[Mesa-dev] [PATCH] i965 new VS: Fix copy propagation of double negatives.
kenneth at whitecape.org
Thu Sep 15 19:52:56 PDT 2011
On 09/15/2011 09:19 AM, Paul Berry wrote:
> When copy propagating a value into an instruction that negates its
> argument, we need to invert the sense of the value's "negate" flag, so
> that -(+x) becomes -x and -(-x) becomes +x.
> Previously, we were always setting the value's "negate" flag to true
> in this circumstance, so that both -(+x) and -(-x) turned into -x.
> Fixes Piglit test vs-double-negative.shader_test.
> .../drivers/dri/i965/brw_vec4_copy_propagation.cpp | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
> diff --git a/src/mesa/drivers/dri/i965/brw_vec4_copy_propagation.cpp b/src/mesa/drivers/dri/i965/brw_vec4_copy_propagation.cpp
> index c46735a..e0b2d2a 100644
> --- a/src/mesa/drivers/dri/i965/brw_vec4_copy_propagation.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_vec4_copy_propagation.cpp
> @@ -196,7 +196,7 @@ try_copy_propagation(struct intel_context *intel,
> value.abs = true;
> if (inst->src[arg].negate)
> - value.negate = true;
> + value.negate = !value.negate;
> /* FINISHME: We can't copy-propagate things that aren't normal
> * vec8s into gen6 math instructions, because of the weird src
Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>
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