trans.c (build_binary_op_trapv): Avoid emitting overflow check for constant result.

	* gcc-interface/trans.c (build_binary_op_trapv): Avoid emitting
	overflow check for constant result.

From-SVN: r141666

diff --git a/gcc/ada/ChangeLog b/gcc/ada/ChangeLog
index f9d899309bad4cd2e69b2c191a48e792e7eab495..68f0623539ddeacf38e2ddf6522dd35bf18aaed9 100644 (file)
--- a/gcc/ada/ChangeLog
+++ b/gcc/ada/ChangeLog
@@ -1,3 +1,8 @@
+2008-11-07  Geert Bosch  <bosch@adacore.com>
+
+       * gcc-interface/trans.c (build_binary_op_trapv): Avoid emitting
+       overflow check for constant result.
+
 2008-11-07  Geert Bosch  <bosch@adacore.com>
 
        * gcc-interface/trans.c (build_binary_op_trapv): Use more efficient

diff --git a/gcc/ada/gcc-interface/trans.c b/gcc/ada/gcc-interface/trans.c
index 5d56ef84cb1911ad38157ad75582166dccff6010..aca7167bae00f8a9700cffc6378b5e9dcea4e17c 100644 (file)
--- a/gcc/ada/gcc-interface/trans.c
+++ b/gcc/ada/gcc-interface/trans.c
@@ -6146,6 +6146,10 @@ build_binary_op_trapv (enum tree_code code,
 
   gnu_expr = build_binary_op (code, gnu_type, lhs, rhs);
 
+  /* If we can fold the expression to a constant, just return it.
+     The caller will deal with overflow, no need to generate a check. */
+  if (TREE_CONSTANT (gnu_expr)) return gnu_expr;
+
   check = fold_build3 (COND_EXPR, integer_type_node,
                       rhs_lt_zero,  check_neg, check_pos);