On Mon, Feb 22, 2016 at 7:13 PM, Matt Turner <matts...@gmail.com> wrote:
Unless there's something unexpected going on, let's say
src0 = 0, src1 = 0, src2 = -0.5
> Allows us to transform
>
> mad res src0 src1 src2
res = -0.5
> mov.sat dst -res
dst = 0.5
>
> into
>
> mad.sat dst -src0 -src1 src2
-0 * -0 + -0.5 = -0.5
dst = 0
I don't think those two are equivalent... unless you can stick a neg
on src2 as well.
>
> instructions in affected programs: 3712 -> 3688 (-0.65%)
> helped: 24
> ---
> src/mesa/drivers/dri/i965/brw_fs_saturate_propagation.cpp | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/src/mesa/drivers/dri/i965/brw_fs_saturate_propagation.cpp
> b/src/mesa/drivers/dri/i965/brw_fs_saturate_propagation.cpp
> index 7c82509..dc2b0c8 100644
> --- a/src/mesa/drivers/dri/i965/brw_fs_saturate_propagation.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_fs_saturate_propagation.cpp
> @@ -86,6 +86,10 @@ opt_saturate_propagation_local(fs_visitor *v, bblock_t
> *block)
> if (scan_inst->opcode == BRW_OPCODE_MUL) {
> scan_inst->src[0].negate = !scan_inst->src[0].negate;
> inst->src[0].negate = false;
> + } else if (scan_inst->opcode == BRW_OPCODE_MAD) {
> + scan_inst->src[0].negate = !scan_inst->src[0].negate;
> + scan_inst->src[1].negate = !scan_inst->src[1].negate;
> + inst->src[0].negate = false;
> } else if (scan_inst->opcode == BRW_OPCODE_ADD) {
> if (scan_inst->src[1].file == IMM) {
> if (!brw_negate_immediate(scan_inst->src[1].type,
> --
> 2.4.10
>
> _______________________________________________
> mesa-dev mailing list
> mesa-dev@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/mesa-dev
_______________________________________________
mesa-dev mailing list
mesa-dev@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/mesa-dev
