[Mesa-dev] [PATCH 5/5] i965/fs: Apply gl_FrontFacing ? -1 : 1 optimization only for floats

[Ian Romanick]

From: Ian Romanick <ian.d.romanick at intel.com>

At the very least, unreal4/sun-temple/102.shader_test uses this pattern
for a signed integer result.  However, that shader did not hit the
optimization in the first place because it uses !gl_FronFacing.  I
changed the shader to use remove the logical-not and reverse the other
operands.  I verified that incorrect code is generated before this
change and correct code is generated after.

I'll send a piglit test out shortly...

No shader-db changes.

Signed-off-by: Ian Romanick <ian.d.romanick at intel.com>
Cc: Matt Turner <mattst88 at gmail.com>
---
 src/mesa/drivers/dri/i965/brw_fs_visitor.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
index 917d3da..3740722 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
@@ -2845,6 +2845,9 @@ fs_visitor::try_opt_frontfacing_ternary(ir_if *ir)
    if (!then_rhs || !else_rhs)
       return false;
 
+   if (then_rhs->type->base_type != GLSL_TYPE_FLOAT)
+      return false;
+
    if ((then_rhs->is_one() && else_rhs->is_negative_one()) ||
        (else_rhs->is_one() && then_rhs->is_negative_one())) {
       then_assign->lhs->accept(this);
-- 
2.1.0