[Bug middle-end/102294] structure assignment slower than memberwise initialization

bart.vanassche at gmail dot com gcc-bugzilla@gcc.gnu.org
Mon Sep 13 01:43:59 GMT 2021


https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102294

--- Comment #3 from Bart Van Assche <bart.vanassche at gmail dot com> ---
Thanks for the quick feedback. I have modified the test program and added
target("no-sse") to the bio_init[123]() functions. With that change applied the
results are as follows:

$ gcc -O2 -o bio_init bio_init.c && ./bio_init
Elapsed time: 0.965606 s
Elapsed time: 0.529943 s
Elapsed time: 0.734645 s
$ clang -O2 -o bio_init-clang bio_init.c && ./bio_init-clang
Elapsed time: 0.633179 s
Elapsed time: 0.605532 s
Elapsed time: 0.504315 s

It seems like clang still generates significantly better code for bio_init3()
than gcc?


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