[Bug target/47769] [missed optimization] use of btr (bit test and reset)

[kretz at kde dot org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47769

--- Comment #2 from Matthias Kretz <kretz at kde dot org> 2011-02-17 10:00:55 UTC ---
Created attachment 23375
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=23375
Test code to see whether btr gets used automatically and to compare speed

compile with
g++ -O3 -march=core2 -msse4 -Wall -funroll-loops

-funroll-loops is not required to see the speedup, but it shows that a higher
instruction level parallelism can be achieved with the use of btr.