[Bug target/86952] Avoid jump table for switch statement with -mindirect-branch=thunk

hjl.tools at gmail dot com gcc-bugzilla@gcc.gnu.org
Mon Dec 31 16:57:00 GMT 2018


https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86952

H.J. Lu <hjl.tools at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |WONTFIX

--- Comment #11 from H.J. Lu <hjl.tools at gmail dot com> ---
(In reply to Martin Liška from comment #10)
> H.J. : Can you please run updated benchmark on a recent machine and provide
> slow down numbers for that?

The numbers aren't stable:

[hjl@gnu-cfl-1 microbenchmark]$ make
./test
30000 loops:
global: 21, total: 625
no jump table: 178424
global: 21, total: 625
jump table   : 266792 (149.53%)
[hjl@gnu-cfl-1 microbenchmark]$ make
./test
30000 loops:
global: 21, total: 625
no jump table: 185068
global: 21, total: 625
jump table   : 266678 (144.10%)
[hjl@gnu-cfl-1 microbenchmark]$ make
./test
30000 loops:
global: 21, total: 625
no jump table: 292810
global: 21, total: 625
jump table   : 214840 (73.37%)
[hjl@gnu-cfl-1 microbenchmark]$ 

Close it for now.


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