[llvm-commits] [llvm] r95831 - /llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

[Jakob Stoklund Olesen]

On Feb 10, 2010, at 5:10 PM, Jakob Stoklund Olesen wrote:

> 
> On Feb 10, 2010, at 4:48 PM, Chris Lattner wrote:
> 
>> 
>> On Feb 10, 2010, at 4:34 PM, Jakob Stoklund Olesen wrote:
>> 
>>> Author: stoklund
>>> Date: Wed Feb 10 18:34:18 2010
>>> New Revision: 95831
>>> 
>>> URL: http://llvm.org/viewvc/llvm-project?rev=95831&view=rev
>>> Log:
>>> Remove duplicate successors from indirectbr instructions before building the machine CFG.
>>> 
>>> This makes early tail duplication run 60 times faster when compiling the Firefox
>>> JavaScript interpreter, see PR6186.
>> 
>> Nice speedup!  Please use SmallVector
> 
> Why SmallVector? The number of successors on an indirectbr varies a lot - I don't expect most of them to be less than some small integer size.

Because when using reserve() there is no overhead to SmallVector except a bit of stack space.

I'll change it.

/jakob