[Bug target/81763] Issues with BMI on 32bit x86 apps on GCC 7.1+

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81763

--- Comment #7 from H.J. Lu <hjl.tools at gmail dot com> ---
(In reply to Mike Lothian from comment #6)
> I tried the test case with
> 
> gcc -O2 -march=native test.c -o test
> 
> and 
> 
> gcc -O2 -march=native -mno-bmi test.c -o test
> 
> Both executables seem to run with no output
> 
> I've only seen the issue in radeonsi in Mesa with LLVM, I'm not sure what's
> happening as the problem doesn't manifest when debugging is enabled so I'm
> not sure how to create a smaller test case

Compile radeonsi one function at a time with and without -mbmi to
find out the smallest function which causes the problem with -mbmi.
If the function is small enough, we can take a guess.