[LLVMdev] [PATCH] increase the max number of physical registers

[Pekka Jääskeläinen]

Chris Lattner wrote:
> Please compare a release-asserts (make ENABLE_OPTIMIZED=1
> DISABLE_ASSERTIONS=1) builds with and without your patch.  Just run
> 'llc' on a collection of large bc files (e.g. kimwitu++ from the
> testsuite, some SPEC2K6 programs if you have access to it, etc) and
> compare them.

OK. I compared the speed + memory consumption for a llc of
a 8M bitcode (AES encryption of 64 blocks, fully unrolled to
a single BB). No difference. Both had about 700M peak virt
memory consumption and it took about 45mins for 10 rounds.

More elaborate results:

Executed:

time for i in $(seq 10); do echo $i; llc aes.bc -f -o aes.o; done;

Peak memory consumption monitored with

while true; do pmap $(pgrep llc) | tail -1; sleep 1; done;

The smallest and largest max values (of the 10 runs)
were picked from the output.

Without the patch:

mem     690960K ... 715476K
real    46m53.966s
user    46m32.299s


With the patch:

mem     691096K ... 715608K
real    46m10.101s
user    45m56.944s

-- 
Pekka