Lambda testcase fails when optimization enabled in gcc and llvm

19 Jul 2019

      Hi Devs,
consider below reduced testcase from boost lamda.

$cat result_of_tests.cpp

#include 
#include 
template typename boost::result_of::type apply1(F
f, A b) {
    return f(b);
}
using namespace boost::lambda;
int main(int, char *[]) {
    int one = 1;
    int d= (apply1<int>(_1 ,one) == 1);
    printf("\n%d\n",d);
    return 0;
}
when compiled with optimization O2
$g++ result_of_tests.cpp  -I ./boost_1_70_0 -O2
$./a.out
0

And,when we compile same testcase with O0
$g++ result_of_tests.cpp  -I ./boost_1_70_0 -O0
$./a.out
1

The above testcases is demonstrated with g++ compiler but behavior is same
on clang as well.
so we thought that this may be boost testcase issue.
When we replace ,
  int d= (apply1<int>(_1 ,one) == 1);
 with
  int d= (apply1(_1 ,one) == 1);

testcase gives correct result with or without optimization.

Wanted to confirm here,is it valid testcase or we have to modify testcase
as per above?

Thanks,
Navya

navya deepika garakapati

Fletcher, John P

navya deepika garakapati

Fletcher, John P

Fletcher, John P

Peter Dimov

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