I experienced crashes running an old code of mine on a system which doesn't support SSE4.1, I debugged a bit and found SSE instructions in the glibc, is that possible? Why isn't this reported in gcc 4.8.1 release notes?
You can see what optimizations are used by GCC with the following command:
$ gcc -Q --help=target
For instance, on my machine, GCC does not enable sse4.1 by default:
$ gcc -Q --help=target | grep msse4.1
-msse4.1 [disabled]
However, it is supported because it appears in /proc/cpuinfo
. And indeed, if I ask GCC to optimize the generated code for my machine, it enables sse4.1:
$ gcc -Q --help=target -march=native | grep msse4.1
-msse4.1 [enabled]
来源:https://stackoverflow.com/questions/20150257/does-gcc-4-8-1-enable-sse-by-default