diff --git a/polly/lib/PollyModule.cpp b/polly/lib/PollyModule.cpp new file mode 100644 index 000000000000..910129f1b486 --- /dev/null +++ b/polly/lib/PollyModule.cpp @@ -0,0 +1,71 @@ +//===------ ModuleInitializers.cpp - Initialize the Polly Module --===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +//===----------------------------------------------------------------------===// + +#include "polly/RegisterPasses.h" +#include "llvm/Transforms/IPO/PassManagerBuilder.h" + +namespace { + +/// @brief Initialize Polly passes when library is loaded. +/// +/// We use the constructor of a statically declared object to initialize the +/// different Polly passes right after the Polly library is loaded. This ensures +/// that the Polly passes are available e.g. in the 'opt' tool. +class StaticInitializer { +public: + StaticInitializer() { + llvm::PassRegistry &Registry = *llvm::PassRegistry::getPassRegistry(); + polly::initializePollyPasses(Registry); + } +}; +static StaticInitializer InitializeEverything; + +static void +registerPollyEarlyAsPossiblePasses(const llvm::PassManagerBuilder &Builder, + llvm::PassManagerBase &PM) { + + if (!polly::shouldEnablePolly()) + return; + + polly::registerPollyPasses(PM); +} + +/// @brief Register Polly to be available as an optimizer +/// +/// We currently register Polly such that it runs as early as possible. This has +/// several implications: +/// +/// 1) We need to schedule more canonicalization passes +/// +/// As nothing is run before Polly, it is necessary to run a set of preparing +/// transformations before Polly to canonicalize the LLVM-IR and to allow +/// Polly to detect and understand the code. +/// +/// 2) LICM and LoopIdiom pass have not yet been run +/// +/// Loop invariant code motion as well as the loop idiom recognition pass make +/// it more difficult for Polly to transform code. LICM may introduce +/// additional data dependences that are hard to eliminate and the loop idiom +/// recognition pass may introduce calls to memset that we currently do not +/// understand. By running Polly early enough (meaning before these passes) we +/// avoid difficulties that may be introduced by these passes. +/// +/// 3) We get the full -O3 optimization sequence after Polly +/// +/// The LLVM-IR that is generated by Polly has been optimized on a high level, +/// but it may be rather inefficient on the lower/scalar level. By scheduling +/// Polly before all other passes, we have the full sequence of -O3 +/// optimizations behind us, such that inefficiencies on the low level can +/// be optimized away. +static llvm::RegisterStandardPasses +RegisterPollyOptimizer(llvm::PassManagerBuilder::EP_EarlyAsPossible, + registerPollyEarlyAsPossiblePasses); +} // end of anonymous namespace.