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-rw-r--r--llvm/lib/Transforms/Scalar/CMakeLists.txt1
-rw-r--r--llvm/lib/Transforms/Scalar/FlattenCFGPass.cpp79
-rw-r--r--llvm/lib/Transforms/Scalar/Scalar.cpp3
-rw-r--r--llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp64
4 files changed, 94 insertions, 53 deletions
diff --git a/llvm/lib/Transforms/Scalar/CMakeLists.txt b/llvm/lib/Transforms/Scalar/CMakeLists.txt
index 4a3585947fc..f5d1db1ec23 100644
--- a/llvm/lib/Transforms/Scalar/CMakeLists.txt
+++ b/llvm/lib/Transforms/Scalar/CMakeLists.txt
@@ -28,6 +28,7 @@ add_llvm_library(LLVMScalarOpts
Scalar.cpp
ScalarReplAggregates.cpp
SimplifyCFGPass.cpp
+ FlattenCFGPass.cpp
Sink.cpp
StructurizeCFG.cpp
TailRecursionElimination.cpp
diff --git a/llvm/lib/Transforms/Scalar/FlattenCFGPass.cpp b/llvm/lib/Transforms/Scalar/FlattenCFGPass.cpp
new file mode 100644
index 00000000000..e7de07f246d
--- /dev/null
+++ b/llvm/lib/Transforms/Scalar/FlattenCFGPass.cpp
@@ -0,0 +1,79 @@
+//===- FlattenCFGPass.cpp - CFG Flatten Pass ----------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements flattening of CFG.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "flattencfg"
+#include "llvm/Transforms/Scalar.h"
+#include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Pass.h"
+#include "llvm/Support/CFG.h"
+#include "llvm/Transforms/Utils/Local.h"
+using namespace llvm;
+
+namespace {
+struct FlattenCFGPass : public FunctionPass {
+ static char ID; // Pass identification, replacement for typeid
+public:
+ FlattenCFGPass() : FunctionPass(ID) {
+ initializeFlattenCFGPassPass(*PassRegistry::getPassRegistry());
+ }
+ bool runOnFunction(Function &F);
+
+ void getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.addRequired<AliasAnalysis>();
+ }
+
+private:
+ AliasAnalysis *AA;
+};
+}
+
+char FlattenCFGPass::ID = 0;
+INITIALIZE_PASS_BEGIN(FlattenCFGPass, "flattencfg", "Flatten the CFG", false,
+ false)
+INITIALIZE_AG_DEPENDENCY(AliasAnalysis)
+INITIALIZE_PASS_END(FlattenCFGPass, "flattencfg", "Flatten the CFG", false,
+ false)
+
+// Public interface to the FlattenCFG pass
+FunctionPass *llvm::createFlattenCFGPass() { return new FlattenCFGPass(); }
+
+/// iterativelyFlattenCFG - Call FlattenCFG on all the blocks in the function,
+/// iterating until no more changes are made.
+static bool iterativelyFlattenCFG(Function &F, AliasAnalysis *AA) {
+ bool Changed = false;
+ bool LocalChange = true;
+ while (LocalChange) {
+ LocalChange = false;
+
+ // Loop over all of the basic blocks and remove them if they are unneeded...
+ //
+ for (Function::iterator BBIt = F.begin(); BBIt != F.end();) {
+ if (FlattenCFG(BBIt++, AA)) {
+ LocalChange = true;
+ }
+ }
+ Changed |= LocalChange;
+ }
+ return Changed;
+}
+
+bool FlattenCFGPass::runOnFunction(Function &F) {
+ AA = &getAnalysis<AliasAnalysis>();
+ bool EverChanged = false;
+ // iterativelyFlattenCFG can make some blocks dead.
+ while (iterativelyFlattenCFG(F, AA)) {
+ removeUnreachableBlocks(F);
+ EverChanged = true;
+ }
+ return EverChanged;
+}
diff --git a/llvm/lib/Transforms/Scalar/Scalar.cpp b/llvm/lib/Transforms/Scalar/Scalar.cpp
index 18cdcfef1c7..758334dba40 100644
--- a/llvm/lib/Transforms/Scalar/Scalar.cpp
+++ b/llvm/lib/Transforms/Scalar/Scalar.cpp
@@ -57,8 +57,7 @@ void llvm::initializeScalarOpts(PassRegistry &Registry) {
initializeSROAPass(Registry);
initializeSROA_DTPass(Registry);
initializeSROA_SSAUpPass(Registry);
- initializeCFGCanonicalizePass(Registry);
- initializeCFGOptimizePass(Registry);
+ initializeCFGSimplifyPassPass(Registry);
initializeStructurizeCFGPass(Registry);
initializeSinkingPass(Registry);
initializeTailCallElimPass(Registry);
diff --git a/llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp b/llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp
index 9ab5f4537ed..6d05640216a 100644
--- a/llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp
+++ b/llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp
@@ -27,7 +27,6 @@
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/TargetTransformInfo.h"
-#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/IR/Attributes.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
@@ -43,61 +42,28 @@ STATISTIC(NumSimpl, "Number of blocks simplified");
namespace {
struct CFGSimplifyPass : public FunctionPass {
- CFGSimplifyPass(char &ID, bool isTargetAware)
- : FunctionPass(ID), IsTargetAware(isTargetAware) {}
- virtual bool runOnFunction(Function &F);
-
- virtual void getAnalysisUsage(AnalysisUsage &AU) const {
- AU.addRequired<TargetTransformInfo>();
- }
-private:
- AliasAnalysis *AA;
- bool IsTargetAware; // Should the pass be target-aware?
-};
-
-// CFGSimplifyPass that does optimizations.
-struct CFGOptimize : public CFGSimplifyPass {
static char ID; // Pass identification, replacement for typeid
-public:
- CFGOptimize() : CFGSimplifyPass(ID, true) {
- initializeCFGOptimizePass(*PassRegistry::getPassRegistry());
+ CFGSimplifyPass() : FunctionPass(ID) {
+ initializeCFGSimplifyPassPass(*PassRegistry::getPassRegistry());
}
+ virtual bool runOnFunction(Function &F);
+
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<TargetTransformInfo>();
- AU.addRequired<AliasAnalysis>();
- }
-};
-
-// CFGSimplifyPass that does canonicalizations.
-struct CFGCanonicalize : public CFGSimplifyPass {
- static char ID; // Pass identification, replacement for typeid
-public:
- CFGCanonicalize() : CFGSimplifyPass(ID, false) {
- initializeCFGCanonicalizePass(*PassRegistry::getPassRegistry());
}
};
}
-char CFGCanonicalize::ID = 0;
-char CFGOptimize::ID = 0;
-INITIALIZE_PASS_BEGIN(CFGCanonicalize, "simplifycfg", "Simplify the CFG", false,
- false)
-INITIALIZE_AG_DEPENDENCY(TargetTransformInfo)
-INITIALIZE_PASS_END(CFGCanonicalize, "simplifycfg", "Simplify the CFG", false,
- false)
-INITIALIZE_PASS_BEGIN(CFGOptimize, "optimizecfg", "optimize the CFG", false,
+char CFGSimplifyPass::ID = 0;
+INITIALIZE_PASS_BEGIN(CFGSimplifyPass, "simplifycfg", "Simplify the CFG", false,
false)
INITIALIZE_AG_DEPENDENCY(TargetTransformInfo)
-INITIALIZE_AG_DEPENDENCY(AliasAnalysis)
-INITIALIZE_PASS_END(CFGOptimize, "optimizecfg", "Optimize the CFG", false,
+INITIALIZE_PASS_END(CFGSimplifyPass, "simplifycfg", "Simplify the CFG", false,
false)
// Public interface to the CFGSimplification pass
-FunctionPass *llvm::createCFGSimplificationPass(bool IsTargetAware) {
- if (IsTargetAware)
- return new CFGOptimize();
- else
- return new CFGCanonicalize();
+FunctionPass *llvm::createCFGSimplificationPass() {
+ return new CFGSimplifyPass();
}
/// changeToUnreachable - Insert an unreachable instruction before the specified
@@ -334,7 +300,7 @@ static bool mergeEmptyReturnBlocks(Function &F) {
/// iterativelySimplifyCFG - Call SimplifyCFG on all the blocks in the function,
/// iterating until no more changes are made.
static bool iterativelySimplifyCFG(Function &F, const TargetTransformInfo &TTI,
- const DataLayout *TD, AliasAnalysis *AA) {
+ const DataLayout *TD) {
bool Changed = false;
bool LocalChange = true;
while (LocalChange) {
@@ -343,7 +309,7 @@ static bool iterativelySimplifyCFG(Function &F, const TargetTransformInfo &TTI,
// Loop over all of the basic blocks and remove them if they are unneeded...
//
for (Function::iterator BBIt = F.begin(); BBIt != F.end(); ) {
- if (SimplifyCFG(BBIt++, TTI, TD, AA)) {
+ if (SimplifyCFG(BBIt++, TTI, TD)) {
LocalChange = true;
++NumSimpl;
}
@@ -357,15 +323,11 @@ static bool iterativelySimplifyCFG(Function &F, const TargetTransformInfo &TTI,
// simplify the CFG.
//
bool CFGSimplifyPass::runOnFunction(Function &F) {
- if (IsTargetAware)
- AA = &getAnalysis<AliasAnalysis>();
- else
- AA = NULL;
const TargetTransformInfo &TTI = getAnalysis<TargetTransformInfo>();
const DataLayout *TD = getAnalysisIfAvailable<DataLayout>();
bool EverChanged = removeUnreachableBlocksFromFn(F);
EverChanged |= mergeEmptyReturnBlocks(F);
- EverChanged |= iterativelySimplifyCFG(F, TTI, TD, AA);
+ EverChanged |= iterativelySimplifyCFG(F, TTI, TD);
// If neither pass changed anything, we're done.
if (!EverChanged) return false;
@@ -379,7 +341,7 @@ bool CFGSimplifyPass::runOnFunction(Function &F) {
return true;
do {
- EverChanged = iterativelySimplifyCFG(F, TTI, TD, AA);
+ EverChanged = iterativelySimplifyCFG(F, TTI, TD);
EverChanged |= removeUnreachableBlocksFromFn(F);
} while (EverChanged);
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