I am using boost v1.69, compiling with g++-7 for an x86 target. If I build with -O2 optimization flags when NDEBUG is defined, I get the following compiler warning: ./../boost/numeric/ublas/matrix_expression.hpp:59:20: error: ‘*((void*)&<anonymous> +8)’ is used uninitialized in this function [-Werror=uninitialized] return e_.size2 (); If I add -fno-partial-inling to the compiler flags, this makes the warning go away. This warning does not appear if NDEBUG is not defined, regardless of optimization flags. This behavior is the same with boost v1.71. I would like to build with the -fpartial-inling optimization when NDEBUG is defined. Is there a workaround to fix this warning? -- Albert -- IMPORTANT: The information contained in this transmission may be privileged, proprietary and confidential and protected from disclosure. It is intended only for the intended recipient. If you are not the intended recipient or a person responsible for delivering this transmission to the intended recipient, you may not disclose, copy or distribute this transmission or take any action in reliance on it. If you received this transmission in error, please notify us immediately by replying to this message and please dispose of and delete this transmission. Thank you. Yaskawa America, Inc.