https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80491
--- Comment #2 from Victor Khimenko ---
An interesting observation: -O1 actually produces perfect code:
$ gcc -S -O1 test.cc -o-
.file "test.cc"
.text
.p2align 4,,15
.globl _Z3addR4pairS0_
.type _Z3addR4pa
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80491
--- Comment #1 from Victor Khimenko ---
Actually even clang's version is not optimal ("addq 8(%rdi), %rdx" then "adcq
$0, %rdx" could be replaced with "adcq 8(%rdi), %rdx"). But at least both calng
and old version of gcc are smart enough to rem
