From fe76989fe741bc78b151220e4d237bfd28ff4d04 Mon Sep 17 00:00:00 2001
From: Daniel Berlin <dberlin@dberlin.org>
Date: Sun, 2 Apr 2017 05:09:15 +0000
Subject: [PATCH] MemorySSA: Add support for caching clobbering access in
stores
Summary:
This enables us to cache the clobbering access for stores, despite the
fact that we can't rewrite the use-def chains themselves.
Early testing shows that, after this change, for larger testcases, it will be a significant net positive (memory and time) to remove the walker caching.
Reviewers: george.burgess.iv, davide
Subscribers: Prazek, llvm-commits
Differential Revision: https://reviews.llvm.org/D31567
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@299322 91177308-0d34-0410-b5e6-96231b3b80d8
---
include/llvm/Transforms/Utils/MemorySSA.h | 61 +++++++++++++++++------
lib/Transforms/Utils/MemorySSA.cpp | 14 +++---
lib/Transforms/Utils/MemorySSAUpdater.cpp | 4 +-
3 files changed, 55 insertions(+), 24 deletions(-)
diff --git a/include/llvm/Transforms/Utils/MemorySSA.h b/include/llvm/Transforms/Utils/MemorySSA.h
index ac3c1cd0d7a..abacfc69e7c 100644
--- a/include/llvm/Transforms/Utils/MemorySSA.h
+++ b/include/llvm/Transforms/Utils/MemorySSA.h
@@ -246,6 +246,16 @@ public:
return MA->getValueID() == MemoryUseVal || MA->getValueID() == MemoryDefVal;
}
+ // Sadly, these have to be public because they are needed in some of the iterators.
+ virtual bool isOptimized() const = 0;
+ virtual MemoryAccess *getOptimized() const = 0;
+ virtual void setOptimized(MemoryAccess *) = 0;
+
+ /// \brief Reset the ID of what this MemoryUse was optimized to, causing it to
+ /// be rewalked by the walker if necessary.
+ /// This really should only be called by tests.
+ virtual void resetOptimized() = 0;
+
protected:
friend class MemorySSA;
friend class MemorySSAUpdater;
@@ -254,8 +264,12 @@ protected:
: MemoryAccess(C, Vty, BB, 1), MemoryInst(MI) {
setDefiningAccess(DMA);
}
-
- void setDefiningAccess(MemoryAccess *DMA) { setOperand(0, DMA); }
+ void setDefiningAccess(MemoryAccess *DMA, bool Optimized = false) {
+ setOperand(0, DMA);
+ if (!Optimized)
+ return;
+ setOptimized(DMA);
+ }
private:
Instruction *MemoryInst;
@@ -288,20 +302,18 @@ public:
void print(raw_ostream &OS) const override;
- void setDefiningAccess(MemoryAccess *DMA, bool Optimized = false) {
- if (Optimized)
- OptimizedID = DMA->getID();
- MemoryUseOrDef::setDefiningAccess(DMA);
+ virtual void setOptimized(MemoryAccess *DMA) override {
+ OptimizedID = DMA->getID();
}
- bool isOptimized() const {
+ virtual bool isOptimized() const override {
return getDefiningAccess() && OptimizedID == getDefiningAccess()->getID();
}
- /// \brief Reset the ID of what this MemoryUse was optimized to, causing it to
- /// be rewalked by the walker if necessary.
- /// This really should only be called by tests.
- void resetOptimized() { OptimizedID = INVALID_MEMORYACCESS_ID; }
+ virtual MemoryAccess *getOptimized() const override {
+ return getDefiningAccess();
+ }
+ virtual void resetOptimized() override { OptimizedID = INVALID_MEMORYACCESS_ID; }
protected:
friend class MemorySSA;
@@ -333,7 +345,8 @@ public:
MemoryDef(LLVMContext &C, MemoryAccess *DMA, Instruction *MI, BasicBlock *BB,
unsigned Ver)
- : MemoryUseOrDef(C, DMA, MemoryDefVal, MI, BB), ID(Ver) {}
+ : MemoryUseOrDef(C, DMA, MemoryDefVal, MI, BB), ID(Ver),
+ Optimized(nullptr), OptimizedID(INVALID_MEMORYACCESS_ID) {}
// allocate space for exactly one operand
void *operator new(size_t s) { return User::operator new(s, 1); }
@@ -343,6 +356,17 @@ public:
return MA->getValueID() == MemoryDefVal;
}
+ virtual void setOptimized(MemoryAccess *MA) override {
+ Optimized = MA;
+ OptimizedID = getDefiningAccess()->getID();
+ }
+ virtual MemoryAccess *getOptimized() const override { return Optimized; }
+ virtual bool isOptimized() const override {
+ return getOptimized() && OptimizedID == getDefiningAccess()->getID();
+ }
+ virtual void resetOptimized() override { OptimizedID = INVALID_MEMORYACCESS_ID; }
+
+
void print(raw_ostream &OS) const override;
protected:
@@ -352,6 +376,8 @@ protected:
private:
const unsigned ID;
+ MemoryAccess *Optimized;
+ unsigned int OptimizedID;
};
template <>
@@ -1075,10 +1101,15 @@ struct def_chain_iterator
def_chain_iterator &operator++() {
// N.B. liveOnEntry has a null defining access.
- if (auto *MUD = dyn_cast<MemoryUseOrDef>(MA))
- MA = MUD->getDefiningAccess();
- else
+ if (auto *MUD = dyn_cast<MemoryUseOrDef>(MA)) {
+ if (MUD->isOptimized())
+ MA = MUD->getOptimized();
+ else
+ MA = MUD->getDefiningAccess();
+ } else {
MA = nullptr;
+ }
+
return *this;
}
diff --git a/lib/Transforms/Utils/MemorySSA.cpp b/lib/Transforms/Utils/MemorySSA.cpp
index 5a3b163992e..8ceec2e2ac8 100644
--- a/lib/Transforms/Utils/MemorySSA.cpp
+++ b/lib/Transforms/Utils/MemorySSA.cpp
@@ -2181,9 +2181,9 @@ MemorySSA::CachingWalker::getClobberingMemoryAccess(MemoryAccess *MA) {
// If this is an already optimized use or def, return the optimized result.
// Note: Currently, we do not store the optimized def result because we'd need
// a separate field, since we can't use it as the defining access.
- if (MemoryUse *MU = dyn_cast<MemoryUse>(StartingAccess))
- if (MU->isOptimized())
- return MU->getDefiningAccess();
+ if (auto *MUD = dyn_cast<MemoryUseOrDef>(StartingAccess))
+ if (MUD->isOptimized())
+ return MUD->getOptimized();
const Instruction *I = StartingAccess->getMemoryInst();
UpwardsMemoryQuery Q(I, StartingAccess);
@@ -2199,8 +2199,8 @@ MemorySSA::CachingWalker::getClobberingMemoryAccess(MemoryAccess *MA) {
if (isUseTriviallyOptimizableToLiveOnEntry(*MSSA->AA, I)) {
MemoryAccess *LiveOnEntry = MSSA->getLiveOnEntryDef();
Cache.insert(StartingAccess, LiveOnEntry, Q.StartingLoc, Q.IsCall);
- if (MemoryUse *MU = dyn_cast<MemoryUse>(StartingAccess))
- MU->setDefiningAccess(LiveOnEntry, true);
+ if (auto *MUD = dyn_cast<MemoryUseOrDef>(StartingAccess))
+ MUD->setDefiningAccess(LiveOnEntry, true);
return LiveOnEntry;
}
@@ -2217,8 +2217,8 @@ MemorySSA::CachingWalker::getClobberingMemoryAccess(MemoryAccess *MA) {
DEBUG(dbgs() << *DefiningAccess << "\n");
DEBUG(dbgs() << "Final Memory SSA clobber for " << *I << " is ");
DEBUG(dbgs() << *Result << "\n");
- if (MemoryUse *MU = dyn_cast<MemoryUse>(StartingAccess))
- MU->setDefiningAccess(Result, true);
+ if (auto *MUD = dyn_cast<MemoryUseOrDef>(StartingAccess))
+ MUD->setDefiningAccess(Result, true);
return Result;
}
diff --git a/lib/Transforms/Utils/MemorySSAUpdater.cpp b/lib/Transforms/Utils/MemorySSAUpdater.cpp
index 7e043956171..c396bd73504 100644
--- a/lib/Transforms/Utils/MemorySSAUpdater.cpp
+++ b/lib/Transforms/Utils/MemorySSAUpdater.cpp
@@ -451,8 +451,8 @@ void MemorySSAUpdater::removeMemoryAccess(MemoryAccess *MA) {
while (!MA->use_empty()) {
Use &U = *MA->use_begin();
- if (MemoryUse *MU = dyn_cast<MemoryUse>(U.getUser()))
- MU->resetOptimized();
+ if (auto *MUD = dyn_cast<MemoryUseOrDef>(U.getUser()))
+ MUD->resetOptimized();
U.set(NewDefTarget);
}
}
--
2.40.0