Update llpc from commit 58d887ee

lgc: Handle primitiveShadingRate in ShaderStage Tessellation evaluation shader
Update SPIR-V header to latest public version
Completely remove dead codes gated by earlier version (< 70)
[NFC] Coding style changes of buffre resource helpers
[llvmraytracing] Handle intersection case for the RayTCurrent function
Disable FMF Reassoc for FMix operation
Rename useGfx10StyleParamExport to attributeThroughExport in LGC
lgc: add compile option 'stridedBufferOverrideMode'
[LGC] Initialize undef output variables
[llvmraytracing] Fix deprecation warning.
[lgc] New Shader Invocation Reordering Dialects
[llvmraytracing] Move statistics reporting to 'CleanupContinuations'
Support untyped pointer in cooperative matrix
[NFC] Rename in/out reader/writer functions
[test/tools] Rename stable ir value test file
[llvmraytracing] Report statistics per function
Update Create{Min/Max}Num API for new LLVM upstream
[Continuations] Add reload on resume mode
Add support for SPV_EXT_optnone
[LGC] Use llvm.amdgcn.dead with init.whole.wave
lgc: force dummy export when the fs is NullFs or no outputs
Add support for SPV_EXT_arithmetic_fence
Move TF optimization to HS body
[LGC] Set correct perSampleShading state on gfx12
[llvmraytracing] Remove 'nocapture readnone' capture from tests
Emit SQTT shader hash tokens in RT shaders
[Continuations][NFC] Add unused value and fragmentation analysis
Adjust for upstream Triple change
lgc : SubgroupBroadcastFirst behavior with only helperlanes
lgccps: Special handling for GpurtGetRayQueryDispatchIdOp
[NFC] Some renaming in LLPC frontend
[NFC] Some renaming in LGC
lgc: Improve waterfall Loop handling for descriptor pointers
Turn sequence of load/store into memcpy
Build traversal module with persistent dispatch
[lgc][LowerBufferOperations] Fix OOB condition for strided buffers
Fix missing PromotePass on Navi2x for mesh shader
[llvmraytracing] Remove unused function declaration
[llvmraytracing] Make lgc.ilcps.(wait)continue only accept a variadic argument list
Use Uniform initializer for LoadStorePair constructor
Replace builtin inputs by function arguments for transform shader
[llvmraytracing] Introduce lgc.cps.dead dialect op
[llvmraytracing] Add dummy hit attribute argument
LGC: Set PsIterSample to true when enable VRS
Add support for OpUntypedVariable without the data type
Optimize the unused elements
Get rid of the redundant SPV binary file in pipe test
Assert for global stacks without persistent dispatch
[NFC] Add clang-format pre-commit hook
Replace builtin inputs by function arguments for transform shader
Unroll the loop that contains dynamic input variables
[LGC] Set correct perSampleShading state on gfx12
cmake: Fatal error if LLVM not found
Add sched_barrier to block the move of s_wait_event
cmake: Have *_BUILD_* variables forced on when PAL_BUILD_FORCE_ON is true
[Continuations] Add spill on suspend mode
New operators for check the RTIP version
lgc: follow-up for the refactor of waterfall loop
[LGC] Make test robust to use of poison instead undef
Remove LLPC_BUILD_GFX11/GFX115 in CMake
lgc : Add Constant check for beginWaterfallLoop
Detect more read-only buffers
Clean up GPURT_CLIENT_INTERFACE_MAJOR_VERSION check
Create gl_FrontFacing with the type of i32
[LGC] Fix per-component case for loop unroll
Remove RayTracingShaderIdentifierExtraBits
[Continuations] Add & enable eviction in the cont-state-builder
Use setLdsByteSize in registerMetadataBuilder
llvmraytracing: add new shader entry point for when Raygen shader resumes execution
Implicit HitObjects Refactor
Align raytracing functions to 128B
llvmraytracing: fix shader-exit.ll test
Disable structured buffers by default for gfx12 and below
lgc: Remove option forceNullFsDummyExport
Support cooperative matrix conversion from Acc to A
[vkgc] Add Vkgc::IUtil function to get symbol disassembly from ELF binary
[LGC] Add convert.lgc test
[LGC] GfxIp11_0 ShadingRate add check for MaskNone
[LGC] Use Triple object as targetMachine input
[LGC] Update use of CreateIntrinsic due to upstream change
Temporarily disable eviction in cont-state-builder
Remove LLPC_BUILD_GFX12 macro
Fixed nested loop
[llvmraytracing] Remove incoming register count metadata
lgc: Initial graphics partial pipeline support
[LGC] Trim .outgoing_vgpr_count
lgc: Remove disableProvokingVertexMode
[LGC] Fix Cooperative Matrix convert
Support hawk point 2
lgc: place irrelevant instructions out of the waterfall loop
Add missing support for untyped pointer in some validations
lgc: SamplePosOffset and InterpLocSample with aux value should not cause sample rate.
Initialize unbound vertices
Add support for GpurtOptions in non-RT pipelines with RayQuery
[llvmraytracing] Move 'splitIntoI32' helper to 'compilerutils'
[LGC] Change the dummy export value to <0.0, poison, poison, poison>
[LGC] Implement cooperative matrix transpose on gfx12
Fix error on raytracing entry kernels that use more than 16 VGPRs
lgc: update expFormat and cbShaderMask to valid values for alpha2Coverage without bound MRTs
[LGC] Combine coopmat fill and conversion
Support OpCooperativeMatrixTransposeNV
Implement VK_KHR_shader_relaxed_extended_instruction support
[NFC] Fix 'unused variable' warnings
[lgcdis] skip outputting instr offset for single symbol disassembly
[NFC] Use unique_ptr for MCInstPrinter
[llvmraytracing] Add transitional support for ShaderExit
[llvmraytracing] Fix unused warnings in 'ContStateBuilder'
[NFC] Fix compiler warnings
Remove 'AmdValue*' handling from 'ProcessGpurtLibrary'
Always use EXCLUDE_FROM_ALL property for LLVM sub directory in llvm.cmake
Update llvm-dialects submodule
Clean up after GpurtOptions change
Update test due to upstream LLVM change
Disable gfx11 TessFactorStoreWithOpt
[LGC] Fix ldexp problems with i8/i64 exponent

Author: qiaojbao

CMakeLists.txt

@@ -37,13 +37,19 @@
 
 cmake_minimum_required(VERSION 3.21)
 
-project(LLPCrepo LANGUAGES C CXX)
-
 set(LLPC_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR})
 
 ### Standalone LLPC build handling
 if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
     include(cmake/CompilerStandalone.cmake)
+    llpc_standalone_pre_project_setup()
+endif()
+
+project(LLPCrepo LANGUAGES C CXX)
+
+### Standalone LLPC build handling
+if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
+    llpc_standalone_post_project_setup()
     set(LLPC_IS_STANDALONE ON)
 endif()
 
@@ -123,7 +129,12 @@ if(ICD_BUILD_LLPC)
     target_link_libraries(vkgc INTERFACE llpc)
 endif()
 
-# Set sub library properties
+### Post-processing for standalone compiler build #################################
+if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
+    include(cmake/PostCompilerStandalone.cmake)
+endif()
+
+### Set sub library properties ####################################################
 if(CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
 
     if (TARGET dumper)

cmake/CompilerStandalone.cmake

@@ -23,60 +23,78 @@
  #
  #######################################################################################################################
 
-# Settings required for a standalone LLPC build that would otherwise be inherited from the driver.
+macro(llpc_standalone_pre_project_setup)
+endmacro()
 
-if(COMMAND cmake_policy)
-    cmake_policy(SET CMP0003 NEW)
-endif(COMMAND cmake_policy)
+macro(llpc_standalone_post_project_setup)
+    # Settings required for a standalone LLPC build that would otherwise be inherited from the driver.
 
-if(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/../pal)
-    set(PAL_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/../pal)
-elseif(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/../../imported/pal)
-    set(PAL_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/../../imported/pal)
-endif()
+    if(COMMAND cmake_policy)
+        cmake_policy(SET CMP0003 NEW)
+    endif(COMMAND cmake_policy)
 
-if(EXISTS ${PROJECT_SOURCE_DIR}/../third_party)
-    set(THIRD_PARTY ${PROJECT_SOURCE_DIR}/../third_party)
-elseif(EXISTS ${PROJECT_SOURCE_DIR}/../../../../third_party)
-    set(THIRD_PARTY ${PROJECT_SOURCE_DIR}/../../../../third_party)
-endif()
-if (THIRD_PARTY)
-    set(XGL_METROHASH_PATH ${THIRD_PARTY}/metrohash CACHE PATH "The path of metrohash.")
-    set(XGL_CWPACK_PATH ${THIRD_PARTY}/cwpack CACHE PATH "The path of cwpack.")
-    add_subdirectory(${XGL_METROHASH_PATH} ${PROJECT_BINARY_DIR}/metrohash)
-    add_subdirectory(${XGL_CWPACK_PATH} ${PROJECT_BINARY_DIR}/cwpack)
-endif()
+    set(LLPC_STANDALONE_BUILD ON)
+    set(LLPC_BUILD_TESTS ON)
 
-# Enable LLPC if we found its prerequisites (and it is not explicitly disabled).
-if (NOT DEFINED ICD_BUILD_LLPC)
-    if (THIRD_PARTY AND PAL_SOURCE_DIR)
-        set(ICD_BUILD_LLPC ON)
-    else()
-        message(STATUS "Vulkan-LLPC prerequisites not found; disabling")
+    if(NOT PAL_SOURCE_DIR)
+        if(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/../pal)
+            set(PAL_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/../pal)
+        elseif(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/../../imported/pal)
+            set(PAL_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/../../imported/pal)
+        endif()
+    endif()
+
+    if(NOT GPURT_SOURCE_DIR)
+        if(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/../gpurt)
+            set(GPURT_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/../gpurt)
+        elseif(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/../../imported/gpurt)
+            set(GPURT_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/../../imported/gpurt)
+        endif()
     endif()
-endif()
-if (ICD_BUILD_LLPC)
-    set(LLPC_BUILD_TESTS ON)
-    set(LLPC_BUILD_TOOLS ON)
 
-    # External Vulkan headers path
-    if(EXISTS ${PROJECT_SOURCE_DIR}/../Vulkan-Headers)
-        set(VULKAN_HEADERS_PATH ${PROJECT_SOURCE_DIR}/../Vulkan-Headers CACHE PATH "The path of Vulkan headers.")
+    if(EXISTS ${PROJECT_SOURCE_DIR}/../third_party)
+        set(THIRD_PARTY ${PROJECT_SOURCE_DIR}/../third_party)
+    elseif(EXISTS ${PROJECT_SOURCE_DIR}/../../../../third_party)
+        set(THIRD_PARTY ${PROJECT_SOURCE_DIR}/../../../../third_party)
+    endif()
+    if (THIRD_PARTY)
+        set(XGL_METROHASH_PATH ${THIRD_PARTY}/metrohash CACHE PATH "The path of metrohash.")
+        set(XGL_CWPACK_PATH ${THIRD_PARTY}/cwpack CACHE PATH "The path of cwpack.")
+        add_subdirectory(${XGL_METROHASH_PATH} ${PROJECT_BINARY_DIR}/metrohash)
+        add_subdirectory(${XGL_CWPACK_PATH} ${PROJECT_BINARY_DIR}/cwpack)
     endif()
 
-    ### Khronos Interface
-    add_library(khronos_vulkan_interface INTERFACE)
-    if(EXISTS ${VULKAN_HEADERS_PATH})
-        target_include_directories(khronos_vulkan_interface INTERFACE ${VULKAN_HEADERS_PATH}/include)
-        target_compile_definitions(khronos_vulkan_interface INTERFACE EXTERNAL_VULKAN_HEADERS=1)
+    # Enable LLPC if we found its prerequisites (and it is not explicitly disabled).
+    if (NOT DEFINED ICD_BUILD_LLPC)
+        if (THIRD_PARTY AND PAL_SOURCE_DIR)
+            set(ICD_BUILD_LLPC ON)
+        else()
+            message(STATUS "Vulkan-LLPC prerequisites not found; disabling")
+        endif()
     endif()
-    if(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/../xgl)
-        target_include_directories(khronos_vulkan_interface INTERFACE ../xgl/icd/api/include/khronos)
-    else()
-        target_include_directories(khronos_vulkan_interface INTERFACE ../../../icd/api/include/khronos)
+    if (ICD_BUILD_LLPC)
+        set(LLPC_BUILD_TOOLS ON)
+
+        # External Vulkan headers path
+        if(EXISTS ${PROJECT_SOURCE_DIR}/../Vulkan-Headers)
+            set(VULKAN_HEADERS_PATH ${PROJECT_SOURCE_DIR}/../Vulkan-Headers CACHE PATH "The path of Vulkan headers.")
+        endif()
+
+        ### Khronos Interface
+        add_library(khronos_vulkan_interface INTERFACE)
+        if(EXISTS ${VULKAN_HEADERS_PATH})
+            target_include_directories(khronos_vulkan_interface INTERFACE ${VULKAN_HEADERS_PATH}/include)
+            target_compile_definitions(khronos_vulkan_interface INTERFACE EXTERNAL_VULKAN_HEADERS=1)
+        endif()
+        if(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/../xgl)
+            target_include_directories(khronos_vulkan_interface INTERFACE ../xgl/icd/api/include/khronos)
+        else()
+            target_include_directories(khronos_vulkan_interface INTERFACE ../../../icd/api/include/khronos)
+        endif()
     endif()
-endif()
 
-set(GPURT_CLIENT_INTERFACE_MAJOR_VERSION 999999)
-set(LLPC_CLIENT_INTERFACE_MAJOR_VERSION 999999)
-set(PAL_CLIENT_INTERFACE_MAJOR_VERSION 999999)
+    set(GPURT_CLIENT_INTERFACE_MAJOR_VERSION 999999)
+    set(LLPC_CLIENT_INTERFACE_MAJOR_VERSION 999999)
+    set(PAL_CLIENT_INTERFACE_MAJOR_VERSION 999999)
+
+endmacro()

lgc/test/Transforms/CpsLoweringWithDvgpr/lit.local.cfg renamed to cmake/PostCompilerStandalone.cmake

@@ -1,7 +1,7 @@
 ##
  #######################################################################################################################
  #
- #  Copyright (c) 2024-2025 Advanced Micro Devices, Inc. All Rights Reserved.
+ #  Copyright (c) 2025 Advanced Micro Devices, Inc. All Rights Reserved.
  #
  #  Permission is hereby granted, free of charge, to any person obtaining a copy
  #  of this software and associated documentation files (the "Software"), to
@@ -23,5 +23,5 @@
  #
  #######################################################################################################################
 
-if "llpc_build_gfx12" not in config.available_features:
-    config.unsupported = True
+# Standalone compiler build post-processing, after adding all compiler targets.
+

cmake/findllvm.cmake

@@ -1,7 +1,7 @@
 ##
  #######################################################################################################################
  #
- #  Copyright (c) 2024 Advanced Micro Devices, Inc. All Rights Reserved.
+ #  Copyright (c) 2024-2025 Advanced Micro Devices, Inc. All Rights Reserved.
  #
  #  Permission is hereby granted, free of charge, to any person obtaining a copy
  #  of this software and associated documentation files (the "Software"), to
@@ -35,3 +35,7 @@ if (NOT LLPC_LLVM_SRC_PATH)
     endif()
     set(LLPC_LLVM_SRC_PATH ${DEFAULT_LLPC_LLVM_SRC_PATH} CACHE PATH "Specify the path to LLVM." FORCE)
 endif()
+
+if (NOT EXISTS ${LLPC_LLVM_SRC_PATH}/include/llvm/IR/LLVMContext.h)
+    message(FATAL_ERROR "LLVM source not found at ${LLPC_LLVM_SRC_PATH}")
+endif()

cmake/llpc_version.cmake

@@ -28,6 +28,7 @@ set(LLPC_SOURCE_DIR "${CMAKE_CURRENT_LIST_DIR}/..")
 # Function to set variable named ${varName} to the first of:
 #
 # - the value it already has (which might be set by driver or developer);
+# - ON if PAL_BUILD_FORCE_ON and the variable name matches PAL_BUILD_* (after prefix replacement to PAL);
 # - the value of the variable whose name has PAL_ instead of LLPC_ (which might be set by driver or developer);
 # - the given default.
 #
@@ -41,8 +42,14 @@ set(LLPC_SOURCE_DIR "${CMAKE_CURRENT_LIST_DIR}/..")
 function(llpc_set_property target scope varName default propertyName)
     if (NOT DEFINED ${varName})
         string(REGEX REPLACE "^[A-Z][A-Z]*_(.*)$" "PAL_\\1" palVarName "${varName}")
+        string(REGEX MATCH "^(PAL_BUILD).*" _match ${palVarName})
+
         if (DEFINED ${palVarName})
             set(${varName} ${${palVarName}})
+        elseif ((PAL_BUILD_FORCE_ON) AND (_match))
+            # If the user has requested that we force BUILD settings on, then
+            # force the setting on (if it matches a PAL_BUILD* variable and isn't explicitly overridden).
+            set(${varName} ON)
         else()
             set(${varName} ${default})
         endif()

cmake/llvm.cmake

@@ -77,11 +77,8 @@ endif()
 if (NOT LLPC_LLVM_BUILD_PATH)
     set(LLPC_LLVM_BUILD_PATH ${PROJECT_BINARY_DIR}/llvm)
 endif()
-if (ICD_BUILD_LLPC)
-    add_subdirectory(${LLPC_LLVM_SRC_PATH} ${LLPC_LLVM_BUILD_PATH})
-else()
-    add_subdirectory(${LLPC_LLVM_SRC_PATH} ${LLPC_LLVM_BUILD_PATH} EXCLUDE_FROM_ALL)
-endif()
+
+add_subdirectory(${LLPC_LLVM_SRC_PATH} ${LLPC_LLVM_BUILD_PATH} EXCLUDE_FROM_ALL)
 
 # Get LLVMConfig onto cmake path.
 list(APPEND CMAKE_MODULE_PATH

cmake/vkgc.cmake

@@ -32,17 +32,6 @@ add_library(vkgc_headers INTERFACE)
 target_link_libraries(vkgc_headers INTERFACE llpc_version)
 
 ### Options that affect the headers ####################################################################################
-#if LLPC_BUILD_GFX11
-if(LLPC_BUILD_GFX11)
-    target_compile_definitions(vkgc_headers INTERFACE LLPC_BUILD_GFX11)
-endif()
-#endif
-
-#if LLPC_BUILD_GFX12
-if(LLPC_BUILD_GFX12)
-    target_compile_definitions(vkgc_headers INTERFACE LLPC_BUILD_GFX12)
-endif()
-#endif
 
 #if LLPC_RAY_TRACING
 if(LLPC_RAY_TRACING)

compilerutils/include/compilerutils/CompilerUtils.h

@@ -86,6 +86,49 @@ void setIsLastUseLoad(llvm::LoadInst &Load);
 // Handle early returns, ensure the function has only one return instruction
 llvm::ReturnInst *unifyReturns(llvm::Function &function, llvm::IRBuilder<> &builder, const llvm::Twine &blockName = "");
 
+// Utility method templates to read and write IR metadata, used by PipelineState and ShaderModes
+//
+// Get a metadata node containing an array of i32 values, which can be read from any type.
+// The array is trimmed to remove trailing zero values. If the whole array would be 0, then this function
+// returns nullptr.
+//
+// @param context : LLVM context
+// @param value : Value to write as array of i32
+// @param atLeastOneValue : True to generate node with one value even if all values are zero
+template <typename T>
+static llvm::MDNode *getArrayOfInt32MetaNode(llvm::LLVMContext &context, const T &value, bool atLeastOneValue) {
+  llvm::IRBuilder<> builder(context);
+  static_assert(sizeof(value) % sizeof(unsigned) == 0, "Bad value type");
+  llvm::ArrayRef<unsigned> values(reinterpret_cast<const unsigned *>(&value), sizeof(value) / sizeof(unsigned));
+
+  while (!values.empty() && values.back() == 0) {
+    if (values.size() == 1 && atLeastOneValue)
+      break;
+    values = values.slice(0, values.size() - 1);
+  }
+  if (values.empty())
+    return nullptr;
+
+  llvm::SmallVector<llvm::Metadata *, 8> operands;
+  for (unsigned value : values)
+    operands.push_back(llvm::ConstantAsMetadata::get(builder.getInt32(value)));
+  return llvm::MDNode::get(context, operands);
+}
+
+// Read an array of i32 values out of a metadata node, writing into any type.
+// Returns the number of i32s read.
+//
+// @param metaNode : Metadata node to read from
+// @param [out] value : Value to write into (caller must zero initialize)
+template <typename T> static unsigned readArrayOfInt32MetaNode(const llvm::MDNode *metaNode, T &value) {
+  static_assert(sizeof(value) % sizeof(unsigned) == 0, "Bad value type");
+  llvm::MutableArrayRef<unsigned> values(reinterpret_cast<unsigned *>(&value), sizeof(value) / sizeof(unsigned));
+  unsigned count = std::min(metaNode->getNumOperands(), unsigned(values.size()));
+  for (unsigned index = 0; index < count; ++index)
+    values[index] = llvm::mdconst::extract<llvm::ConstantInt>(metaNode->getOperand(index))->getZExtValue();
+  return count;
+}
+
 struct CrossModuleInlinerResult {
   llvm::Value *returnValue;
   llvm::iterator_range<llvm::Function::iterator> newBBs;
@@ -135,6 +178,10 @@ class CrossModuleInliner {
   // target module.
   llvm::GlobalValue *findCopiedGlobal(llvm::GlobalValue &sourceGv, llvm::Module &targetModule);
 
+  // Register the type remapping for values when we want to inline other module functions.
+  // Return true if register successfully, otherwise return false.
+  bool registerTypeRemapping(llvm::Type *sourceType, llvm::Type *targetType);
+
   // Default implementation that finds global values using getCrossModuleName.
   static llvm::GlobalValue &defaultGetGlobalInModuleFunc(CrossModuleInliner &inliner, llvm::GlobalValue &sourceGv,
                                                          llvm::Module &targetModule);
@@ -167,6 +214,16 @@ llvm::Value *simplifyingCreateConstGEP1_32(llvm::IRBuilder<> &builder, llvm::Typ
 llvm::Value *simplifyingCreateConstInBoundsGEP1_32(llvm::IRBuilder<> &builder, llvm::Type *ty, llvm::Value *ptr,
                                                    uint32_t idx);
 
+// =====================================================================================================================
+// Split the input into pieces of i32.
+//
+// @param layout : Data layout
+// @param builder : IR builder
+// @param input : A collection of inputs (structures, arrays, vectors, pointers, or basic primitive types)
+// @param [out] output : A collection of outputs by flattening the inputs to scalar values
+void splitIntoI32(const llvm::DataLayout &layout, llvm::IRBuilder<> &builder, llvm::ArrayRef<llvm::Value *> input,
+                  llvm::SmallVector<llvm::Value *> &output);
+
 namespace bb {
 std::string getLabel(const llvm::Function *func);
 std::string getLabel(const llvm::BasicBlock *bb);

compilerutils/include/compilerutils/ModuleBunch.h

@@ -1,7 +1,7 @@
 /*
  ***********************************************************************************************************************
  *
- *  Copyright (c) 2023-2024 Advanced Micro Devices, Inc. All Rights Reserved.
+ *  Copyright (c) 2023-2025 Advanced Micro Devices, Inc. All Rights Reserved.
  *
  *  Permission is hereby granted, free of charge, to any person obtaining a copy
  *  of this software and associated documentation files (the "Software"), to
@@ -61,6 +61,9 @@ class ModuleBunch {
   size_t size() const { return end() - begin(); }
   bool empty() const { return size() == 0; }
 
+  // Clear the list of modules. This does not need renormalize() after it.
+  void clear() { Modules.clear(); }
+
   // Access the array of Modules in the ModuleBunch, directly accessing the unique_ptrs
   // for erasing/removing/replacing them.
   // After doing that, call renormalize() to remove any holes.