nir: clamp-color-output support

Handled by tgsi_emulate for glsl->tgsi case.

Signed-off-by: Rob Clark <robclark@freedesktop.org>
Reviewed-by: Connor Abbott <cwabbott0@gmail.com>

src/compiler/Makefile.sources

@@ -186,6 +186,7 @@ NIR_FILES = \
 	nir/nir_liveness.c \
 	nir/nir_lower_alu_to_scalar.c \
 	nir/nir_lower_atomics.c \
+	nir/nir_lower_clamp_color_outputs.c \
 	nir/nir_lower_clip.c \
 	nir/nir_lower_double_ops.c \
 	nir/nir_lower_double_packing.c \

src/compiler/nir/nir.h

@@ -2409,6 +2409,8 @@ void nir_lower_clip_fs(nir_shader *shader, unsigned ucp_enables);
 
 void nir_lower_two_sided_color(nir_shader *shader);
 
+void nir_lower_clamp_color_outputs(nir_shader *shader);
+
 void nir_lower_atomics(nir_shader *shader,
                        const struct gl_shader_program *shader_program);
 void nir_lower_to_source_mods(nir_shader *shader);

src/compiler/nir/nir_lower_clamp_color_outputs.c

@@ -0,0 +1,117 @@
+/*
+ * Copyright © 2015 Red Hat
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+
+#include "nir.h"
+#include "nir_builder.h"
+
+typedef struct {
+   nir_shader *shader;
+   nir_builder b;
+} lower_state;
+
+static bool
+is_color_output(lower_state *state, nir_variable *out)
+{
+   switch (state->shader->stage) {
+   case MESA_SHADER_VERTEX:
+   case MESA_SHADER_GEOMETRY:
+      switch (out->data.location) {
+      case VARYING_SLOT_COL0:
+      case VARYING_SLOT_COL1:
+      case VARYING_SLOT_BFC0:
+      case VARYING_SLOT_BFC1:
+         return true;
+      default:
+         return false;
+      }
+      break;
+   case MESA_SHADER_FRAGMENT:
+      switch (out->data.location) {
+      case FRAG_RESULT_COLOR:
+         return true;
+      default:
+         return false;
+      }
+      break;
+   default:
+      return false;
+   }
+}
+
+static void
+lower_intrinsic(lower_state *state, nir_intrinsic_instr *intr)
+{
+   nir_variable *out;
+   nir_builder *b = &state->b;
+   nir_ssa_def *s;
+
+   if (intr->intrinsic != nir_intrinsic_store_var)
+      return;
+
+   out = intr->variables[0]->var;
+
+   if (out->data.mode != nir_var_shader_out)
+      return;
+
+   if (is_color_output(state, out)) {
+      b->cursor = nir_before_instr(&intr->instr);
+      s = nir_ssa_for_src(b, intr->src[0], intr->num_components);
+      s = nir_fsat(b, s);
+      nir_instr_rewrite_src(&intr->instr, &intr->src[0], nir_src_for_ssa(s));
+   }
+}
+
+static bool
+lower_block(lower_state *state, nir_block *block)
+{
+   nir_foreach_instr_safe(instr, block) {
+      if (instr->type == nir_instr_type_intrinsic)
+         lower_intrinsic(state, nir_instr_as_intrinsic(instr));
+   }
+
+   return true;
+}
+static void
+lower_impl(lower_state *state, nir_function_impl *impl)
+{
+   nir_builder_init(&state->b, impl);
+
+   nir_foreach_block(block, impl) {
+      lower_block(state, block);
+   }
+   nir_metadata_preserve(impl, nir_metadata_block_index |
+                               nir_metadata_dominance);
+}
+
+void nir_lower_clamp_color_outputs(nir_shader *shader)
+{
+   lower_state state = {
+      .shader = shader,
+   };
+
+   nir_foreach_function(function, shader) {
+      if (function->impl)
+         lower_impl(&state, function->impl);
+   }
+}