Re: [Qemu-devel] [PATCH] RFC: TCG constant propagation.

[Filip Navara]

On Tue, Jul 21, 2009 at 4:38 PM, Filip Navara<address@hidden> wrote:
> Add support for constant propagation to TCG. This has to be paired with the 
> liveness
> analysis to remove the dead code. Not all possible operations are covered, 
> but the
> most common ones are. This improves the code generation for several ARM 
> instructions,
> like MVN (immediate), and it may help other targets as well.
> ---
>  tcg/tcg.c |  164 
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 164 insertions(+), 0 deletions(-)

Attached is updated version of the patch which adds profiling code for
the TCG pass and hopefully fixes it for TCG 64-bit targets.

Also it looks that the actual code size is worse for TCG ARM target
with this optimization. To mitigate it I propose the other attached
patch which uses the barrel shifter for more optimal generation of the
"movi" operation. I can't test it, so any help is welcome.

Best regards,
Filip Navara

0001-TCG-constant-propagation.patch
Description: Binary data

0002-Use-ARM-barrel-shifter-for-more-optimal-generation-o.patch
Description: Binary data