[Mesa-dev] [PATCH 2/2] tgsi/scan: turn a huge if-else-if.. chain into a switch statement

[Marek Olšák]

From: Marek Olšák <marek.olsak at amd.com>

---
 src/gallium/auxiliary/tgsi/tgsi_scan.c | 44 +++++++++++++++++++++++-----------
 1 file changed, 30 insertions(+), 14 deletions(-)

diff --git a/src/gallium/auxiliary/tgsi/tgsi_scan.c b/src/gallium/auxiliary/tgsi/tgsi_scan.c
index 26cb2be..40a1340 100644
--- a/src/gallium/auxiliary/tgsi/tgsi_scan.c
+++ b/src/gallium/auxiliary/tgsi/tgsi_scan.c
@@ -448,62 +448,72 @@ scan_declaration(struct tgsi_shader_info *info,
          info->output_array_last[array_id] = fulldecl->Range.Last;
          break;
       }
       info->array_max[file] = MAX2(info->array_max[file], array_id);
    }
 
    for (reg = fulldecl->Range.First; reg <= fulldecl->Range.Last; reg++) {
       unsigned semName = fulldecl->Semantic.Name;
       unsigned semIndex = fulldecl->Semantic.Index +
          (reg - fulldecl->Range.First);
+      int buffer;
+      unsigned index, target, type;
 
       /* only first 32 regs will appear in this bitfield */
       info->file_mask[file] |= (1 << reg);
       info->file_count[file]++;
       info->file_max[file] = MAX2(info->file_max[file], (int)reg);
 
-      if (file == TGSI_FILE_CONSTANT) {
-         int buffer = 0;
+      switch (file) {
+      case TGSI_FILE_CONSTANT:
+         buffer = 0;
 
          if (fulldecl->Declaration.Dimension)
             buffer = fulldecl->Dim.Index2D;
 
          info->const_file_max[buffer] =
             MAX2(info->const_file_max[buffer], (int)reg);
          info->const_buffers_declared |= 1u << buffer;
-      } else if (file == TGSI_FILE_IMAGE) {
+         break;
+
+      case TGSI_FILE_IMAGE:
          info->images_declared |= 1u << reg;
          if (fulldecl->Image.Resource == TGSI_TEXTURE_BUFFER)
             info->images_buffers |= 1 << reg;
-      } else if (file == TGSI_FILE_BUFFER) {
+         break;
+
+      case TGSI_FILE_BUFFER:
          info->shader_buffers_declared |= 1u << reg;
-      } else if (file == TGSI_FILE_INPUT) {
+         break;
+
+      case TGSI_FILE_INPUT:
          info->input_semantic_name[reg] = (ubyte) semName;
          info->input_semantic_index[reg] = (ubyte) semIndex;
          info->input_interpolate[reg] = (ubyte)fulldecl->Interp.Interpolate;
          info->input_interpolate_loc[reg] = (ubyte)fulldecl->Interp.Location;
          info->input_cylindrical_wrap[reg] = (ubyte)fulldecl->Interp.CylindricalWrap;
 
          /* Vertex shaders can have inputs with holes between them. */
          info->num_inputs = MAX2(info->num_inputs, reg + 1);
 
          if (semName == TGSI_SEMANTIC_PRIMID)
             info->uses_primid = TRUE;
          else if (procType == PIPE_SHADER_FRAGMENT) {
             if (semName == TGSI_SEMANTIC_POSITION)
                info->reads_position = TRUE;
             else if (semName == TGSI_SEMANTIC_FACE)
                info->uses_frontface = TRUE;
          }
-      }
-      else if (file == TGSI_FILE_SYSTEM_VALUE) {
-         unsigned index = fulldecl->Range.First;
+         break;
+
+      case TGSI_FILE_SYSTEM_VALUE:
+         index = fulldecl->Range.First;
 
          info->system_value_semantic_name[index] = semName;
          info->num_system_values = MAX2(info->num_system_values, index + 1);
 
          switch (semName) {
          case TGSI_SEMANTIC_INSTANCEID:
             info->uses_instanceid = TRUE;
             break;
          case TGSI_SEMANTIC_VERTEXID:
             info->uses_vertexid = TRUE;
@@ -523,22 +533,23 @@ scan_declaration(struct tgsi_shader_info *info,
          case TGSI_SEMANTIC_POSITION:
             info->reads_position = TRUE;
             break;
          case TGSI_SEMANTIC_FACE:
             info->uses_frontface = TRUE;
             break;
          case TGSI_SEMANTIC_SAMPLEMASK:
             info->reads_samplemask = TRUE;
             break;
          }
-      }
-      else if (file == TGSI_FILE_OUTPUT) {
+         break;
+
+      case TGSI_FILE_OUTPUT:
          info->output_semantic_name[reg] = (ubyte) semName;
          info->output_semantic_index[reg] = (ubyte) semIndex;
          info->num_outputs = MAX2(info->num_outputs, reg + 1);
 
          if (semName == TGSI_SEMANTIC_COLOR)
             info->colors_written |= 1 << semIndex;
 
          if (procType == PIPE_SHADER_VERTEX ||
              procType == PIPE_SHADER_GEOMETRY ||
              procType == PIPE_SHADER_TESS_CTRL ||
@@ -571,37 +582,42 @@ scan_declaration(struct tgsi_shader_info *info,
                info->writes_samplemask = TRUE;
                break;
             }
          }
 
          if (procType == PIPE_SHADER_VERTEX) {
             if (semName == TGSI_SEMANTIC_EDGEFLAG) {
                info->writes_edgeflag = TRUE;
             }
          }
-      } else if (file == TGSI_FILE_SAMPLER) {
+         break;
+
+      case TGSI_FILE_SAMPLER:
          STATIC_ASSERT(sizeof(info->samplers_declared) * 8 >= PIPE_MAX_SAMPLERS);
          info->samplers_declared |= 1u << reg;
-      } else if (file == TGSI_FILE_SAMPLER_VIEW) {
-         unsigned target = fulldecl->SamplerView.Resource;
-         unsigned type = fulldecl->SamplerView.ReturnTypeX;
+         break;
+
+      case TGSI_FILE_SAMPLER_VIEW:
+         target = fulldecl->SamplerView.Resource;
+         type = fulldecl->SamplerView.ReturnTypeX;
 
          assert(target < TGSI_TEXTURE_UNKNOWN);
          if (info->sampler_targets[reg] == TGSI_TEXTURE_UNKNOWN) {
             /* Save sampler target for this sampler index */
             info->sampler_targets[reg] = target;
             info->sampler_type[reg] = type;
          } else {
             /* if previously declared, make sure targets agree */
             assert(info->sampler_targets[reg] == target);
             assert(info->sampler_type[reg] == type);
          }
+         break;
       }
    }
 }
 
 
 static void
 scan_immediate(struct tgsi_shader_info *info)
 {
    uint reg = info->immediate_count++;
    uint file = TGSI_FILE_IMMEDIATE;
-- 
2.7.4