-doipc is apparently not an adequate replacement for -dowls: ktrvariant.sac
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|
Bugzilla Link |
1086 |
Created on |
Sep 24, 2013 19:53 |
Version |
svn |
OS |
Linux |
Architecture |
PC |
Attachments |
ktrvariant.sac |
Extended Description
Created an attachment (id=984)
source code to reproduce fault
This was observed on Build #18308, in the ipc unit test suite:
sac2c ktrvariant.sac -O3
sac@rattler:~/sac/testsuite/optimizations/ipc$ time a.out; echo $?
real 0m0.608s
user 0m0.600s
sys 0m0.000s
0
sac@rattler:~/sac/testsuite/optimizations/ipc$ sac2c ktrvariant.sac -O3 -nowls
sac@rattler:~/sac/testsuite/optimizations/ipc$ time a.out; echo $?
real 0m1.978s
user 0m1.240s
sys 0m0.730s
0
sac@rattler:~/sac/testsuite/optimizations/ipc$ sac2c ktrvariant.sac -O3 -noipc
sac@rattler:~/sac/testsuite/optimizations/ipc$ time a.out; echo $?
real 0m0.608s
user 0m0.590s
sys 0m0.010s
0
sac@rattler:~/sac/testsuite/optimizations/ipc$ sac2c ktrvariant.sac -O3 -noipc -nowls
sac@rattler:~/sac/testsuite/optimizations/ipc$ time a.out; echo $?
real 0m2.180s
user 0m1.490s
sys 0m0.680s
0
Bodo claimed, earlier today, that IPC should (my words) be able to
supplant WLS. The above timings show that, for this test, at least:
1. If WLS is enabled, IPC does nothing more for us.
2. If WLS is disabled, IPC is not able to do generate code that
performs as well as WLS.