[Bug target/66112] __builtin_mul_overflow for int16_t emits poor code

[gcc.hall at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66112

--- Comment #7 from Jeremy <gcc.hall at gmail dot com> ---
Comment on attachment 35522
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=35522
gcc5-pr66112.patch

Done, PR66120