Comment 6 for bug 1797335

I can't reproduce this here. I'll note that I'm testing on a Broadwell and you're on a Haswell, but I'd hope that doesn't make a huge difference, unless H.J. Lu's latest round of CPU detection stuff has gone amok.

model name : Intel(R) Core(TM) i7-5600U CPU @ 2.60GHz

(xenial-amd64)adconrad@nosferatu:~/Downloads$ /lib/x86_64-linux-gnu/libc.so.6 | head -n1
GNU C Library (Ubuntu GLIBC 2.23-0ubuntu10) stable release version 2.23, by Roland McGrath et al.
(xenial-amd64)adconrad@nosferatu:~/Downloads$ time ./strstr aa
matches = 3000000

real 0m0.559s
user 0m0.556s
sys 0m0.001s

(bionic-amd64)adconrad@nosferatu:~/Downloads$ /lib/x86_64-linux-gnu/libc.so.6 | head -n1
GNU C Library (Ubuntu GLIBC 2.27-3ubuntu1) stable release version 2.27.
(bionic-amd64)adconrad@nosferatu:~/Downloads$ time ./strstr aa
matches = 3000000

real 0m0.527s
user 0m0.522s
sys 0m0.001s

(base)adconrad@nosferatu:~/Downloads$ /lib/x86_64-linux-gnu/libc.so.6 | head -n1
GNU C Library (Ubuntu GLIBC 2.28-0ubuntu1) stable release version 2.28.
(base)adconrad@nosferatu:~/Downloads$ time ./strstr aa
matches = 3000000

real 0m0.528s
user 0m0.525s
sys 0m0.002s