freedreno/ir3: support load_front_face intrinsic

With tgsi_to_nir we get this as a normal input with VARYING_SLOT_FACE.
But glsl_to_nir plus nir_lower_system_values this becomes an intrinsic.

Signed-off-by: Rob Clark <robclark@freedesktop.org>

diff --git a/src/gallium/drivers/freedreno/ir3/ir3_compiler_nir.c b/src/gallium/drivers/freedreno/ir3/ir3_compiler_nir.c
index 1ea2dd9cbf713e0ba3668d49d874c76be7745942..11ec014db824bc6902e12670deb95066624b05bc 100644 (file)
--- a/src/gallium/drivers/freedreno/ir3/ir3_compiler_nir.c
+++ b/src/gallium/drivers/freedreno/ir3/ir3_compiler_nir.c
@@ -556,6 +556,10 @@ create_frag_coord(struct ir3_compile *ctx, unsigned comp)
        }
 }
 
+/* NOTE: this creates the "TGSI" style fragface (ie. input slot
+ * VARYING_SLOT_FACE).  For NIR style nir_intrinsic_load_front_face
+ * we can just use the value from hw directly (since it is boolean)
+ */
 static struct ir3_instruction *
 create_frag_face(struct ir3_compile *ctx, unsigned comp)
 {
@@ -1224,7 +1228,7 @@ emit_intrinsic(struct ir3_compile *ctx, nir_intrinsic_instr *intr)
                break;
        case nir_intrinsic_load_vertex_id_zero_base:
                if (!ctx->vertex_id) {
-                       ctx->vertex_id = create_input(ctx->block, 0);
+                       ctx->vertex_id = create_input(b, 0);
                        add_sysval_input(ctx, SYSTEM_VALUE_VERTEX_ID_ZERO_BASE,
                                        ctx->vertex_id);
                }
@@ -1232,7 +1236,7 @@ emit_intrinsic(struct ir3_compile *ctx, nir_intrinsic_instr *intr)
                break;
        case nir_intrinsic_load_instance_id:
                if (!ctx->instance_id) {
-                       ctx->instance_id = create_input(ctx->block, 0);
+                       ctx->instance_id = create_input(b, 0);
                        add_sysval_input(ctx, SYSTEM_VALUE_INSTANCE_ID,
                                        ctx->instance_id);
                }
@@ -1244,6 +1248,14 @@ emit_intrinsic(struct ir3_compile *ctx, nir_intrinsic_instr *intr)
                        dst[i] = create_driver_param(ctx, IR3_DP_UCP0_X + n);
                }
                break;
+       case nir_intrinsic_load_front_face:
+               if (!ctx->frag_face) {
+                       ctx->so->frag_face = true;
+                       ctx->frag_face = create_input(b, 0);
+                       ctx->frag_face->regs[0]->flags |= IR3_REG_HALF;
+               }
+               dst[0] = ir3_ADD_S(b, ctx->frag_face, 0, create_immed(b, 1), 0);
+               break;
        case nir_intrinsic_discard_if:
        case nir_intrinsic_discard: {
                struct ir3_instruction *cond, *kill;