Micro-optimization in HandleVertexAttribPointer

gpu/command_buffer/service/gles2_cmd_decoder.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "gpu/command_buffer/service/gles2_cmd_decoder.h"
 
 #include <stdio.h>
 
 #include <algorithm>
 #include <list>
@@ skipping 7187 matching lines @@
         GL_INVALID_VALUE, "glVertexAttribPointer", "stride > 255");
     return error::kNoError;
   }
   if (offset < 0) {
     LOCAL_SET_GL_ERROR(
         GL_INVALID_VALUE, "glVertexAttribPointer", "offset < 0");
     return error::kNoError;
   }
   GLsizei component_size =
       GLES2Util::GetGLTypeSizeForTexturesAndBuffers(type);
-  if (offset % component_size > 0) {
+  // component_size must be a power of two to use & as optimized modulo.
+  DCHECK(GLES2Util::IsPOT(component_size));
+  if (offset & (component_size - 1)) {
     LOCAL_SET_GL_ERROR(
         GL_INVALID_OPERATION,
         "glVertexAttribPointer", "offset not valid for type");
     return error::kNoError;
   }
-  if (stride % component_size > 0) {
+  if (stride & (component_size - 1)) {
     LOCAL_SET_GL_ERROR(
         GL_INVALID_OPERATION,
         "glVertexAttribPointer", "stride not valid for type");
     return error::kNoError;
   }
   state_.vertex_attrib_manager
       ->SetAttribInfo(indx,
                       state_.bound_array_buffer.get(),
                       size,
                       type,
@@ skipping 752 matching lines @@
 const int kS3TCBlockHeight = 4;
 const int kS3TCDXT1BlockSize = 8;
 const int kS3TCDXT3AndDXT5BlockSize = 16;
 
 bool IsValidDXTSize(GLint level, GLsizei size) {
   return (size == 1) ||
          (size == 2) || !(size % kS3TCBlockWidth);
 }
 
 bool IsValidPVRTCSize(GLint level, GLsizei size) {
-  // Ensure that the size is a power of two
-  return (size & (size - 1)) == 0;
+  return GLES2Util::IsPOT(size);
 }
 
 }  // anonymous namespace.
 
 bool GLES2DecoderImpl::ValidateCompressedTexFuncData(
     const char* function_name,
     GLsizei width, GLsizei height, GLenum format, size_t size) {
   unsigned int bytes_required = 0;
 
   switch (format) {
@@ skipping 2930 matching lines @@
   }
 }
 
 // Include the auto-generated part of this file. We split this because it means
 // we can easily edit the non-auto generated parts right here in this file
 // instead of having to edit some template or the code generator.
 #include "gpu/command_buffer/service/gles2_cmd_decoder_autogen.h"
 
 }  // namespace gles2
 }  // namespace gpu