[LLVMdev] [PATCH / PROPOSAL] bitcode encoding that is ~15% smaller for large bitcode files...

Renato Golin rengolin at systemcall.org
Thu Sep 27 02:57:43 PDT 2012

On 26 September 2012 22:08, Jan Voung <jvoung at chromium.org> wrote:
> I think most of the instructions operands are encoded as VBR(N)
> for some N number of bits, and it seems to me that VBR(8) is like ULEB?
> I think that the default N is 6 bits, but I haven't tried tweaking these
> parameters.

It has a similar purpose, but slightly different. SLEB (the signed
version) wouldn't use the whole word for -1, since the sign expansion
happens after the number is encoded to 7 bits package, so any negative
number that can be represented using 7 bits would still be stored in a



More information about the llvm-dev mailing list