Re: Bug with Visual Studio Optimizer?

Marco Manfredini <>
Mon, 26 Nov 2007 12:58:01 CST
Ulrich Eckhardt wrote:

Jason Hise wrote:

The following code prints GOOD in debug mode, and BAD in release
mode. Is that allowed by the standard? This was the root cause of a
very difficult to hunt down bug in my program, where I was using the
function addresses as keys into a map. I am wondering if I should
submit a bug report to Microsoft.

#include <iostream>

template<typename Type>
void foo() { }

int main()
    std::cout << (&foo<int> == &foo<float>
        ? "BAD" : "GOOD") << std::endl;
    return 0;

Just wondering, you aren't using that ten year old, unsupported and
deprecated VC6, are you? In that case, this behaviour is a known bug
and you're not going to get it fixed except by upgrading.

This also happens with the regular VC-2005 compiler. It mercilessly
prunes everything which has no apparent effect or use or isn't
different enough and often enough really crosses a line or two.

The worksaround is to put candy into foo():

template<typename T>
const std::type_info &foo()
         return typeid(T); // all foo's have a distinct effect

or, alternatively:

template<typename T>
void foo()
         std::cout << typeid(T);

IYesNo yes=YesNoFactory.getFactoryInstance().YES;

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