With unsigned shift counts the generated code should be shorter, since Julia then knows in which direction to shift.
-erik On Tue, Aug 30, 2016 at 7:24 PM, mmh <mumo...@gmail.com> wrote: > Is there an unsafe version of >> and << that does not do range checks? > > > On Tuesday, August 30, 2016 at 6:46:36 PM UTC-4, Yichao Yu wrote: >> >> >> >> On Tue, Aug 30, 2016 at 6:25 PM, mmh <mum...@gmail.com> wrote: >> >>> >>> <https://lh3.googleusercontent.com/-5n6yH4HI3KA/V8YHuRMLoiI/AAAAAAAAAC8/5zqKJIGP4wwpjw7hmKgLgTxvt3WVYKY2ACLcB/s1600/snip_20160830182427.png> >>> >>> >>> >> FWIW, your "simple" function has 10 operations that generates ~40 >> instructions when fully inlined including the range check for the shifts, >> prologue, epilogue, struct return etc, that seems like a reasonable number >> for me. >> >>> >>> >>> >>> <https://lh3.googleusercontent.com/-UmVvAEvHCMI/V8YGuOL_FqI/AAAAAAAAACw/aH6yx-CJAvIHxB3EMYa1nuW8JOtbJjCrgCLcB/s1600/snip_20160830182032.png> >>> >>> <https://lh3.googleusercontent.com/-UmVvAEvHCMI/V8YGuOL_FqI/AAAAAAAAACw/aH6yx-CJAvIHxB3EMYa1nuW8JOtbJjCrgCLcB/s1600/snip_20160830182032.png>The >>> output for the Int32 and Int64 case >>> <https://lh3.googleusercontent.com/-UmVvAEvHCMI/V8YGuOL_FqI/AAAAAAAAACw/aH6yx-CJAvIHxB3EMYa1nuW8JOtbJjCrgCLcB/s1600/snip_20160830182032.png> >>> >>> <https://lh3.googleusercontent.com/-UmVvAEvHCMI/V8YGuOL_FqI/AAAAAAAAACw/aH6yx-CJAvIHxB3EMYa1nuW8JOtbJjCrgCLcB/s1600/snip_20160830182032.png>The >>> following looks particularly bad for the Int32 case >>> <https://lh3.googleusercontent.com/-UmVvAEvHCMI/V8YGuOL_FqI/AAAAAAAAACw/aH6yx-CJAvIHxB3EMYa1nuW8JOtbJjCrgCLcB/s1600/snip_20160830182032.png> >>> >>> <https://lh3.googleusercontent.com/-UmVvAEvHCMI/V8YGuOL_FqI/AAAAAAAAACw/aH6yx-CJAvIHxB3EMYa1nuW8JOtbJjCrgCLcB/s1600/snip_20160830182032.png> >>> movabsq $">>", %rax >>> <https://lh3.googleusercontent.com/-UmVvAEvHCMI/V8YGuOL_FqI/AAAAAAAAACw/aH6yx-CJAvIHxB3EMYa1nuW8JOtbJjCrgCLcB/s1600/snip_20160830182032.png> >>> movl $6, %edx >>> <https://lh3.googleusercontent.com/-UmVvAEvHCMI/V8YGuOL_FqI/AAAAAAAAACw/aH6yx-CJAvIHxB3EMYa1nuW8JOtbJjCrgCLcB/s1600/snip_20160830182032.png> >>> callq *%rax >>> <https://lh3.googleusercontent.com/-UmVvAEvHCMI/V8YGuOL_FqI/AAAAAAAAACw/aH6yx-CJAvIHxB3EMYa1nuW8JOtbJjCrgCLcB/s1600/snip_20160830182032.png> >>> >>> >>> >>> <https://lh3.googleusercontent.com/-PhTsfPn5Lo0/V8YHFRbgGmI/AAAAAAAAAC4/-243A3nwrWMSKPis1vkMH85RGCjMNyGAwCLcB/s1600/snip_20160830182154.png> >>> >>> <https://lh3.googleusercontent.com/-RdeaFTCAHJA/V8YG2CTJ2CI/AAAAAAAAAC0/hXguNBdd6MM7VlsvMPjX-QwjyIJv140RQCLcB/s1600/snip_20160830182101.png> >>> >>> >> -- Erik Schnetter <schnet...@gmail.com> http://www.perimeterinstitute.ca/personal/eschnetter/
