问题
I searched the gcc 4.8.1 documents but couldn't find an answer to this:
I have some SSE4.1 code and fallback code, at runtime I detect whether the system supports SSE4.1 and in case it doesn't, I use the fallback code.
So far so good, but with latest gcc versions this is what happens:
- my application crashes because SSE4.1 instructions are being spread throughout the code every time a string comparison is performed
Since I'm compiling all my files with -msse41 this sounds reasonable but crashes my code. My question is this: is there any way to restrict SSE41 usage to just that code which makes use of SSE4.1? Unfortunately these are header files used everywhere so it would be rather difficult to just compile those translation units with msse41
回答1:
As of GCC 4.8, you can use multi-versioned functions, see http://gcc.gnu.org/gcc-4.8/changes.html, look for "Function Multiversioning Support with G++". Disclaimer: I did not use this (as of yet).
来源：https://stackoverflow.com/questions/20215775/sse4-1-automatically-put-in-string-comparison-on-newer-gcc