Re: [Qemu-devel] [PATCH 0/5] tcg conditional set, round 4

[Richard Henderson]

On 12/21/2009 02:21 PM, Laurent Desnogues wrote:
> As far as I know these CPU's don't need the full movcond but
> only the variant with vtrue.

I know that.  And I looked into TCG very closely to figure out how to 
implement just that.  Except then I have to modify TCG to special-case 
movcond to know that DEST is both input and output.  This is *much* more 
work than simply having the back-end use a matching constraint on VFALSE.

> Even if movcond was quick to generate
> host code, for instance for ARM, you'd have to explicitly detect
> conditional moves

One of us is confused.  Why would I have to explicitly detect 
conditional moves?


r~