Bug 1311

Created attachment 739 [details]
Backtrace

I might be doing something wrong, but since this used to work 
without any issue, here is a minimal example segfaulting on 3.3-rc1.


> cat test.cc 

#include <Eigen/Core>

int main() {
	
	Eigen::Matrix< double, 3, 2 > block ;
	block.setOnes() ;

	Eigen::Vector2d rhs = Eigen::Vector2d::Zero() ;

	Eigen::Vector3d res = 1. * ( block * rhs )  ;


	return 0 ;
}


> g++-5 -I eigen-33r1/  test.cc -o test && ./test 
Segmentation fault
> g++-5 -I eigen-33b2  test.cc -o test && ./test 

Happens with recent versions of gcc and clang
> g++-6 -I eigen-33r1/  test.cc -o test && ./test 
Segmentation fault
> clang++ -I eigen-33r1/  test.cc -o test && ./test 
Segmentation fault

..but can disappear once optimizations are enabled
> clang++ -O3 -I eigen-eigen-e35a38ad89fe/  test.cc -o test && ./test
>


Regression seems to have been introduced in commit  e35a38a

> g++-5 -I eigen-eigen-e35a38ad89fe/  test.cc -o test && ./test 
Segmentation fault
> g++-5 -I eigen-eigen-0b62bc896f80/  test.cc -o test && ./test 
>

Reverting this patch on 3.3-rc1 fixed the issue on my side.