c++ - GCC: program doesn't work with compilation option -O3

Question

I'm writing a C++ program that doesn't work (I get a segmentation fault) when I compile it with optimizations (options -O1, -O2, -O3, etc.), but it works just fine when I compile it without optimizations.

Is there any chance that the error is in my code? or should I assume that this is a bug in GCC?

My GCC version is 3.4.6.

Is there any known workaround for this kind of problem?

There is a big difference in speed between the optimized and unoptimized version of my program, so I really need to use optimizations.

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This is my original functor. The one that works fine with no levels of optimizations and throws a segmentation fault with any level of optimization:

struct distanceToPointSort{
    indexedDocument* point ;
    distanceToPointSort(indexedDocument* p): point(p) {}
    bool operator() (indexedDocument* p1,indexedDocument* p2){
        return distance(point,p1) < distance(point,p2) ;
    }
} ;

And this one works flawlessly with any level of optimization:

struct distanceToPointSort{
    indexedDocument* point ;
    distanceToPointSort(indexedDocument* p): point(p) {}
    bool operator() (indexedDocument* p1,indexedDocument* p2){

        float d1=distance(point,p1) ;
        float d2=distance(point,p2) ;

        std::cout << "" ;  //without this line, I get a segmentation fault anyways

        return d1 < d2 ;
    }
} ;

Unfortunately, this problem is hard to reproduce because it happens with some specific values. I get the segmentation fault upon sorting just one out of more than a thousand vectors, so it really depends on the specific combination of values each vector has.

Answer 1

I would assume your code is wrong first.
Though it is hard to tell.

Does your code compile with 0 warnings?

 g++ -Wall -Wextra -pedantic -ansi