--- /dev/null
+//===- MergedLoadStoreMotion.cpp - merge and hoist/sink load/stores -------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//! \file
+//! \brief This pass performs merges of loads and stores on both sides of a
+// diamond (hammock). It hoists the loads and sinks the stores.
+//
+// The algorithm iteratively hoists two loads to the same address out of a
+// diamond (hammock) and merges them into a single load in the header. Similar
+// it sinks and merges two stores to the tail block (footer). The algorithm
+// iterates over the instructions of one side of the diamond and attempts to
+// find a matching load/store on the other side. It hoists / sinks when it
+// thinks it safe to do so. This optimization helps with eg. hiding load
+// latencies, triggering if-conversion, and reducing static code size.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TRANSFORMS_SCALAR_MERGEDLOADSTOREMOTION_H
+#define LLVM_TRANSFORMS_SCALAR_MERGEDLOADSTOREMOTION_H
+
+#include "llvm/IR/Module.h"
+#include "llvm/IR/PassManager.h"
+
+namespace llvm {
+class MergedLoadStoreMotionPass
+ : public PassInfoMixin<MergedLoadStoreMotionPass> {
+public:
+ PreservedAnalyses run(Function &F, AnalysisManager<Function> &AM);
+};
+}
+
+#endif // LLVM_TRANSFORMS_SCALAR_MERGEDLOADSTOREMOTION_H
//
//===----------------------------------------------------------------------===//
+#include "llvm/Transforms/Scalar/MergedLoadStoreMotion.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/CFG.h"
// MergedLoadStoreMotion Pass
//===----------------------------------------------------------------------===//
-namespace {
-class MergedLoadStoreMotion : public FunctionPass {
- AliasAnalysis *AA;
- MemoryDependenceResults *MD;
-
-public:
- static char ID; // Pass identification, replacement for typeid
- MergedLoadStoreMotion() : FunctionPass(ID), MD(nullptr) {
- initializeMergedLoadStoreMotionPass(*PassRegistry::getPassRegistry());
- }
-
- bool runOnFunction(Function &F) override;
-
-private:
- // This transformation requires dominator postdominator info
- void getAnalysisUsage(AnalysisUsage &AU) const override {
- AU.setPreservesCFG();
- AU.addRequired<AAResultsWrapperPass>();
- AU.addPreserved<GlobalsAAWrapperPass>();
- AU.addPreserved<MemoryDependenceWrapperPass>();
- }
-};
-
-char MergedLoadStoreMotion::ID = 0;
-} // anonymous namespace
-
// The mergeLoad/Store algorithms could have Size0 * Size1 complexity,
// where Size0 and Size1 are the #instructions on the two sides of
// the diamond. The constant chosen here is arbitrary. Compiler Time
// Control is enforced by the check Size0 * Size1 < MagicCompileTimeControl.
const int MagicCompileTimeControl = 250;
-///
-/// \brief createMergedLoadStoreMotionPass - The public interface to this file.
-///
-FunctionPass *llvm::createMergedLoadStoreMotionPass() {
- return new MergedLoadStoreMotion();
-}
-
-INITIALIZE_PASS_BEGIN(MergedLoadStoreMotion, "mldst-motion",
- "MergedLoadStoreMotion", false, false)
-INITIALIZE_PASS_DEPENDENCY(MemoryDependenceWrapperPass)
-INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)
-INITIALIZE_PASS_END(MergedLoadStoreMotion, "mldst-motion",
- "MergedLoadStoreMotion", false, false)
-
///
/// \brief Remove instruction from parent and update memory dependence analysis.
///
///
/// \brief Run the transformation for each function
///
-bool MergedLoadStoreMotion::runOnFunction(Function &F) {
- if (skipFunction(F))
- return false;
-
- auto *MDWP = getAnalysisIfAvailable<MemoryDependenceWrapperPass>();
- MD = MDWP ? &MDWP->getMemDep() : nullptr;
- AA = &getAnalysis<AAResultsWrapperPass>().getAAResults();
-
+static bool runMergedLoadStoreMotion(Function &F, AliasAnalysis *AA,
+ MemoryDependenceResults *MD) {
bool Changed = false;
DEBUG(dbgs() << "Instruction Merger\n");
}
return Changed;
}
+
+PreservedAnalyses
+MergedLoadStoreMotionPass::run(Function &F, AnalysisManager<Function> &AM) {
+ auto &AA = AM.getResult<AAManager>(F);
+ auto *MD = AM.getCachedResult<MemoryDependenceAnalysis>(F);
+ if (!runMergedLoadStoreMotion(F, &AA, MD))
+ return PreservedAnalyses::all();
+ return PreservedAnalyses::none();
+}
+
+namespace {
+class MergedLoadStoreMotionLegacyPass : public FunctionPass {
+ AliasAnalysis *AA;
+ MemoryDependenceResults *MD;
+
+public:
+ static char ID; // Pass identification, replacement for typeid
+ MergedLoadStoreMotionLegacyPass() : FunctionPass(ID), MD(nullptr) {
+ initializeMergedLoadStoreMotionLegacyPassPass(
+ *PassRegistry::getPassRegistry());
+ }
+
+ bool runOnFunction(Function &F) override {
+ if (skipFunction(F))
+ return false;
+
+ AA = &getAnalysis<AAResultsWrapperPass>().getAAResults();
+ auto *MDWP = getAnalysisIfAvailable<MemoryDependenceWrapperPass>();
+ MD = MDWP ? &MDWP->getMemDep() : nullptr;
+ return runMergedLoadStoreMotion(F, AA, MD);
+ }
+
+private:
+ // This transformation requires dominator postdominator info
+ void getAnalysisUsage(AnalysisUsage &AU) const override {
+ AU.setPreservesCFG();
+ AU.addRequired<AAResultsWrapperPass>();
+ AU.addPreserved<GlobalsAAWrapperPass>();
+ AU.addPreserved<MemoryDependenceWrapperPass>();
+ }
+};
+
+char MergedLoadStoreMotionLegacyPass::ID = 0;
+} // anonymous namespace
+
+///
+/// \brief createMergedLoadStoreMotionPass - The public interface to this file.
+///
+FunctionPass *llvm::createMergedLoadStoreMotionPass() {
+ return new MergedLoadStoreMotionLegacyPass();
+}
+
+INITIALIZE_PASS_BEGIN(MergedLoadStoreMotionLegacyPass, "mldst-motion",
+ "MergedLoadStoreMotion", false, false)
+INITIALIZE_PASS_DEPENDENCY(MemoryDependenceWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)
+INITIALIZE_PASS_END(MergedLoadStoreMotionLegacyPass, "mldst-motion",
+ "MergedLoadStoreMotion", false, false)
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