[Mesa-dev] [PATCH] i965/fs: Allow LRPs with uniform registers.

[Eric Anholt]

Improves GLB2.7 performance on my HSW by 0.671455% +/- 0.225037% (n=62).
---
 src/mesa/drivers/dri/i965/brw_fs_visitor.cpp |   11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
index f1539d5..8aae516 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
@@ -198,10 +198,19 @@ fs_visitor::visit(ir_dereference_array *ir)
    this->result = src;
 }
 
+static bool
+is_valid_3src(fs_reg reg)
+{
+   return reg.file == GRF || reg.file == UNIFORM;
+}
+
 void
 fs_visitor::emit_lrp(fs_reg dst, fs_reg x, fs_reg y, fs_reg a)
 {
-   if (intel->gen < 6 || x.file != GRF || y.file != GRF || a.file != GRF) {
+   if (intel->gen < 6 ||
+       !is_valid_3src(x) ||
+       !is_valid_3src(y) ||
+       !is_valid_3src(a)) {
       /* We can't use the LRP instruction.  Emit x*(1-a) + y*a. */
       fs_reg y_times_a           = fs_reg(this, glsl_type::float_type);
       fs_reg one_minus_a         = fs_reg(this, glsl_type::float_type);
-- 
1.7.10.4