https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86029
--- Comment #3 from Zsolt <hg2ecz at ham dot hu> ---
smallrx$ clang-6.0 -O3 -march=native rx.c -S
smallrx$ cat rx.s | grep mulsc
callq __mulsc3
callq __mulsc3
callq __mulsc3
smallrx$ gcc -O3 -march=native rx.c -S
smallrx$ cat rx.s | grep mulsc
call __mulsc3@PLT
call __mulsc3@PLT
call __mulsc3@PLT
What is the difference between gcc's and clang's __mulsc3?
More test result:
$ gcc -O1 -march=native rx.c -lm -o rx
$ dd if=/dev/urandom bs=1M count=30 | time -p ./rx 145500000 145525000 f >
/dev/null
... gcc -O1 isn't slower than gcc -O2 or gcc -O3 ???
$ clang-6.0 -O1 -march=native rx.c -lm -o rx
$ dd if=/dev/urandom bs=1M count=30 | time -p ./rx 145500000 145525000 f >
/dev/null
... 5x faster the "clang -O1" than "gcc -O3".
