i965: Use NIR for lowering texture swizzle

Now that nir_lower_tex can do texture swizzle lowering, we can use that
instead of repeating more-or-less the same code in both backends.  This
both allows us to share code and means that things like the tg4
work-arounds are somewhat simpler because they don't have to take the
swizzle into account.

Reviewed-by: Connor Abbott <cwabbott0@gmail.com>

6 files changed, 44 insertions, 196 deletions

diff --git a/src/mesa/drivers/dri/i965/brw_fs.h b/src/mesa/drivers/dri/i965/brw_fs.h
index 3e29b3e929f..2d408b2f363 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.h
+++ b/src/mesa/drivers/dri/i965/brw_fs.h
@@ -116,10 +116,6 @@ public:
    void setup_uniform_clipplane_values(gl_clip_plane *clip_planes);
    void compute_clip_distance(gl_clip_plane *clip_planes);
 
-   uint32_t gather_channel(int orig_chan, uint32_t sampler);
-   void swizzle_result(ir_texture_opcode op, int dest_components,
-                       fs_reg orig_val, uint32_t sampler);
-
    fs_inst *get_instruction_generating_reg(fs_inst *start,
 					   fs_inst *end,
 					   const fs_reg &reg);
diff --git a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
index 03049062c20..1e202165cb6 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
@@ -116,24 +116,6 @@ fs_visitor::emit_texture(ir_texture_opcode op,
 {
    fs_inst *inst = NULL;
 
-   if (op == ir_tg4) {
-      /* When tg4 is used with the degenerate ZERO/ONE swizzles, don't bother
-       * emitting anything other than setting up the constant result.
-       */
-      int swiz = GET_SWZ(key_tex->swizzles[sampler], gather_component);
-      if (swiz == SWIZZLE_ZERO || swiz == SWIZZLE_ONE) {
-
-         fs_reg res = vgrf(glsl_type::vec4_type);
-         this->result = res;
-
-         for (int i=0; i<4; i++) {
-            bld.MOV(res, brw_imm_f(swiz == SWIZZLE_ZERO ? 0.0f : 1.0f));
-            res = offset(res, bld, 1);
-         }
-         return;
-      }
-   }
-
    if (op == ir_query_levels) {
       /* textureQueryLevels() is implemented in terms of TXS so we need to
        * pass a valid LOD argument.
@@ -220,8 +202,15 @@ fs_visitor::emit_texture(ir_texture_opcode op,
       inst->offset = offset_value.ud;
 
    if (op == ir_tg4) {
-      inst->offset |=
-         gather_channel(gather_component, sampler) << 16; /* M0.2:16-17 */
+      if (gather_component == 1 &&
+          key_tex->gather_channel_quirk_mask & (1 << sampler)) {
+         /* gather4 sampler is broken for green channel on RG32F --
+          * we must ask for blue instead.
+          */
+         inst->offset |= 2 << 16;
+      } else {
+         inst->offset |= gather_component << 16;
+      }
 
       if (devinfo->gen == 6)
          emit_gen6_gather_wa(key_tex->gen6_gather_wa[sampler], dst);
@@ -245,7 +234,12 @@ fs_visitor::emit_texture(ir_texture_opcode op,
       bld.LOAD_PAYLOAD(dst, fixed_payload, components, 0);
    }
 
-   swizzle_result(op, dest_type->vector_elements, dst, sampler);
+   if (op == ir_query_levels) {
+      /* # levels is in .w */
+      dst = offset(dst, bld, 3);
+   }
+
+   this->result = dst;
 }
 
 /**
@@ -278,75 +272,6 @@ fs_visitor::emit_gen6_gather_wa(uint8_t wa, fs_reg dst)
    }
 }
 
-/**
- * Set up the gather channel based on the swizzle, for gather4.
- */
-uint32_t
-fs_visitor::gather_channel(int orig_chan, uint32_t sampler)
-{
-   int swiz = GET_SWZ(key_tex->swizzles[sampler], orig_chan);
-   switch (swiz) {
-      case SWIZZLE_X: return 0;
-      case SWIZZLE_Y:
-         /* gather4 sampler is broken for green channel on RG32F --
-          * we must ask for blue instead.
-          */
-         if (key_tex->gather_channel_quirk_mask & (1 << sampler))
-            return 2;
-         return 1;
-      case SWIZZLE_Z: return 2;
-      case SWIZZLE_W: return 3;
-      default:
-         unreachable("Not reached"); /* zero, one swizzles handled already */
-   }
-}
-
-/**
- * Swizzle the result of a texture result.  This is necessary for
- * EXT_texture_swizzle as well as DEPTH_TEXTURE_MODE for shadow comparisons.
- */
-void
-fs_visitor::swizzle_result(ir_texture_opcode op, int dest_components,
-                           fs_reg orig_val, uint32_t sampler)
-{
-   if (op == ir_query_levels) {
-      /* # levels is in .w */
-      this->result = offset(orig_val, bld, 3);
-      return;
-   }
-
-   this->result = orig_val;
-
-   /* txs,lod don't actually sample the texture, so swizzling the result
-    * makes no sense.
-    */
-   if (op == ir_txs || op == ir_lod || op == ir_tg4)
-      return;
-
-   if (dest_components == 1) {
-      /* Ignore DEPTH_TEXTURE_MODE swizzling. */
-   } else if (key_tex->swizzles[sampler] != SWIZZLE_NOOP) {
-      fs_reg swizzled_result = vgrf(glsl_type::vec4_type);
-      swizzled_result.type = orig_val.type;
-
-      for (int i = 0; i < 4; i++) {
-	 int swiz = GET_SWZ(key_tex->swizzles[sampler], i);
-	 fs_reg l = swizzled_result;
-	 l = offset(l, bld, i);
-
-	 if (swiz == SWIZZLE_ZERO) {
-            bld.MOV(l, brw_imm_f(0.0f));
-	 } else if (swiz == SWIZZLE_ONE) {
-            bld.MOV(l, brw_imm_f(1.0f));
-	 } else {
-            bld.MOV(l, offset(orig_val, bld,
-                                  GET_SWZ(key_tex->swizzles[sampler], i)));
-	 }
-      }
-      this->result = swizzled_result;
-   }
-}
-
 /** Emits a dummy fragment shader consisting of magenta for bringup purposes. */
 void
 fs_visitor::emit_dummy_fs()
diff --git a/src/mesa/drivers/dri/i965/brw_nir.c b/src/mesa/drivers/dri/i965/brw_nir.c
index b8eeaa0d9b2..91358d8f389 100644
--- a/src/mesa/drivers/dri/i965/brw_nir.c
+++ b/src/mesa/drivers/dri/i965/brw_nir.c
@@ -435,6 +435,16 @@ brw_nir_apply_sampler_key(nir_shader *nir,
       tex_options.saturate_r = key_tex->gl_clamp_mask[2];
    }
 
+   /* Prior to Haswell, we have to fake texture swizzle */
+   for (unsigned s = 0; s < MAX_SAMPLERS; s++) {
+      if (key_tex->swizzles[s] == SWIZZLE_NOOP)
+         continue;
+
+      tex_options.swizzle_result |= (1 << s);
+      for (unsigned c = 0; c < 4; c++)
+         tex_options.swizzles[s][c] = GET_SWZ(key_tex->swizzles[s], c);
+   }
+
    if (nir_lower_tex(nir, &tex_options)) {
       nir_validate_shader(nir);
       nir = nir_optimize(nir, is_scalar);
diff --git a/src/mesa/drivers/dri/i965/brw_vec4.h b/src/mesa/drivers/dri/i965/brw_vec4.h
index ec8abf49cd8..3f674326284 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4.h
+++ b/src/mesa/drivers/dri/i965/brw_vec4.h
@@ -275,13 +275,9 @@ public:
                      bool is_cube_array,
                      uint32_t sampler, src_reg sampler_reg);
 
-   uint32_t gather_channel(unsigned gather_component, uint32_t sampler);
    src_reg emit_mcs_fetch(const glsl_type *coordinate_type, src_reg coordinate,
                           src_reg sampler);
    void emit_gen6_gather_wa(uint8_t wa, dst_reg dst);
-   void swizzle_result(ir_texture_opcode op, dst_reg dest,
-                       src_reg orig_val, uint32_t sampler,
-                       const glsl_type *dest_type);
 
    void emit_ndc_computation();
    void emit_psiz_and_flags(dst_reg reg);
diff --git a/src/mesa/drivers/dri/i965/brw_vec4_nir.cpp b/src/mesa/drivers/dri/i965/brw_vec4_nir.cpp
index 8d2ebfb7c89..c777acf70a7 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4_nir.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4_nir.cpp
@@ -1590,17 +1590,6 @@ vec4_visitor::nir_emit_texture(nir_tex_instr *instr)
                                  nir_tex_instr_dest_size(instr));
    dst_reg dest = get_nir_dest(instr->dest, instr->dest_type);
 
-   /* When tg4 is used with the degenerate ZERO/ONE swizzles, don't bother
-    * emitting anything other than setting up the constant result.
-    */
-   if (instr->op == nir_texop_tg4) {
-      int swiz = GET_SWZ(key_tex->swizzles[sampler], instr->component);
-      if (swiz == SWIZZLE_ZERO || swiz == SWIZZLE_ONE) {
-         emit(MOV(dest, brw_imm_f(swiz == SWIZZLE_ONE ? 1.0f : 0.0f)));
-         return;
-      }
-   }
-
    /* Load the texture operation sources */
    for (unsigned i = 0; i < instr->num_srcs; i++) {
       switch (instr->src[i].src_type) {
@@ -1716,8 +1705,17 @@ vec4_visitor::nir_emit_texture(nir_tex_instr *instr)
    }
 
    /* Stuff the channel select bits in the top of the texture offset */
-   if (instr->op == nir_texop_tg4)
-      constant_offset |= gather_channel(instr->component, sampler) << 16;
+   if (instr->op == nir_texop_tg4) {
+      if (instr->component == 1 &&
+          (key_tex->gather_channel_quirk_mask & (1 << sampler))) {
+         /* gather4 sampler is broken for green channel on RG32F --
+          * we must ask for blue instead.
+          */
+         constant_offset |= 2 << 16;
+      } else {
+         constant_offset |= instr->component << 16;
+      }
+   }
 
    ir_texture_opcode op = ir_texture_opcode_for_nir_texop(instr->op);
 
diff --git a/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp b/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
index 2e4695a2845..04ea1775ceb 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
@@ -920,8 +920,7 @@ vec4_visitor::emit_texture(ir_texture_opcode op,
       unreachable("Unrecognized tex op");
    }
 
-   vec4_instruction *inst = new(mem_ctx) vec4_instruction(
-      opcode, dst_reg(this, dest_type));
+   vec4_instruction *inst = new(mem_ctx) vec4_instruction(opcode, dest);
 
    inst->offset = constant_offset;
 
@@ -1072,8 +1071,13 @@ vec4_visitor::emit_texture(ir_texture_opcode op,
       emit_gen6_gather_wa(key_tex->gen6_gather_wa[sampler], inst->dst);
    }
 
-   swizzle_result(op, dest,
-                  src_reg(inst->dst), sampler, dest_type);
+   if (op == ir_query_levels) {
+      /* # levels is in .w */
+      src_reg swizzled(dest);
+      swizzled.swizzle = BRW_SWIZZLE4(SWIZZLE_W, SWIZZLE_W,
+                                      SWIZZLE_W, SWIZZLE_W);
+      emit(MOV(dest, swizzled));
+   }
 }
 
 /**
@@ -1103,87 +1107,6 @@ vec4_visitor::emit_gen6_gather_wa(uint8_t wa, dst_reg dst)
    }
 }
 
-/**
- * Set up the gather channel based on the swizzle, for gather4.
- */
-uint32_t
-vec4_visitor::gather_channel(unsigned gather_component, uint32_t sampler)
-{
-   int swiz = GET_SWZ(key_tex->swizzles[sampler], gather_component);
-   switch (swiz) {
-      case SWIZZLE_X: return 0;
-      case SWIZZLE_Y:
-         /* gather4 sampler is broken for green channel on RG32F --
-          * we must ask for blue instead.
-          */
-         if (key_tex->gather_channel_quirk_mask & (1 << sampler))
-            return 2;
-         return 1;
-      case SWIZZLE_Z: return 2;
-      case SWIZZLE_W: return 3;
-      default:
-         unreachable("Not reached"); /* zero, one swizzles handled already */
-   }
-}
-
-void
-vec4_visitor::swizzle_result(ir_texture_opcode op, dst_reg dest,
-                             src_reg orig_val, uint32_t sampler,
-                             const glsl_type *dest_type)
-{
-   int s = key_tex->swizzles[sampler];
-
-   dst_reg swizzled_result = dest;
-
-   if (op == ir_query_levels) {
-      /* # levels is in .w */
-      orig_val.swizzle = BRW_SWIZZLE4(SWIZZLE_W, SWIZZLE_W, SWIZZLE_W, SWIZZLE_W);
-      emit(MOV(swizzled_result, orig_val));
-      return;
-   }
-
-   if (op == ir_txs || dest_type == glsl_type::float_type
-			|| s == SWIZZLE_NOOP || op == ir_tg4) {
-      emit(MOV(swizzled_result, orig_val));
-      return;
-   }
-
-
-   int zero_mask = 0, one_mask = 0, copy_mask = 0;
-   int swizzle[4] = {0};
-
-   for (int i = 0; i < 4; i++) {
-      switch (GET_SWZ(s, i)) {
-      case SWIZZLE_ZERO:
-	 zero_mask |= (1 << i);
-	 break;
-      case SWIZZLE_ONE:
-	 one_mask |= (1 << i);
-	 break;
-      default:
-	 copy_mask |= (1 << i);
-	 swizzle[i] = GET_SWZ(s, i);
-	 break;
-      }
-   }
-
-   if (copy_mask) {
-      orig_val.swizzle = BRW_SWIZZLE4(swizzle[0], swizzle[1], swizzle[2], swizzle[3]);
-      swizzled_result.writemask = copy_mask;
-      emit(MOV(swizzled_result, orig_val));
-   }
-
-   if (zero_mask) {
-      swizzled_result.writemask = zero_mask;
-      emit(MOV(swizzled_result, brw_imm_f(0.0f)));
-   }
-
-   if (one_mask) {
-      swizzled_result.writemask = one_mask;
-      emit(MOV(swizzled_result, brw_imm_f(1.0f)));
-   }
-}
-
 void
 vec4_visitor::gs_emit_vertex(int stream_id)
 {