From: Kenneth Graunke <kenneth@whitecape.org>
Date: Fri, 6 Mar 2015 09:24:30 +0000 (-0800)
Subject: nir: Only do gl_FrontFacing workaround in glsl_to_nir for the FS.
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=8dcc1f2c10b3dc6ded38e7a6c302f60061ba587c;p=mesa.git

nir: Only do gl_FrontFacing workaround in glsl_to_nir for the FS.

Vertex shaders can have shader inputs where location happens to be
VARYING_SLOT_FACE.  Without predicating this on the shader stage,
we suddenly end up with load_front_face intrinsics in vertex shaders,
which is nonsensical.

Fixes spec/arb_vertex_buffer_object/pos-array when using NIR for VS.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Jason Ekstrand <jason.ekstrand@intel.com>
---

diff --git a/src/glsl/nir/glsl_to_nir.cpp b/src/glsl/nir/glsl_to_nir.cpp
index ddad207232e..047cb51e85d 100644
--- a/src/glsl/nir/glsl_to_nir.cpp
+++ b/src/glsl/nir/glsl_to_nir.cpp
@@ -251,7 +251,8 @@ nir_visitor::visit(ir_variable *ir)
       break;
 
    case ir_var_shader_in:
-      if (ir->data.location == VARYING_SLOT_FACE) {
+      if (stage == MESA_SHADER_FRAGMENT &&
+          ir->data.location == VARYING_SLOT_FACE) {
          /* For whatever reason, GLSL IR makes gl_FrontFacing an input */
          var->data.location = SYSTEM_VALUE_FRONT_FACE;
          var->data.mode = nir_var_system_value;