 +3830,37 @@ rs6000_option_override_internal (bool global_init_p)
   /* Add some warnings for VSX.  */
   if (TARGET_VSX)
     {
-      const char *msg = NULL;
+      bool explicit_vsx_p = rs6000_isa_flags_explicit & OPTION_MASK_VSX;
       if (!TARGET_HARD_FLOAT)
 	{
-	  if (rs6000_isa_flags_explicit & OPTION_MASK_VSX)
-	    msg = N_("%<-mvsx%> requires hardware floating point");
-	  else
+	  if (explicit_vsx_p)
 	    {
-	      rs6000_isa_flags &= ~ OPTION_MASK_VSX;
-	      rs6000_isa_flags_explicit |= OPTION_MASK_VSX;
+	      if (rs6000_isa_flags_explicit & OPTION_MASK_SOFT_FLOAT)
+		error ("%<-mvsx%> and %<-msoft-float%> are incompatible");
+	      else
+		warning (0, N_("%<-mvsx%> requires hardware floating-point"));
 	    }
+	  rs6000_isa_flags &= ~OPTION_MASK_VSX;
+	  rs6000_isa_flags_explicit |= OPTION_MASK_VSX;
 	}
       else if (TARGET_AVOID_XFORM > 0)
-	msg = N_("%<-mvsx%> needs indexed addressing");
-      else if (!TARGET_ALTIVEC && (rs6000_isa_flags_explicit
-				   & OPTION_MASK_ALTIVEC))
-        {
-	  if (rs6000_isa_flags_explicit & OPTION_MASK_VSX)
-	    msg = N_("%<-mvsx%> and %<-mno-altivec%> are incompatible");
-	  else
-	    msg = N_("%<-mno-altivec%> disables vsx");
-        }
-
-      if (msg)
 	{
-	  warning (0, msg);
-	  rs6000_isa_flags &= ~ OPTION_MASK_VSX;
+	  if (explicit_vsx_p && OPTION_SET_P (TARGET_AVOID_XFORM))
+	    error ("%<-mvsx%> and %<-mavoid-indexed-addresses%>"
+		   " are incompatible");
+	  else
+	    warning (0, N_("%<-mvsx%> needs indexed addressing"));
+	  rs6000_isa_flags &= ~OPTION_MASK_VSX;
+	  rs6000_isa_flags_explicit |= OPTION_MASK_VSX;
+	}
+      else if (!TARGET_ALTIVEC
+	       && (rs6000_isa_flags_explicit & OPTION_MASK_ALTIVEC))
+	{
+	  if (explicit_vsx_p)
+	    error ("%<-mvsx%> and %<-mno-altivec%> are incompatible");
+	  else
+	    warning (0, N_("%<-mno-altivec%> disables vsx"));
+	  rs6000_isa_flags &= ~OPTION_MASK_VSX;
 	  rs6000_isa_flags_explicit |= OPTION_MASK_VSX;
 	}
     }
diff --git a/gcc/testsuite/gcc.target/powerpc/warn-1.c b/gcc/testsuite/gcc.target/powerpc/error-1.c
similarity index 70%
rename from gcc/testsuite/gcc.target/powerpc/warn-1.c
rename to gcc/testsuite/gcc.target/powerpc/error-1.c
index 76ac0c4e26e..d38eba8bb8a 100644
--- a/gcc/testsuite/gcc.target/powerpc/warn-1.c
+++ b/gcc/testsuite/gcc.target/powerpc/error-1.c
@@ -3,7 +3,7 @@
 /* { dg-require-effective-target powerpc_vsx_ok } */
 /* { dg-options "-O -mvsx -mno-altivec" } */
 
-/* { dg-warning "'-mvsx' and '-mno-altivec' are incompatible" "" { target *-*-* } 0 } */
+/* { dg-error "'-mvsx' and '-mno-altivec' are incompatible" "" { target *-*-* } 0 } */
 
 double
 foo (double *x, double *y)
@@ -16,4 +16,3 @@ foo (double *x, double *y)
   return z[0] * z[1];
 }
 
-/* { dg-final { scan-assembler-not "xsadddp" } } */