http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58717
Bug ID: 58717
Summary: Pre-calculation optimization is omitted
Product: gcc
Version: 4.8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: masoud_mxm at yahoo dot com
Created attachment 30997
--> http://gcc.gnu.org/bugzilla/attachment.cgi?id=30997&action=edit
Two .cpp source code
It seems newer versions of gcc (4.8+) don't pre-calculate functions for
constant inputs (Asked the issue here:
http://stackoverflow.com/q/19350097/952747). Two source codes attached.
unsigned long long s(unsigned long long n)
{
auto s = 0ULL;
for (auto i = 0ULL; i < n; i++)
s += i;
return s;
}
const auto N = 1000000000ULL;
auto x = s(N); // It computes in run-time and dose NOT compute in compile-time!
