[llvm] r187764 - Factor FlattenCFG out from SimplifyCFG
Serge Pavlov
sepavloff at gmail.com
Tue Aug 6 01:48:27 PDT 2013
The problem is fixed in r187786.
2013/8/6 Timur Iskhodzhanov <timurrrr at google.com>
> FYI this has broken the MSVS build
>
> 100>------ Build started: Project: LLVMTransformUtils, Configuration:
> Debug Win32 ------
> ...
> 100> FlattenCFG.cpp
> 100> llvm\lib\Transforms\Utils\FlattenCFG.cpp(301):
> error C2027: use of undefined type 'llvm::raw_ostream'
>
> 2013/8/6 Tom Stellard <thomas.stellard at amd.com>:
> > Author: tstellar
> > Date: Mon Aug 5 21:43:45 2013
> > New Revision: 187764
> >
> > URL: http://llvm.org/viewvc/llvm-project?rev=187764&view=rev
> > Log:
> > Factor FlattenCFG out from SimplifyCFG
> >
> > Patch by: Mei Ye
> >
> > Added:
> > llvm/trunk/lib/Transforms/Scalar/FlattenCFGPass.cpp
> > llvm/trunk/lib/Transforms/Utils/FlattenCFG.cpp
> > llvm/trunk/test/CodeGen/R600/parallelandifcollapse.ll
> > - copied, changed from r187754,
> llvm/trunk/test/Transforms/SimplifyCFG/R600/parallelorifcollapse.ll
> > llvm/trunk/test/CodeGen/R600/parallelorifcollapse.ll
> > - copied, changed from r187754,
> llvm/trunk/test/Transforms/SimplifyCFG/R600/parallelandifcollapse.ll
> > Modified:
> > llvm/trunk/include/llvm/InitializePasses.h
> > llvm/trunk/include/llvm/Transforms/Scalar.h
> > llvm/trunk/include/llvm/Transforms/Utils/BasicBlockUtils.h
> > llvm/trunk/include/llvm/Transforms/Utils/Local.h
> > llvm/trunk/lib/Target/R600/AMDGPUTargetMachine.cpp
> > llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp
> > llvm/trunk/lib/Transforms/Scalar/CMakeLists.txt
> > llvm/trunk/lib/Transforms/Scalar/Scalar.cpp
> > llvm/trunk/lib/Transforms/Scalar/SimplifyCFGPass.cpp
> > llvm/trunk/lib/Transforms/Utils/BasicBlockUtils.cpp
> > llvm/trunk/lib/Transforms/Utils/CMakeLists.txt
> > llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp
> > llvm/trunk/test/Transforms/SimplifyCFG/R600/lit.local.cfg
> > llvm/trunk/test/Transforms/SimplifyCFG/R600/parallelandifcollapse.ll
> > llvm/trunk/test/Transforms/SimplifyCFG/R600/parallelorifcollapse.ll
> > llvm/trunk/test/Transforms/SimplifyCFG/lit.local.cfg
> > llvm/trunk/tools/lto/LTOCodeGenerator.cpp
> >
> > Modified: llvm/trunk/include/llvm/InitializePasses.h
> > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/InitializePasses.h?rev=187764&r1=187763&r2=187764&view=diff
> >
> ==============================================================================
> > --- llvm/trunk/include/llvm/InitializePasses.h (original)
> > +++ llvm/trunk/include/llvm/InitializePasses.h Mon Aug 5 21:43:45 2013
> > @@ -86,8 +86,8 @@ void initializeCallGraphViewerPass(PassR
> > void initializeCFGOnlyPrinterPass(PassRegistry&);
> > void initializeCFGOnlyViewerPass(PassRegistry&);
> > void initializeCFGPrinterPass(PassRegistry&);
> > -void initializeCFGOptimizePass(PassRegistry&);
> > -void initializeCFGCanonicalizePass(PassRegistry&);
> > +void initializeCFGSimplifyPassPass(PassRegistry&);
> > +void initializeFlattenCFGPassPass(PassRegistry&);
> > void initializeStructurizeCFGPass(PassRegistry&);
> > void initializeCFGViewerPass(PassRegistry&);
> > void initializeCalculateSpillWeightsPass(PassRegistry&);
> >
> > Modified: llvm/trunk/include/llvm/Transforms/Scalar.h
> > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Transforms/Scalar.h?rev=187764&r1=187763&r2=187764&view=diff
> >
> ==============================================================================
> > --- llvm/trunk/include/llvm/Transforms/Scalar.h (original)
> > +++ llvm/trunk/include/llvm/Transforms/Scalar.h Mon Aug 5 21:43:45 2013
> > @@ -196,7 +196,14 @@ FunctionPass *createJumpThreadingPass();
> > // CFGSimplification - Merge basic blocks, eliminate unreachable blocks,
> > // simplify terminator instructions, etc...
> > //
> > -FunctionPass *createCFGSimplificationPass(bool IsTargetAware = false);
> > +FunctionPass *createCFGSimplificationPass();
> > +
> >
> +//===----------------------------------------------------------------------===//
> > +//
> > +// FlattenCFG - flatten CFG, reduce number of conditional branches by
> using
> > +// parallel-and and parallel-or mode, etc...
> > +//
> > +FunctionPass *createFlattenCFGPass();
> >
> >
> //===----------------------------------------------------------------------===//
> > //
> >
> > Modified: llvm/trunk/include/llvm/Transforms/Utils/BasicBlockUtils.h
> > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Transforms/Utils/BasicBlockUtils.h?rev=187764&r1=187763&r2=187764&view=diff
> >
> ==============================================================================
> > --- llvm/trunk/include/llvm/Transforms/Utils/BasicBlockUtils.h (original)
> > +++ llvm/trunk/include/llvm/Transforms/Utils/BasicBlockUtils.h Mon Aug
> 5 21:43:45 2013
> > @@ -205,6 +205,15 @@ ReturnInst *FoldReturnIntoUncondBranch(R
> > TerminatorInst *SplitBlockAndInsertIfThen(Instruction *Cmp,
> > bool Unreachable, MDNode *BranchWeights = 0);
> >
> > +///
> > +/// GetIfCondition - Check whether BB is the merge point of a if-region.
> > +/// If so, return the boolean condition that determines which entry into
> > +/// BB will be taken. Also, return by references the block that will be
> > +/// entered from if the condition is true, and the block that will be
> > +/// entered if the condition is false.
> > +
> > +Value *GetIfCondition(BasicBlock *BB, BasicBlock *&IfTrue,
> > + BasicBlock *&IfFalse);
> > } // End llvm namespace
> >
> > #endif
> >
> > Modified: llvm/trunk/include/llvm/Transforms/Utils/Local.h
> > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Transforms/Utils/Local.h?rev=187764&r1=187763&r2=187764&view=diff
> >
> ==============================================================================
> > --- llvm/trunk/include/llvm/Transforms/Utils/Local.h (original)
> > +++ llvm/trunk/include/llvm/Transforms/Utils/Local.h Mon Aug 5 21:43:45
> 2013
> > @@ -137,7 +137,13 @@ bool EliminateDuplicatePHINodes(BasicBlo
> > /// the basic block that was pointed to.
> > ///
> > bool SimplifyCFG(BasicBlock *BB, const TargetTransformInfo &TTI,
> > - const DataLayout *TD = 0, AliasAnalysis *AA = 0);
> > + const DataLayout *TD = 0);
> > +
> > +/// FlatternCFG - This function is used to flatten a CFG. For
> > +/// example, it uses parallel-and and parallel-or mode to collapse
> > +// if-conditions and merge if-regions with identical statements.
> > +///
> > +bool FlattenCFG(BasicBlock *BB, AliasAnalysis *AA = 0);
> >
> > /// FoldBranchToCommonDest - If this basic block is ONLY a setcc and a
> branch,
> > /// and if a predecessor branches to us and one of our successors, fold
> the
> >
> > Modified: llvm/trunk/lib/Target/R600/AMDGPUTargetMachine.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/R600/AMDGPUTargetMachine.cpp?rev=187764&r1=187763&r2=187764&view=diff
> >
> ==============================================================================
> > --- llvm/trunk/lib/Target/R600/AMDGPUTargetMachine.cpp (original)
> > +++ llvm/trunk/lib/Target/R600/AMDGPUTargetMachine.cpp Mon Aug 5
> 21:43:45 2013
> > @@ -91,7 +91,6 @@ public:
> > AMDGPUTargetMachine &getAMDGPUTargetMachine() const {
> > return getTM<AMDGPUTargetMachine>();
> > }
> > -
> > virtual bool addPreISel();
> > virtual bool addInstSelector();
> > virtual bool addPreRegAlloc();
> > @@ -120,6 +119,7 @@ void AMDGPUTargetMachine::addAnalysisPas
> > bool
> > AMDGPUPassConfig::addPreISel() {
> > const AMDGPUSubtarget &ST = TM->getSubtarget<AMDGPUSubtarget>();
> > + addPass(createFlattenCFGPass());
> > if (ST.getGeneration() > AMDGPUSubtarget::NORTHERN_ISLANDS) {
> > addPass(createStructurizeCFGPass());
> > addPass(createSIAnnotateControlFlowPass());
> >
> > Modified: llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp?rev=187764&r1=187763&r2=187764&view=diff
> >
> ==============================================================================
> > --- llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp (original)
> > +++ llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp Mon Aug 5
> 21:43:45 2013
> > @@ -235,7 +235,7 @@ void PassManagerBuilder::populateModuleP
> > }
> >
> > MPM.add(createAggressiveDCEPass()); // Delete dead
> instructions
> > - MPM.add(createCFGSimplificationPass(true)); // Merge & remove BBs
> > + MPM.add(createCFGSimplificationPass()); // Merge & remove BBs
> > MPM.add(createInstructionCombiningPass()); // Clean up after
> everything.
> >
> > // As an experimental mode, run any vectorization passes in a separate
> > @@ -371,7 +371,7 @@ void PassManagerBuilder::populateLTOPass
> > PM.add(createJumpThreadingPass());
> >
> > // Delete basic blocks, which optimization passes may have killed.
> > - PM.add(createCFGSimplificationPass(true));
> > + PM.add(createCFGSimplificationPass());
> >
> > // Now that we have optimized the program, discard unreachable
> functions.
> > PM.add(createGlobalDCEPass());
> >
> > Modified: llvm/trunk/lib/Transforms/Scalar/CMakeLists.txt
> > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/CMakeLists.txt?rev=187764&r1=187763&r2=187764&view=diff
> >
> ==============================================================================
> > --- llvm/trunk/lib/Transforms/Scalar/CMakeLists.txt (original)
> > +++ llvm/trunk/lib/Transforms/Scalar/CMakeLists.txt Mon Aug 5 21:43:45
> 2013
> > @@ -28,6 +28,7 @@ add_llvm_library(LLVMScalarOpts
> > Scalar.cpp
> > ScalarReplAggregates.cpp
> > SimplifyCFGPass.cpp
> > + FlattenCFGPass.cpp
> > Sink.cpp
> > StructurizeCFG.cpp
> > TailRecursionElimination.cpp
> >
> > Added: llvm/trunk/lib/Transforms/Scalar/FlattenCFGPass.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/FlattenCFGPass.cpp?rev=187764&view=auto
> >
> ==============================================================================
> > --- llvm/trunk/lib/Transforms/Scalar/FlattenCFGPass.cpp (added)
> > +++ llvm/trunk/lib/Transforms/Scalar/FlattenCFGPass.cpp Mon Aug 5
> 21:43:45 2013
> > @@ -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;
> > +}
> >
> > Modified: llvm/trunk/lib/Transforms/Scalar/Scalar.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/Scalar.cpp?rev=187764&r1=187763&r2=187764&view=diff
> >
> ==============================================================================
> > --- llvm/trunk/lib/Transforms/Scalar/Scalar.cpp (original)
> > +++ llvm/trunk/lib/Transforms/Scalar/Scalar.cpp Mon Aug 5 21:43:45 2013
> > @@ -57,8 +57,7 @@ void llvm::initializeScalarOpts(PassRegi
> > initializeSROAPass(Registry);
> > initializeSROA_DTPass(Registry);
> > initializeSROA_SSAUpPass(Registry);
> > - initializeCFGCanonicalizePass(Registry);
> > - initializeCFGOptimizePass(Registry);
> > + initializeCFGSimplifyPassPass(Registry);
> > initializeStructurizeCFGPass(Registry);
> > initializeSinkingPass(Registry);
> > initializeTailCallElimPass(Registry);
> >
> > Modified: llvm/trunk/lib/Transforms/Scalar/SimplifyCFGPass.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/SimplifyCFGPass.cpp?rev=187764&r1=187763&r2=187764&view=diff
> >
> ==============================================================================
> > --- llvm/trunk/lib/Transforms/Scalar/SimplifyCFGPass.cpp (original)
> > +++ llvm/trunk/lib/Transforms/Scalar/SimplifyCFGPass.cpp Mon Aug 5
> 21:43:45 2013
> > @@ -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 si
> >
> > 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(Funct
> > /// 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(Funct
> > // 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(Funct
> > // 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(Func
> > return true;
> >
> > do {
> > - EverChanged = iterativelySimplifyCFG(F, TTI, TD, AA);
> > + EverChanged = iterativelySimplifyCFG(F, TTI, TD);
> > EverChanged |= removeUnreachableBlocksFromFn(F);
> > } while (EverChanged);
> >
> >
> > Modified: llvm/trunk/lib/Transforms/Utils/BasicBlockUtils.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/BasicBlockUtils.cpp?rev=187764&r1=187763&r2=187764&view=diff
> >
> ==============================================================================
> > --- llvm/trunk/lib/Transforms/Utils/BasicBlockUtils.cpp (original)
> > +++ llvm/trunk/lib/Transforms/Utils/BasicBlockUtils.cpp Mon Aug 5
> 21:43:45 2013
> > @@ -665,3 +665,104 @@ TerminatorInst *llvm::SplitBlockAndInser
> > ReplaceInstWithInst(HeadOldTerm, HeadNewTerm);
> > return CheckTerm;
> > }
> > +
> > +/// GetIfCondition - Given a basic block (BB) with two predecessors,
> > +/// check to see if the merge at this block is due
> > +/// to an "if condition". If so, return the boolean condition that
> determines
> > +/// which entry into BB will be taken. Also, return by references the
> block
> > +/// that will be entered from if the condition is true, and the block
> that will
> > +/// be entered if the condition is false.
> > +///
> > +/// This does no checking to see if the true/false blocks have large or
> unsavory
> > +/// instructions in them.
> > +Value *llvm::GetIfCondition(BasicBlock *BB, BasicBlock *&IfTrue,
> > + BasicBlock *&IfFalse) {
> > + PHINode *SomePHI = dyn_cast<PHINode>(BB->begin());
> > + BasicBlock *Pred1 = NULL;
> > + BasicBlock *Pred2 = NULL;
> > +
> > + if (SomePHI) {
> > + if (SomePHI->getNumIncomingValues() != 2)
> > + return NULL;
> > + Pred1 = SomePHI->getIncomingBlock(0);
> > + Pred2 = SomePHI->getIncomingBlock(1);
> > + } else {
> > + pred_iterator PI = pred_begin(BB), PE = pred_end(BB);
> > + if (PI == PE) // No predecessor
> > + return NULL;
> > + Pred1 = *PI++;
> > + if (PI == PE) // Only one predecessor
> > + return NULL;
> > + Pred2 = *PI++;
> > + if (PI != PE) // More than two predecessors
> > + return NULL;
> > + }
> > +
> > + // We can only handle branches. Other control flow will be lowered to
> > + // branches if possible anyway.
> > + BranchInst *Pred1Br = dyn_cast<BranchInst>(Pred1->getTerminator());
> > + BranchInst *Pred2Br = dyn_cast<BranchInst>(Pred2->getTerminator());
> > + if (Pred1Br == 0 || Pred2Br == 0)
> > + return 0;
> > +
> > + // Eliminate code duplication by ensuring that Pred1Br is conditional
> if
> > + // either are.
> > + if (Pred2Br->isConditional()) {
> > + // If both branches are conditional, we don't have an "if
> statement". In
> > + // reality, we could transform this case, but since the condition
> will be
> > + // required anyway, we stand no chance of eliminating it, so the
> xform is
> > + // probably not profitable.
> > + if (Pred1Br->isConditional())
> > + return 0;
> > +
> > + std::swap(Pred1, Pred2);
> > + std::swap(Pred1Br, Pred2Br);
> > + }
> > +
> > + if (Pred1Br->isConditional()) {
> > + // The only thing we have to watch out for here is to make sure
> that Pred2
> > + // doesn't have incoming edges from other blocks. If it does, the
> condition
> > + // doesn't dominate BB.
> > + if (Pred2->getSinglePredecessor() == 0)
> > + return 0;
> > +
> > + // If we found a conditional branch predecessor, make sure that it
> branches
> > + // to BB and Pred2Br. If it doesn't, this isn't an "if statement".
> > + if (Pred1Br->getSuccessor(0) == BB &&
> > + Pred1Br->getSuccessor(1) == Pred2) {
> > + IfTrue = Pred1;
> > + IfFalse = Pred2;
> > + } else if (Pred1Br->getSuccessor(0) == Pred2 &&
> > + Pred1Br->getSuccessor(1) == BB) {
> > + IfTrue = Pred2;
> > + IfFalse = Pred1;
> > + } else {
> > + // We know that one arm of the conditional goes to BB, so the
> other must
> > + // go somewhere unrelated, and this must not be an "if statement".
> > + return 0;
> > + }
> > +
> > + return Pred1Br->getCondition();
> > + }
> > +
> > + // Ok, if we got here, both predecessors end with an unconditional
> branch to
> > + // BB. Don't panic! If both blocks only have a single (identical)
> > + // predecessor, and THAT is a conditional branch, then we're all ok!
> > + BasicBlock *CommonPred = Pred1->getSinglePredecessor();
> > + if (CommonPred == 0 || CommonPred != Pred2->getSinglePredecessor())
> > + return 0;
> > +
> > + // Otherwise, if this is a conditional branch, then we can use it!
> > + BranchInst *BI = dyn_cast<BranchInst>(CommonPred->getTerminator());
> > + if (BI == 0) return 0;
> > +
> > + assert(BI->isConditional() && "Two successors but not conditional?");
> > + if (BI->getSuccessor(0) == Pred1) {
> > + IfTrue = Pred1;
> > + IfFalse = Pred2;
> > + } else {
> > + IfTrue = Pred2;
> > + IfFalse = Pred1;
> > + }
> > + return BI->getCondition();
> > +}
> >
> > Modified: llvm/trunk/lib/Transforms/Utils/CMakeLists.txt
> > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/CMakeLists.txt?rev=187764&r1=187763&r2=187764&view=diff
> >
> ==============================================================================
> > --- llvm/trunk/lib/Transforms/Utils/CMakeLists.txt (original)
> > +++ llvm/trunk/lib/Transforms/Utils/CMakeLists.txt Mon Aug 5 21:43:45
> 2013
> > @@ -25,6 +25,7 @@ add_llvm_library(LLVMTransformUtils
> > PromoteMemoryToRegister.cpp
> > SSAUpdater.cpp
> > SimplifyCFG.cpp
> > + FlattenCFG.cpp
> > SimplifyIndVar.cpp
> > SimplifyInstructions.cpp
> > SimplifyLibCalls.cpp
> >
> > Added: llvm/trunk/lib/Transforms/Utils/FlattenCFG.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/FlattenCFG.cpp?rev=187764&view=auto
> >
> ==============================================================================
> > --- llvm/trunk/lib/Transforms/Utils/FlattenCFG.cpp (added)
> > +++ llvm/trunk/lib/Transforms/Utils/FlattenCFG.cpp Mon Aug 5 21:43:45
> 2013
> > @@ -0,0 +1,487 @@
> > +//===- FlatternCFG.cpp - Code to perform CFG flattening
> ---------------===//
> > +//
> > +// The LLVM Compiler Infrastructure
> > +//
> > +// This file is distributed under the University of Illinois Open Source
> > +// License. See LICENSE.TXT for details.
> > +//
> >
> +//===----------------------------------------------------------------------===//
> > +//
> > +// Reduce conditional branches in CFG.
> > +//
> >
> +//===----------------------------------------------------------------------===//
> > +
> > +#define DEBUG_TYPE "flattencfg"
> > +#include "llvm/Transforms/Utils/Local.h"
> > +#include "llvm/ADT/SmallPtrSet.h"
> > +#include "llvm/Analysis/AliasAnalysis.h"
> > +#include "llvm/Analysis/ValueTracking.h"
> > +#include "llvm/IR/IRBuilder.h"
> > +#include "llvm/Support/Debug.h"
> > +#include "llvm/Transforms/Utils/BasicBlockUtils.h"
> > +using namespace llvm;
> > +
> > +namespace {
> > +class FlattenCFGOpt {
> > + AliasAnalysis *AA;
> > + /// \brief Use parallel-and or parallel-or to generate conditions for
> > + /// conditional branches.
> > + bool FlattenParallelAndOr(BasicBlock *BB, IRBuilder<> &Builder, Pass
> *P = 0);
> > + /// \brief If \param BB is the merge block of an if-region, attempt
> to merge
> > + /// the if-region with an adjacent if-region upstream if two
> if-regions
> > + /// contain identical instructions.
> > + bool MergeIfRegion(BasicBlock *BB, IRBuilder<> &Builder, Pass *P = 0);
> > + /// \brief Compare a pair of blocks: \p Block1 and \p Block2, which
> > + /// are from two if-regions whose entry blocks are \p Head1 and \p
> > + /// Head2. \returns true if \p Block1 and \p Block2 contain identical
> > + /// instructions, and have no memory reference alias with \p Head2.
> > + /// This is used as a legality check for merging if-regions.
> > + bool CompareIfRegionBlock(BasicBlock *Head1, BasicBlock *Head2,
> > + BasicBlock *Block1, BasicBlock *Block2);
> > +
> > +public:
> > + FlattenCFGOpt(AliasAnalysis *AA) : AA(AA) {}
> > + bool run(BasicBlock *BB);
> > +};
> > +}
> > +
> > +/// If \param [in] BB has more than one predecessor that is a
> conditional
> > +/// branch, attempt to use parallel and/or for the branch condition.
> \returns
> > +/// true on success.
> > +///
> > +/// Before:
> > +/// ......
> > +/// %cmp10 = fcmp une float %tmp1, %tmp2
> > +/// br i1 %cmp1, label %if.then, label %lor.rhs
> > +///
> > +/// lor.rhs:
> > +/// ......
> > +/// %cmp11 = fcmp une float %tmp3, %tmp4
> > +/// br i1 %cmp11, label %if.then, label %ifend
> > +///
> > +/// if.end: // the merge block
> > +/// ......
> > +///
> > +/// if.then: // has two predecessors, both of them contains conditional
> branch.
> > +/// ......
> > +/// br label %if.end;
> > +///
> > +/// After:
> > +/// ......
> > +/// %cmp10 = fcmp une float %tmp1, %tmp2
> > +/// ......
> > +/// %cmp11 = fcmp une float %tmp3, %tmp4
> > +/// %cmp12 = or i1 %cmp10, %cmp11 // parallel-or mode.
> > +/// br i1 %cmp12, label %if.then, label %ifend
> > +///
> > +/// if.end:
> > +/// ......
> > +///
> > +/// if.then:
> > +/// ......
> > +/// br label %if.end;
> > +///
> > +/// Current implementation handles two cases.
> > +/// Case 1: \param BB is on the else-path.
> > +///
> > +/// BB1
> > +/// / |
> > +/// BB2 |
> > +/// / \ |
> > +/// BB3 \ | where, BB1, BB2 contain conditional branches.
> > +/// \ | / BB3 contains unconditional branch.
> > +/// \ | / BB4 corresponds to \param BB which is also the
> merge.
> > +/// BB => BB4
> > +///
> > +///
> > +/// Corresponding source code:
> > +///
> > +/// if (a == b && c == d)
> > +/// statement; // BB3
> > +///
> > +/// Case 2: \param BB BB is on the then-path.
> > +///
> > +/// BB1
> > +/// / |
> > +/// | BB2
> > +/// \ / | where BB1, BB2 contain conditional branches.
> > +/// BB => BB3 | BB3 contains unconditiona branch and
> corresponds
> > +/// \ / to \param BB. BB4 is the merge.
> > +/// BB4
> > +///
> > +/// Corresponding source code:
> > +///
> > +/// if (a == b || c == d)
> > +/// statement; // BB3
> > +///
> > +/// In both cases, \param BB is the common successor of conditional
> branches.
> > +/// In Case 1, \param BB (BB4) has an unconditional branch (BB3) as
> > +/// its predecessor. In Case 2, \param BB (BB3) only has conditional
> branches
> > +/// as its predecessors.
> > +///
> > +bool FlattenCFGOpt::FlattenParallelAndOr(BasicBlock *BB, IRBuilder<>
> &Builder,
> > + Pass *P) {
> > + PHINode *PHI = dyn_cast<PHINode>(BB->begin());
> > + if (PHI)
> > + return false; // For simplicity, avoid cases containing PHI nodes.
> > +
> > + BasicBlock *LastCondBlock = NULL;
> > + BasicBlock *FirstCondBlock = NULL;
> > + BasicBlock *UnCondBlock = NULL;
> > + int Idx = -1;
> > +
> > + // Check predecessors of \param BB.
> > + SmallPtrSet<BasicBlock *, 16> Preds(pred_begin(BB), pred_end(BB));
> > + for (SmallPtrSetIterator<BasicBlock *> PI = Preds.begin(), PE =
> Preds.end();
> > + PI != PE; ++PI) {
> > + BasicBlock *Pred = *PI;
> > + BranchInst *PBI = dyn_cast<BranchInst>(Pred->getTerminator());
> > +
> > + // All predecessors should terminate with a branch.
> > + if (!PBI)
> > + return false;
> > +
> > + BasicBlock *PP = Pred->getSinglePredecessor();
> > +
> > + if (PBI->isUnconditional()) {
> > + // Case 1: Pred (BB3) is an unconditional block, it should
> > + // have a single predecessor (BB2) that is also a predecessor
> > + // of \param BB (BB4) and should not have address-taken.
> > + // There should exist only one such unconditional
> > + // branch among the predecessors.
> > + if (UnCondBlock || !PP || (Preds.count(PP) == 0) ||
> > + Pred->hasAddressTaken())
> > + return false;
> > +
> > + UnCondBlock = Pred;
> > + continue;
> > + }
> > +
> > + // Only conditional branches are allowed beyond this point.
> > + assert(PBI->isConditional());
> > +
> > + // Condition's unique use should be the branch instruction.
> > + Value *PC = PBI->getCondition();
> > + if (!PC || !PC->hasOneUse())
> > + return false;
> > +
> > + if (PP && Preds.count(PP)) {
> > + // These are internal condition blocks to be merged from, e.g.,
> > + // BB2 in both cases.
> > + // Should not be address-taken.
> > + if (Pred->hasAddressTaken())
> > + return false;
> > +
> > + // Instructions in the internal condition blocks should be safe
> > + // to hoist up.
> > + for (BasicBlock::iterator BI = Pred->begin(), BE = PBI; BI !=
> BE;) {
> > + Instruction *CI = BI++;
> > + if (isa<PHINode>(CI) || !isSafeToSpeculativelyExecute(CI))
> > + return false;
> > + }
> > + } else {
> > + // This is the condition block to be merged into, e.g. BB1 in
> > + // both cases.
> > + if (FirstCondBlock)
> > + return false;
> > + FirstCondBlock = Pred;
> > + }
> > +
> > + // Find whether BB is uniformly on the true (or false) path
> > + // for all of its predecessors.
> > + BasicBlock *PS1 = PBI->getSuccessor(0);
> > + BasicBlock *PS2 = PBI->getSuccessor(1);
> > + BasicBlock *PS = (PS1 == BB) ? PS2 : PS1;
> > + int CIdx = (PS1 == BB) ? 0 : 1;
> > +
> > + if (Idx == -1)
> > + Idx = CIdx;
> > + else if (CIdx != Idx)
> > + return false;
> > +
> > + // PS is the successor which is not BB. Check successors to identify
> > + // the last conditional branch.
> > + if (Preds.count(PS) == 0) {
> > + // Case 2.
> > + LastCondBlock = Pred;
> > + } else {
> > + // Case 1
> > + BranchInst *BPS = dyn_cast<BranchInst>(PS->getTerminator());
> > + if (BPS && BPS->isUnconditional()) {
> > + // Case 1: PS(BB3) should be an unconditional branch.
> > + LastCondBlock = Pred;
> > + }
> > + }
> > + }
> > +
> > + if (!FirstCondBlock || !LastCondBlock || (FirstCondBlock ==
> LastCondBlock))
> > + return false;
> > +
> > + TerminatorInst *TBB = LastCondBlock->getTerminator();
> > + BasicBlock *PS1 = TBB->getSuccessor(0);
> > + BasicBlock *PS2 = TBB->getSuccessor(1);
> > + BranchInst *PBI1 = dyn_cast<BranchInst>(PS1->getTerminator());
> > + BranchInst *PBI2 = dyn_cast<BranchInst>(PS2->getTerminator());
> > +
> > + // If PS1 does not jump into PS2, but PS2 jumps into PS1,
> > + // attempt branch inversion.
> > + if (!PBI1 || !PBI1->isUnconditional() ||
> > + (PS1->getTerminator()->getSuccessor(0) != PS2)) {
> > + // Check whether PS2 jumps into PS1.
> > + if (!PBI2 || !PBI2->isUnconditional() ||
> > + (PS2->getTerminator()->getSuccessor(0) != PS1))
> > + return false;
> > +
> > + // Do branch inversion.
> > + BasicBlock *CurrBlock = LastCondBlock;
> > + bool EverChanged = false;
> > + while (1) {
> > + BranchInst *BI = dyn_cast<BranchInst>(CurrBlock->getTerminator());
> > + CmpInst *CI = dyn_cast<CmpInst>(BI->getCondition());
> > + CmpInst::Predicate Predicate = CI->getPredicate();
> > + // Cannonicalize icmp_ne -> icmp_eq, fcmp_one -> fcmp_oeq
> > + if ((Predicate == CmpInst::ICMP_NE) || (Predicate ==
> CmpInst::FCMP_ONE)) {
> > + CI->setPredicate(ICmpInst::getInversePredicate(Predicate));
> > + BI->swapSuccessors();
> > + EverChanged = true;
> > + }
> > + if (CurrBlock == FirstCondBlock)
> > + break;
> > + CurrBlock = CurrBlock->getSinglePredecessor();
> > + }
> > + return EverChanged;
> > + }
> > +
> > + // PS1 must have a conditional branch.
> > + if (!PBI1 || !PBI1->isUnconditional())
> > + return false;
> > +
> > + // PS2 should not contain PHI node.
> > + PHI = dyn_cast<PHINode>(PS2->begin());
> > + if (PHI)
> > + return false;
> > +
> > + // Do the transformation.
> > + BasicBlock *CB;
> > + BranchInst *PBI =
> dyn_cast<BranchInst>(FirstCondBlock->getTerminator());
> > + bool Iteration = true;
> > + BasicBlock *SaveInsertBB = Builder.GetInsertBlock();
> > + BasicBlock::iterator SaveInsertPt = Builder.GetInsertPoint();
> > + Value *PC = PBI->getCondition();
> > +
> > + do {
> > + CB = PBI->getSuccessor(1 - Idx);
> > + // Delete the conditional branch.
> > + FirstCondBlock->getInstList().pop_back();
> > + FirstCondBlock->getInstList()
> > + .splice(FirstCondBlock->end(), CB->getInstList());
> > + PBI = cast<BranchInst>(FirstCondBlock->getTerminator());
> > + Value *CC = PBI->getCondition();
> > + // Merge conditions.
> > + Builder.SetInsertPoint(PBI);
> > + Value *NC;
> > + if (Idx == 0)
> > + // Case 2, use parallel or.
> > + NC = Builder.CreateOr(PC, CC);
> > + else
> > + // Case 1, use parallel and.
> > + NC = Builder.CreateAnd(PC, CC);
> > +
> > + PBI->replaceUsesOfWith(CC, NC);
> > + PC = NC;
> > + if (CB == LastCondBlock)
> > + Iteration = false;
> > + // Remove internal conditional branches.
> > + CB->dropAllReferences();
> > + // make CB unreachable and let downstream to delete the block.
> > + new UnreachableInst(CB->getContext(), CB);
> > + } while (Iteration);
> > +
> > + Builder.SetInsertPoint(SaveInsertBB, SaveInsertPt);
> > + DEBUG(dbgs() << "Use parallel and/or in:\n" << *FirstCondBlock);
> > + return true;
> > +}
> > +
> > +/// Compare blocks from two if-regions, where \param Head1 is the entry
> of the
> > +/// 1st if-region. \param Head2 is the entry of the 2nd if-region.
> \param
> > +/// Block1 is a block in the 1st if-region to compare. \param Block2 is
> a block
> > +// in the 2nd if-region to compare. \returns true if \param Block1
> and \param
> > +/// Block2 have identical instructions and do not have memory reference
> alias
> > +/// with \param Head2.
> > +///
> > +bool FlattenCFGOpt::CompareIfRegionBlock(BasicBlock *Head1, BasicBlock
> *Head2,
> > + BasicBlock *Block1,
> > + BasicBlock *Block2) {
> > + TerminatorInst *PTI2 = Head2->getTerminator();
> > + Instruction *PBI2 = Head2->begin();
> > +
> > + bool eq1 = (Block1 == Head1);
> > + bool eq2 = (Block2 == Head2);
> > + if (eq1 || eq2) {
> > + // An empty then-path or else-path.
> > + return (eq1 == eq2);
> > + }
> > +
> > + // Check whether instructions in Block1 and Block2 are identical
> > + // and do not alias with instructions in Head2.
> > + BasicBlock::iterator iter1 = Block1->begin();
> > + BasicBlock::iterator end1 = Block1->getTerminator();
> > + BasicBlock::iterator iter2 = Block2->begin();
> > + BasicBlock::iterator end2 = Block2->getTerminator();
> > +
> > + while (1) {
> > + if (iter1 == end1) {
> > + if (iter2 != end2)
> > + return false;
> > + break;
> > + }
> > +
> > + if (!iter1->isIdenticalTo(iter2))
> > + return false;
> > +
> > + // Illegal to remove instructions with side effects except
> > + // non-volatile stores.
> > + if (iter1->mayHaveSideEffects()) {
> > + Instruction *CurI = &*iter1;
> > + StoreInst *SI = dyn_cast<StoreInst>(CurI);
> > + if (!SI || SI->isVolatile())
> > + return false;
> > + }
> > +
> > + // For simplicity and speed, data dependency check can be
> > + // avoided if read from memory doesn't exist.
> > + if (iter1->mayReadFromMemory())
> > + return false;
> > +
> > + if (iter1->mayWriteToMemory()) {
> > + for (BasicBlock::iterator BI = PBI2, BE = PTI2; BI != BE; ++BI) {
> > + if (BI->mayReadFromMemory() || BI->mayWriteToMemory()) {
> > + // Check alias with Head2.
> > + if (!AA || AA->alias(iter1, BI))
> > + return false;
> > + }
> > + }
> > + }
> > + ++iter1;
> > + ++iter2;
> > + }
> > +
> > + return true;
> > +}
> > +
> > +/// Check whether \param BB is the merge block of a if-region. If yes,
> check
> > +/// whether there exists an adjacent if-region upstream, the two
> if-regions
> > +/// contain identical instuctions and can be legally merged. \returns
> true if
> > +/// the two if-regions are merged.
> > +///
> > +/// From:
> > +/// if (a)
> > +/// statement;
> > +/// if (b)
> > +/// statement;
> > +///
> > +/// To:
> > +/// if (a || b)
> > +/// statement;
> > +///
> > +bool FlattenCFGOpt::MergeIfRegion(BasicBlock *BB, IRBuilder<> &Builder,
> > + Pass *P) {
> > + BasicBlock *IfTrue2, *IfFalse2;
> > + Value *IfCond2 = GetIfCondition(BB, IfTrue2, IfFalse2);
> > + Instruction *CInst2 = dyn_cast_or_null<Instruction>(IfCond2);
> > + if (!CInst2)
> > + return false;
> > +
> > + BasicBlock *SecondEntryBlock = CInst2->getParent();
> > + if (SecondEntryBlock->hasAddressTaken())
> > + return false;
> > +
> > + BasicBlock *IfTrue1, *IfFalse1;
> > + Value *IfCond1 = GetIfCondition(SecondEntryBlock, IfTrue1, IfFalse1);
> > + Instruction *CInst1 = dyn_cast_or_null<Instruction>(IfCond1);
> > + if (!CInst1)
> > + return false;
> > +
> > + BasicBlock *FirstEntryBlock = CInst1->getParent();
> > +
> > + // Either then-path or else-path should be empty.
> > + if ((IfTrue1 != FirstEntryBlock) && (IfFalse1 != FirstEntryBlock))
> > + return false;
> > + if ((IfTrue2 != SecondEntryBlock) && (IfFalse2 != SecondEntryBlock))
> > + return false;
> > +
> > + TerminatorInst *PTI2 = SecondEntryBlock->getTerminator();
> > + Instruction *PBI2 = SecondEntryBlock->begin();
> > +
> > + if (!CompareIfRegionBlock(FirstEntryBlock, SecondEntryBlock, IfTrue1,
> > + IfTrue2))
> > + return false;
> > +
> > + if (!CompareIfRegionBlock(FirstEntryBlock, SecondEntryBlock, IfFalse1,
> > + IfFalse2))
> > + return false;
> > +
> > + // Check whether \param SecondEntryBlock has side-effect and is safe
> to
> > + // speculate.
> > + for (BasicBlock::iterator BI = PBI2, BE = PTI2; BI != BE; ++BI) {
> > + Instruction *CI = BI;
> > + if (isa<PHINode>(CI) || CI->mayHaveSideEffects() ||
> > + !isSafeToSpeculativelyExecute(CI))
> > + return false;
> > + }
> > +
> > + // Merge \param SecondEntryBlock into \param FirstEntryBlock.
> > + FirstEntryBlock->getInstList().pop_back();
> > + FirstEntryBlock->getInstList()
> > + .splice(FirstEntryBlock->end(), SecondEntryBlock->getInstList());
> > + BranchInst *PBI =
> dyn_cast<BranchInst>(FirstEntryBlock->getTerminator());
> > + Value *CC = PBI->getCondition();
> > + BasicBlock *SaveInsertBB = Builder.GetInsertBlock();
> > + BasicBlock::iterator SaveInsertPt = Builder.GetInsertPoint();
> > + Builder.SetInsertPoint(PBI);
> > + Value *NC = Builder.CreateOr(CInst1, CC);
> > + PBI->replaceUsesOfWith(CC, NC);
> > + Builder.SetInsertPoint(SaveInsertBB, SaveInsertPt);
> > +
> > + // Remove IfTrue1
> > + if (IfTrue1 != FirstEntryBlock) {
> > + IfTrue1->dropAllReferences();
> > + IfTrue1->eraseFromParent();
> > + }
> > +
> > + // Remove IfFalse1
> > + if (IfFalse1 != FirstEntryBlock) {
> > + IfFalse1->dropAllReferences();
> > + IfFalse1->eraseFromParent();
> > + }
> > +
> > + // Remove \param SecondEntryBlock
> > + SecondEntryBlock->dropAllReferences();
> > + SecondEntryBlock->eraseFromParent();
> > + DEBUG(dbgs() << "If conditions merged into:\n" << *FirstEntryBlock);
> > + return true;
> > +}
> > +
> > +bool FlattenCFGOpt::run(BasicBlock *BB) {
> > + bool Changed = false;
> > + assert(BB && BB->getParent() && "Block not embedded in function!");
> > + assert(BB->getTerminator() && "Degenerate basic block encountered!");
> > +
> > + IRBuilder<> Builder(BB);
> > +
> > + if (FlattenParallelAndOr(BB, Builder))
> > + return true;
> > +
> > + if (MergeIfRegion(BB, Builder))
> > + return true;
> > +
> > + return Changed;
> > +}
> > +
> > +/// FlattenCFG - This function is used to flatten a CFG. For
> > +/// example, it uses parallel-and and parallel-or mode to collapse
> > +// if-conditions and merge if-regions with identical statements.
> > +///
> > +bool llvm::FlattenCFG(BasicBlock *BB, AliasAnalysis *AA) {
> > + return FlattenCFGOpt(AA).run(BB);
> > +}
> >
> > Modified: llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp?rev=187764&r1=187763&r2=187764&view=diff
> >
> ==============================================================================
> > --- llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp (original)
> > +++ llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp Mon Aug 5 21:43:45
> 2013
> > @@ -19,7 +19,6 @@
> > #include "llvm/ADT/SmallPtrSet.h"
> > #include "llvm/ADT/SmallVector.h"
> > #include "llvm/ADT/Statistic.h"
> > -#include "llvm/Analysis/AliasAnalysis.h"
> > #include "llvm/Analysis/InstructionSimplify.h"
> > #include "llvm/Analysis/TargetTransformInfo.h"
> > #include "llvm/Analysis/ValueTracking.h"
> > @@ -66,10 +65,6 @@ static cl::opt<bool>
> > HoistCondStores("simplifycfg-hoist-cond-stores", cl::Hidden,
> cl::init(true),
> > cl::desc("Hoist conditional stores if an unconditional store
> preceeds"));
> >
> > -static cl::opt<bool>
> > -ParallelAndOr("simplifycfg-parallel-and-or", cl::Hidden, cl::init(true),
> > - cl::desc("Use parallel-and-or mode for branch
> conditions"));
> > -
> > STATISTIC(NumBitMaps, "Number of switch instructions turned into
> bitmaps");
> > STATISTIC(NumLookupTables, "Number of switch instructions turned into
> lookup tables");
> > STATISTIC(NumSinkCommons, "Number of common instructions sunk down to
> the end block");
> > @@ -95,8 +90,6 @@ namespace {
> > class SimplifyCFGOpt {
> > const TargetTransformInfo &TTI;
> > const DataLayout *const TD;
> > - AliasAnalysis *AA;
> > -
> > Value *isValueEqualityComparison(TerminatorInst *TI);
> > BasicBlock *GetValueEqualityComparisonCases(TerminatorInst *TI,
> > std::vector<ValueEqualityComparisonCase>
> &Cases);
> > @@ -113,25 +106,10 @@ class SimplifyCFGOpt {
> > bool SimplifyIndirectBr(IndirectBrInst *IBI);
> > bool SimplifyUncondBranch(BranchInst *BI, IRBuilder <> &Builder);
> > bool SimplifyCondBranch(BranchInst *BI, IRBuilder <>&Builder);
> > - /// \brief Use parallel-and or parallel-or to generate conditions for
> > - /// conditional branches.
> > - bool SimplifyParallelAndOr(BasicBlock *BB, IRBuilder<> &Builder, Pass
> *P = 0);
> > - /// \brief If \param BB is the merge block of an if-region, attempt
> to merge
> > - /// the if-region with an adjacent if-region upstream if two
> if-regions
> > - /// contain identical instructions.
> > - bool MergeIfRegion(BasicBlock *BB, IRBuilder<> &Builder, Pass *P = 0);
> > - /// \brief Compare a pair of blocks: \p Block1 and \p Block2, which
> > - /// are from two if-regions whose entry blocks are \p Head1 and \p
> > - /// Head2. \returns true if \p Block1 and \p Block2 contain identical
> > - /// instructions, and have no memory reference alias with \p Head2.
> > - /// This is used as a legality check for merging if-regions.
> > - bool CompareIfRegionBlock(BasicBlock *Head1, BasicBlock *Head2,
> > - BasicBlock *Block1, BasicBlock *Block2);
> >
> > public:
> > - SimplifyCFGOpt(const TargetTransformInfo &TTI, const DataLayout *TD,
> > - AliasAnalysis *AA)
> > - : TTI(TTI), TD(TD), AA(AA) {}
> > + SimplifyCFGOpt(const TargetTransformInfo &TTI, const DataLayout *TD)
> > + : TTI(TTI), TD(TD) {}
> > bool run(BasicBlock *BB);
> > };
> > }
> > @@ -217,108 +195,6 @@ static void AddPredecessorToBlock(BasicB
> > PN->addIncoming(PN->getIncomingValueForBlock(ExistPred), NewPred);
> > }
> >
> > -
> > -/// GetIfCondition - Given a basic block (BB) with two predecessors,
> > -/// check to see if the merge at this block is due
> > -/// to an "if condition". If so, return the boolean condition that
> determines
> > -/// which entry into BB will be taken. Also, return by references the
> block
> > -/// that will be entered from if the condition is true, and the block
> that will
> > -/// be entered if the condition is false.
> > -///
> > -/// This does no checking to see if the true/false blocks have large or
> unsavory
> > -/// instructions in them.
> > -static Value *GetIfCondition(BasicBlock *BB, BasicBlock *&IfTrue,
> > - BasicBlock *&IfFalse) {
> > - PHINode *SomePHI = dyn_cast<PHINode>(BB->begin());
> > - BasicBlock *Pred1 = NULL;
> > - BasicBlock *Pred2 = NULL;
> > -
> > - if (SomePHI) {
> > - if (SomePHI->getNumIncomingValues() != 2)
> > - return NULL;
> > - Pred1 = SomePHI->getIncomingBlock(0);
> > - Pred2 = SomePHI->getIncomingBlock(1);
> > - } else {
> > - pred_iterator PI = pred_begin(BB), PE = pred_end(BB);
> > - if (PI == PE) // No predecessor
> > - return NULL;
> > - Pred1 = *PI++;
> > - if (PI == PE) // Only one predecessor
> > - return NULL;
> > - Pred2 = *PI++;
> > - if (PI != PE) // More than two predecessors
> > - return NULL;
> > - }
> > -
> > - // We can only handle branches. Other control flow will be lowered to
> > - // branches if possible anyway.
> > - BranchInst *Pred1Br = dyn_cast<BranchInst>(Pred1->getTerminator());
> > - BranchInst *Pred2Br = dyn_cast<BranchInst>(Pred2->getTerminator());
> > - if (Pred1Br == 0 || Pred2Br == 0)
> > - return 0;
> > -
> > - // Eliminate code duplication by ensuring that Pred1Br is conditional
> if
> > - // either are.
> > - if (Pred2Br->isConditional()) {
> > - // If both branches are conditional, we don't have an "if
> statement". In
> > - // reality, we could transform this case, but since the condition
> will be
> > - // required anyway, we stand no chance of eliminating it, so the
> xform is
> > - // probably not profitable.
> > - if (Pred1Br->isConditional())
> > - return 0;
> > -
> > - std::swap(Pred1, Pred2);
> > - std::swap(Pred1Br, Pred2Br);
> > - }
> > -
> > - if (Pred1Br->isConditional()) {
> > - // The only thing we have to watch out for here is to make sure
> that Pred2
> > - // doesn't have incoming edges from other blocks. If it does, the
> condition
> > - // doesn't dominate BB.
> > - if (Pred2->getSinglePredecessor() == 0)
> > - return 0;
> > -
> > - // If we found a conditional branch predecessor, make sure that it
> branches
> > - // to BB and Pred2Br. If it doesn't, this isn't an "if statement".
> > - if (Pred1Br->getSuccessor(0) == BB &&
> > - Pred1Br->getSuccessor(1) == Pred2) {
> > - IfTrue = Pred1;
> > - IfFalse = Pred2;
> > - } else if (Pred1Br->getSuccessor(0) == Pred2 &&
> > - Pred1Br->getSuccessor(1) == BB) {
> > - IfTrue = Pred2;
> > - IfFalse = Pred1;
> > - } else {
> > - // We know that one arm of the conditional goes to BB, so the
> other must
> > - // go somewhere unrelated, and this must not be an "if statement".
> > - return 0;
> > - }
> > -
> > - return Pred1Br->getCondition();
> > - }
> > -
> > - // Ok, if we got here, both predecessors end with an unconditional
> branch to
> > - // BB. Don't panic! If both blocks only have a single (identical)
> > - // predecessor, and THAT is a conditional branch, then we're all ok!
> > - BasicBlock *CommonPred = Pred1->getSinglePredecessor();
> > - if (CommonPred == 0 || CommonPred != Pred2->getSinglePredecessor())
> > - return 0;
> > -
> > - // Otherwise, if this is a conditional branch, then we can use it!
> > - BranchInst *BI = dyn_cast<BranchInst>(CommonPred->getTerminator());
> > - if (BI == 0) return 0;
> > -
> > - assert(BI->isConditional() && "Two successors but not conditional?");
> > - if (BI->getSuccessor(0) == Pred1) {
> > - IfTrue = Pred1;
> > - IfFalse = Pred2;
> > - } else {
> > - IfTrue = Pred2;
> > - IfFalse = Pred1;
> > - }
> > - return BI->getCondition();
> > -}
> > -
> > /// ComputeSpeculationCost - Compute an abstract "cost" of speculating
> the
> > /// given instruction, which is assumed to be safe to speculate. 1 means
> > /// cheap, 2 means less cheap, and UINT_MAX means prohibitively
> expensive.
> > @@ -4102,386 +3978,6 @@ bool SimplifyCFGOpt::SimplifyCondBranch(
> > return false;
> > }
> >
> > -/// If \param [in] BB has more than one predecessor that is a
> conditional
> > -/// branch, attempt to use parallel and/or for the branch condition.
> \returns
> > -/// true on success.
> > -///
> > -/// Before:
> > -/// ......
> > -/// %cmp10 = fcmp une float %tmp1, %tmp2
> > -/// br i1 %cmp1, label %if.then, label %lor.rhs
> > -///
> > -/// lor.rhs:
> > -/// ......
> > -/// %cmp11 = fcmp une float %tmp3, %tmp4
> > -/// br i1 %cmp11, label %if.then, label %ifend
> > -///
> > -/// if.end: // the merge block
> > -/// ......
> > -///
> > -/// if.then: // has two predecessors, both of them contains conditional
> branch.
> > -/// ......
> > -/// br label %if.end;
> > -///
> > -/// After:
> > -/// ......
> > -/// %cmp10 = fcmp une float %tmp1, %tmp2
> > -/// ......
> > -/// %cmp11 = fcmp une float %tmp3, %tmp4
> > -/// %cmp12 = or i1 %cmp10, %cmp11 // parallel-or mode.
> > -/// br i1 %cmp12, label %if.then, label %ifend
> > -///
> > -/// if.end:
> > -/// ......
> > -///
> > -/// if.then:
> > -/// ......
> > -/// br label %if.end;
> > -///
> > -/// Current implementation handles two cases.
> > -/// Case 1: \param BB is on the else-path.
> > -///
> > -/// BB1
> > -/// / |
> > -/// BB2 |
> > -/// / \ |
> > -/// BB3 \ | where, BB1, BB2 contain conditional branches.
> > -/// \ | / BB3 contains unconditional branch.
> > -/// \ | / BB4 corresponds to \param BB which is also the
> merge.
> > -/// BB => BB4
> > -///
> > -///
> > -/// Corresponding source code:
> > -///
> > -/// if (a == b && c == d)
> > -/// statement; // BB3
> > -///
> > -/// Case 2: \param BB BB is on the then-path.
> > -///
> > -/// BB1
> > -/// / |
> > -/// | BB2
> > -/// \ / | where BB1, BB2 contain conditional branches.
> > -/// BB => BB3 | BB3 contains unconditiona branch and
> corresponds
> > -/// \ / to \param BB. BB4 is the merge.
> > -/// BB4
> > -///
> > -/// Corresponding source code:
> > -///
> > -/// if (a == b || c == d)
> > -/// statement; // BB3
> > -///
> > -/// In both cases, \param BB is the common successor of conditional
> branches.
> > -/// In Case 1, \param BB (BB4) has an unconditional branch (BB3) as
> > -/// its predecessor. In Case 2, \param BB (BB3) only has conditional
> branches
> > -/// as its predecessors.
> > -///
> > -bool SimplifyCFGOpt::SimplifyParallelAndOr(BasicBlock *BB, IRBuilder<>
> &Builder,
> > - Pass *P) {
> > - PHINode *PHI = dyn_cast<PHINode>(BB->begin());
> > - if (PHI)
> > - return false; // For simplicity, avoid cases containing PHI nodes.
> > -
> > - BasicBlock *LastCondBlock = NULL;
> > - BasicBlock *FirstCondBlock = NULL;
> > - BasicBlock *UnCondBlock = NULL;
> > - int Idx = -1;
> > -
> > - // Check predecessors of \param BB.
> > - SmallPtrSet<BasicBlock*, 16> Preds(pred_begin(BB), pred_end(BB));
> > - for (SmallPtrSetIterator<BasicBlock*> PI = Preds.begin(), PE =
> Preds.end();
> > - PI != PE; ++PI) {
> > - BasicBlock *Pred = *PI;
> > - BranchInst *PBI = dyn_cast<BranchInst>(Pred->getTerminator());
> > -
> > - // All predecessors should terminate with a branch.
> > - if (!PBI)
> > - return false;
> > -
> > - BasicBlock *PP = Pred->getSinglePredecessor();
> > -
> > - if (PBI->isUnconditional()) {
> > - // Case 1: Pred (BB3) is an unconditional block, it should
> > - // have a single predecessor (BB2) that is also a predecessor
> > - // of \param BB (BB4) and should not have address-taken.
> > - // There should exist only one such unconditional
> > - // branch among the predecessors.
> > - if (UnCondBlock || !PP || (Preds.count(PP) == 0) ||
> > - Pred->hasAddressTaken())
> > - return false;
> > -
> > - UnCondBlock = Pred;
> > - continue;
> > - }
> > -
> > - // Only conditional branches are allowed beyond this point.
> > - assert(PBI->isConditional());
> > -
> > - // Condition's unique use should be the branch instruction.
> > - Value *PC = PBI->getCondition();
> > - if (!PC || !PC->hasOneUse())
> > - return false;
> > -
> > - if (PP && Preds.count(PP)) {
> > - // These are internal condition blocks to be merged from, e.g.,
> > - // BB2 in both cases.
> > - // Should not be address-taken.
> > - if (Pred->hasAddressTaken())
> > - return false;
> > -
> > - // Instructions in the internal condition blocks should be safe
> > - // to hoist up.
> > - for (BasicBlock::iterator BI = Pred->begin(), BE = PBI; BI !=
> BE;) {
> > - Instruction *CI = BI++;
> > - if (isa<PHINode>(CI) ||
> > - !isSafeToSpeculativelyExecute(CI))
> > - return false;
> > - }
> > - } else {
> > - // This is the condition block to be merged into, e.g. BB1 in
> > - // both cases.
> > - if (FirstCondBlock)
> > - return false;
> > - FirstCondBlock = Pred;
> > - }
> > -
> > - // Find whether BB is uniformly on the true (or false) path
> > - // for all of its predecessors.
> > - BasicBlock *PS1 = PBI->getSuccessor(0);
> > - BasicBlock *PS2 = PBI->getSuccessor(1);
> > - BasicBlock *PS = (PS1 == BB) ? PS2 : PS1;
> > - int CIdx = (PS1 == BB) ? 0 : 1;
> > -
> > - if (Idx == -1)
> > - Idx = CIdx;
> > - else if (CIdx != Idx)
> > - return false;
> > -
> > - // PS is the successor which is not BB. Check successors to identify
> > - // the last conditional branch.
> > - if (Preds.count(PS) == 0) {
> > - // Case 2.
> > - // BB must have an unique successor.
> > - TerminatorInst *TBB = BB->getTerminator();
> > - if (TBB->getNumSuccessors() != 1)
> > - return false;
> > -
> > - BasicBlock *SBB = TBB->getSuccessor(0);
> > - PHI = dyn_cast<PHINode>(SBB->begin());
> > - if (PHI)
> > - return false;
> > -
> > - // PS (BB4) should be BB's successor.
> > - if (SBB != PS)
> > - return false;
> > - LastCondBlock = Pred;
> > - } else {
> > - BranchInst *BPS = dyn_cast<BranchInst>(PS->getTerminator());
> > - if (BPS && BPS->isUnconditional()) {
> > - // Case 1: PS(BB3) should be an unconditional branch.
> > - LastCondBlock = Pred;
> > - }
> > - }
> > - }
> > -
> > - if (!FirstCondBlock || !LastCondBlock || (FirstCondBlock ==
> LastCondBlock))
> > - return false;
> > -
> > - // Do the transformation.
> > - BasicBlock *CB;
> > - bool Iteration = true;
> > - BasicBlock *SaveInsertBB = Builder.GetInsertBlock();
> > - BasicBlock::iterator SaveInsertPt = Builder.GetInsertPoint();
> > - BranchInst *PBI =
> dyn_cast<BranchInst>(FirstCondBlock->getTerminator());
> > - Value *PC = PBI->getCondition();
> > - do {
> > - CB = PBI->getSuccessor(1 - Idx);
> > - // Delete the conditional branch.
> > - FirstCondBlock->getInstList().pop_back();
> > - FirstCondBlock->getInstList().splice(FirstCondBlock->end(),
> CB->getInstList());
> > - PBI = cast<BranchInst>(FirstCondBlock->getTerminator());
> > - Value *CC = PBI->getCondition();
> > - // Merge conditions.
> > - Builder.SetInsertPoint(PBI);
> > - Value *NC;
> > - if (Idx == 0)
> > - // Case 2, use parallel or.
> > - NC = Builder.CreateOr(PC, CC);
> > - else
> > - // Case 1, use parallel and.
> > - NC = Builder.CreateAnd(PC, CC);
> > -
> > - PBI->replaceUsesOfWith(CC, NC);
> > - PC = NC;
> > - if (CB == LastCondBlock)
> > - Iteration = false;
> > - // Remove internal conditional branches.
> > - CB->dropAllReferences();
> > - // make CB unreachable and let downstream to delete the block.
> > - new UnreachableInst(CB->getContext(), CB);
> > - } while (Iteration);
> > - if (SaveInsertBB)
> > - Builder.SetInsertPoint(SaveInsertBB, SaveInsertPt);
> > - DEBUG(dbgs() << "Use parallel and/or in:\n" << *FirstCondBlock);
> > - return true;
> > -}
> > -
> > -/// Compare blocks from two if-regions, where \param Head1 is the entry
> of the
> > -/// 1st if-region. \param Head2 is the entry of the 2nd if-region.
> \param
> > -/// Block1 is a block in the 1st if-region to compare. \param Block2 is
> a block
> > -// in the 2nd if-region to compare. \returns true if \param Block1
> and \param
> > -/// Block2 have identical instructions and do not have memory reference
> alias
> > -/// with \param Head2.
> > -///
> > -bool SimplifyCFGOpt::CompareIfRegionBlock(BasicBlock *Head1, BasicBlock
> *Head2,
> > - BasicBlock *Block1,
> BasicBlock *Block2) {
> > - TerminatorInst *PTI2 = Head2->getTerminator();
> > - Instruction *PBI2 = Head2->begin();
> > -
> > - bool eq1 = (Block1 == Head1);
> > - bool eq2 = (Block2 == Head2);
> > - if (eq1 || eq2) {
> > - // An empty then-path or else-path.
> > - return (eq1 == eq2);
> > - }
> > -
> > - // Check whether instructions in Block1 and Block2 are identical
> > - // and do not alias with instructions in Head2.
> > - BasicBlock::iterator iter1 = Block1->begin();
> > - BasicBlock::iterator end1 = Block1->getTerminator();
> > - BasicBlock::iterator iter2 = Block2->begin();
> > - BasicBlock::iterator end2 = Block2->getTerminator();
> > -
> > - while (1) {
> > - if (iter1 == end1) {
> > - if (iter2 != end2)
> > - return false;
> > - break;
> > - }
> > -
> > - if (!iter1->isIdenticalTo(iter2))
> > - return false;
> > -
> > - // Illegal to remove instructions with side effects except
> > - // non-volatile stores.
> > - if (iter1->mayHaveSideEffects()) {
> > - Instruction *CurI = &*iter1;
> > - StoreInst *SI = dyn_cast<StoreInst>(CurI);
> > - if (!SI || SI->isVolatile())
> > - return false;
> > - }
> > -
> > - // For simplicity and speed, data dependency check can be
> > - // avoided if read from memory doesn't exist.
> > - if (iter1->mayReadFromMemory())
> > - return false;
> > -
> > - if (iter1->mayWriteToMemory()) {
> > - for (BasicBlock::iterator BI = PBI2, BE = PTI2; BI != BE; ++BI) {
> > - if (BI->mayReadFromMemory() || BI->mayWriteToMemory()) {
> > - // Check alias with Head2.
> > - if (!AA || AA->alias(iter1, BI))
> > - return false;
> > - }
> > - }
> > - }
> > - ++iter1;
> > - ++iter2;
> > - }
> > -
> > - return true;
> > -}
> > -
> > -/// Check whether \param BB is the merge block of a if-region. If yes,
> check
> > -/// whether there exists an adjacent if-region upstream, the two
> if-regions
> > -/// contain identical instuctions and can be legally merged. \returns
> true if
> > -/// the two if-regions are merged.
> > -///
> > -/// From:
> > -/// if (a)
> > -/// statement;
> > -/// if (b)
> > -/// statement;
> > -///
> > -/// To:
> > -/// if (a || b)
> > -/// statement;
> > -///
> > -bool SimplifyCFGOpt::MergeIfRegion(BasicBlock *BB, IRBuilder<> &Builder,
> > - Pass *P) {
> > - BasicBlock *IfTrue2, *IfFalse2;
> > - Value *IfCond2 = GetIfCondition(BB, IfTrue2, IfFalse2);
> > - Instruction *CInst2 = dyn_cast_or_null<Instruction>(IfCond2);
> > - if (!CInst2)
> > - return false;
> > -
> > - BasicBlock *SecondEntryBlock = CInst2->getParent();
> > - if (SecondEntryBlock->hasAddressTaken())
> > - return false;
> > -
> > - BasicBlock *IfTrue1, *IfFalse1;
> > - Value *IfCond1 = GetIfCondition(SecondEntryBlock, IfTrue1, IfFalse1);
> > - Instruction *CInst1 = dyn_cast_or_null<Instruction>(IfCond1);
> > - if (!CInst1)
> > - return false;
> > -
> > - BasicBlock *FirstEntryBlock = CInst1->getParent();
> > -
> > - // Either then-path or else-path should be empty.
> > - if ((IfTrue1 != FirstEntryBlock) && (IfFalse1 != FirstEntryBlock))
> > - return false;
> > - if ((IfTrue2 != SecondEntryBlock) && (IfFalse2 != SecondEntryBlock))
> > - return false;
> > -
> > - TerminatorInst *PTI2 = SecondEntryBlock->getTerminator();
> > - Instruction *PBI2 = SecondEntryBlock->begin();
> > -
> > - if (!CompareIfRegionBlock(FirstEntryBlock, SecondEntryBlock, IfTrue1,
> IfTrue2))
> > - return false;
> > -
> > - if (!CompareIfRegionBlock(FirstEntryBlock, SecondEntryBlock,
> IfFalse1, IfFalse2))
> > - return false;
> > -
> > - // Check whether \param SecondEntryBlock has side-effect and is safe
> to speculate.
> > - for (BasicBlock::iterator BI = PBI2, BE = PTI2; BI != BE; ++BI) {
> > - Instruction *CI = BI;
> > - if (isa<PHINode>(CI) || CI->mayHaveSideEffects() ||
> > - !isSafeToSpeculativelyExecute(CI))
> > - return false;
> > - }
> > -
> > - // Merge \param SecondEntryBlock into \param FirstEntryBlock.
> > - FirstEntryBlock->getInstList().pop_back();
> > - FirstEntryBlock->getInstList().splice(FirstEntryBlock->end(),
> SecondEntryBlock->getInstList());
> > - BranchInst *PBI =
> dyn_cast<BranchInst>(FirstEntryBlock->getTerminator());
> > - Value *CC = PBI->getCondition();
> > - BasicBlock *SaveInsertBB = Builder.GetInsertBlock();
> > - BasicBlock::iterator SaveInsertPt = Builder.GetInsertPoint();
> > - Builder.SetInsertPoint(PBI);
> > - Value *NC = Builder.CreateOr(CInst1, CC);
> > - PBI->replaceUsesOfWith(CC, NC);
> > - if (SaveInsertBB)
> > - Builder.SetInsertPoint(SaveInsertBB, SaveInsertPt);
> > -
> > - // Remove IfTrue1
> > - if (IfTrue1 != FirstEntryBlock) {
> > - IfTrue1->dropAllReferences();
> > - IfTrue1->eraseFromParent();
> > - }
> > -
> > - // Remove IfFalse1
> > - if (IfFalse1 != FirstEntryBlock) {
> > - IfFalse1->dropAllReferences();
> > - IfFalse1->eraseFromParent();
> > - }
> > -
> > - // Remove \param SecondEntryBlock
> > - SecondEntryBlock->dropAllReferences();
> > - SecondEntryBlock->eraseFromParent();
> > - DEBUG(dbgs() << "If conditions merged into:\n" << *FirstEntryBlock);
> > - return true;
> > -}
> > -
> > /// Check if passing a value to an instruction will cause undefined
> behavior.
> > static bool passingValueIsAlwaysUndefined(Value *V, Instruction *I) {
> > Constant *C = dyn_cast<Constant>(V);
> > @@ -4584,11 +4080,6 @@ bool SimplifyCFGOpt::run(BasicBlock *BB)
> > return true;
> >
> > IRBuilder<> Builder(BB);
> > - // Whether to optimize conditional branches.
> > - bool OptCB = (ParallelAndOr && AA && TTI.hasBranchDivergence());
> > -
> > - if (OptCB && SimplifyParallelAndOr(BB, Builder))
> > - return true;
> >
> > // If there is a trivial two-entry PHI node in this basic block, and
> we can
> > // eliminate it, do so now.
> > @@ -4617,9 +4108,6 @@ bool SimplifyCFGOpt::run(BasicBlock *BB)
> > if (SimplifyIndirectBr(IBI)) return true;
> > }
> >
> > - if (OptCB && MergeIfRegion(BB, Builder))
> > - return true;
> > -
> > return Changed;
> > }
> >
> > @@ -4629,6 +4117,6 @@ bool SimplifyCFGOpt::run(BasicBlock *BB)
> > /// of the CFG. It returns true if a modification was made.
> > ///
> > bool llvm::SimplifyCFG(BasicBlock *BB, const TargetTransformInfo &TTI,
> > - const DataLayout *TD, AliasAnalysis *AA) {
> > - return SimplifyCFGOpt(TTI, TD, AA).run(BB);
> > + const DataLayout *TD) {
> > + return SimplifyCFGOpt(TTI, TD).run(BB);
> > }
> >
> > Copied: llvm/trunk/test/CodeGen/R600/parallelandifcollapse.ll (from
> r187754,
> llvm/trunk/test/Transforms/SimplifyCFG/R600/parallelorifcollapse.ll)
> > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/R600/parallelandifcollapse.ll?p2=llvm/trunk/test/CodeGen/R600/parallelandifcollapse.ll&p1=llvm/trunk/test/Transforms/SimplifyCFG/R600/parallelorifcollapse.ll&r1=187754&r2=187764&rev=187764&view=diff
> >
> ==============================================================================
> > --- llvm/trunk/test/Transforms/SimplifyCFG/R600/parallelorifcollapse.ll
> (original)
> > +++ llvm/trunk/test/CodeGen/R600/parallelandifcollapse.ll Mon Aug 5
> 21:43:45 2013
> > @@ -1,14 +1,12 @@
> > ; Function Attrs: nounwind
> > -; RUN: opt < %s -mtriple=r600-unknown-linux-gnu -optimizecfg -basicaa
> -S | FileCheck %s
> > +; RUN: llc < %s -march=r600 -mcpu=redwood | FileCheck %s
> > ;
> > -; CFG optimization should use parallel-or mode to generate branch
> conditions and
> > -; then merge if-regions with the same bodies, which should result in 2
> branches.
> > -; To see the assembly output without this transformation, remove
> -basicaa option.
> > +; CFG flattening should use parallel-and mode to generate branch
> conditions and
> > +; then merge if-regions with the same bodies.
> > ;
> > -; CHECK: or i1
> > -; CHECK-NEXT: br
> > -; CHECK: br
> > -; CHECK: ret
> > +; CHECK: AND_INT
> > +; CHECK-NEXT: AND_INT
> > +; CHECK-NEXT: OR_INT
> > define void @_Z9chk1D_512v() #0 {
> > entry:
> > %a0 = alloca i32, align 4
> >
> > Copied: llvm/trunk/test/CodeGen/R600/parallelorifcollapse.ll (from
> r187754,
> llvm/trunk/test/Transforms/SimplifyCFG/R600/parallelandifcollapse.ll)
> > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/R600/parallelorifcollapse.ll?p2=llvm/trunk/test/CodeGen/R600/parallelorifcollapse.ll&p1=llvm/trunk/test/Transforms/SimplifyCFG/R600/parallelandifcollapse.ll&r1=187754&r2=187764&rev=187764&view=diff
> >
> ==============================================================================
> > --- llvm/trunk/test/Transforms/SimplifyCFG/R600/parallelandifcollapse.ll
> (original)
> > +++ llvm/trunk/test/CodeGen/R600/parallelorifcollapse.ll Mon Aug 5
> 21:43:45 2013
> > @@ -1,14 +1,12 @@
> > ; Function Attrs: nounwind
> > -; RUN: opt < %s -mtriple=r600-unknown-linux-gnu -optimizecfg -basicaa
> -S | FileCheck %s
> > +; RUN: llc < %s -march=r600 -mcpu=redwood | FileCheck %s
> > ;
> > -; CFG optimization should use parallel-and mode to generate branch
> conditions and
> > -; then merge if-regions with the same bodies, which should result in 2
> branches.
> > -; To see the assembly output without this transformation, remove
> -basicaa option.
> > -;
> > -; CHECK: or i1
> > -; CHECK-NEXT: br
> > -; CHECK: br
> > -; CHECK: ret
> > +; CFG flattening should use parallel-or to generate branch conditions
> and
> > +; then merge if-regions with the same bodies.
> > +;
> > +; CHECK: OR_INT
> > +; CHECK-NEXT: OR_INT
> > +; CHECK-NEXT: OR_INT
> > define void @_Z9chk1D_512v() #0 {
> > entry:
> > %a0 = alloca i32, align 4
> >
> > Modified: llvm/trunk/test/Transforms/SimplifyCFG/R600/lit.local.cfg
> > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/SimplifyCFG/R600/lit.local.cfg?rev=187764&r1=187763&r2=187764&view=diff
> >
> ==============================================================================
> > --- llvm/trunk/test/Transforms/SimplifyCFG/R600/lit.local.cfg (original)
> > +++ llvm/trunk/test/Transforms/SimplifyCFG/R600/lit.local.cfg Mon Aug 5
> 21:43:45 2013
> > @@ -1,6 +0,0 @@
> > -config.suffixes = ['.ll', '.c', '.cpp']
> > -
> > -targets = set(config.root.targets_to_build.split())
> > -if not 'R600' in targets:
> > - config.unsupported = True
> > -
> >
> > Modified:
> llvm/trunk/test/Transforms/SimplifyCFG/R600/parallelandifcollapse.ll
> > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/SimplifyCFG/R600/parallelandifcollapse.ll?rev=187764&r1=187763&r2=187764&view=diff
> >
> ==============================================================================
> > --- llvm/trunk/test/Transforms/SimplifyCFG/R600/parallelandifcollapse.ll
> (original)
> > +++ llvm/trunk/test/Transforms/SimplifyCFG/R600/parallelandifcollapse.ll
> Mon Aug 5 21:43:45 2013
> > @@ -1,63 +0,0 @@
> > -; Function Attrs: nounwind
> > -; RUN: opt < %s -mtriple=r600-unknown-linux-gnu -optimizecfg -basicaa
> -S | FileCheck %s
> > -;
> > -; CFG optimization should use parallel-and mode to generate branch
> conditions and
> > -; then merge if-regions with the same bodies, which should result in 2
> branches.
> > -; To see the assembly output without this transformation, remove
> -basicaa option.
> > -;
> > -; CHECK: or i1
> > -; CHECK-NEXT: br
> > -; CHECK: br
> > -; CHECK: ret
> > -define void @_Z9chk1D_512v() #0 {
> > -entry:
> > - %a0 = alloca i32, align 4
> > - %b0 = alloca i32, align 4
> > - %c0 = alloca i32, align 4
> > - %d0 = alloca i32, align 4
> > - %a1 = alloca i32, align 4
> > - %b1 = alloca i32, align 4
> > - %c1 = alloca i32, align 4
> > - %d1 = alloca i32, align 4
> > - %data = alloca i32, align 4
> > - %0 = load i32* %a0, align 4
> > - %1 = load i32* %b0, align 4
> > - %cmp = icmp ne i32 %0, %1
> > - br i1 %cmp, label %land.lhs.true, label %if.else
> > -
> > -land.lhs.true: ; preds = %entry
> > - %2 = load i32* %c0, align 4
> > - %3 = load i32* %d0, align 4
> > - %cmp1 = icmp ne i32 %2, %3
> > - br i1 %cmp1, label %if.then, label %if.else
> > -
> > -if.then: ; preds =
> %land.lhs.true
> > - br label %if.end
> > -
> > -if.else: ; preds =
> %land.lhs.true, %entry
> > - store i32 1, i32* %data, align 4
> > - br label %if.end
> > -
> > -if.end: ; preds = %if.else,
> %if.then
> > - %4 = load i32* %a1, align 4
> > - %5 = load i32* %b1, align 4
> > - %cmp2 = icmp ne i32 %4, %5
> > - br i1 %cmp2, label %land.lhs.true3, label %if.else6
> > -
> > -land.lhs.true3: ; preds = %if.end
> > - %6 = load i32* %c1, align 4
> > - %7 = load i32* %d1, align 4
> > - %cmp4 = icmp ne i32 %6, %7
> > - br i1 %cmp4, label %if.then5, label %if.else6
> > -
> > -if.then5: ; preds =
> %land.lhs.true3
> > - br label %if.end7
> > -
> > -if.else6: ; preds =
> %land.lhs.true3, %if.end
> > - store i32 1, i32* %data, align 4
> > - br label %if.end7
> > -
> > -if.end7: ; preds = %if.else6,
> %if.then5
> > - ret void
> > -}
> > -
> >
> > Modified:
> llvm/trunk/test/Transforms/SimplifyCFG/R600/parallelorifcollapse.ll
> > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/SimplifyCFG/R600/parallelorifcollapse.ll?rev=187764&r1=187763&r2=187764&view=diff
> >
> ==============================================================================
> > --- llvm/trunk/test/Transforms/SimplifyCFG/R600/parallelorifcollapse.ll
> (original)
> > +++ llvm/trunk/test/Transforms/SimplifyCFG/R600/parallelorifcollapse.ll
> Mon Aug 5 21:43:45 2013
> > @@ -1,56 +0,0 @@
> > -; Function Attrs: nounwind
> > -; RUN: opt < %s -mtriple=r600-unknown-linux-gnu -optimizecfg -basicaa
> -S | FileCheck %s
> > -;
> > -; CFG optimization should use parallel-or mode to generate branch
> conditions and
> > -; then merge if-regions with the same bodies, which should result in 2
> branches.
> > -; To see the assembly output without this transformation, remove
> -basicaa option.
> > -;
> > -; CHECK: or i1
> > -; CHECK-NEXT: br
> > -; CHECK: br
> > -; CHECK: ret
> > -define void @_Z9chk1D_512v() #0 {
> > -entry:
> > - %a0 = alloca i32, align 4
> > - %b0 = alloca i32, align 4
> > - %c0 = alloca i32, align 4
> > - %d0 = alloca i32, align 4
> > - %a1 = alloca i32, align 4
> > - %b1 = alloca i32, align 4
> > - %c1 = alloca i32, align 4
> > - %d1 = alloca i32, align 4
> > - %data = alloca i32, align 4
> > - %0 = load i32* %a0, align 4
> > - %1 = load i32* %b0, align 4
> > - %cmp = icmp ne i32 %0, %1
> > - br i1 %cmp, label %land.lhs.true, label %if.end
> > -
> > -land.lhs.true: ; preds = %entry
> > - %2 = load i32* %c0, align 4
> > - %3 = load i32* %d0, align 4
> > - %cmp1 = icmp ne i32 %2, %3
> > - br i1 %cmp1, label %if.then, label %if.end
> > -
> > -if.then: ; preds =
> %land.lhs.true
> > - store i32 1, i32* %data, align 4
> > - br label %if.end
> > -
> > -if.end: ; preds = %if.then,
> %land.lhs.true, %entry
> > - %4 = load i32* %a1, align 4
> > - %5 = load i32* %b1, align 4
> > - %cmp2 = icmp ne i32 %4, %5
> > - br i1 %cmp2, label %land.lhs.true3, label %if.end6
> > -
> > -land.lhs.true3: ; preds = %if.end
> > - %6 = load i32* %c1, align 4
> > - %7 = load i32* %d1, align 4
> > - %cmp4 = icmp ne i32 %6, %7
> > - br i1 %cmp4, label %if.then5, label %if.end6
> > -
> > -if.then5: ; preds =
> %land.lhs.true3
> > - store i32 1, i32* %data, align 4
> > - br label %if.end6
> > -
> > -if.end6: ; preds = %if.then5,
> %land.lhs.true3, %if.end
> > - ret void
> > -}
> >
> > Modified: llvm/trunk/test/Transforms/SimplifyCFG/lit.local.cfg
> > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/SimplifyCFG/lit.local.cfg?rev=187764&r1=187763&r2=187764&view=diff
> >
> ==============================================================================
> > --- llvm/trunk/test/Transforms/SimplifyCFG/lit.local.cfg (original)
> > +++ llvm/trunk/test/Transforms/SimplifyCFG/lit.local.cfg Mon Aug 5
> 21:43:45 2013
> > @@ -1 +0,0 @@
> > -config.suffixes = ['.ll', '.c', '.cpp']
> >
> > Modified: llvm/trunk/tools/lto/LTOCodeGenerator.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/lto/LTOCodeGenerator.cpp?rev=187764&r1=187763&r2=187764&view=diff
> >
> ==============================================================================
> > --- llvm/trunk/tools/lto/LTOCodeGenerator.cpp (original)
> > +++ llvm/trunk/tools/lto/LTOCodeGenerator.cpp Mon Aug 5 21:43:45 2013
> > @@ -118,7 +118,7 @@ void LTOCodeGenerator::initializeLTOPass
> > initializeGVNPass(R);
> > initializeMemCpyOptPass(R);
> > initializeDCEPass(R);
> > - initializeCFGCanonicalizePass(R);
> > + initializeCFGSimplifyPassPass(R);
> > }
> >
> > bool LTOCodeGenerator::addModule(LTOModule* mod, std::string& errMsg) {
> >
> >
> > _______________________________________________
> > llvm-commits mailing list
> > llvm-commits at cs.uiuc.edu
> > http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
>
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
>
--
Thanks,
--Serge
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