[MemorySSA] LCSSA preserves MemorySSA.
Summary:
Enabling MemorySSA in the old pass manager leads to MemorySSA being run
twice due to the fact that LCSSA and LoopSimplify do not preserve
MemorySSA. This is the first step to address that: target LCSSA.
LCSSA does not make any changes that invalidate MemorySSA, so it
preserves it by design. It must preserve AA as well, for this to hold.
After this patch, MemorySSA is still run twice in the old pass manager.
Step two follows: target LoopSimplify.
Subscribers: mehdi_amini, jlebar, Prazek, llvm-commits, george.burgess.iv, chandlerc
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D60832
llvm-svn: 359032
diff --git a/llvm/lib/Analysis/LoopAnalysisManager.cpp b/llvm/lib/Analysis/LoopAnalysisManager.cpp
index 8ae92e1..d0cfb3e 100644
--- a/llvm/lib/Analysis/LoopAnalysisManager.cpp
+++ b/llvm/lib/Analysis/LoopAnalysisManager.cpp
@@ -18,11 +18,6 @@
using namespace llvm;
namespace llvm {
-/// Enables memory ssa as a dependency for loop passes in legacy pass manager.
-cl::opt<bool> EnableMSSALoopDependency(
- "enable-mssa-loop-dependency", cl::Hidden, cl::init(false),
- cl::desc("Enable MemorySSA dependency for loop pass manager"));
-
// Explicit template instantiations and specialization definitions for core
// template typedefs.
template class AllAnalysesOn<Loop>;
diff --git a/llvm/lib/Analysis/MemorySSA.cpp b/llvm/lib/Analysis/MemorySSA.cpp
index cd6235d..271d56d 100644
--- a/llvm/lib/Analysis/MemorySSA.cpp
+++ b/llvm/lib/Analysis/MemorySSA.cpp
@@ -81,6 +81,11 @@
#else
bool llvm::VerifyMemorySSA = false;
#endif
+/// Enables memory ssa as a dependency for loop passes in legacy pass manager.
+cl::opt<bool> llvm::EnableMSSALoopDependency(
+ "enable-mssa-loop-dependency", cl::Hidden, cl::init(false),
+ cl::desc("Enable MemorySSA dependency for loop pass manager"));
+
static cl::opt<bool, true>
VerifyMemorySSAX("verify-memoryssa", cl::location(VerifyMemorySSA),
cl::Hidden, cl::desc("Enable verification of MemorySSA."));
diff --git a/llvm/lib/Transforms/Utils/LCSSA.cpp b/llvm/lib/Transforms/Utils/LCSSA.cpp
index 5ddb738..29e7c52 100644
--- a/llvm/lib/Transforms/Utils/LCSSA.cpp
+++ b/llvm/lib/Transforms/Utils/LCSSA.cpp
@@ -34,9 +34,9 @@
#include "llvm/Analysis/BranchProbabilityInfo.h"
#include "llvm/Analysis/GlobalsModRef.h"
#include "llvm/Analysis/LoopPass.h"
+#include "llvm/Analysis/MemorySSA.h"
#include "llvm/Analysis/ScalarEvolution.h"
#include "llvm/Analysis/ScalarEvolutionAliasAnalysis.h"
-#include "llvm/Transforms/Utils/Local.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/Function.h"
@@ -45,6 +45,7 @@
#include "llvm/IR/PredIteratorCache.h"
#include "llvm/Pass.h"
#include "llvm/Transforms/Utils.h"
+#include "llvm/Transforms/Utils/Local.h"
#include "llvm/Transforms/Utils/LoopUtils.h"
#include "llvm/Transforms/Utils/SSAUpdater.h"
using namespace llvm;
@@ -444,6 +445,7 @@
AU.addPreserved<ScalarEvolutionWrapperPass>();
AU.addPreserved<SCEVAAWrapperPass>();
AU.addPreserved<BranchProbabilityInfoWrapperPass>();
+ AU.addPreserved<MemorySSAWrapperPass>();
// This is needed to perform LCSSA verification inside LPPassManager
AU.addRequired<LCSSAVerificationPass>();
@@ -490,5 +492,6 @@
// BPI maps terminators to probabilities, since we don't modify the CFG, no
// updates are needed to preserve it.
PA.preserve<BranchProbabilityAnalysis>();
+ PA.preserve<MemorySSAAnalysis>();
return PA;
}