I've just started trying to install version 1.60 of boost using the gcc 5.3.0 compiler. With a vanilla download and no chnages it all seems to compile correctly, but I have a problem with 2 library regressions tests not terminating. They have both run for over 18 hours before I had to kill them. I was using the options and configuration "out of the box" so optimization was -O3. I downloaded the regressions tests from https://github.com/boostorg/regression and installed in the boost source tree under 'tools' I then compiled and run them : B=$PWD cd tools/regressions-develop/build $B/b2 --boost-root=$B export PATH=$B:$B/tools/regression-develop/stage/bin:$PATH cd $B/lib/maths/test b2 threading=multi variant=release toolset=gcc-5.3.0 test_binomial_real_concept2 The last few lines of the output file are: test_binomial.cpp(671): error: in "test_main": check x == (RealType)floor(binomial_quantile_data[i][3]) has failed [60 != 61] test_binomial.cpp(673): error: in "test_main": check x == (RealType)floor(binomial_quantile_data[i][4]) has failed [61 != 64] test_binomial.cpp(673): error: in "test_main": check x == (RealType)floor(binomial_quantile_data[i][4]) has failed [60 != 59] test_binomial.cpp(673): error: in "test_main": check x == (RealType)floor(binomial_quantile_data[i][4]) has failed [60 != 59] the same looping forever occurs with test_binomial_real_concept4 as well. However, editing the Jamfile.v2 file to add an entry '<optimization>off' for the test, allows the test to complete successfully and the test_binomial_real_concept2.output having no errors. I've done the same test using gcc 5.2.0 and gcc 5.1.0 as well with the same results. However, boost 1.56 using gcc 5.3.0 completes all of it's tests successfully. Is this a known issue or, if not, is there any more information that I can supply to help diagnose why this isn't working? Many thanks, S