diff --git a/Android.mk b/Android.mk
index c32732d..80c61b0 100644
--- a/Android.mk
+++ b/Android.mk
@@ -61,6 +61,7 @@
 		source/val/validate_instruction.cpp \
 		source/val/validate_memory.cpp \
 		source/val/validate_memory_semantics.cpp \
+		source/val/validate_mesh_shading.cpp \
 		source/val/validate_misc.cpp \
 		source/val/validate_mode_setting.cpp \
 		source/val/validate_layout.cpp \
diff --git a/BUILD.gn b/BUILD.gn
index ac75cba..4f1c43e 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -526,6 +526,7 @@
     "source/val/validate_memory.cpp",
     "source/val/validate_memory_semantics.cpp",
     "source/val/validate_memory_semantics.h",
+    "source/val/validate_mesh_shading.h",
     "source/val/validate_misc.cpp",
     "source/val/validate_mode_setting.cpp",
     "source/val/validate_non_uniform.cpp",
diff --git a/source/CMakeLists.txt b/source/CMakeLists.txt
index ab4578b..668579a 100644
--- a/source/CMakeLists.txt
+++ b/source/CMakeLists.txt
@@ -318,6 +318,7 @@
   ${CMAKE_CURRENT_SOURCE_DIR}/val/validate_logicals.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/val/validate_memory.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/val/validate_memory_semantics.cpp
+  ${CMAKE_CURRENT_SOURCE_DIR}/val/validate_mesh_shading.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/val/validate_misc.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/val/validate_mode_setting.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/val/validate_non_uniform.cpp
diff --git a/source/val/validate.cpp b/source/val/validate.cpp
index 9a685f2..efb9225 100644
--- a/source/val/validate.cpp
+++ b/source/val/validate.cpp
@@ -209,6 +209,8 @@
     return error;
   }
 
+  bool has_mask_task_nv = false;
+  bool has_mask_task_ext = false;
   std::vector<Instruction*> visited_entry_points;
   for (auto& instruction : vstate->ordered_instructions()) {
     {
@@ -247,6 +249,11 @@
           }
         }
         visited_entry_points.push_back(inst);
+
+        has_mask_task_nv |= (execution_model == SpvExecutionModelTaskNV ||
+                             execution_model == SpvExecutionModelMeshNV);
+        has_mask_task_ext |= (execution_model == SpvExecutionModelTaskEXT ||
+                              execution_model == SpvExecutionModelMeshEXT);
       }
       if (inst->opcode() == SpvOpFunctionCall) {
         if (!vstate->in_function_body()) {
@@ -298,6 +305,12 @@
     return vstate->diag(SPV_ERROR_INVALID_LAYOUT, nullptr)
            << "Missing required OpSamplerImageAddressingModeNV instruction.";
 
+  if (has_mask_task_ext && has_mask_task_nv)
+    return vstate->diag(SPV_ERROR_INVALID_LAYOUT, nullptr)
+           << vstate->VkErrorID(7102)
+           << "Module can't mix MeshEXT/TaskEXT with MeshNV/TaskNV Execution "
+              "Model.";
+
   // Catch undefined forward references before performing further checks.
   if (auto error = ValidateForwardDecls(*vstate)) return error;
 
@@ -352,6 +365,7 @@
     if (auto error = LiteralsPass(*vstate, &instruction)) return error;
     if (auto error = RayQueryPass(*vstate, &instruction)) return error;
     if (auto error = RayTracingPass(*vstate, &instruction)) return error;
+    if (auto error = MeshShadingPass(*vstate, &instruction)) return error;
   }
 
   // Validate the preconditions involving adjacent instructions. e.g. SpvOpPhi
diff --git a/source/val/validate.h b/source/val/validate.h
index 85c32d3..4b953ba 100644
--- a/source/val/validate.h
+++ b/source/val/validate.h
@@ -203,6 +203,9 @@
 /// Validates correctness of ray tracing instructions.
 spv_result_t RayTracingPass(ValidationState_t& _, const Instruction* inst);
 
+/// Validates correctness of mesh shading instructions.
+spv_result_t MeshShadingPass(ValidationState_t& _, const Instruction* inst);
+
 /// Calculates the reachability of basic blocks.
 void ReachabilityPass(ValidationState_t& _);
 
diff --git a/source/val/validate_cfg.cpp b/source/val/validate_cfg.cpp
index c684a99..cf22dea 100644
--- a/source/val/validate_cfg.cpp
+++ b/source/val/validate_cfg.cpp
@@ -1068,6 +1068,7 @@
     case SpvOpTerminateRayKHR:
     case SpvOpEmitMeshTasksEXT:
       _.current_function().RegisterBlockEnd(std::vector<uint32_t>());
+      // Ops with dedicated passes check for the Execution Model there
       if (opcode == SpvOpKill) {
         _.current_function().RegisterExecutionModelLimitation(
             SpvExecutionModelFragment,
@@ -1088,11 +1089,6 @@
             SpvExecutionModelAnyHitKHR,
             "OpTerminateRayKHR requires AnyHitKHR execution model");
       }
-      if (opcode == SpvOpEmitMeshTasksEXT) {
-        _.current_function().RegisterExecutionModelLimitation(
-            SpvExecutionModelTaskEXT,
-            "OpEmitMeshTasksEXT requires TaskEXT execution model");
-      }
 
       break;
     default:
diff --git a/source/val/validate_memory.cpp b/source/val/validate_memory.cpp
index f939542..58d6911 100644
--- a/source/val/validate_memory.cpp
+++ b/source/val/validate_memory.cpp
@@ -640,6 +640,19 @@
     }
   }
 
+  if (inst->operands().size() > 3) {
+    if (storage_class == SpvStorageClassTaskPayloadWorkgroupEXT) {
+      return _.diag(SPV_ERROR_INVALID_ID, inst)
+             << "OpVariable, <id> '" << _.getIdName(inst->id())
+             << "', initializer are not allowed for TaskPayloadWorkgroupEXT";
+    }
+    if (storage_class == SpvStorageClassInput) {
+      return _.diag(SPV_ERROR_INVALID_ID, inst)
+             << "OpVariable, <id> '" << _.getIdName(inst->id())
+             << "', initializer are not allowed for Input";
+    }
+  }
+
   if (storage_class == SpvStorageClassPhysicalStorageBuffer) {
     return _.diag(SPV_ERROR_INVALID_ID, inst)
            << "PhysicalStorageBuffer must not be used with OpVariable.";
diff --git a/source/val/validate_mesh_shading.cpp b/source/val/validate_mesh_shading.cpp
new file mode 100644
index 0000000..a7f0726
--- /dev/null
+++ b/source/val/validate_mesh_shading.cpp
@@ -0,0 +1,123 @@
+// Copyright (c) 2022 The Khronos Group Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Validates ray query instructions from SPV_KHR_ray_query
+
+#include "source/opcode.h"
+#include "source/val/instruction.h"
+#include "source/val/validate.h"
+#include "source/val/validation_state.h"
+
+namespace spvtools {
+namespace val {
+
+spv_result_t MeshShadingPass(ValidationState_t& _, const Instruction* inst) {
+  const SpvOp opcode = inst->opcode();
+  switch (opcode) {
+    case SpvOpEmitMeshTasksEXT: {
+      _.function(inst->function()->id())
+          ->RegisterExecutionModelLimitation(
+              [](SpvExecutionModel model, std::string* message) {
+                if (model != SpvExecutionModelTaskEXT) {
+                  if (message) {
+                    *message =
+                        "OpEmitMeshTasksEXT requires TaskEXT execution model";
+                  }
+                  return false;
+                }
+                return true;
+              });
+
+      const uint32_t group_count_x = _.GetOperandTypeId(inst, 0);
+      if (!_.IsUnsignedIntScalarType(group_count_x) ||
+          _.GetBitWidth(group_count_x) != 32) {
+        return _.diag(SPV_ERROR_INVALID_DATA, inst)
+               << "Group Count X must be a 32-bit unsigned int scalar";
+      }
+
+      const uint32_t group_count_y = _.GetOperandTypeId(inst, 1);
+      if (!_.IsUnsignedIntScalarType(group_count_y) ||
+          _.GetBitWidth(group_count_y) != 32) {
+        return _.diag(SPV_ERROR_INVALID_DATA, inst)
+               << "Group Count Y must be a 32-bit unsigned int scalar";
+      }
+
+      const uint32_t group_count_z = _.GetOperandTypeId(inst, 2);
+      if (!_.IsUnsignedIntScalarType(group_count_z) ||
+          _.GetBitWidth(group_count_z) != 32) {
+        return _.diag(SPV_ERROR_INVALID_DATA, inst)
+               << "Group Count Z must be a 32-bit unsigned int scalar";
+      }
+
+      if (inst->operands().size() == 4) {
+        const auto payload = _.FindDef(inst->GetOperandAs<uint32_t>(3));
+        if (payload->opcode() != SpvOpVariable) {
+          return _.diag(SPV_ERROR_INVALID_DATA, inst)
+                 << "Payload must be the result of a OpVariable";
+        }
+        if (SpvStorageClass(payload->GetOperandAs<uint32_t>(2)) !=
+            SpvStorageClassTaskPayloadWorkgroupEXT) {
+          return _.diag(SPV_ERROR_INVALID_DATA, inst)
+                 << "Payload OpVariable must have a storage class of "
+                    "TaskPayloadWorkgroupEXT";
+        }
+      }
+      break;
+    }
+
+    case SpvOpSetMeshOutputsEXT: {
+      _.function(inst->function()->id())
+          ->RegisterExecutionModelLimitation(
+              [](SpvExecutionModel model, std::string* message) {
+                if (model != SpvExecutionModelMeshEXT) {
+                  if (message) {
+                    *message =
+                        "OpSetMeshOutputsEXT requires MeshEXT execution model";
+                  }
+                  return false;
+                }
+                return true;
+              });
+
+      const uint32_t vertex_count = _.GetOperandTypeId(inst, 0);
+      if (!_.IsUnsignedIntScalarType(vertex_count) ||
+          _.GetBitWidth(vertex_count) != 32) {
+        return _.diag(SPV_ERROR_INVALID_DATA, inst)
+               << "Vertex Count must be a 32-bit unsigned int scalar";
+      }
+
+      const uint32_t primitive_count = _.GetOperandTypeId(inst, 1);
+      if (!_.IsUnsignedIntScalarType(primitive_count) ||
+          _.GetBitWidth(primitive_count) != 32) {
+        return _.diag(SPV_ERROR_INVALID_DATA, inst)
+               << "Primitive Count must be a 32-bit unsigned int scalar";
+      }
+
+      break;
+    }
+
+    case SpvOpWritePackedPrimitiveIndices4x8NV: {
+      // No validation rules (for the moment).
+      break;
+    }
+
+    default:
+      break;
+  }
+
+  return SPV_SUCCESS;
+}
+
+}  // namespace val
+}  // namespace spvtools
diff --git a/source/val/validate_mode_setting.cpp b/source/val/validate_mode_setting.cpp
index 09a9d48..11e11e9 100644
--- a/source/val/validate_mode_setting.cpp
+++ b/source/val/validate_mode_setting.cpp
@@ -241,6 +241,39 @@
                     "OutputTriangleStrip execution modes.";
         }
         break;
+      case SpvExecutionModelMeshEXT:
+        if (!execution_modes ||
+            1 != std::count_if(execution_modes->begin(), execution_modes->end(),
+                               [](const SpvExecutionMode& mode) {
+                                 switch (mode) {
+                                   case SpvExecutionModeOutputPoints:
+                                   case SpvExecutionModeOutputLinesEXT:
+                                   case SpvExecutionModeOutputTrianglesEXT:
+                                     return true;
+                                   default:
+                                     return false;
+                                 }
+                               })) {
+          return _.diag(SPV_ERROR_INVALID_DATA, inst)
+                 << "MeshEXT execution model entry points must specify exactly "
+                    "one of OutputPoints, OutputLinesEXT, or "
+                    "OutputTrianglesEXT Execution Modes.";
+        } else if (2 != std::count_if(
+                            execution_modes->begin(), execution_modes->end(),
+                            [](const SpvExecutionMode& mode) {
+                              switch (mode) {
+                                case SpvExecutionModeOutputPrimitivesEXT:
+                                case SpvExecutionModeOutputVertices:
+                                  return true;
+                                default:
+                                  return false;
+                              }
+                            })) {
+          return _.diag(SPV_ERROR_INVALID_DATA, inst)
+                 << "MeshEXT execution model entry points must specify both "
+                    "OutputPrimitivesEXT and OutputVertices Execution Modes.";
+        }
+        break;
       default:
         break;
     }
@@ -443,6 +476,20 @@
         }
       }
       break;
+    case SpvExecutionModeOutputLinesEXT:
+    case SpvExecutionModeOutputTrianglesEXT:
+    case SpvExecutionModeOutputPrimitivesEXT:
+      if (!std::all_of(models->begin(), models->end(),
+                       [](const SpvExecutionModel& model) {
+                         return (model == SpvExecutionModelMeshEXT ||
+                                 model == SpvExecutionModelMeshNV);
+                       })) {
+        return _.diag(SPV_ERROR_INVALID_DATA, inst)
+               << "Execution mode can only be used with the MeshEXT or MeshNV "
+                  "execution "
+                  "model.";
+      }
+      break;
     case SpvExecutionModePixelCenterInteger:
     case SpvExecutionModeOriginUpperLeft:
     case SpvExecutionModeOriginLowerLeft:
diff --git a/source/val/validate_ray_tracing.cpp b/source/val/validate_ray_tracing.cpp
index 78bac19..5b5c8da 100644
--- a/source/val/validate_ray_tracing.cpp
+++ b/source/val/validate_ray_tracing.cpp
@@ -112,8 +112,10 @@
       if (payload->opcode() != SpvOpVariable) {
         return _.diag(SPV_ERROR_INVALID_DATA, inst)
                << "Payload must be the result of a OpVariable";
-      } else if (payload->word(3) != SpvStorageClassRayPayloadKHR &&
-                 payload->word(3) != SpvStorageClassIncomingRayPayloadKHR) {
+      } else if (payload->GetOperandAs<uint32_t>(2) !=
+                     SpvStorageClassRayPayloadKHR &&
+                 payload->GetOperandAs<uint32_t>(2) !=
+                     SpvStorageClassIncomingRayPayloadKHR) {
         return _.diag(SPV_ERROR_INVALID_DATA, inst)
                << "Payload must have storage class RayPayloadKHR or "
                   "IncomingRayPayloadKHR";
@@ -185,8 +187,9 @@
       if (callable_data->opcode() != SpvOpVariable) {
         return _.diag(SPV_ERROR_INVALID_DATA, inst)
                << "Callable Data must be the result of a OpVariable";
-      } else if (callable_data->word(3) != SpvStorageClassCallableDataKHR &&
-                 callable_data->word(3) !=
+      } else if (callable_data->GetOperandAs<uint32_t>(2) !=
+                     SpvStorageClassCallableDataKHR &&
+                 callable_data->GetOperandAs<uint32_t>(2) !=
                      SpvStorageClassIncomingCallableDataKHR) {
         return _.diag(SPV_ERROR_INVALID_DATA, inst)
                << "Callable Data must have storage class CallableDataKHR or "
diff --git a/source/val/validation_state.cpp b/source/val/validation_state.cpp
index fa8c624..47f6ba0 100644
--- a/source/val/validation_state.cpp
+++ b/source/val/validation_state.cpp
@@ -765,6 +765,21 @@
               }
               return true;
             });
+  } else if (storage_class == SpvStorageClassTaskPayloadWorkgroupEXT) {
+    function(consumer->function()->id())
+        ->RegisterExecutionModelLimitation(
+            [](SpvExecutionModel model, std::string* message) {
+              if (model != SpvExecutionModelTaskEXT &&
+                  model != SpvExecutionModelMeshEXT) {
+                if (message) {
+                  *message =
+                      "TaskPayloadWorkgroupEXT Storage Class is limited to "
+                      "TaskEXT and MeshKHR execution model";
+                }
+                return false;
+              }
+              return true;
+            });
   }
 }
 
@@ -2110,6 +2125,8 @@
       return VUID_WRAP(VUID-StandaloneSpirv-Uniform-06925);
     case 6997:
       return VUID_WRAP(VUID-StandaloneSpirv-SubgroupVoteKHR-06997);
+    case 7102:
+      return VUID_WRAP(VUID-StandaloneSpirv-MeshEXT-07102);
     case 7320:
       return VUID_WRAP(VUID-StandaloneSpirv-ExecutionModel-07320);
     case 7290:
diff --git a/test/val/val_id_test.cpp b/test/val/val_id_test.cpp
index 3cf7575..deda95b 100644
--- a/test/val/val_id_test.cpp
+++ b/test/val/val_id_test.cpp
@@ -2091,9 +2091,9 @@
 TEST_F(ValidateIdWithMessage, OpVariableInitializerConstantGood) {
   std::string spirv = kGLSL450MemoryModel + R"(
 %1 = OpTypeInt 32 0
-%2 = OpTypePointer Input %1
+%2 = OpTypePointer Output %1
 %3 = OpConstant %1 42
-%4 = OpVariable %2 Input %3)";
+%4 = OpVariable %2 Output %3)";
   CompileSuccessfully(spirv.c_str());
   EXPECT_EQ(SPV_SUCCESS, ValidateInstructions());
 }
diff --git a/test/val/val_memory_test.cpp b/test/val/val_memory_test.cpp
index ec1a000..35e8af7 100644
--- a/test/val/val_memory_test.cpp
+++ b/test/val/val_memory_test.cpp
@@ -472,6 +472,55 @@
                 "= OpVariable %_ptr_Input_float Input %float_1\n"));
 }
 
+TEST_F(ValidateMemory, UniversalInitializerWithDisallowedStorageClassesBad) {
+  std::string spirv = R"(
+OpCapability Shader
+OpMemoryModel Logical GLSL450
+OpEntryPoint Fragment %func "func"
+OpExecutionMode %func OriginUpperLeft
+%float = OpTypeFloat 32
+%float_ptr = OpTypePointer Input %float
+%init_val = OpConstant %float 1.0
+%1 = OpVariable %float_ptr Input %init_val
+%void = OpTypeVoid
+%functy = OpTypeFunction %void
+%func = OpFunction %void None %functy
+%2 = OpLabel
+OpReturn
+OpFunctionEnd
+)";
+  CompileSuccessfully(spirv.c_str(), SPV_ENV_UNIVERSAL_1_3);
+  EXPECT_EQ(SPV_ERROR_INVALID_ID, ValidateInstructions(SPV_ENV_UNIVERSAL_1_3));
+  EXPECT_THAT(
+      getDiagnosticString(),
+      HasSubstr(
+          "OpVariable, <id> '5[%5]', initializer are not allowed for Input"));
+}
+
+TEST_F(ValidateMemory, InitializerWithTaskPayloadWorkgroupEXT) {
+  std::string spirv = R"(
+               OpCapability MeshShadingEXT
+               OpExtension "SPV_EXT_mesh_shader"
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint TaskEXT %main "main" %payload
+       %void = OpTypeVoid
+       %func = OpTypeFunction %void
+       %uint = OpTypeInt 32 0
+%_ptr_TaskPayloadWorkgroupEXT = OpTypePointer TaskPayloadWorkgroupEXT %uint
+     %uint_1 = OpConstant %uint 1
+    %payload = OpVariable %_ptr_TaskPayloadWorkgroupEXT TaskPayloadWorkgroupEXT %uint_1
+       %main = OpFunction %void None %func
+      %label = OpLabel
+               OpReturn
+               OpFunctionEnd
+)";
+  CompileSuccessfully(spirv.c_str(), SPV_ENV_UNIVERSAL_1_5);
+  EXPECT_EQ(SPV_ERROR_INVALID_ID, ValidateInstructions(SPV_ENV_UNIVERSAL_1_5));
+  EXPECT_THAT(getDiagnosticString(),
+              HasSubstr("OpVariable, <id> '2[%2]', initializer are not allowed "
+                        "for TaskPayloadWorkgroupEXT"));
+}
+
 TEST_F(ValidateMemory, ArrayLenCorrectResultType) {
   std::string spirv = R"(
                OpCapability Shader
diff --git a/test/val/val_mesh_shading_test.cpp b/test/val/val_mesh_shading_test.cpp
index d10f40d..ce6999d 100644
--- a/test/val/val_mesh_shading_test.cpp
+++ b/test/val/val_mesh_shading_test.cpp
@@ -90,6 +90,515 @@
               HasSubstr("Return must appear in a block"));
 }
 
+TEST_F(ValidateMeshShading, BasicTaskSuccess) {
+  const std::string body = R"(
+               OpCapability MeshShadingEXT
+               OpExtension "SPV_EXT_mesh_shader"
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint TaskEXT %main "main"
+       %void = OpTypeVoid
+       %func = OpTypeFunction %void
+       %main = OpFunction %void None %func
+      %label = OpLabel
+               OpReturn
+               OpFunctionEnd
+)";
+
+  CompileSuccessfully(body, SPV_ENV_UNIVERSAL_1_5);
+  EXPECT_EQ(SPV_SUCCESS, ValidateInstructions(SPV_ENV_UNIVERSAL_1_5));
+}
+
+TEST_F(ValidateMeshShading, BasicMeshSuccess) {
+  const std::string body = R"(
+               OpCapability MeshShadingEXT
+               OpExtension "SPV_EXT_mesh_shader"
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint MeshEXT %main "main"
+               OpExecutionMode %main OutputVertices 1
+               OpExecutionMode %main OutputPrimitivesEXT 1
+               OpExecutionMode %main OutputTrianglesEXT
+       %void = OpTypeVoid
+       %func = OpTypeFunction %void
+       %main = OpFunction %void None %func
+      %label = OpLabel
+               OpReturn
+               OpFunctionEnd
+)";
+
+  CompileSuccessfully(body, SPV_ENV_UNIVERSAL_1_5);
+  EXPECT_EQ(SPV_SUCCESS, ValidateInstructions(SPV_ENV_UNIVERSAL_1_5));
+}
+
+TEST_F(ValidateMeshShading, VulkanBasicMeshAndTaskSuccess) {
+  const std::string body = R"(
+               OpCapability MeshShadingEXT
+               OpExtension "SPV_EXT_mesh_shader"
+               OpExtension "SPV_NV_mesh_shader"
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint MeshEXT %mainMesh "mainMesh"
+               OpEntryPoint TaskEXT %mainTask "mainTask"
+               OpExecutionMode %mainMesh OutputVertices 1
+               OpExecutionMode %mainMesh OutputPrimitivesEXT 1
+               OpExecutionMode %mainMesh OutputTrianglesEXT
+       %void = OpTypeVoid
+       %func = OpTypeFunction %void
+   %mainMesh = OpFunction %void None %func
+  %labelMesh = OpLabel
+               OpReturn
+               OpFunctionEnd
+   %mainTask = OpFunction %void None %func
+  %labelTask = OpLabel
+               OpReturn
+               OpFunctionEnd
+)";
+
+  CompileSuccessfully(body, SPV_ENV_VULKAN_1_2);
+  EXPECT_EQ(SPV_SUCCESS, ValidateInstructions(SPV_ENV_VULKAN_1_2));
+}
+
+TEST_F(ValidateMeshShading, VulkanBasicMeshAndTaskBad) {
+  const std::string body = R"(
+               OpCapability MeshShadingEXT
+               OpCapability MeshShadingNV
+               OpExtension "SPV_EXT_mesh_shader"
+               OpExtension "SPV_NV_mesh_shader"
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint MeshEXT %mainMesh "mainMesh"
+               OpEntryPoint TaskNV %mainTask "mainTask"
+               OpExecutionMode %mainMesh OutputVertices 1
+               OpExecutionMode %mainMesh OutputPrimitivesEXT 1
+               OpExecutionMode %mainMesh OutputTrianglesEXT
+       %void = OpTypeVoid
+       %func = OpTypeFunction %void
+   %mainMesh = OpFunction %void None %func
+  %labelMesh = OpLabel
+               OpReturn
+               OpFunctionEnd
+   %mainTask = OpFunction %void None %func
+  %labelTask = OpLabel
+               OpReturn
+               OpFunctionEnd
+)";
+
+  CompileSuccessfully(body, SPV_ENV_VULKAN_1_2);
+  EXPECT_EQ(SPV_ERROR_INVALID_LAYOUT, ValidateInstructions(SPV_ENV_VULKAN_1_2));
+  EXPECT_THAT(getDiagnosticString(),
+              AnyVUID("VUID-StandaloneSpirv-MeshEXT-07102"));
+  EXPECT_THAT(getDiagnosticString(),
+              HasSubstr("Module can't mix MeshEXT/TaskEXT with MeshNV/TaskNV "
+                        "Execution Model."));
+}
+
+TEST_F(ValidateMeshShading, MeshMissingOutputVertices) {
+  const std::string body = R"(
+               OpCapability MeshShadingEXT
+               OpExtension "SPV_EXT_mesh_shader"
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint MeshEXT %main "main"
+               OpExecutionMode %main OutputPrimitivesEXT 1
+               OpExecutionMode %main OutputTrianglesEXT
+       %void = OpTypeVoid
+       %func = OpTypeFunction %void
+       %main = OpFunction %void None %func
+      %label = OpLabel
+               OpReturn
+               OpFunctionEnd
+)";
+
+  CompileSuccessfully(body, SPV_ENV_UNIVERSAL_1_5);
+  EXPECT_EQ(SPV_ERROR_INVALID_DATA,
+            ValidateInstructions(SPV_ENV_UNIVERSAL_1_5));
+  EXPECT_THAT(
+      getDiagnosticString(),
+      HasSubstr("MeshEXT execution model entry points must specify both "
+                "OutputPrimitivesEXT and OutputVertices Execution Modes."));
+}
+
+TEST_F(ValidateMeshShading, MeshMissingOutputPrimitivesEXT) {
+  const std::string body = R"(
+               OpCapability MeshShadingEXT
+               OpExtension "SPV_EXT_mesh_shader"
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint MeshEXT %main "main"
+               OpExecutionMode %main OutputVertices 1
+               OpExecutionMode %main OutputTrianglesEXT
+       %void = OpTypeVoid
+       %func = OpTypeFunction %void
+       %main = OpFunction %void None %func
+      %label = OpLabel
+               OpReturn
+               OpFunctionEnd
+)";
+
+  CompileSuccessfully(body, SPV_ENV_UNIVERSAL_1_5);
+  EXPECT_EQ(SPV_ERROR_INVALID_DATA,
+            ValidateInstructions(SPV_ENV_UNIVERSAL_1_5));
+  EXPECT_THAT(
+      getDiagnosticString(),
+      HasSubstr("MeshEXT execution model entry points must specify both "
+                "OutputPrimitivesEXT and OutputVertices Execution Modes."));
+}
+
+TEST_F(ValidateMeshShading, MeshMissingOutputType) {
+  const std::string body = R"(
+               OpCapability MeshShadingEXT
+               OpExtension "SPV_EXT_mesh_shader"
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint MeshEXT %main "main"
+               OpExecutionMode %main OutputVertices 1
+               OpExecutionMode %main OutputPrimitivesEXT 1
+       %void = OpTypeVoid
+       %func = OpTypeFunction %void
+       %main = OpFunction %void None %func
+      %label = OpLabel
+               OpReturn
+               OpFunctionEnd
+)";
+
+  CompileSuccessfully(body, SPV_ENV_UNIVERSAL_1_5);
+  EXPECT_EQ(SPV_ERROR_INVALID_DATA,
+            ValidateInstructions(SPV_ENV_UNIVERSAL_1_5));
+  EXPECT_THAT(getDiagnosticString(),
+              HasSubstr("MeshEXT execution model entry points must specify "
+                        "exactly one of OutputPoints, OutputLinesEXT, or "
+                        "OutputTrianglesEXT Execution Modes."));
+}
+
+TEST_F(ValidateMeshShading, MeshMultipleOutputType) {
+  const std::string body = R"(
+               OpCapability MeshShadingEXT
+               OpExtension "SPV_EXT_mesh_shader"
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint MeshEXT %main "main"
+               OpExecutionMode %main OutputVertices 1
+               OpExecutionMode %main OutputPrimitivesEXT 1
+               OpExecutionMode %main OutputLinesEXT
+               OpExecutionMode %main OutputTrianglesEXT
+       %void = OpTypeVoid
+       %func = OpTypeFunction %void
+       %main = OpFunction %void None %func
+      %label = OpLabel
+               OpReturn
+               OpFunctionEnd
+)";
+
+  CompileSuccessfully(body, SPV_ENV_UNIVERSAL_1_5);
+  EXPECT_EQ(SPV_ERROR_INVALID_DATA,
+            ValidateInstructions(SPV_ENV_UNIVERSAL_1_5));
+  EXPECT_THAT(getDiagnosticString(),
+              HasSubstr("MeshEXT execution model entry points must specify "
+                        "exactly one of OutputPoints, OutputLinesEXT, or "
+                        "OutputTrianglesEXT Execution Modes."));
+}
+
+TEST_F(ValidateMeshShading, BadExecutionModelOutputLinesEXT) {
+  const std::string body = R"(
+               OpCapability MeshShadingEXT
+               OpExtension "SPV_EXT_mesh_shader"
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint GLCompute %main "main"
+               OpExecutionMode %main OutputLinesEXT
+       %void = OpTypeVoid
+       %func = OpTypeFunction %void
+       %main = OpFunction %void None %func
+      %label = OpLabel
+               OpReturn
+               OpFunctionEnd
+)";
+
+  CompileSuccessfully(body, SPV_ENV_UNIVERSAL_1_5);
+  EXPECT_EQ(SPV_ERROR_INVALID_DATA,
+            ValidateInstructions(SPV_ENV_UNIVERSAL_1_5));
+  EXPECT_THAT(getDiagnosticString(),
+              HasSubstr("Execution mode can only be used with the MeshEXT or "
+                        "MeshNV execution model."));
+}
+
+TEST_F(ValidateMeshShading, BadExecutionModelOutputTrianglesEXT) {
+  const std::string body = R"(
+               OpCapability MeshShadingEXT
+               OpExtension "SPV_EXT_mesh_shader"
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint GLCompute %main "main"
+               OpExecutionMode %main OutputTrianglesEXT
+       %void = OpTypeVoid
+       %func = OpTypeFunction %void
+       %main = OpFunction %void None %func
+      %label = OpLabel
+               OpReturn
+               OpFunctionEnd
+)";
+
+  CompileSuccessfully(body, SPV_ENV_UNIVERSAL_1_5);
+  EXPECT_EQ(SPV_ERROR_INVALID_DATA,
+            ValidateInstructions(SPV_ENV_UNIVERSAL_1_5));
+  EXPECT_THAT(getDiagnosticString(),
+              HasSubstr("Execution mode can only be used with the MeshEXT or "
+                        "MeshNV execution model."));
+}
+
+TEST_F(ValidateMeshShading, BadExecutionModelOutputPrimitivesEXT) {
+  const std::string body = R"(
+               OpCapability MeshShadingEXT
+               OpExtension "SPV_EXT_mesh_shader"
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint GLCompute %main "main"
+               OpExecutionMode %main OutputPrimitivesEXT 1
+       %void = OpTypeVoid
+       %func = OpTypeFunction %void
+       %main = OpFunction %void None %func
+      %label = OpLabel
+               OpReturn
+               OpFunctionEnd
+)";
+
+  CompileSuccessfully(body, SPV_ENV_UNIVERSAL_1_5);
+  EXPECT_EQ(SPV_ERROR_INVALID_DATA,
+            ValidateInstructions(SPV_ENV_UNIVERSAL_1_5));
+  EXPECT_THAT(getDiagnosticString(),
+              HasSubstr("Execution mode can only be used with the MeshEXT or "
+                        "MeshNV execution model."));
+}
+
+TEST_F(ValidateMeshShading, OpEmitMeshTasksBadGroupCountSignedInt) {
+  const std::string body = R"(
+               OpCapability MeshShadingEXT
+               OpExtension "SPV_EXT_mesh_shader"
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint TaskEXT %main "main"
+       %void = OpTypeVoid
+       %func = OpTypeFunction %void
+        %int = OpTypeInt 32 1
+       %uint = OpTypeInt 32 0
+      %int_1 = OpConstant %int 1
+     %uint_1 = OpConstant %uint 1
+       %main = OpFunction %void None %func
+       %label = OpLabel
+               OpEmitMeshTasksEXT %int_1 %uint_1 %uint_1
+               OpFunctionEnd
+)";
+
+  CompileSuccessfully(body, SPV_ENV_UNIVERSAL_1_5);
+  EXPECT_EQ(SPV_ERROR_INVALID_DATA,
+            ValidateInstructions(SPV_ENV_UNIVERSAL_1_5));
+  EXPECT_THAT(getDiagnosticString(),
+              HasSubstr("Group Count X must be a 32-bit unsigned int scalar"));
+}
+
+TEST_F(ValidateMeshShading, OpEmitMeshTasksBadGroupCountVector) {
+  const std::string body = R"(
+               OpCapability MeshShadingEXT
+               OpExtension "SPV_EXT_mesh_shader"
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint TaskEXT %main "main"
+       %void = OpTypeVoid
+       %func = OpTypeFunction %void
+       %uint = OpTypeInt 32 0
+     %v2uint = OpTypeVector %uint 2
+%_ptr_v2uint = OpTypePointer Function %v2uint
+     %uint_1 = OpConstant %uint 1
+  %composite = OpConstantComposite %v2uint %uint_1 %uint_1
+  %_ptr_uint = OpTypePointer Function %uint
+       %main = OpFunction %void None %func
+      %label = OpLabel
+          %x = OpVariable %_ptr_v2uint Function
+               OpStore %x %composite
+         %13 = OpAccessChain %_ptr_uint %x %uint_1
+         %14 = OpLoad %uint %13
+               OpEmitMeshTasksEXT %14 %composite %uint_1
+               OpFunctionEnd
+)";
+
+  CompileSuccessfully(body, SPV_ENV_UNIVERSAL_1_5);
+  EXPECT_EQ(SPV_ERROR_INVALID_DATA,
+            ValidateInstructions(SPV_ENV_UNIVERSAL_1_5));
+  EXPECT_THAT(getDiagnosticString(),
+              HasSubstr("Group Count Y must be a 32-bit unsigned int scalar"));
+}
+
+TEST_F(ValidateMeshShading, OpEmitMeshTasksBadPayload) {
+  const std::string body = R"(
+               OpCapability MeshShadingEXT
+               OpExtension "SPV_EXT_mesh_shader"
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint TaskEXT %main "main" %payload
+       %void = OpTypeVoid
+       %func = OpTypeFunction %void
+       %uint = OpTypeInt 32 0
+       %task = OpTypeStruct %uint
+%_ptr_Uniform = OpTypePointer Uniform %task
+    %payload = OpVariable %_ptr_Uniform Uniform
+     %uint_1 = OpConstant %uint 1
+       %main = OpFunction %void None %func
+      %label = OpLabel
+               OpEmitMeshTasksEXT %uint_1 %uint_1 %uint_1 %payload
+               OpFunctionEnd
+)";
+
+  CompileSuccessfully(body, SPV_ENV_UNIVERSAL_1_5);
+  EXPECT_EQ(SPV_ERROR_INVALID_DATA,
+            ValidateInstructions(SPV_ENV_UNIVERSAL_1_5));
+  EXPECT_THAT(getDiagnosticString(),
+              HasSubstr("Payload OpVariable must have a storage class of "
+                        "TaskPayloadWorkgroupEXT"));
+}
+
+TEST_F(ValidateMeshShading, TaskPayloadWorkgroupBadExecutionModel) {
+  const std::string body = R"(
+               OpCapability MeshShadingEXT
+               OpExtension "SPV_EXT_mesh_shader"
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint GLCompute %main "main" %payload
+       %void = OpTypeVoid
+       %func = OpTypeFunction %void
+       %uint = OpTypeInt 32 0
+%_ptr_TaskPayloadWorkgroupEXT = OpTypePointer TaskPayloadWorkgroupEXT %uint
+    %payload = OpVariable %_ptr_TaskPayloadWorkgroupEXT TaskPayloadWorkgroupEXT
+       %main = OpFunction %void None %func
+      %label = OpLabel
+       %load = OpLoad %uint %payload
+               OpReturn
+               OpFunctionEnd
+)";
+
+  CompileSuccessfully(body, SPV_ENV_UNIVERSAL_1_5);
+  EXPECT_EQ(SPV_ERROR_INVALID_ID, ValidateInstructions(SPV_ENV_UNIVERSAL_1_5));
+  EXPECT_THAT(getDiagnosticString(),
+              HasSubstr("TaskPayloadWorkgroupEXT Storage Class is limited to "
+                        "TaskEXT and MeshKHR execution model"));
+}
+
+TEST_F(ValidateMeshShading, OpSetMeshOutputsBadVertexCount) {
+  const std::string body = R"(
+               OpCapability MeshShadingEXT
+               OpExtension "SPV_EXT_mesh_shader"
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint MeshEXT %main "main"
+               OpExecutionMode %main OutputVertices 1
+               OpExecutionMode %main OutputPrimitivesNV 1
+               OpExecutionMode %main OutputTrianglesNV
+       %void = OpTypeVoid
+          %3 = OpTypeFunction %void
+        %int = OpTypeInt 32 1
+       %uint = OpTypeInt 32 0
+  %_ptr_int = OpTypePointer Function %int
+      %int_1 = OpConstant %int 1
+     %uint_1 = OpConstant %uint 1
+       %main = OpFunction %void None %3
+          %5 = OpLabel
+          %x = OpVariable %_ptr_int Function
+               OpStore %x %int_1
+       %load = OpLoad %int %x
+               OpSetMeshOutputsEXT %load %uint_1
+               OpReturn
+               OpFunctionEnd
+)";
+
+  CompileSuccessfully(body, SPV_ENV_UNIVERSAL_1_5);
+  EXPECT_EQ(SPV_ERROR_INVALID_DATA,
+            ValidateInstructions(SPV_ENV_UNIVERSAL_1_5));
+  EXPECT_THAT(getDiagnosticString(),
+              HasSubstr("Vertex Count must be a 32-bit unsigned int scalar"));
+}
+
+TEST_F(ValidateMeshShading, OpSetMeshOutputsBadPrimitiveCount) {
+  const std::string body = R"(
+               OpCapability MeshShadingEXT
+               OpExtension "SPV_EXT_mesh_shader"
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint MeshEXT %main "main"
+               OpExecutionMode %main OutputVertices 1
+               OpExecutionMode %main OutputPrimitivesNV 1
+               OpExecutionMode %main OutputTrianglesNV
+       %void = OpTypeVoid
+          %3 = OpTypeFunction %void
+        %int = OpTypeInt 32 1
+       %uint = OpTypeInt 32 0
+      %int_1 = OpConstant %int 1
+     %uint_1 = OpConstant %uint 1
+       %main = OpFunction %void None %3
+          %5 = OpLabel
+               OpSetMeshOutputsEXT %uint_1 %int_1
+               OpReturn
+               OpFunctionEnd
+)";
+
+  CompileSuccessfully(body, SPV_ENV_UNIVERSAL_1_5);
+  EXPECT_EQ(SPV_ERROR_INVALID_DATA,
+            ValidateInstructions(SPV_ENV_UNIVERSAL_1_5));
+  EXPECT_THAT(
+      getDiagnosticString(),
+      HasSubstr("Primitive Count must be a 32-bit unsigned int scalar"));
+}
+
+TEST_F(ValidateMeshShading, OpSetMeshOutputsBadExecutionModel) {
+  const std::string body = R"(
+               OpCapability MeshShadingEXT
+               OpExtension "SPV_EXT_mesh_shader"
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint TaskEXT %main "main"
+       %void = OpTypeVoid
+          %3 = OpTypeFunction %void
+       %uint = OpTypeInt 32 0
+     %uint_1 = OpConstant %uint 1
+       %main = OpFunction %void None %3
+          %5 = OpLabel
+               OpSetMeshOutputsEXT %uint_1 %uint_1
+               OpReturn
+               OpFunctionEnd
+)";
+
+  CompileSuccessfully(body, SPV_ENV_UNIVERSAL_1_5);
+  EXPECT_EQ(SPV_ERROR_INVALID_ID, ValidateInstructions(SPV_ENV_UNIVERSAL_1_5));
+  EXPECT_THAT(
+      getDiagnosticString(),
+      HasSubstr("OpSetMeshOutputsEXT requires MeshEXT execution model"));
+}
+
+TEST_F(ValidateMeshShading, OpSetMeshOutputsZeroSuccess) {
+  const std::string body = R"(
+               OpCapability MeshShadingEXT
+               OpExtension "SPV_EXT_mesh_shader"
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint MeshEXT %main "main"
+               OpExecutionMode %main OutputVertices 1
+               OpExecutionMode %main OutputPrimitivesNV 1
+               OpExecutionMode %main OutputTrianglesNV
+       %void = OpTypeVoid
+          %3 = OpTypeFunction %void
+       %uint = OpTypeInt 32 0
+     %uint_0 = OpConstant %uint 0
+       %main = OpFunction %void None %3
+          %5 = OpLabel
+               OpSetMeshOutputsEXT %uint_0 %uint_0
+               OpReturn
+               OpFunctionEnd
+)";
+
+  CompileSuccessfully(body, SPV_ENV_UNIVERSAL_1_5);
+  EXPECT_EQ(SPV_SUCCESS, ValidateInstructions(SPV_ENV_UNIVERSAL_1_5));
+}
+
+TEST_F(ValidateMeshShading, OpEmitMeshTasksZeroSuccess) {
+  const std::string body = R"(
+               OpCapability MeshShadingEXT
+               OpExtension "SPV_EXT_mesh_shader"
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint TaskEXT %main "main"
+       %void = OpTypeVoid
+       %func = OpTypeFunction %void
+       %uint = OpTypeInt 32 0
+     %uint_0 = OpConstant %uint 1
+       %main = OpFunction %void None %func
+      %label = OpLabel
+               OpEmitMeshTasksEXT %uint_0 %uint_0 %uint_0
+               OpFunctionEnd
+)";
+
+  CompileSuccessfully(body, SPV_ENV_UNIVERSAL_1_5);
+  EXPECT_EQ(SPV_SUCCESS, ValidateInstructions(SPV_ENV_UNIVERSAL_1_5));
+}
+
 }  // namespace
 }  // namespace val
 }  // namespace spvtools