broadcom/vc5: Use SETMSF to handle discards.

A bit of spec text suggested that (like vc4) condition codes should be
used for discards, and the simulator was fine with it, but the 7268
disagrees and you have to use SETMSF instead or the color comes through.
Fixes glsl-fs-discard-01 and many of the interpolation-with-clipping
tests.

2 files changed, 12 insertions, 25 deletions

diff --git a/src/broadcom/compiler/nir_to_vir.c b/src/broadcom/compiler/nir_to_vir.c
index 167b80bac93..3b032b704ea 100644
--- a/src/broadcom/compiler/nir_to_vir.c
+++ b/src/broadcom/compiler/nir_to_vir.c
@@ -1030,12 +1030,6 @@ ntq_emit_alu(struct v3d_compile *c, nir_alu_instr *instr)
 static void
 emit_frag_end(struct v3d_compile *c)
 {
-        uint32_t discard_cond = V3D_QPU_COND_NONE;
-        if (c->s->info.fs.uses_discard) {
-                vir_PF(c, vir_MOV(c, c->discard), V3D_QPU_PF_PUSHZ);
-                discard_cond = V3D_QPU_COND_IFA;
-        }
-
         /* XXX
         if (c->output_sample_mask_index != -1) {
                 vir_MS_MASK(c, c->outputs[c->output_sample_mask_index]);
@@ -1046,7 +1040,6 @@ emit_frag_end(struct v3d_compile *c)
                 struct qinst *inst = vir_MOV_dest(c,
                                                   vir_reg(QFILE_TLBU, 0),
                                                   c->outputs[c->output_position_index]);
-                vir_set_cond(inst, discard_cond);
 
                 inst->src[vir_get_implicit_uniform_src(inst)] =
                         vir_uniform_ui(c,
@@ -1057,7 +1050,6 @@ emit_frag_end(struct v3d_compile *c)
                 struct qinst *inst = vir_MOV_dest(c,
                                                   vir_reg(QFILE_TLBU, 0),
                                                   vir_reg(QFILE_NULL, 0));
-                vir_set_cond(inst, discard_cond);
 
                 inst->src[vir_get_implicit_uniform_src(inst)] =
                         vir_uniform_ui(c,
@@ -1092,14 +1084,12 @@ emit_frag_end(struct v3d_compile *c)
                                  TLB_VEC_SIZE_MINUS_1_SHIFT);
 
                         inst = vir_MOV_dest(c, vir_reg(QFILE_TLBU, 0), color[0]);
-                        vir_set_cond(inst, discard_cond);
                         inst->src[vir_get_implicit_uniform_src(inst)] =
                                 vir_uniform_ui(c, conf);
 
                         for (int i = 1; i < num_components; i++) {
                                 inst = vir_MOV_dest(c, vir_reg(QFILE_TLB, 0),
                                                     color[i]);
-                                vir_set_cond(inst, discard_cond);
                         }
                         break;
 
@@ -1129,14 +1119,12 @@ emit_frag_end(struct v3d_compile *c)
 
                         if (c->fs_key->f32_color_rb & (1 << rt)) {
                                 inst = vir_MOV_dest(c, vir_reg(QFILE_TLBU, 0), color[0]);
-                                vir_set_cond(inst, discard_cond);
                                 inst->src[vir_get_implicit_uniform_src(inst)] =
                                         vir_uniform_ui(c, conf);
 
                                 for (int i = 1; i < num_components; i++) {
                                         inst = vir_MOV_dest(c, vir_reg(QFILE_TLB, 0),
                                                             color[i]);
-                                        vir_set_cond(inst, discard_cond);
                                 }
                         } else {
                                 inst = vir_VFPACK_dest(c, vir_reg(QFILE_TLB, 0), r, g);
@@ -1145,10 +1133,8 @@ emit_frag_end(struct v3d_compile *c)
                                         inst->src[vir_get_implicit_uniform_src(inst)] =
                                                 vir_uniform_ui(c, conf);
                                 }
-                                vir_set_cond(inst, discard_cond);
 
                                 inst = vir_VFPACK_dest(c, vir_reg(QFILE_TLB, 0), b, a);
-                                vir_set_cond(inst, discard_cond);
                         }
                         break;
                 }
@@ -1665,10 +1651,12 @@ ntq_emit_intrinsic(struct v3d_compile *c, nir_intrinsic_instr *instr)
         case nir_intrinsic_discard:
                 if (c->execute.file != QFILE_NULL) {
                         vir_PF(c, c->execute, V3D_QPU_PF_PUSHZ);
-                        vir_MOV_cond(c, V3D_QPU_COND_IFA, c->discard,
-                                     vir_uniform_ui(c, ~0));
+                        vir_set_cond(vir_SETMSF_dest(c, vir_reg(QFILE_NULL, 0),
+                                                     vir_uniform_ui(c, 0)),
+                                V3D_QPU_COND_IFA);
                 } else {
-                        vir_MOV_dest(c, c->discard, vir_uniform_ui(c, ~0));
+                        vir_SETMSF_dest(c, vir_reg(QFILE_NULL, 0),
+                                        vir_uniform_ui(c, 0));
                 }
                 break;
 
@@ -1683,9 +1671,14 @@ ntq_emit_intrinsic(struct v3d_compile *c, nir_intrinsic_instr *instr)
                          */
                         vir_PF(c, vir_AND(c, c->execute, vir_NOT(c, cond)),
                                V3D_QPU_PF_PUSHZ);
-                        vir_MOV_cond(c, V3D_QPU_COND_IFA, c->discard, cond);
+                        vir_set_cond(vir_SETMSF_dest(c, vir_reg(QFILE_NULL, 0),
+                                                     vir_uniform_ui(c, 0)),
+                                     V3D_QPU_COND_IFA);
                 } else {
-                        vir_OR_dest(c, c->discard, c->discard, cond);
+                        vir_PF(c, cond, V3D_QPU_PF_PUSHZ);
+                        vir_set_cond(vir_SETMSF_dest(c, vir_reg(QFILE_NULL, 0),
+                                                     vir_uniform_ui(c, 0)),
+                                     V3D_QPU_COND_IFNA);
                 }
 
                 break;
@@ -1953,9 +1946,6 @@ nir_to_vir(struct v3d_compile *c)
                 c->payload_w_centroid = vir_MOV(c, vir_reg(QFILE_REG, 1));
                 c->payload_z = vir_MOV(c, vir_reg(QFILE_REG, 2));
 
-                if (c->s->info.fs.uses_discard)
-                        c->discard = vir_MOV(c, vir_uniform_ui(c, 0));
-
                 if (c->fs_key->is_points) {
                         c->point_x = emit_fragment_varying(c, NULL, 0);
                         c->point_y = emit_fragment_varying(c, NULL, 0);
diff --git a/src/broadcom/compiler/v3d_compiler.h b/src/broadcom/compiler/v3d_compiler.h
index 08db4fb0e2b..021c88f7b93 100644
--- a/src/broadcom/compiler/v3d_compiler.h
+++ b/src/broadcom/compiler/v3d_compiler.h
@@ -458,9 +458,6 @@ struct v3d_compile {
         /* Fragment shader payload regs. */
         struct qreg payload_w, payload_w_centroid, payload_z;
 
-        /** boolean (~0 -> true) if the fragment has been discarded. */
-        struct qreg discard;
-
         uint8_t vattr_sizes[V3D_MAX_VS_INPUTS];
         uint32_t num_vpm_writes;