diff --git a/gcc/ada/gcc-interface/decl.cc b/gcc/ada/gcc-interface/decl.cc
index 655ba0b8a1051718f2c7e5f76aa0a1c9a1c7093a..4252e627b0ceee69581b313a2f6838687fab3b6b 100644
--- a/gcc/ada/gcc-interface/decl.cc
+++ b/gcc/ada/gcc-interface/decl.cc
@@ -1430,7 +1430,7 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, bool definition)
 			post_error
 			  ("??too large object cannot be allocated statically",
 			   gnat_entity);
-			post_error ("\\?dynamic allocation will be used instead",
+			post_error ("\\??dynamic allocation will be used instead",
 				    gnat_entity);
 		      }
 
@@ -6565,7 +6565,7 @@ gnat_to_gnu_subprog_type (Entity_Id gnat_subprog, bool definition,
 			    ("??cannot import type-generic 'G'C'C builtin!",
 			     gnat_subprog);
 			  post_error
-			    ("\\?use a supported result type",
+			    ("\\??use a supported result type",
 			     gnat_subprog);
 			  gnu_builtin_decl = NULL_TREE;
 			}
@@ -6587,7 +6587,7 @@ gnat_to_gnu_subprog_type (Entity_Id gnat_subprog, bool definition,
 			    ("??cannot import type-generic 'G'C'C builtin!",
 			     gnat_subprog);
 			  post_error
-			    ("\\?use a supported second parameter type",
+			    ("\\??use a supported second parameter type",
 			     gnat_subprog);
 			  gnu_builtin_decl = NULL_TREE;
 			}
@@ -6608,7 +6608,7 @@ gnat_to_gnu_subprog_type (Entity_Id gnat_subprog, bool definition,
 			    ("??cannot import type-generic 'G'C'C builtin!",
 			     gnat_subprog);
 			  post_error
-			    ("\\?use a supported third parameter type",
+			    ("\\??use a supported third parameter type",
 			     gnat_subprog);
 			  gnu_builtin_decl = NULL_TREE;
 			}
diff --git a/gcc/ada/gcc-interface/trans.cc b/gcc/ada/gcc-interface/trans.cc
index 92e000686fb2f5daf3dfcc37d7ee950595eafbd7..710907bb999f27d2cbc984862dcea29ec8f5c12c 100644
--- a/gcc/ada/gcc-interface/trans.cc
+++ b/gcc/ada/gcc-interface/trans.cc
@@ -4949,10 +4949,10 @@ Call_to_gnu (Node_Id gnat_node, tree *gnu_result_type_p, tree gnu_target,
 		    ("unchecked conversion implemented by copy??",
 		     gnat_actual);
 		  post_error
-		    ("\\?use pragma Universal_Aliasing on either type",
+		    ("\\??use pragma Universal_Aliasing on either type",
 		     gnat_actual);
 		  post_error
-		    ("\\?to enable RM 13.9(12) implementation permission",
+		    ("\\??to enable RM 13.9(12) implementation permission",
 		     gnat_actual);
 		}
 
@@ -4962,10 +4962,10 @@ Call_to_gnu (Node_Id gnat_node, tree *gnu_result_type_p, tree gnu_target,
 		    ("value conversion implemented by copy??",
 		     gnat_actual);
 		  post_error
-		    ("\\?use pair of types with same root type",
+		    ("\\??use pair of types with same root type",
 		     gnat_actual);
 		  post_error
-		    ("\\?to avoid new object in RM 4.6(58.5/5)",
+		    ("\\??to avoid new object in RM 4.6(58.5/5)",
 		     gnat_actual);
 		}
 	    }
@@ -10644,9 +10644,9 @@ validate_unchecked_conversion (Node_Id gnat_node)
 	{
 	  post_error_ne ("??possible aliasing problem for type&",
 			 gnat_node, Target_Type (gnat_node));
-	  post_error ("\\?use -fno-strict-aliasing switch for references",
+	  post_error ("\\??use -fno-strict-aliasing switch for references",
 		      gnat_node);
-	  post_error_ne ("\\?or use `pragma No_Strict_Aliasing (&);`",
+	  post_error_ne ("\\??or use `pragma No_Strict_Aliasing (&);`",
 			 gnat_node, Target_Type (gnat_node));
 	}
     }
@@ -10670,7 +10670,7 @@ validate_unchecked_conversion (Node_Id gnat_node)
 	{
 	  post_error_ne ("??possible aliasing problem for type&",
 			 gnat_node, Target_Type (gnat_node));
-	  post_error ("\\?use -fno-strict-aliasing switch for references",
+	  post_error ("\\??use -fno-strict-aliasing switch for references",
 		      gnat_node);
 	}
     }