trans.c (gnat_to_gnu): Remove superfluous tests on…

trans.c (gnat_to_gnu): Remove superfluous tests on Backend_Overflow_Checks_On_Target and rework comments.

	* gcc-interface/trans.c (gnat_to_gnu): Remove superfluous tests on
	Backend_Overflow_Checks_On_Target and rework comments.

From-SVN: r271689

gcc/ada/ChangeLog

 2019-05-28  Eric Botcazou  <ebotcazou@adacore.com>
 
+	* gcc-interface/trans.c (gnat_to_gnu): Remove superfluous tests on
+	Backend_Overflow_Checks_On_Target and rework comments.
+
+2019-05-28  Eric Botcazou  <ebotcazou@adacore.com>
+
 	* gcc-interface/trans.c (walk_nesting_tree): New static function.
 	(finalize_nrv): Use it to walk the entire nesting tree.
 

gcc/ada/gcc-interface/trans.c

@@ -7587,16 +7587,15 @@ gnat_to_gnu (Node_Id gnat_node)
 	    gnu_rhs = convert (gnu_type, gnu_rhs);
 	  }
 
-	/* Instead of expanding overflow checks for addition, subtraction
-	   and multiplication itself, the front end will leave this to
-	   the back end when Backend_Overflow_Checks_On_Target is set.  */
+	/* For signed integer addition, subtraction and multiplication, do an
+	   overflow check if required.  */
 	if (Do_Overflow_Check (gnat_node)
-	    && Backend_Overflow_Checks_On_Target
 	    && (code == PLUS_EXPR || code == MINUS_EXPR || code == MULT_EXPR)
 	    && !TYPE_UNSIGNED (gnu_type)
 	    && !FLOAT_TYPE_P (gnu_type))
-	  gnu_result = build_binary_op_trapv (code, gnu_type,
-					      gnu_lhs, gnu_rhs, gnat_node);
+	  gnu_result
+	    = build_binary_op_trapv (code, gnu_type, gnu_lhs, gnu_rhs,
+				     gnat_node);
 	else
 	  {
 	    /* Some operations, e.g. comparisons of arrays, generate complex
@@ -7657,19 +7656,17 @@ gnat_to_gnu (Node_Id gnat_node)
       gnu_expr = gnat_to_gnu (Right_Opnd (gnat_node));
       gnu_result_type = get_unpadded_type (Etype (gnat_node));
 
-      /* Instead of expanding overflow checks for negation and absolute
-	 value itself, the front end will leave this to the back end
-	 when Backend_Overflow_Checks_On_Target is set.  */
+      /* For signed integer negation and absolute value, do an overflow check
+	 if required.  */
       if (Do_Overflow_Check (gnat_node)
-	  && Backend_Overflow_Checks_On_Target
 	  && !TYPE_UNSIGNED (gnu_result_type)
 	  && !FLOAT_TYPE_P (gnu_result_type))
 	gnu_result
-	  = build_unary_op_trapv (gnu_codes[kind],
-				  gnu_result_type, gnu_expr, gnat_node);
+	  = build_unary_op_trapv (gnu_codes[kind], gnu_result_type, gnu_expr,
+				  gnat_node);
       else
-	gnu_result = build_unary_op (gnu_codes[kind],
-				     gnu_result_type, gnu_expr);
+	gnu_result
+	  = build_unary_op (gnu_codes[kind], gnu_result_type, gnu_expr);
       break;
 
     case N_Allocator: