Merge pull request #269 from frasercrmck/no-run-remove-fences

[compiler] Remove the RemoveFencesPass

doc/modules/compiler/utils.rst

@@ -1139,13 +1139,6 @@ Removing this information is useful for debugging since the backend is less
 likely to optimize away variables in the stack no longer used, as a result this
 pass should only be run on debug builds of the module.
 
-RemoveFencesPass
-----------------
-
-Removing memory fences can result in invalid code or incorrect behaviour in
-general. This pass is a workaround for backends that do not yet support memory
-fences.
-
 RemoveExceptionsPass
 --------------------
 

modules/compiler/source/base/source/base_module_pass_machinery.cpp

@@ -49,7 +49,6 @@
 #include <compiler/utils/prepare_barriers_pass.h>
 #include <compiler/utils/reduce_to_function_pass.h>
 #include <compiler/utils/remove_exceptions_pass.h>
-#include <compiler/utils/remove_fences_pass.h>
 #include <compiler/utils/remove_lifetime_intrinsics_pass.h>
 #include <compiler/utils/rename_builtins_pass.h>
 #include <compiler/utils/replace_address_space_qualifier_functions_pass.h>

modules/compiler/source/base/source/base_module_pass_registry.def

@@ -177,7 +177,6 @@ FUNCTION_PASS("software-div", compiler::SoftwareDivisionPass())
 FUNCTION_PASS("replace-addrspace-fns", compiler::utils::ReplaceAddressSpaceQualifierFunctionsPass())
 FUNCTION_PASS("remove-lifetime", compiler::utils::RemoveLifetimeIntrinsicsPass())
 FUNCTION_PASS("remove-exceptions", compiler::utils::RemoveExceptionsPass())
-FUNCTION_PASS("remove-fences", compiler::utils::RemoveFencesPass())
 FUNCTION_PASS("replace-mem-intrins", compiler::utils::ReplaceMemIntrinsicsPass())
 FUNCTION_PASS("print<generic-metadata>", compiler::utils::GenericMetadataPrinterPass(llvm::dbgs()))
 FUNCTION_PASS("print<vectorize-metadata>", compiler::utils::VectorizeMetadataPrinterPass(llvm::dbgs()))

modules/compiler/targets/host/source/HostPassMachinery.cpp

@@ -32,7 +32,6 @@
 #include <compiler/utils/metadata_analysis.h>
 #include <compiler/utils/pipeline_parse_helpers.h>
 #include <compiler/utils/remove_exceptions_pass.h>
-#include <compiler/utils/remove_fences_pass.h>
 #include <compiler/utils/remove_lifetime_intrinsics_pass.h>
 #include <compiler/utils/replace_address_space_qualifier_functions_pass.h>
 #include <compiler/utils/replace_local_module_scope_variables_pass.h>
@@ -311,20 +310,6 @@ llvm::ModulePassManager HostPassMachinery::getKernelFinalizationPasses(
         compiler::utils::RemoveLifetimeIntrinsicsPass()));
   }
 
-  // ENORMOUS WARNING:
-  // Removing memory fences can result in invalid code or incorrect behaviour in
-  // general. This pass is a workaround for backends that do not yet support
-  // memory fences.  This is not required for any of the LLVM backends used by
-  // host, but the pass is used here to ensure that it is tested.
-  // The memory model on OpenCL 1.2 is so underspecified that we can get away
-  // with removing fences. In OpenCL 3.0 the memory model is better defined, and
-  // just removing fences could result in incorrect behavior for valid 3.0
-  // OpenCL applications.
-  if (options.standard != compiler::Standard::OpenCLC30) {
-    PM.addPass(llvm::createModuleToFunctionPassAdaptor(
-        compiler::utils::RemoveFencesPass()));
-  }
-
   PM.addPass(compiler::utils::ComputeLocalMemoryUsagePass());
 
   PM.addPass(compiler::utils::AddMetadataPass<

modules/compiler/utils/CMakeLists.txt

@@ -52,7 +52,6 @@ add_ca_library(compiler-utils STATIC
   ${CMAKE_CURRENT_SOURCE_DIR}/include/compiler/utils/prepare_barriers_pass.h
   ${CMAKE_CURRENT_SOURCE_DIR}/include/compiler/utils/reduce_to_function_pass.h
   ${CMAKE_CURRENT_SOURCE_DIR}/include/compiler/utils/remove_exceptions_pass.h
-  ${CMAKE_CURRENT_SOURCE_DIR}/include/compiler/utils/remove_fences_pass.h
   ${CMAKE_CURRENT_SOURCE_DIR}/include/compiler/utils/remove_lifetime_intrinsics_pass.h
   ${CMAKE_CURRENT_SOURCE_DIR}/include/compiler/utils/rename_builtins_pass.h
   ${CMAKE_CURRENT_SOURCE_DIR}/include/compiler/utils/replace_address_space_qualifier_functions_pass.h
@@ -104,7 +103,6 @@ add_ca_library(compiler-utils STATIC
   ${CMAKE_CURRENT_SOURCE_DIR}/source/prepare_barriers_pass.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/source/reduce_to_function_pass.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/source/remove_exceptions_pass.cpp
-  ${CMAKE_CURRENT_SOURCE_DIR}/source/remove_fences_pass.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/source/remove_lifetime_intrinsics_pass.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/source/rename_builtins_pass.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/source/replace_address_space_qualifier_functions_pass.cpp