[llvm-commits] [llvm] r151111 - /llvm/trunk/lib/CodeGen/RegAllocFast.cpp

[Jakob Stoklund Olesen]

On Feb 21, 2012, at 5:18 PM, Chad Rosier <mcrosier at apple.com> wrote:

> 
> On Feb 21, 2012, at 5:02 PM, Jakob Stoklund Olesen wrote:
> 
>> Author: stoklund
>> Date: Tue Feb 21 19:02:37 2012
>> New Revision: 151111
>> 
>> URL: http://llvm.org/viewvc/llvm-project?rev=151111&view=rev
>> Log:
>> Use SparseSet for the RAFast live virtual register map.
>> 
>> This makes RAFast 4% faster, and it gets rid of the dodgy DenseMap
>> iteration.
> 
> Very nice!!  What exactly were you testing to get the 4% estimate?

I have a -O0 bitcode file for 464.h264ref / armv7. I ran llc -time-passes and checked the user time for the fast allocator.

Note that RAFast is only 7% of codegen time at -O0, so the overall impact on clang -O0 is probably in the noise.

/jakob