Hi!
On the following testcase, the first function is cp_folded into
return i == 0 ? 2147483648(OVF): 2147483647;
The problem is that we don't diagnose then the overflow at all.
We already have code that sets *overflow_p under right conditions,
just there wasn't any permerror call.
Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
trunk?
2016-03-22 Jakub Jelinek <ja...@redhat.com>
PR c++/70323
* constexpr.c (cxx_eval_constant_expression): Diagnose overflow
on TREE_OVERFLOW constants.
* g++.dg/cpp0x/constexpr-70323.C: New test.
--- gcc/cp/constexpr.c.jj 2016-03-22 09:05:32.000000000 +0100
+++ gcc/cp/constexpr.c 2016-03-22 10:38:58.598077573 +0100
@@ -3306,8 +3306,13 @@ cxx_eval_constant_expression (const cons
}
if (CONSTANT_CLASS_P (t))
{
- if (TREE_OVERFLOW (t) && (!flag_permissive || ctx->quiet))
- *overflow_p = true;
+ if (TREE_OVERFLOW (t))
+ {
+ if (!ctx->quiet)
+ permerror (input_location, "overflow in constant expression");
+ if (!flag_permissive || ctx->quiet)
+ *overflow_p = true;
+ }
return t;
}
--- gcc/testsuite/g++.dg/cpp0x/constexpr-70323.C.jj 2016-03-22
10:42:54.093884158 +0100
+++ gcc/testsuite/g++.dg/cpp0x/constexpr-70323.C 2016-03-22
10:42:29.000000000 +0100
@@ -0,0 +1,10 @@
+// PR c++/70323
+// { dg-do compile { target c++11 } }
+
+constexpr int overflow_if_0 (int i) { return __INT_MAX__ + !i; }
+constexpr int overflow_if_1 (int i) { return __INT_MAX__ + i; }
+
+constexpr bool i0_0 = overflow_if_0 (0); // { dg-error "overflow in constant
expression" }
+constexpr bool i0_1 = overflow_if_0 (1);
+constexpr bool i1_0 = overflow_if_1 (0);
+constexpr bool i1_1 = overflow_if_1 (1); // { dg-error "overflow in constant
expression" }
Jakub
