[llvm] r303850 - [GVNSink] GVNSink pass
Davide Italiano via llvm-commits
llvm-commits at lists.llvm.org
Sat May 27 17:28:53 PDT 2017
On Sat, May 27, 2017 at 7:34 AM, Zachary Turner via llvm-commits
<llvm-commits at lists.llvm.org> wrote:
> It's not on a bot, it only happens on my local machine where I build debug.
> And yes, it's while running tests
>
Same here. Galina, any chance we can get a bot for this configuration?
Apparently only few of us build with MSVC in debug so breakages like
this are likely to go unnoticed.
--
Davide
> On Fri, May 26, 2017 at 11:22 PM James Molloy <james at jamesmolloy.co.uk>
> wrote:
>>
>> Hi,
>>
>> Hal; gah yes; the patch commit message was taken from the phab review that
>> was ongoing for ages and I didn't remove that paragraph.
>>
>> Zachary- sorry about that. I'm on vacation at the moment so don't have
>> access to any Dev machine. The pass is turned off, so I presume the only way
>> to get this assert currently is in gvnsink's own regression tests?
>>
>> I suppose the options are: quick switch to std::sort to pacify the bot and
>> I'll ensure the code is actually correct later, xfail the tests or revert.
>>
>> Apologies, if I'd seen a buildbot failure for this I'd have fixed it on
>> Thursday.
>>
>> James
>> On Sat, 27 May 2017 at 03:35, Zachary Turner via llvm-commits
>> <llvm-commits at lists.llvm.org> wrote:
>>>
>>> Is this being addressed?
>>>
>>> This asserts on MSVC in a debug build because it uses debug iterators
>>> that check this kind of thing.
>>>
>>>
>>> On Thu, May 25, 2017 at 9:05 AM Benjamin Kramer via llvm-commits
>>> <llvm-commits at lists.llvm.org> wrote:
>>>>
>>>> On Thu, May 25, 2017 at 2:51 PM, James Molloy via llvm-commits
>>>> <llvm-commits at lists.llvm.org> wrote:
>>>> > Author: jamesm
>>>> > Date: Thu May 25 07:51:11 2017
>>>> > New Revision: 303850
>>>> >
>>>> > URL: http://llvm.org/viewvc/llvm-project?rev=303850&view=rev
>>>> > Log:
>>>> > [GVNSink] GVNSink pass
>>>> >
>>>> > This patch provides an initial prototype for a pass that sinks
>>>> > instructions based on GVN information, similar to GVNHoist. It is not yet
>>>> > ready for commiting but I've uploaded it to gather some initial thoughts.
>>>> >
>>>> > This pass attempts to sink instructions into successors, reducing
>>>> > static
>>>> > instruction count and enabling if-conversion.
>>>> > We use a variant of global value numbering to decide what can be sunk.
>>>> > Consider:
>>>> >
>>>> > [ %a1 = add i32 %b, 1 ] [ %c1 = add i32 %d, 1 ]
>>>> > [ %a2 = xor i32 %a1, 1 ] [ %c2 = xor i32 %c1, 1 ]
>>>> > \ /
>>>> > [ %e = phi i32 %a2, %c2 ]
>>>> > [ add i32 %e, 4 ]
>>>> >
>>>> > GVN would number %a1 and %c1 differently because they compute
>>>> > different
>>>> > results - the VN of an instruction is a function of its opcode and the
>>>> > transitive closure of its operands. This is the key property for
>>>> > hoisting
>>>> > and CSE.
>>>> >
>>>> > What we want when sinking however is for a numbering that is a
>>>> > function of
>>>> > the *uses* of an instruction, which allows us to answer the question
>>>> > "if I
>>>> > replace %a1 with %c1, will it contribute in an equivalent way to all
>>>> > successive instructions?". The (new) PostValueTable class in GVN
>>>> > provides this
>>>> > mapping.
>>>> >
>>>> > This pass has some shown really impressive improvements especially for
>>>> > codesize already on internal benchmarks, so I have high hopes it can replace
>>>> > all the sinking logic in SimplifyCFG.
>>>> >
>>>> > Differential revision: https://reviews.llvm.org/D24805
>>>> >
>>>> > Added:
>>>> > llvm/trunk/lib/Transforms/Scalar/GVNSink.cpp
>>>> > llvm/trunk/test/Transforms/GVNSink/
>>>> > llvm/trunk/test/Transforms/GVNSink/dither.ll
>>>> > llvm/trunk/test/Transforms/GVNSink/indirect-call.ll
>>>> > llvm/trunk/test/Transforms/GVNSink/sink-common-code.ll
>>>> > llvm/trunk/test/Transforms/GVNSink/struct.ll
>>>> > Modified:
>>>> > llvm/trunk/include/llvm/InitializePasses.h
>>>> > llvm/trunk/include/llvm/Transforms/Scalar.h
>>>> > llvm/trunk/include/llvm/Transforms/Scalar/GVN.h
>>>> > llvm/trunk/include/llvm/Transforms/Utils/Local.h
>>>> > 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/Utils/Local.cpp
>>>> > llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp
>>>> >
>>>> > Modified: llvm/trunk/include/llvm/InitializePasses.h
>>>> > URL:
>>>> > http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/InitializePasses.h?rev=303850&r1=303849&r2=303850&view=diff
>>>> >
>>>> > ==============================================================================
>>>> > --- llvm/trunk/include/llvm/InitializePasses.h (original)
>>>> > +++ llvm/trunk/include/llvm/InitializePasses.h Thu May 25 07:51:11
>>>> > 2017
>>>> > @@ -144,6 +144,7 @@ void initializeGCMachineCodeAnalysisPass
>>>> > void initializeGCModuleInfoPass(PassRegistry&);
>>>> > void initializeGCOVProfilerLegacyPassPass(PassRegistry&);
>>>> > void initializeGVNHoistLegacyPassPass(PassRegistry&);
>>>> > +void initializeGVNSinkLegacyPassPass(PassRegistry&);
>>>> > void initializeGVNLegacyPassPass(PassRegistry&);
>>>> > void initializeGlobalDCELegacyPassPass(PassRegistry&);
>>>> > void initializeGlobalMergePass(PassRegistry&);
>>>> >
>>>> > Modified: llvm/trunk/include/llvm/Transforms/Scalar.h
>>>> > URL:
>>>> > http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Transforms/Scalar.h?rev=303850&r1=303849&r2=303850&view=diff
>>>> >
>>>> > ==============================================================================
>>>> > --- llvm/trunk/include/llvm/Transforms/Scalar.h (original)
>>>> > +++ llvm/trunk/include/llvm/Transforms/Scalar.h Thu May 25 07:51:11
>>>> > 2017
>>>> > @@ -356,6 +356,13 @@ FunctionPass *createGVNHoistPass();
>>>> >
>>>> >
>>>> > //===----------------------------------------------------------------------===//
>>>> > //
>>>> > +// GVNSink - This pass uses an "inverted" value numbering to decide
>>>> > the
>>>> > +// similarity of expressions and sinks similar expressions into
>>>> > successors.
>>>> > +//
>>>> > +FunctionPass *createGVNSinkPass();
>>>> > +
>>>> >
>>>> > +//===----------------------------------------------------------------------===//
>>>> > +//
>>>> > // MergedLoadStoreMotion - This pass merges loads and stores in
>>>> > diamonds. Loads
>>>> > // are hoisted into the header, while stores sink into the footer.
>>>> > //
>>>> >
>>>> > Modified: llvm/trunk/include/llvm/Transforms/Scalar/GVN.h
>>>> > URL:
>>>> > http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Transforms/Scalar/GVN.h?rev=303850&r1=303849&r2=303850&view=diff
>>>> >
>>>> > ==============================================================================
>>>> > --- llvm/trunk/include/llvm/Transforms/Scalar/GVN.h (original)
>>>> > +++ llvm/trunk/include/llvm/Transforms/Scalar/GVN.h Thu May 25
>>>> > 07:51:11 2017
>>>> > @@ -238,7 +238,12 @@ struct GVNHoistPass : PassInfoMixin<GVNH
>>>> > /// \brief Run the pass over the function.
>>>> > PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
>>>> > };
>>>> > -
>>>> > +/// \brief Uses an "inverted" value numbering to decide the
>>>> > similarity of
>>>> > +/// expressions and sinks similar expressions into successors.
>>>> > +struct GVNSinkPass : PassInfoMixin<GVNSinkPass> {
>>>> > + /// \brief Run the pass over the function.
>>>> > + PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
>>>> > +};
>>>> > }
>>>> >
>>>> > #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=303850&r1=303849&r2=303850&view=diff
>>>> >
>>>> > ==============================================================================
>>>> > --- llvm/trunk/include/llvm/Transforms/Utils/Local.h (original)
>>>> > +++ llvm/trunk/include/llvm/Transforms/Utils/Local.h Thu May 25
>>>> > 07:51:11 2017
>>>> > @@ -410,6 +410,14 @@ bool recognizeBSwapOrBitReverseIdiom(
>>>> > void maybeMarkSanitizerLibraryCallNoBuiltin(CallInst *CI,
>>>> > const TargetLibraryInfo
>>>> > *TLI);
>>>> >
>>>> >
>>>> > +//===----------------------------------------------------------------------===//
>>>> > +// Transform predicates
>>>> > +//
>>>> > +
>>>> > +/// Given an instruction, is it legal to set operand OpIdx to a
>>>> > non-constant
>>>> > +/// value?
>>>> > +bool canReplaceOperandWithVariable(const Instruction *I, unsigned
>>>> > OpIdx);
>>>> > +
>>>> > } // End llvm namespace
>>>> >
>>>> > #endif
>>>> >
>>>> > Modified: llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp
>>>> > URL:
>>>> > http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp?rev=303850&r1=303849&r2=303850&view=diff
>>>> >
>>>> > ==============================================================================
>>>> > --- llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp (original)
>>>> > +++ llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp Thu May 25
>>>> > 07:51:11 2017
>>>> > @@ -155,6 +155,10 @@ static cl::opt<bool>
>>>> > cl::Hidden,
>>>> > cl::desc("Enable the simple loop
>>>> > unswitch pass."));
>>>> >
>>>> > +static cl::opt<bool> EnableGVNSink(
>>>> > + "enable-gvn-sink", cl::init(false), cl::Hidden,
>>>> > + cl::desc("Enable the GVN sinking pass (default = on)"));
>>>> > +
>>>> > PassManagerBuilder::PassManagerBuilder() {
>>>> > OptLevel = 2;
>>>> > SizeLevel = 0;
>>>> > @@ -307,6 +311,11 @@ void PassManagerBuilder::addFunctionSimp
>>>> > MPM.add(createEarlyCSEPass()); // Catch trivial
>>>> > redundancies
>>>> > if (EnableGVNHoist)
>>>> > MPM.add(createGVNHoistPass());
>>>> > + if (EnableGVNSink) {
>>>> > + MPM.add(createGVNSinkPass());
>>>> > + MPM.add(createCFGSimplificationPass());
>>>> > + }
>>>> > +
>>>> > // Speculative execution if the target has divergent branches;
>>>> > otherwise nop.
>>>> > MPM.add(createSpeculativeExecutionIfHasBranchDivergencePass());
>>>> > MPM.add(createJumpThreadingPass()); // Thread jumps.
>>>> >
>>>> > Modified: llvm/trunk/lib/Transforms/Scalar/CMakeLists.txt
>>>> > URL:
>>>> > http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/CMakeLists.txt?rev=303850&r1=303849&r2=303850&view=diff
>>>> >
>>>> > ==============================================================================
>>>> > --- llvm/trunk/lib/Transforms/Scalar/CMakeLists.txt (original)
>>>> > +++ llvm/trunk/lib/Transforms/Scalar/CMakeLists.txt Thu May 25
>>>> > 07:51:11 2017
>>>> > @@ -13,6 +13,7 @@ add_llvm_library(LLVMScalarOpts
>>>> > GuardWidening.cpp
>>>> > GVN.cpp
>>>> > GVNHoist.cpp
>>>> > + GVNSink.cpp
>>>> > IVUsersPrinter.cpp
>>>> > InductiveRangeCheckElimination.cpp
>>>> > IndVarSimplify.cpp
>>>> >
>>>> > Added: llvm/trunk/lib/Transforms/Scalar/GVNSink.cpp
>>>> > URL:
>>>> > http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/GVNSink.cpp?rev=303850&view=auto
>>>> >
>>>> > ==============================================================================
>>>> > --- llvm/trunk/lib/Transforms/Scalar/GVNSink.cpp (added)
>>>> > +++ llvm/trunk/lib/Transforms/Scalar/GVNSink.cpp Thu May 25 07:51:11
>>>> > 2017
>>>> > @@ -0,0 +1,870 @@
>>>> > +//===- GVNSink.cpp - sink expressions into successors
>>>> > -------------------===//
>>>> > +//
>>>> > +// The LLVM Compiler Infrastructure
>>>> > +//
>>>> > +// This file is distributed under the University of Illinois Open
>>>> > Source
>>>> > +// License. See LICENSE.TXT for details.
>>>> > +//
>>>> >
>>>> > +//===----------------------------------------------------------------------===//
>>>> > +//
>>>> > +/// \file GVNSink.cpp
>>>> > +/// This pass attempts to sink instructions into successors, reducing
>>>> > static
>>>> > +/// instruction count and enabling if-conversion.
>>>> > +///
>>>> > +/// We use a variant of global value numbering to decide what can be
>>>> > sunk.
>>>> > +/// Consider:
>>>> > +///
>>>> > +/// [ %a1 = add i32 %b, 1 ] [ %c1 = add i32 %d, 1 ]
>>>> > +/// [ %a2 = xor i32 %a1, 1 ] [ %c2 = xor i32 %c1, 1 ]
>>>> > +/// \ /
>>>> > +/// [ %e = phi i32 %a2, %c2 ]
>>>> > +/// [ add i32 %e, 4 ]
>>>> > +///
>>>> > +///
>>>> > +/// GVN would number %a1 and %c1 differently because they compute
>>>> > different
>>>> > +/// results - the VN of an instruction is a function of its opcode
>>>> > and the
>>>> > +/// transitive closure of its operands. This is the key property for
>>>> > hoisting
>>>> > +/// and CSE.
>>>> > +///
>>>> > +/// What we want when sinking however is for a numbering that is a
>>>> > function of
>>>> > +/// the *uses* of an instruction, which allows us to answer the
>>>> > question "if I
>>>> > +/// replace %a1 with %c1, will it contribute in an equivalent way to
>>>> > all
>>>> > +/// successive instructions?". The PostValueTable class in GVN
>>>> > provides this
>>>> > +/// mapping.
>>>> > +///
>>>> >
>>>> > +//===----------------------------------------------------------------------===//
>>>> > +
>>>> > +#include "llvm/ADT/DenseMap.h"
>>>> > +#include "llvm/ADT/DenseMapInfo.h"
>>>> > +#include "llvm/ADT/DenseSet.h"
>>>> > +#include "llvm/ADT/Hashing.h"
>>>> > +#include "llvm/ADT/Optional.h"
>>>> > +#include "llvm/ADT/PostOrderIterator.h"
>>>> > +#include "llvm/ADT/SCCIterator.h"
>>>> > +#include "llvm/ADT/SmallPtrSet.h"
>>>> > +#include "llvm/ADT/Statistic.h"
>>>> > +#include "llvm/ADT/StringExtras.h"
>>>> > +#include "llvm/Analysis/GlobalsModRef.h"
>>>> > +#include "llvm/Analysis/MemorySSA.h"
>>>> > +#include "llvm/Analysis/PostDominators.h"
>>>> > +#include "llvm/Analysis/TargetTransformInfo.h"
>>>> > +#include "llvm/Analysis/ValueTracking.h"
>>>> > +#include "llvm/IR/Instructions.h"
>>>> > +#include "llvm/IR/Verifier.h"
>>>> > +#include "llvm/Support/MathExtras.h"
>>>> > +#include "llvm/Transforms/Scalar.h"
>>>> > +#include "llvm/Transforms/Scalar/GVN.h"
>>>> > +#include "llvm/Transforms/Scalar/GVNExpression.h"
>>>> > +#include "llvm/Transforms/Utils/BasicBlockUtils.h"
>>>> > +#include "llvm/Transforms/Utils/Local.h"
>>>> > +#include <unordered_set>
>>>> > +using namespace llvm;
>>>> > +
>>>> > +#define DEBUG_TYPE "gvn-sink"
>>>> > +
>>>> > +STATISTIC(NumRemoved, "Number of instructions removed");
>>>> > +
>>>> > +namespace {
>>>> > +
>>>> > +static bool isMemoryInst(const Instruction *I) {
>>>> > + return isa<LoadInst>(I) || isa<StoreInst>(I) ||
>>>> > + (isa<InvokeInst>(I) &&
>>>> > !cast<InvokeInst>(I)->doesNotAccessMemory()) ||
>>>> > + (isa<CallInst>(I) &&
>>>> > !cast<CallInst>(I)->doesNotAccessMemory());
>>>> > +}
>>>> > +
>>>> > +/// Iterates through instructions in a set of blocks in reverse order
>>>> > from the
>>>> > +/// first non-terminator. For example (assume all blocks have size
>>>> > n):
>>>> > +/// LockstepReverseIterator I([B1, B2, B3]);
>>>> > +/// *I-- = [B1[n], B2[n], B3[n]];
>>>> > +/// *I-- = [B1[n-1], B2[n-1], B3[n-1]];
>>>> > +/// *I-- = [B1[n-2], B2[n-2], B3[n-2]];
>>>> > +/// ...
>>>> > +///
>>>> > +/// It continues until all blocks have been exhausted. Use \c
>>>> > getActiveBlocks()
>>>> > +/// to
>>>> > +/// determine which blocks are still going and the order they appear
>>>> > in the
>>>> > +/// list returned by operator*.
>>>> > +class LockstepReverseIterator {
>>>> > + ArrayRef<BasicBlock *> Blocks;
>>>> > + SmallPtrSet<BasicBlock *, 4> ActiveBlocks;
>>>> > + SmallVector<Instruction *, 4> Insts;
>>>> > + bool Fail;
>>>> > +
>>>> > +public:
>>>> > + LockstepReverseIterator(ArrayRef<BasicBlock *> Blocks) :
>>>> > Blocks(Blocks) {
>>>> > + reset();
>>>> > + }
>>>> > +
>>>> > + void reset() {
>>>> > + Fail = false;
>>>> > + ActiveBlocks.clear();
>>>> > + for (BasicBlock *BB : Blocks)
>>>> > + ActiveBlocks.insert(BB);
>>>> > + Insts.clear();
>>>> > + for (BasicBlock *BB : Blocks) {
>>>> > + if (BB->size() <= 1) {
>>>> > + // Block wasn't big enough - only contained a terminator.
>>>> > + ActiveBlocks.erase(BB);
>>>> > + continue;
>>>> > + }
>>>> > + Insts.push_back(BB->getTerminator()->getPrevNode());
>>>> > + }
>>>> > + if (Insts.empty())
>>>> > + Fail = true;
>>>> > + }
>>>> > +
>>>> > + bool isValid() const { return !Fail; }
>>>> > + ArrayRef<Instruction *> operator*() const { return Insts; }
>>>> > + SmallPtrSet<BasicBlock *, 4> &getActiveBlocks() { return
>>>> > ActiveBlocks; }
>>>> > +
>>>> > + void restrictToBlocks(SmallPtrSetImpl<BasicBlock *> &Blocks) {
>>>> > + for (auto II = Insts.begin(); II != Insts.end();) {
>>>> > + if (std::find(Blocks.begin(), Blocks.end(), (*II)->getParent())
>>>> > ==
>>>> > + Blocks.end()) {
>>>> > + ActiveBlocks.erase((*II)->getParent());
>>>> > + II = Insts.erase(II);
>>>> > + } else {
>>>> > + ++II;
>>>> > + }
>>>> > + }
>>>> > + }
>>>> > +
>>>> > + void operator--() {
>>>> > + if (Fail)
>>>> > + return;
>>>> > + SmallVector<Instruction *, 4> NewInsts;
>>>> > + for (auto *Inst : Insts) {
>>>> > + if (Inst == &Inst->getParent()->front())
>>>> > + ActiveBlocks.erase(Inst->getParent());
>>>> > + else
>>>> > + NewInsts.push_back(Inst->getPrevNode());
>>>> > + }
>>>> > + if (NewInsts.empty()) {
>>>> > + Fail = true;
>>>> > + return;
>>>> > + }
>>>> > + Insts = NewInsts;
>>>> > + }
>>>> > +};
>>>> > +
>>>> >
>>>> > +//===----------------------------------------------------------------------===//
>>>> > +
>>>> > +/// Candidate solution for sinking. There may be different ways to
>>>> > +/// sink instructions, differing in the number of instructions sunk,
>>>> > +/// the number of predecessors sunk from and the number of PHIs
>>>> > +/// required.
>>>> > +struct SinkingInstructionCandidate {
>>>> > + unsigned NumBlocks;
>>>> > + unsigned NumInstructions;
>>>> > + unsigned NumPHIs;
>>>> > + unsigned NumMemoryInsts;
>>>> > + int Cost = -1;
>>>> > + SmallVector<BasicBlock *, 4> Blocks;
>>>> > +
>>>> > + void calculateCost(unsigned NumOrigPHIs, unsigned NumOrigBlocks) {
>>>> > + unsigned NumExtraPHIs = NumPHIs - NumOrigPHIs;
>>>> > + unsigned SplitEdgeCost = (NumOrigBlocks > NumBlocks) ? 2 : 0;
>>>> > + Cost = (NumInstructions * (NumBlocks - 1)) -
>>>> > + (NumExtraPHIs *
>>>> > + NumExtraPHIs) // PHIs are expensive, so make sure they're
>>>> > worth it.
>>>> > + - SplitEdgeCost;
>>>> > + }
>>>> > + bool operator>=(const SinkingInstructionCandidate &Other) const {
>>>> > + return Cost >= Other.Cost;
>>>> > + }
>>>> > +};
>>>> > +
>>>> > +llvm::raw_ostream &operator<<(llvm::raw_ostream &OS,
>>>> > + const SinkingInstructionCandidate &C) {
>>>> > + OS << "<Candidate Cost=" << C.Cost << " #Blocks=" << C.NumBlocks
>>>> > + << " #Insts=" << C.NumInstructions << " #PHIs=" << C.NumPHIs <<
>>>> > ">";
>>>> > + return OS;
>>>> > +}
>>>> > +
>>>> >
>>>> > +//===----------------------------------------------------------------------===//
>>>> > +
>>>> > +/// Describes a PHI node that may or may not exist. These track the
>>>> > PHIs
>>>> > +/// that must be created if we sunk a sequence of instructions. It
>>>> > provides
>>>> > +/// a hash function for efficient equality comparisons.
>>>> > +class ModelledPHI {
>>>> > + SmallVector<Value *, 4> Values;
>>>> > + SmallVector<BasicBlock *, 4> Blocks;
>>>> > +
>>>> > +public:
>>>> > + ModelledPHI() {}
>>>> > + ModelledPHI(const PHINode *PN) {
>>>> > + for (unsigned I = 0, E = PN->getNumIncomingValues(); I != E; ++I)
>>>> > + Blocks.push_back(PN->getIncomingBlock(I));
>>>> > + std::sort(Blocks.begin(), Blocks.end());
>>>> > +
>>>> > + // This assumes the PHI is already well-formed and there aren't
>>>> > conflicting
>>>> > + // incoming values for the same block.
>>>> > + for (auto *B : Blocks)
>>>> > + Values.push_back(PN->getIncomingValueForBlock(B));
>>>> > + }
>>>> > + /// Create a dummy ModelledPHI that will compare unequal to any
>>>> > other ModelledPHI
>>>> > + /// without the same ID.
>>>> > + /// \note This is specifically for DenseMapInfo - do not use this!
>>>> > + static ModelledPHI createDummy(unsigned ID) {
>>>> > + ModelledPHI M;
>>>> > + M.Values.push_back(reinterpret_cast<Value*>(ID));
>>>> > + return M;
>>>> > + }
>>>> > +
>>>> > + /// Create a PHI from an array of incoming values and incoming
>>>> > blocks.
>>>> > + template <typename VArray, typename BArray>
>>>> > + ModelledPHI(const VArray &V, const BArray &B) {
>>>> > + std::copy(V.begin(), V.end(), std::back_inserter(Values));
>>>> > + std::copy(B.begin(), B.end(), std::back_inserter(Blocks));
>>>> > + }
>>>> > +
>>>> > + /// Create a PHI from [I[OpNum] for I in Insts].
>>>> > + template <typename BArray>
>>>> > + ModelledPHI(ArrayRef<Instruction *> Insts, unsigned OpNum, const
>>>> > BArray &B) {
>>>> > + std::copy(B.begin(), B.end(), std::back_inserter(Blocks));
>>>> > + for (auto *I : Insts)
>>>> > + Values.push_back(I->getOperand(OpNum));
>>>> > + }
>>>> > +
>>>> > + /// Restrict the PHI's contents down to only \c NewBlocks.
>>>> > + /// \c NewBlocks must be a subset of \c this->Blocks.
>>>> > + void restrictToBlocks(const SmallPtrSetImpl<BasicBlock *>
>>>> > &NewBlocks) {
>>>> > + auto BI = Blocks.begin();
>>>> > + auto VI = Values.begin();
>>>> > + while (BI != Blocks.end()) {
>>>> > + assert(VI != Values.end());
>>>> > + if (std::find(NewBlocks.begin(), NewBlocks.end(), *BI) ==
>>>> > + NewBlocks.end()) {
>>>> > + BI = Blocks.erase(BI);
>>>> > + VI = Values.erase(VI);
>>>> > + } else {
>>>> > + ++BI;
>>>> > + ++VI;
>>>> > + }
>>>> > + }
>>>> > + assert(Blocks.size() == NewBlocks.size());
>>>> > + }
>>>> > +
>>>> > + ArrayRef<Value *> getValues() const { return Values; }
>>>> > +
>>>> > + bool areAllIncomingValuesSame() const {
>>>> > + return all_of(Values, [&](Value *V) { return V == Values[0]; });
>>>> > + }
>>>> > + bool areAllIncomingValuesSameType() const {
>>>> > + return all_of(
>>>> > + Values, [&](Value *V) { return V->getType() ==
>>>> > Values[0]->getType(); });
>>>> > + }
>>>> > + bool areAnyIncomingValuesConstant() const {
>>>> > + return any_of(Values, [&](Value *V) { return isa<Constant>(V);
>>>> > });
>>>> > + }
>>>> > + // Hash functor
>>>> > + unsigned hash() const {
>>>> > + return (unsigned)hash_combine_range(Values.begin(),
>>>> > Values.end());
>>>> > + }
>>>> > + bool operator==(const ModelledPHI &Other) const {
>>>> > + return Values == Other.Values && Blocks == Other.Blocks;
>>>> > + }
>>>> > +};
>>>> > +
>>>> > +template <typename ModelledPHI> struct DenseMapInfo {
>>>> > + static inline ModelledPHI &getEmptyKey() {
>>>> > + static ModelledPHI Dummy = ModelledPHI::createDummy(0);
>>>> > + return Dummy;
>>>> > + }
>>>> > + static inline ModelledPHI &getTombstoneKey() {
>>>> > + static ModelledPHI Dummy = ModelledPHI::createDummy(1);
>>>> > + return Dummy;
>>>> > + }
>>>> > + static unsigned getHashValue(const ModelledPHI &V) { return
>>>> > V.hash(); }
>>>> > + static bool isEqual(const ModelledPHI &LHS, const ModelledPHI &RHS)
>>>> > {
>>>> > + return LHS == RHS;
>>>> > + }
>>>> > +};
>>>> > +
>>>> > +typedef DenseSet<ModelledPHI, DenseMapInfo<ModelledPHI>>
>>>> > ModelledPHISet;
>>>> > +
>>>> >
>>>> > +//===----------------------------------------------------------------------===//
>>>> > +// ValueTable
>>>> >
>>>> > +//===----------------------------------------------------------------------===//
>>>> > +// This is a value number table where the value number is a function
>>>> > of the
>>>> > +// *uses* of a value, rather than its operands. Thus, if VN(A) ==
>>>> > VN(B) we know
>>>> > +// that the program would be equivalent if we replaced A with PHI(A,
>>>> > B).
>>>> >
>>>> > +//===----------------------------------------------------------------------===//
>>>> > +
>>>> > +/// A GVN expression describing how an instruction is used. The
>>>> > operands
>>>> > +/// field of BasicExpression is used to store uses, not operands.
>>>> > +///
>>>> > +/// This class also contains fields for discriminators used when
>>>> > determining
>>>> > +/// equivalence of instructions with sideeffects.
>>>> > +class InstructionUseExpr : public GVNExpression::BasicExpression {
>>>> > + unsigned MemoryUseOrder = -1;
>>>> > + bool Volatile = false;
>>>> > +
>>>> > +public:
>>>> > + InstructionUseExpr(Instruction *I, ArrayRecycler<Value *> &R,
>>>> > + BumpPtrAllocator &A)
>>>> > + : GVNExpression::BasicExpression(I->getNumUses()) {
>>>> > + allocateOperands(R, A);
>>>> > + setOpcode(I->getOpcode());
>>>> > + setType(I->getType());
>>>> > +
>>>> > + for (auto &U : I->uses())
>>>> > + op_push_back(U.getUser());
>>>> > + std::sort(op_begin(), op_end());
>>>> > + }
>>>> > + void setMemoryUseOrder(unsigned MUO) { MemoryUseOrder = MUO; }
>>>> > + void setVolatile(bool V) { Volatile = V; }
>>>> > +
>>>> > + virtual hash_code getHashValue() const {
>>>> > + return
>>>> > hash_combine(GVNExpression::BasicExpression::getHashValue(),
>>>> > + MemoryUseOrder, Volatile);
>>>> > + }
>>>> > +
>>>> > + template <typename Function> hash_code getHashValue(Function MapFn)
>>>> > {
>>>> > + hash_code H =
>>>> > + hash_combine(getOpcode(), getType(), MemoryUseOrder,
>>>> > Volatile);
>>>> > + for (auto *V : operands())
>>>> > + H = hash_combine(H, MapFn(V));
>>>> > + return H;
>>>> > + }
>>>> > +};
>>>> > +
>>>> > +class ValueTable {
>>>> > + DenseMap<Value *, uint32_t> ValueNumbering;
>>>> > + DenseMap<GVNExpression::Expression *, uint32_t>
>>>> > ExpressionNumbering;
>>>> > + DenseMap<size_t, uint32_t> HashNumbering;
>>>> > + BumpPtrAllocator Allocator;
>>>> > + ArrayRecycler<Value *> Recycler;
>>>> > + uint32_t nextValueNumber;
>>>> > +
>>>> > + /// Create an expression for I based on its opcode and its uses. If
>>>> > I
>>>> > + /// touches or reads memory, the expression is also based upon its
>>>> > memory
>>>> > + /// order - see \c getMemoryUseOrder().
>>>> > + InstructionUseExpr *createExpr(Instruction *I) {
>>>> > + InstructionUseExpr *E =
>>>> > + new (Allocator) InstructionUseExpr(I, Recycler, Allocator);
>>>> > + if (isMemoryInst(I))
>>>> > + E->setMemoryUseOrder(getMemoryUseOrder(I));
>>>> > +
>>>> > + if (CmpInst *C = dyn_cast<CmpInst>(I)) {
>>>> > + CmpInst::Predicate Predicate = C->getPredicate();
>>>> > + E->setOpcode((C->getOpcode() << 8) | Predicate);
>>>> > + }
>>>> > + return E;
>>>> > + }
>>>> > +
>>>> > + /// Helper to compute the value number for a memory instruction
>>>> > + /// (LoadInst/StoreInst), including checking the memory ordering
>>>> > and
>>>> > + /// volatility.
>>>> > + template <class Inst> InstructionUseExpr *createMemoryExpr(Inst *I)
>>>> > {
>>>> > + if (isStrongerThanUnordered(I->getOrdering()) || I->isAtomic())
>>>> > + return nullptr;
>>>> > + InstructionUseExpr *E = createExpr(I);
>>>> > + E->setVolatile(I->isVolatile());
>>>> > + return E;
>>>> > + }
>>>> > +
>>>> > +public:
>>>> > + /// Returns the value number for the specified value, assigning
>>>> > + /// it a new number if it did not have one before.
>>>> > + uint32_t lookupOrAdd(Value *V) {
>>>> > + auto VI = ValueNumbering.find(V);
>>>> > + if (VI != ValueNumbering.end())
>>>> > + return VI->second;
>>>> > +
>>>> > + if (!isa<Instruction>(V)) {
>>>> > + ValueNumbering[V] = nextValueNumber;
>>>> > + return nextValueNumber++;
>>>> > + }
>>>> > +
>>>> > + Instruction *I = cast<Instruction>(V);
>>>> > + InstructionUseExpr *exp = nullptr;
>>>> > + switch (I->getOpcode()) {
>>>> > + case Instruction::Load:
>>>> > + exp = createMemoryExpr(cast<LoadInst>(I));
>>>> > + break;
>>>> > + case Instruction::Store:
>>>> > + exp = createMemoryExpr(cast<StoreInst>(I));
>>>> > + break;
>>>> > + case Instruction::Call:
>>>> > + case Instruction::Invoke:
>>>> > + case Instruction::Add:
>>>> > + case Instruction::FAdd:
>>>> > + case Instruction::Sub:
>>>> > + case Instruction::FSub:
>>>> > + case Instruction::Mul:
>>>> > + case Instruction::FMul:
>>>> > + case Instruction::UDiv:
>>>> > + case Instruction::SDiv:
>>>> > + case Instruction::FDiv:
>>>> > + case Instruction::URem:
>>>> > + case Instruction::SRem:
>>>> > + case Instruction::FRem:
>>>> > + case Instruction::Shl:
>>>> > + case Instruction::LShr:
>>>> > + case Instruction::AShr:
>>>> > + case Instruction::And:
>>>> > + case Instruction::Or:
>>>> > + case Instruction::Xor:
>>>> > + case Instruction::ICmp:
>>>> > + case Instruction::FCmp:
>>>> > + case Instruction::Trunc:
>>>> > + case Instruction::ZExt:
>>>> > + case Instruction::SExt:
>>>> > + case Instruction::FPToUI:
>>>> > + case Instruction::FPToSI:
>>>> > + case Instruction::UIToFP:
>>>> > + case Instruction::SIToFP:
>>>> > + case Instruction::FPTrunc:
>>>> > + case Instruction::FPExt:
>>>> > + case Instruction::PtrToInt:
>>>> > + case Instruction::IntToPtr:
>>>> > + case Instruction::BitCast:
>>>> > + case Instruction::Select:
>>>> > + case Instruction::ExtractElement:
>>>> > + case Instruction::InsertElement:
>>>> > + case Instruction::ShuffleVector:
>>>> > + case Instruction::InsertValue:
>>>> > + case Instruction::GetElementPtr:
>>>> > + exp = createExpr(I);
>>>> > + break;
>>>> > + default:
>>>> > + break;
>>>> > + }
>>>> > +
>>>> > + if (!exp) {
>>>> > + ValueNumbering[V] = nextValueNumber;
>>>> > + return nextValueNumber++;
>>>> > + }
>>>> > +
>>>> > + uint32_t e = ExpressionNumbering[exp];
>>>> > + if (!e) {
>>>> > + hash_code H = exp->getHashValue([=](Value *V) { return
>>>> > lookupOrAdd(V); });
>>>> > + auto I = HashNumbering.find(H);
>>>> > + if (I != HashNumbering.end()) {
>>>> > + e = I->second;
>>>> > + } else {
>>>> > + e = nextValueNumber++;
>>>> > + HashNumbering[H] = e;
>>>> > + ExpressionNumbering[exp] = e;
>>>> > + }
>>>> > + }
>>>> > + ValueNumbering[V] = e;
>>>> > + return e;
>>>> > + }
>>>> > +
>>>> > + /// Returns the value number of the specified value. Fails if the
>>>> > value has
>>>> > + /// not yet been numbered.
>>>> > + uint32_t lookup(Value *V) const {
>>>> > + auto VI = ValueNumbering.find(V);
>>>> > + assert(VI != ValueNumbering.end() && "Value not numbered?");
>>>> > + return VI->second;
>>>> > + }
>>>> > +
>>>> > + /// Removes all value numberings and resets the value table.
>>>> > + void clear() {
>>>> > + ValueNumbering.clear();
>>>> > + ExpressionNumbering.clear();
>>>> > + HashNumbering.clear();
>>>> > + Recycler.clear(Allocator);
>>>> > + nextValueNumber = 1;
>>>> > + }
>>>> > +
>>>> > + ValueTable() : nextValueNumber(1) {}
>>>> > +
>>>> > + /// \c Inst uses or touches memory. Return an ID describing the
>>>> > memory state
>>>> > + /// at \c Inst such that if getMemoryUseOrder(I1) ==
>>>> > getMemoryUseOrder(I2),
>>>> > + /// the exact same memory operations happen after I1 and I2.
>>>> > + ///
>>>> > + /// This is a very hard problem in general, so we use
>>>> > domain-specific
>>>> > + /// knowledge that we only ever check for equivalence between
>>>> > blocks sharing a
>>>> > + /// single immediate successor that is common, and when determining
>>>> > if I1 ==
>>>> > + /// I2 we will have already determined that next(I1) == next(I2).
>>>> > This
>>>> > + /// inductive property allows us to simply return the value number
>>>> > of the next
>>>> > + /// instruction that defines memory.
>>>> > + uint32_t getMemoryUseOrder(Instruction *Inst) {
>>>> > + auto *BB = Inst->getParent();
>>>> > + for (auto I = std::next(Inst->getIterator()), E = BB->end();
>>>> > + I != E && !I->isTerminator(); ++I) {
>>>> > + if (!isMemoryInst(&*I))
>>>> > + continue;
>>>> > + if (isa<LoadInst>(&*I))
>>>> > + continue;
>>>> > + CallInst *CI = dyn_cast<CallInst>(&*I);
>>>> > + if (CI && CI->onlyReadsMemory())
>>>> > + continue;
>>>> > + InvokeInst *II = dyn_cast<InvokeInst>(&*I);
>>>> > + if (II && II->onlyReadsMemory())
>>>> > + continue;
>>>> > + return lookupOrAdd(&*I);
>>>> > + }
>>>> > + return 0;
>>>> > + }
>>>> > +};
>>>> > +
>>>> >
>>>> > +//===----------------------------------------------------------------------===//
>>>> > +
>>>> > +class GVNSink {
>>>> > +public:
>>>> > + GVNSink() : VN() {}
>>>> > + bool run(Function &F) {
>>>> > + DEBUG(dbgs() << "GVNSink: running on function @" << F.getName()
>>>> > << "\n");
>>>> > +
>>>> > + unsigned NumSunk = 0;
>>>> > + ReversePostOrderTraversal<Function*> RPOT(&F);
>>>> > + for (auto *N : RPOT)
>>>> > + NumSunk += sinkBB(N);
>>>> > +
>>>> > + return NumSunk > 0;
>>>> > + }
>>>> > +
>>>> > +private:
>>>> > + ValueTable VN;
>>>> > +
>>>> > + bool isInstructionBlacklisted(Instruction *I) {
>>>> > + // These instructions may change or break semantics if moved.
>>>> > + if (isa<PHINode>(I) || I->isEHPad() || isa<AllocaInst>(I) ||
>>>> > + I->getType()->isTokenTy())
>>>> > + return true;
>>>> > + return false;
>>>> > + }
>>>> > +
>>>> > + /// The main heuristic function. Analyze the set of instructions
>>>> > pointed to by
>>>> > + /// LRI and return a candidate solution if these instructions can
>>>> > be sunk, or
>>>> > + /// None otherwise.
>>>> > + Optional<SinkingInstructionCandidate> analyzeInstructionForSinking(
>>>> > + LockstepReverseIterator &LRI, unsigned &InstNum, unsigned
>>>> > &MemoryInstNum,
>>>> > + ModelledPHISet &NeededPHIs, SmallPtrSetImpl<Value *>
>>>> > &PHIContents);
>>>> > +
>>>> > + /// Create a ModelledPHI for each PHI in BB, adding to PHIs.
>>>> > + void analyzeInitialPHIs(BasicBlock *BB, ModelledPHISet &PHIs,
>>>> > + SmallPtrSetImpl<Value *> &PHIContents) {
>>>> > + for (auto &I : *BB) {
>>>> > + auto *PN = dyn_cast<PHINode>(&I);
>>>> > + if (!PN)
>>>> > + return;
>>>> > +
>>>> > + auto MPHI = ModelledPHI(PN);
>>>> > + PHIs.insert(MPHI);
>>>> > + for (auto *V : MPHI.getValues())
>>>> > + PHIContents.insert(V);
>>>> > + }
>>>> > + }
>>>> > +
>>>> > + /// The main instruction sinking driver. Set up state and try and
>>>> > sink
>>>> > + /// instructions into BBEnd from its predecessors.
>>>> > + unsigned sinkBB(BasicBlock *BBEnd);
>>>> > +
>>>> > + /// Perform the actual mechanics of sinking an instruction from
>>>> > Blocks into
>>>> > + /// BBEnd, which is their only successor.
>>>> > + void sinkLastInstruction(ArrayRef<BasicBlock *> Blocks, BasicBlock
>>>> > *BBEnd);
>>>> > +
>>>> > + /// Remove PHIs that all have the same incoming value.
>>>> > + void foldPointlessPHINodes(BasicBlock *BB) {
>>>> > + auto I = BB->begin();
>>>> > + while (PHINode *PN = dyn_cast<PHINode>(I++)) {
>>>> > + if (!all_of(PN->incoming_values(),
>>>> > + [&](const Value *V) { return V ==
>>>> > PN->getIncomingValue(0); }))
>>>> > + continue;
>>>> > + if (PN->getIncomingValue(0) != PN)
>>>> > + PN->replaceAllUsesWith(PN->getIncomingValue(0));
>>>> > + else
>>>> > + PN->replaceAllUsesWith(UndefValue::get(PN->getType()));
>>>> > + PN->eraseFromParent();
>>>> > + }
>>>> > + }
>>>> > +};
>>>> > +
>>>> > +Optional<SinkingInstructionCandidate>
>>>> > GVNSink::analyzeInstructionForSinking(
>>>> > + LockstepReverseIterator &LRI, unsigned &InstNum, unsigned
>>>> > &MemoryInstNum,
>>>> > + ModelledPHISet &NeededPHIs, SmallPtrSetImpl<Value *> &PHIContents)
>>>> > {
>>>> > + auto Insts = *LRI;
>>>> > + DEBUG(dbgs() << " -- Analyzing instruction set: [\n"; for (auto *I
>>>> > + : Insts)
>>>> > {
>>>> > + I->dump();
>>>> > + } dbgs() << " ]\n";);
>>>> > +
>>>> > + DenseMap<uint32_t, unsigned> VNums;
>>>> > + for (auto *I : Insts) {
>>>> > + uint32_t N = VN.lookupOrAdd(I);
>>>> > + DEBUG(dbgs() << " VN=" << utohexstr(N) << " for" << *I << "\n");
>>>> > + if (N == ~0U)
>>>> > + return None;
>>>> > + VNums[N]++;
>>>> > + }
>>>> > + unsigned VNumToSink =
>>>> > + std::max_element(VNums.begin(), VNums.end(),
>>>> > + [](const std::pair<uint32_t, unsigned> &I,
>>>> > + const std::pair<uint32_t, unsigned> &J) {
>>>> > + return I.second < J.second;
>>>> > + })
>>>> > + ->first;
>>>> > +
>>>> > + if (VNums[VNumToSink] == 1)
>>>> > + // Can't sink anything!
>>>> > + return None;
>>>> > +
>>>> > + // Now restrict the number of incoming blocks down to only those
>>>> > with
>>>> > + // VNumToSink.
>>>> > + auto &ActivePreds = LRI.getActiveBlocks();
>>>> > + unsigned InitialActivePredSize = ActivePreds.size();
>>>> > + SmallVector<Instruction *, 4> NewInsts;
>>>> > + for (auto *I : Insts) {
>>>> > + if (VN.lookup(I) != VNumToSink)
>>>> > + ActivePreds.erase(I->getParent());
>>>> > + else
>>>> > + NewInsts.push_back(I);
>>>> > + }
>>>> > + for (auto *I : NewInsts)
>>>> > + if (isInstructionBlacklisted(I))
>>>> > + return None;
>>>> > +
>>>> > + // If we've restricted the incoming blocks, restrict all needed
>>>> > PHIs also
>>>> > + // to that set.
>>>> > + bool RecomputePHIContents = false;
>>>> > + if (ActivePreds.size() != InitialActivePredSize) {
>>>> > + ModelledPHISet NewNeededPHIs;
>>>> > + for (auto P : NeededPHIs) {
>>>> > + P.restrictToBlocks(ActivePreds);
>>>> > + NewNeededPHIs.insert(P);
>>>> > + }
>>>> > + NeededPHIs = NewNeededPHIs;
>>>> > + LRI.restrictToBlocks(ActivePreds);
>>>> > + RecomputePHIContents = true;
>>>> > + }
>>>> > +
>>>> > + // The sunk instruction's results.
>>>> > + ModelledPHI NewPHI(NewInsts, ActivePreds);
>>>> > +
>>>> > + // Does sinking this instruction render previous PHIs redundant?
>>>> > + if (NeededPHIs.find(NewPHI) != NeededPHIs.end()) {
>>>> > + NeededPHIs.erase(NewPHI);
>>>> > + RecomputePHIContents = true;
>>>> > + }
>>>> > +
>>>> > + if (RecomputePHIContents) {
>>>> > + // The needed PHIs have changed, so recompute the set of all
>>>> > needed
>>>> > + // values.
>>>> > + PHIContents.clear();
>>>> > + for (auto &PHI : NeededPHIs)
>>>> > + PHIContents.insert(PHI.getValues().begin(),
>>>> > PHI.getValues().end());
>>>> > + }
>>>> > +
>>>> > + // Is this instruction required by a later PHI that doesn't match
>>>> > this PHI?
>>>> > + // if so, we can't sink this instruction.
>>>> > + for (auto *V : NewPHI.getValues())
>>>> > + if (PHIContents.count(V))
>>>> > + // V exists in this PHI, but the whole PHI is different to
>>>> > NewPHI
>>>> > + // (else it would have been removed earlier). We cannot
>>>> > continue
>>>> > + // because this isn't representable.
>>>> > + return None;
>>>> > +
>>>> > + // Which operands need PHIs?
>>>> > + // FIXME: If any of these fail, we should partition up the
>>>> > candidates to
>>>> > + // try and continue making progress.
>>>> > + Instruction *I0 = NewInsts[0];
>>>> > + for (unsigned OpNum = 0, E = I0->getNumOperands(); OpNum != E;
>>>> > ++OpNum) {
>>>> > + ModelledPHI PHI(NewInsts, OpNum, ActivePreds);
>>>> > + if (PHI.areAllIncomingValuesSame())
>>>> > + continue;
>>>> > + if (!canReplaceOperandWithVariable(I0, OpNum))
>>>> > + // We can 't create a PHI from this instruction!
>>>> > + return None;
>>>> > + if (NeededPHIs.count(PHI))
>>>> > + continue;
>>>> > + if (!PHI.areAllIncomingValuesSameType())
>>>> > + return None;
>>>> > + // Don't create indirect calls! The called value is the final
>>>> > operand.
>>>> > + if ((isa<CallInst>(I0) || isa<InvokeInst>(I0)) && OpNum == E - 1
>>>> > &&
>>>> > + PHI.areAnyIncomingValuesConstant())
>>>> > + return None;
>>>> > +
>>>> > + NeededPHIs.reserve(NeededPHIs.size());
>>>> > + NeededPHIs.insert(PHI);
>>>> > + PHIContents.insert(PHI.getValues().begin(),
>>>> > PHI.getValues().end());
>>>> > + }
>>>> > +
>>>> > + if (isMemoryInst(NewInsts[0]))
>>>> > + ++MemoryInstNum;
>>>> > +
>>>> > + SinkingInstructionCandidate Cand;
>>>> > + Cand.NumInstructions = ++InstNum;
>>>> > + Cand.NumMemoryInsts = MemoryInstNum;
>>>> > + Cand.NumBlocks = ActivePreds.size();
>>>> > + Cand.NumPHIs = NeededPHIs.size();
>>>> > + for (auto *C : ActivePreds)
>>>> > + Cand.Blocks.push_back(C);
>>>> > +
>>>> > + return Cand;
>>>> > +}
>>>> > +
>>>> > +unsigned GVNSink::sinkBB(BasicBlock *BBEnd) {
>>>> > + DEBUG(dbgs() << "GVNSink: running on basic block ";
>>>> > + BBEnd->printAsOperand(dbgs()); dbgs() << "\n");
>>>> > + SmallVector<BasicBlock *, 4> Preds;
>>>> > + for (auto *B : predecessors(BBEnd)) {
>>>> > + auto *T = B->getTerminator();
>>>> > + if (isa<BranchInst>(T) || isa<SwitchInst>(T))
>>>> > + Preds.push_back(B);
>>>> > + else
>>>> > + return 0;
>>>> > + }
>>>> > + if (Preds.size() < 2)
>>>> > + return 0;
>>>> > + std::sort(Preds.begin(), Preds.end());
>>>> > +
>>>> > + unsigned NumOrigPreds = Preds.size();
>>>> > + // We can only sink instructions through unconditional branches.
>>>> > + for (auto I = Preds.begin(); I != Preds.end();) {
>>>> > + if ((*I)->getTerminator()->getNumSuccessors() != 1)
>>>> > + I = Preds.erase(I);
>>>> > + else
>>>> > + ++I;
>>>> > + }
>>>> > +
>>>> > + LockstepReverseIterator LRI(Preds);
>>>> > + SmallVector<SinkingInstructionCandidate, 4> Candidates;
>>>> > + unsigned InstNum = 0, MemoryInstNum = 0;
>>>> > + ModelledPHISet NeededPHIs;
>>>> > + SmallPtrSet<Value *, 4> PHIContents;
>>>> > + analyzeInitialPHIs(BBEnd, NeededPHIs, PHIContents);
>>>> > + unsigned NumOrigPHIs = NeededPHIs.size();
>>>> > +
>>>> > + while (LRI.isValid()) {
>>>> > + auto Cand = analyzeInstructionForSinking(LRI, InstNum,
>>>> > MemoryInstNum,
>>>> > + NeededPHIs,
>>>> > PHIContents);
>>>> > + if (!Cand)
>>>> > + break;
>>>> > + Cand->calculateCost(NumOrigPHIs, Preds.size());
>>>> > + Candidates.emplace_back(*Cand);
>>>> > + --LRI;
>>>> > + }
>>>> > +
>>>> > + std::stable_sort(
>>>> > + Candidates.begin(), Candidates.end(),
>>>> > + [](const SinkingInstructionCandidate &A,
>>>> > + const SinkingInstructionCandidate &B) { return A >= B; });
>>>>
>>>> std::stable_sort requires a strict weak ordering, so the predicate
>>>> should never return true if A and B are equal. This code violates
>>>> that.
>>>>
>>>> > + DEBUG(dbgs() << " -- Sinking candidates:\n"; for (auto &C
>>>> > + : Candidates)
>>>> > dbgs()
>>>> > + << " " << C <<
>>>> > "\n";);
>>>> > +
>>>> > + // Pick the top candidate, as long it is positive!
>>>> > + if (Candidates.empty() || Candidates.front().Cost <= 0)
>>>> > + return 0;
>>>> > + auto C = Candidates.front();
>>>> > +
>>>> > + DEBUG(dbgs() << " -- Sinking: " << C << "\n");
>>>> > + BasicBlock *InsertBB = BBEnd;
>>>> > + if (C.Blocks.size() < NumOrigPreds) {
>>>> > + DEBUG(dbgs() << " -- Splitting edge to ";
>>>> > BBEnd->printAsOperand(dbgs());
>>>> > + dbgs() << "\n");
>>>> > + InsertBB = SplitBlockPredecessors(BBEnd, C.Blocks,
>>>> > ".gvnsink.split");
>>>> > + if (!InsertBB) {
>>>> > + DEBUG(dbgs() << " -- FAILED to split edge!\n");
>>>> > + // Edge couldn't be split.
>>>> > + return 0;
>>>> > + }
>>>> > + }
>>>> > +
>>>> > + for (unsigned I = 0; I < C.NumInstructions; ++I)
>>>> > + sinkLastInstruction(C.Blocks, InsertBB);
>>>> > +
>>>> > + return C.NumInstructions;
>>>> > +}
>>>> > +
>>>> > +void GVNSink::sinkLastInstruction(ArrayRef<BasicBlock *> Blocks,
>>>> > + BasicBlock *BBEnd) {
>>>> > + SmallVector<Instruction *, 4> Insts;
>>>> > + for (BasicBlock *BB : Blocks)
>>>> > + Insts.push_back(BB->getTerminator()->getPrevNode());
>>>> > + Instruction *I0 = Insts.front();
>>>> > +
>>>> > + SmallVector<Value *, 4> NewOperands;
>>>> > + for (unsigned O = 0, E = I0->getNumOperands(); O != E; ++O) {
>>>> > + bool NeedPHI = any_of(Insts, [&I0, O](const Instruction *I) {
>>>> > + return I->getOperand(O) != I0->getOperand(O);
>>>> > + });
>>>> > + if (!NeedPHI) {
>>>> > + NewOperands.push_back(I0->getOperand(O));
>>>> > + continue;
>>>> > + }
>>>> > +
>>>> > + // Create a new PHI in the successor block and populate it.
>>>> > + auto *Op = I0->getOperand(O);
>>>> > + assert(!Op->getType()->isTokenTy() && "Can't PHI tokens!");
>>>> > + auto *PN = PHINode::Create(Op->getType(), Insts.size(),
>>>> > + Op->getName() + ".sink",
>>>> > &BBEnd->front());
>>>> > + for (auto *I : Insts)
>>>> > + PN->addIncoming(I->getOperand(O), I->getParent());
>>>> > + NewOperands.push_back(PN);
>>>> > + }
>>>> > +
>>>> > + // Arbitrarily use I0 as the new "common" instruction; remap its
>>>> > operands
>>>> > + // and move it to the start of the successor block.
>>>> > + for (unsigned O = 0, E = I0->getNumOperands(); O != E; ++O)
>>>> > + I0->getOperandUse(O).set(NewOperands[O]);
>>>> > + I0->moveBefore(&*BBEnd->getFirstInsertionPt());
>>>> > +
>>>> > + // Update metadata and IR flags.
>>>> > + for (auto *I : Insts)
>>>> > + if (I != I0) {
>>>> > + combineMetadataForCSE(I0, I);
>>>> > + I0->andIRFlags(I);
>>>> > + }
>>>> > +
>>>> > + for (auto *I : Insts)
>>>> > + if (I != I0)
>>>> > + I->replaceAllUsesWith(I0);
>>>> > + foldPointlessPHINodes(BBEnd);
>>>> > +
>>>> > + // Finally nuke all instructions apart from the common instruction.
>>>> > + for (auto *I : Insts)
>>>> > + if (I != I0)
>>>> > + I->eraseFromParent();
>>>> > +
>>>> > + NumRemoved += Insts.size() - 1;
>>>> > +}
>>>> > +
>>>> >
>>>> > +////////////////////////////////////////////////////////////////////////////////
>>>> > +// Pass machinery / boilerplate
>>>> > +
>>>> > +class GVNSinkLegacyPass : public FunctionPass {
>>>> > +public:
>>>> > + static char ID;
>>>> > +
>>>> > + GVNSinkLegacyPass() : FunctionPass(ID) {
>>>> > +
>>>> > initializeGVNSinkLegacyPassPass(*PassRegistry::getPassRegistry());
>>>> > + }
>>>> > +
>>>> > + bool runOnFunction(Function &F) override {
>>>> > + if (skipFunction(F))
>>>> > + return false;
>>>> > + GVNSink G;
>>>> > + return G.run(F);
>>>> > + }
>>>> > +
>>>> > + void getAnalysisUsage(AnalysisUsage &AU) const override {
>>>> > + AU.addPreserved<GlobalsAAWrapperPass>();
>>>> > + }
>>>> > +};
>>>> > +} // namespace
>>>> > +
>>>> > +PreservedAnalyses GVNSinkPass::run(Function &F,
>>>> > FunctionAnalysisManager &AM) {
>>>> > + GVNSink G;
>>>> > + if (!G.run(F))
>>>> > + return PreservedAnalyses::all();
>>>> > +
>>>> > + PreservedAnalyses PA;
>>>> > + PA.preserve<GlobalsAA>();
>>>> > + return PA;
>>>> > +}
>>>> > +
>>>> > +char GVNSinkLegacyPass::ID = 0;
>>>> > +INITIALIZE_PASS_BEGIN(GVNSinkLegacyPass, "gvn-sink",
>>>> > + "Early GVN sinking of Expressions", false,
>>>> > false)
>>>> > +INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
>>>> > +INITIALIZE_PASS_DEPENDENCY(PostDominatorTreeWrapperPass)
>>>> > +INITIALIZE_PASS_END(GVNSinkLegacyPass, "gvn-sink",
>>>> > + "Early GVN sinking of Expressions", false, false)
>>>> > +
>>>> > +FunctionPass *llvm::createGVNSinkPass() { return new
>>>> > GVNSinkLegacyPass(); }
>>>> >
>>>> > Modified: llvm/trunk/lib/Transforms/Scalar/Scalar.cpp
>>>> > URL:
>>>> > http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/Scalar.cpp?rev=303850&r1=303849&r2=303850&view=diff
>>>> >
>>>> > ==============================================================================
>>>> > --- llvm/trunk/lib/Transforms/Scalar/Scalar.cpp (original)
>>>> > +++ llvm/trunk/lib/Transforms/Scalar/Scalar.cpp Thu May 25 07:51:11
>>>> > 2017
>>>> > @@ -48,6 +48,7 @@ void llvm::initializeScalarOpts(PassRegi
>>>> > initializeEarlyCSELegacyPassPass(Registry);
>>>> > initializeEarlyCSEMemSSALegacyPassPass(Registry);
>>>> > initializeGVNHoistLegacyPassPass(Registry);
>>>> > + initializeGVNSinkLegacyPassPass(Registry);
>>>> > initializeFlattenCFGPassPass(Registry);
>>>> > initializeInductiveRangeCheckEliminationPass(Registry);
>>>> > initializeIndVarSimplifyLegacyPassPass(Registry);
>>>> >
>>>> > Modified: llvm/trunk/lib/Transforms/Utils/Local.cpp
>>>> > URL:
>>>> > http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/Local.cpp?rev=303850&r1=303849&r2=303850&view=diff
>>>> >
>>>> > ==============================================================================
>>>> > --- llvm/trunk/lib/Transforms/Utils/Local.cpp (original)
>>>> > +++ llvm/trunk/lib/Transforms/Utils/Local.cpp Thu May 25 07:51:11 2017
>>>> > @@ -2109,3 +2109,48 @@ void llvm::maybeMarkSanitizerLibraryCall
>>>> > !F->doesNotAccessMemory())
>>>> > CI->addAttribute(AttributeList::FunctionIndex,
>>>> > Attribute::NoBuiltin);
>>>> > }
>>>> > +
>>>> > +bool llvm::canReplaceOperandWithVariable(const Instruction *I,
>>>> > unsigned OpIdx) {
>>>> > + // We can't have a PHI with a metadata type.
>>>> > + if (I->getOperand(OpIdx)->getType()->isMetadataTy())
>>>> > + return false;
>>>> > +
>>>> > + // Early exit.
>>>> > + if (!isa<Constant>(I->getOperand(OpIdx)))
>>>> > + return true;
>>>> > +
>>>> > + switch (I->getOpcode()) {
>>>> > + default:
>>>> > + return true;
>>>> > + case Instruction::Call:
>>>> > + case Instruction::Invoke:
>>>> > + // Many arithmetic intrinsics have no issue taking a
>>>> > + // variable, however it's hard to distingish these from
>>>> > + // specials such as @llvm.frameaddress that require a constant.
>>>> > + if (isa<IntrinsicInst>(I))
>>>> > + return false;
>>>> > +
>>>> > + // Constant bundle operands may need to retain their
>>>> > constant-ness for
>>>> > + // correctness.
>>>> > + if (ImmutableCallSite(I).isBundleOperand(OpIdx))
>>>> > + return false;
>>>> > + return true;
>>>> > + case Instruction::ShuffleVector:
>>>> > + // Shufflevector masks are constant.
>>>> > + return OpIdx != 2;
>>>> > + case Instruction::ExtractValue:
>>>> > + case Instruction::InsertValue:
>>>> > + // All operands apart from the first are constant.
>>>> > + return OpIdx == 0;
>>>> > + case Instruction::Alloca:
>>>> > + return false;
>>>> > + case Instruction::GetElementPtr:
>>>> > + if (OpIdx == 0)
>>>> > + return true;
>>>> > + gep_type_iterator It = gep_type_begin(I);
>>>> > + for (auto E = std::next(It, OpIdx); It != E; ++It)
>>>> > + if (It.isStruct())
>>>> > + return false;
>>>> > + return true;
>>>> > + }
>>>> > +}
>>>> >
>>>> > Modified: llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp
>>>> > URL:
>>>> > http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp?rev=303850&r1=303849&r2=303850&view=diff
>>>> >
>>>> > ==============================================================================
>>>> > --- llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp (original)
>>>> > +++ llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp Thu May 25
>>>> > 07:51:11 2017
>>>> > @@ -1376,53 +1376,6 @@ HoistTerminator:
>>>> > return true;
>>>> > }
>>>> >
>>>> > -// Is it legal to place a variable in operand \c OpIdx of \c I?
>>>> > -// FIXME: This should be promoted to Instruction.
>>>> > -static bool canReplaceOperandWithVariable(const Instruction *I,
>>>> > - unsigned OpIdx) {
>>>> > - // We can't have a PHI with a metadata type.
>>>> > - if (I->getOperand(OpIdx)->getType()->isMetadataTy())
>>>> > - return false;
>>>> > -
>>>> > - // Early exit.
>>>> > - if (!isa<Constant>(I->getOperand(OpIdx)))
>>>> > - return true;
>>>> > -
>>>> > - switch (I->getOpcode()) {
>>>> > - default:
>>>> > - return true;
>>>> > - case Instruction::Call:
>>>> > - case Instruction::Invoke:
>>>> > - // FIXME: many arithmetic intrinsics have no issue taking a
>>>> > - // variable, however it's hard to distingish these from
>>>> > - // specials such as @llvm.frameaddress that require a constant.
>>>> > - if (isa<IntrinsicInst>(I))
>>>> > - return false;
>>>> > -
>>>> > - // Constant bundle operands may need to retain their
>>>> > constant-ness for
>>>> > - // correctness.
>>>> > - if (ImmutableCallSite(I).isBundleOperand(OpIdx))
>>>> > - return false;
>>>> > -
>>>> > - return true;
>>>> > -
>>>> > - case Instruction::ShuffleVector:
>>>> > - // Shufflevector masks are constant.
>>>> > - return OpIdx != 2;
>>>> > - case Instruction::ExtractValue:
>>>> > - case Instruction::InsertValue:
>>>> > - // All operands apart from the first are constant.
>>>> > - return OpIdx == 0;
>>>> > - case Instruction::Alloca:
>>>> > - return false;
>>>> > - case Instruction::GetElementPtr:
>>>> > - if (OpIdx == 0)
>>>> > - return true;
>>>> > - gep_type_iterator It = std::next(gep_type_begin(I), OpIdx - 1);
>>>> > - return It.isSequential();
>>>> > - }
>>>> > -}
>>>> > -
>>>> > // All instructions in Insts belong to different blocks that all
>>>> > unconditionally
>>>> > // branch to a common successor. Analyze each instruction and return
>>>> > true if it
>>>> > // would be possible to sink them into their successor, creating one
>>>> > common
>>>> >
>>>> > Added: llvm/trunk/test/Transforms/GVNSink/dither.ll
>>>> > URL:
>>>> > http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/GVNSink/dither.ll?rev=303850&view=auto
>>>> >
>>>> > ==============================================================================
>>>> > --- llvm/trunk/test/Transforms/GVNSink/dither.ll (added)
>>>> > +++ llvm/trunk/test/Transforms/GVNSink/dither.ll Thu May 25 07:51:11
>>>> > 2017
>>>> > @@ -0,0 +1,42 @@
>>>> > +; RUN: opt < %s -S -gvn-sink | FileCheck %s
>>>> > +
>>>> > +; Because %tmp17 has flipped operands to its equivalents %tmp14 and
>>>> > %tmp7, we
>>>> > +; can't sink the zext as we'd need a shuffling PHI in between.
>>>> > +;
>>>> > +; Just sinking the zext isn't profitable, so ensure nothing is sunk.
>>>> > +
>>>> > +; CHECK-LABEL: @hoge
>>>> > +; CHECK-NOT: bb18.gvnsink.split
>>>> > +define void @hoge() {
>>>> > +bb:
>>>> > + br i1 undef, label %bb4, label %bb11
>>>> > +
>>>> > +bb4: ; preds = %bb3
>>>> > + br i1 undef, label %bb6, label %bb8
>>>> > +
>>>> > +bb6: ; preds = %bb5
>>>> > + %tmp = zext i16 undef to i64
>>>> > + %tmp7 = add i64 %tmp, undef
>>>> > + br label %bb18
>>>> > +
>>>> > +bb8: ; preds = %bb5
>>>> > + %tmp9 = zext i16 undef to i64
>>>> > + br label %bb18
>>>> > +
>>>> > +bb11: ; preds = %bb10
>>>> > + br i1 undef, label %bb12, label %bb15
>>>> > +
>>>> > +bb12: ; preds = %bb11
>>>> > + %tmp13 = zext i16 undef to i64
>>>> > + %tmp14 = add i64 %tmp13, undef
>>>> > + br label %bb18
>>>> > +
>>>> > +bb15: ; preds = %bb11
>>>> > + %tmp16 = zext i16 undef to i64
>>>> > + %tmp17 = add i64 undef, %tmp16
>>>> > + br label %bb18
>>>> > +
>>>> > +bb18: ; preds = %bb15,
>>>> > %bb12, %bb8, %bb6
>>>> > + %tmp19 = phi i64 [ %tmp7, %bb6 ], [ undef, %bb8 ], [ %tmp14, %bb12
>>>> > ], [ %tmp17, %bb15 ]
>>>> > + unreachable
>>>> > +}
>>>> >
>>>> > Added: llvm/trunk/test/Transforms/GVNSink/indirect-call.ll
>>>> > URL:
>>>> > http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/GVNSink/indirect-call.ll?rev=303850&view=auto
>>>> >
>>>> > ==============================================================================
>>>> > --- llvm/trunk/test/Transforms/GVNSink/indirect-call.ll (added)
>>>> > +++ llvm/trunk/test/Transforms/GVNSink/indirect-call.ll Thu May 25
>>>> > 07:51:11 2017
>>>> > @@ -0,0 +1,70 @@
>>>> > +; RUN: opt < %s -gvn-sink -simplifycfg -simplifycfg-sink-common=false
>>>> > -S | FileCheck %s
>>>> > +
>>>> > +declare i8 @ext(i1)
>>>> > +
>>>> > +define zeroext i1 @test1(i1 zeroext %flag, i32 %blksA, i32 %blksB,
>>>> > i32 %nblks, i8(i1)* %ext) {
>>>> > +entry:
>>>> > + %cmp = icmp uge i32 %blksA, %nblks
>>>> > + br i1 %flag, label %if.then, label %if.else
>>>> > +
>>>> > +; CHECK-LABEL: test1
>>>> > +; CHECK: call i8 @ext
>>>> > +; CHECK: call i8 %ext
>>>> > +if.then:
>>>> > + %frombool1 = call i8 @ext(i1 %cmp)
>>>> > + br label %if.end
>>>> > +
>>>> > +if.else:
>>>> > + %frombool3 = call i8 %ext(i1 %cmp)
>>>> > + br label %if.end
>>>> > +
>>>> > +if.end:
>>>> > + %obeys.0 = phi i8 [ %frombool1, %if.then ], [ %frombool3, %if.else
>>>> > ]
>>>> > + %tobool4 = icmp ne i8 %obeys.0, 0
>>>> > + ret i1 %tobool4
>>>> > +}
>>>> > +
>>>> > +define zeroext i1 @test2(i1 zeroext %flag, i32 %blksA, i32 %blksB,
>>>> > i32 %nblks, i8(i1)* %ext) {
>>>> > +entry:
>>>> > + %cmp = icmp uge i32 %blksA, %nblks
>>>> > + br i1 %flag, label %if.then, label %if.else
>>>> > +
>>>> > +; CHECK-LABEL: test2
>>>> > +; CHECK: call i8 %ext
>>>> > +; CHECK-NOT: call
>>>> > +if.then:
>>>> > + %frombool1 = call i8 %ext(i1 %cmp)
>>>> > + br label %if.end
>>>> > +
>>>> > +if.else:
>>>> > + %frombool3 = call i8 %ext(i1 %cmp)
>>>> > + br label %if.end
>>>> > +
>>>> > +if.end:
>>>> > + %obeys.0 = phi i8 [ %frombool1, %if.then ], [ %frombool3, %if.else
>>>> > ]
>>>> > + %tobool4 = icmp ne i8 %obeys.0, 0
>>>> > + ret i1 %tobool4
>>>> > +}
>>>> > +
>>>> > +define zeroext i1 @test3(i1 zeroext %flag, i32 %blksA, i32 %blksB,
>>>> > i32 %nblks, i8(i1)* %ext1, i8(i1)* %ext2) {
>>>> > +entry:
>>>> > + %cmp = icmp uge i32 %blksA, %nblks
>>>> > + br i1 %flag, label %if.then, label %if.else
>>>> > +
>>>> > +; CHECK-LABEL: test3
>>>> > +; CHECK: %[[x:.*]] = select i1 %flag, i8 (i1)* %ext1, i8 (i1)* %ext2
>>>> > +; CHECK: call i8 %[[x]](i1 %cmp)
>>>> > +; CHECK-NOT: call
>>>> > +if.then:
>>>> > + %frombool1 = call i8 %ext1(i1 %cmp)
>>>> > + br label %if.end
>>>> > +
>>>> > +if.else:
>>>> > + %frombool3 = call i8 %ext2(i1 %cmp)
>>>> > + br label %if.end
>>>> > +
>>>> > +if.end:
>>>> > + %obeys.0 = phi i8 [ %frombool1, %if.then ], [ %frombool3, %if.else
>>>> > ]
>>>> > + %tobool4 = icmp ne i8 %obeys.0, 0
>>>> > + ret i1 %tobool4
>>>> > +}
>>>> >
>>>> > Added: llvm/trunk/test/Transforms/GVNSink/sink-common-code.ll
>>>> > URL:
>>>> > http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/GVNSink/sink-common-code.ll?rev=303850&view=auto
>>>> >
>>>> > ==============================================================================
>>>> > --- llvm/trunk/test/Transforms/GVNSink/sink-common-code.ll (added)
>>>> > +++ llvm/trunk/test/Transforms/GVNSink/sink-common-code.ll Thu May 25
>>>> > 07:51:11 2017
>>>> > @@ -0,0 +1,694 @@
>>>> > +; RUN: opt < %s -gvn-sink -simplifycfg -simplifycfg-sink-common=false
>>>> > -S | FileCheck %s
>>>> > +
>>>> > +define zeroext i1 @test1(i1 zeroext %flag, i32 %blksA, i32 %blksB,
>>>> > i32 %nblks) {
>>>> > +entry:
>>>> > + br i1 %flag, label %if.then, label %if.else
>>>> > +
>>>> > +; CHECK-LABEL: test1
>>>> > +; CHECK: add
>>>> > +; CHECK: select
>>>> > +; CHECK: icmp
>>>> > +; CHECK-NOT: br
>>>> > +if.then:
>>>> > + %cmp = icmp uge i32 %blksA, %nblks
>>>> > + %frombool1 = zext i1 %cmp to i8
>>>> > + br label %if.end
>>>> > +
>>>> > +if.else:
>>>> > + %add = add i32 %nblks, %blksB
>>>> > + %cmp2 = icmp ule i32 %add, %blksA
>>>> > + %frombool3 = zext i1 %cmp2 to i8
>>>> > + br label %if.end
>>>> > +
>>>> > +if.end:
>>>> > + %obeys.0 = phi i8 [ %frombool1, %if.then ], [ %frombool3, %if.else
>>>> > ]
>>>> > + %tobool4 = icmp ne i8 %obeys.0, 0
>>>> > + ret i1 %tobool4
>>>> > +}
>>>> > +
>>>> > +define zeroext i1 @test2(i1 zeroext %flag, i32 %blksA, i32 %blksB,
>>>> > i32 %nblks) {
>>>> > +entry:
>>>> > + br i1 %flag, label %if.then, label %if.else
>>>> > +
>>>> > +; CHECK-LABEL: test2
>>>> > +; CHECK: add
>>>> > +; CHECK: select
>>>> > +; CHECK: icmp
>>>> > +; CHECK-NOT: br
>>>> > +if.then:
>>>> > + %cmp = icmp uge i32 %blksA, %nblks
>>>> > + %frombool1 = zext i1 %cmp to i8
>>>> > + br label %if.end
>>>> > +
>>>> > +if.else:
>>>> > + %add = add i32 %nblks, %blksB
>>>> > + %cmp2 = icmp uge i32 %blksA, %add
>>>> > + %frombool3 = zext i1 %cmp2 to i8
>>>> > + br label %if.end
>>>> > +
>>>> > +if.end:
>>>> > + %obeys.0 = phi i8 [ %frombool1, %if.then ], [ %frombool3, %if.else
>>>> > ]
>>>> > + %tobool4 = icmp ne i8 %obeys.0, 0
>>>> > + ret i1 %tobool4
>>>> > +}
>>>> > +
>>>> > +declare i32 @foo(i32, i32) nounwind readnone
>>>> > +
>>>> > +define i32 @test3(i1 zeroext %flag, i32 %x, i32 %y) {
>>>> > +entry:
>>>> > + br i1 %flag, label %if.then, label %if.else
>>>> > +
>>>> > +if.then:
>>>> > + %x0 = call i32 @foo(i32 %x, i32 0) nounwind readnone
>>>> > + %y0 = call i32 @foo(i32 %x, i32 1) nounwind readnone
>>>> > + br label %if.end
>>>> > +
>>>> > +if.else:
>>>> > + %x1 = call i32 @foo(i32 %y, i32 0) nounwind readnone
>>>> > + %y1 = call i32 @foo(i32 %y, i32 1) nounwind readnone
>>>> > + br label %if.end
>>>> > +
>>>> > +if.end:
>>>> > + %xx = phi i32 [ %x0, %if.then ], [ %x1, %if.else ]
>>>> > + %yy = phi i32 [ %y0, %if.then ], [ %y1, %if.else ]
>>>> > + %ret = add i32 %xx, %yy
>>>> > + ret i32 %ret
>>>> > +}
>>>> > +
>>>> > +; CHECK-LABEL: test3
>>>> > +; CHECK: select
>>>> > +; CHECK: call
>>>> > +; CHECK: call
>>>> > +; CHECK: add
>>>> > +; CHECK-NOT: br
>>>> > +
>>>> > +define i32 @test4(i1 zeroext %flag, i32 %x, i32* %y) {
>>>> > +entry:
>>>> > + br i1 %flag, label %if.then, label %if.else
>>>> > +
>>>> > +if.then:
>>>> > + %a = add i32 %x, 5
>>>> > + store i32 %a, i32* %y
>>>> > + br label %if.end
>>>> > +
>>>> > +if.else:
>>>> > + %b = add i32 %x, 7
>>>> > + store i32 %b, i32* %y
>>>> > + br label %if.end
>>>> > +
>>>> > +if.end:
>>>> > + ret i32 1
>>>> > +}
>>>> > +
>>>> > +; CHECK-LABEL: test4
>>>> > +; CHECK: select
>>>> > +; CHECK: store
>>>> > +; CHECK-NOT: store
>>>> > +
>>>> > +define i32 @test5(i1 zeroext %flag, i32 %x, i32* %y) {
>>>> > +entry:
>>>> > + br i1 %flag, label %if.then, label %if.else
>>>> > +
>>>> > +if.then:
>>>> > + %a = add i32 %x, 5
>>>> > + store volatile i32 %a, i32* %y
>>>> > + br label %if.end
>>>> > +
>>>> > +if.else:
>>>> > + %b = add i32 %x, 7
>>>> > + store i32 %b, i32* %y
>>>> > + br label %if.end
>>>> > +
>>>> > +if.end:
>>>> > + ret i32 1
>>>> > +}
>>>> > +
>>>> > +; CHECK-LABEL: test5
>>>> > +; CHECK: store volatile
>>>> > +; CHECK: store
>>>> > +
>>>> > +define i32 @test6(i1 zeroext %flag, i32 %x, i32* %y) {
>>>> > +entry:
>>>> > + br i1 %flag, label %if.then, label %if.else
>>>> > +
>>>> > +if.then:
>>>> > + %a = add i32 %x, 5
>>>> > + store volatile i32 %a, i32* %y
>>>> > + br label %if.end
>>>> > +
>>>> > +if.else:
>>>> > + %b = add i32 %x, 7
>>>> > + store volatile i32 %b, i32* %y
>>>> > + br label %if.end
>>>> > +
>>>> > +if.end:
>>>> > + ret i32 1
>>>> > +}
>>>> > +
>>>> > +; CHECK-LABEL: test6
>>>> > +; CHECK: select
>>>> > +; CHECK: store volatile
>>>> > +; CHECK-NOT: store
>>>> > +
>>>> > +define i32 @test7(i1 zeroext %flag, i32 %x, i32* %y) {
>>>> > +entry:
>>>> > + br i1 %flag, label %if.then, label %if.else
>>>> > +
>>>> > +if.then:
>>>> > + %z = load volatile i32, i32* %y
>>>> > + %a = add i32 %z, 5
>>>> > + store volatile i32 %a, i32* %y
>>>> > + br label %if.end
>>>> > +
>>>> > +if.else:
>>>> > + %w = load volatile i32, i32* %y
>>>> > + %b = add i32 %w, 7
>>>> > + store volatile i32 %b, i32* %y
>>>> > + br label %if.end
>>>> > +
>>>> > +if.end:
>>>> > + ret i32 1
>>>> > +}
>>>> > +
>>>> > +; CHECK-LABEL: test7
>>>> > +; CHECK-DAG: select
>>>> > +; CHECK-DAG: load volatile
>>>> > +; CHECK: store volatile
>>>> > +; CHECK-NOT: load
>>>> > +; CHECK-NOT: store
>>>> > +
>>>> > +; The extra store in %if.then means %z and %w are not equivalent.
>>>> > +define i32 @test9(i1 zeroext %flag, i32 %x, i32* %y, i32* %p) {
>>>> > +entry:
>>>> > + br i1 %flag, label %if.then, label %if.else
>>>> > +
>>>> > +if.then:
>>>> > + store i32 7, i32* %p
>>>> > + %z = load volatile i32, i32* %y
>>>> > + store i32 6, i32* %p
>>>> > + %a = add i32 %z, 5
>>>> > + store volatile i32 %a, i32* %y
>>>> > + br label %if.end
>>>> > +
>>>> > +if.else:
>>>> > + %w = load volatile i32, i32* %y
>>>> > + %b = add i32 %w, 7
>>>> > + store volatile i32 %b, i32* %y
>>>> > + br label %if.end
>>>> > +
>>>> > +if.end:
>>>> > + ret i32 1
>>>> > +}
>>>> > +
>>>> > +; CHECK-LABEL: test9
>>>> > +; CHECK: add
>>>> > +; CHECK: add
>>>> > +
>>>> > +%struct.anon = type { i32, i32 }
>>>> > +
>>>> > +; The GEP indexes a struct type so cannot have a variable last index.
>>>> > +define i32 @test10(i1 zeroext %flag, i32 %x, i32* %y, %struct.anon*
>>>> > %s) {
>>>> > +entry:
>>>> > + br i1 %flag, label %if.then, label %if.else
>>>> > +
>>>> > +if.then:
>>>> > + %dummy = add i32 %x, 5
>>>> > + %gepa = getelementptr inbounds %struct.anon, %struct.anon* %s, i32
>>>> > 0, i32 0
>>>> > + store volatile i32 %x, i32* %gepa
>>>> > + br label %if.end
>>>> > +
>>>> > +if.else:
>>>> > + %dummy1 = add i32 %x, 6
>>>> > + %gepb = getelementptr inbounds %struct.anon, %struct.anon* %s, i32
>>>> > 0, i32 1
>>>> > + store volatile i32 %x, i32* %gepb
>>>> > + br label %if.end
>>>> > +
>>>> > +if.end:
>>>> > + ret i32 1
>>>> > +}
>>>> > +
>>>> > +; CHECK-LABEL: test10
>>>> > +; CHECK: getelementptr
>>>> > +; CHECK: store volatile
>>>> > +; CHECK: getelementptr
>>>> > +; CHECK: store volatile
>>>> > +
>>>> > +; The shufflevector's mask operand cannot be merged in a PHI.
>>>> > +define i32 @test11(i1 zeroext %flag, i32 %w, <2 x i32> %x, <2 x i32>
>>>> > %y) {
>>>> > +entry:
>>>> > + br i1 %flag, label %if.then, label %if.else
>>>> > +
>>>> > +if.then:
>>>> > + %dummy = add i32 %w, 5
>>>> > + %sv1 = shufflevector <2 x i32> %x, <2 x i32> %y, <2 x i32> <i32 0,
>>>> > i32 1>
>>>> > + br label %if.end
>>>> > +
>>>> > +if.else:
>>>> > + %dummy1 = add i32 %w, 6
>>>> > + %sv2 = shufflevector <2 x i32> %x, <2 x i32> %y, <2 x i32> <i32 1,
>>>> > i32 0>
>>>> > + br label %if.end
>>>> > +
>>>> > +if.end:
>>>> > + %p = phi <2 x i32> [ %sv1, %if.then ], [ %sv2, %if.else ]
>>>> > + ret i32 1
>>>> > +}
>>>> > +
>>>> > +; CHECK-LABEL: test11
>>>> > +; CHECK: shufflevector
>>>> > +; CHECK: shufflevector
>>>> > +
>>>> > +; We can't common an intrinsic!
>>>> > +define i32 @test12(i1 zeroext %flag, i32 %w, i32 %x, i32 %y) {
>>>> > +entry:
>>>> > + br i1 %flag, label %if.then, label %if.else
>>>> > +
>>>> > +if.then:
>>>> > + %dummy = add i32 %w, 5
>>>> > + %sv1 = call i32 @llvm.ctlz.i32(i32 %x)
>>>> > + br label %if.end
>>>> > +
>>>> > +if.else:
>>>> > + %dummy1 = add i32 %w, 6
>>>> > + %sv2 = call i32 @llvm.cttz.i32(i32 %x)
>>>> > + br label %if.end
>>>> > +
>>>> > +if.end:
>>>> > + %p = phi i32 [ %sv1, %if.then ], [ %sv2, %if.else ]
>>>> > + ret i32 1
>>>> > +}
>>>> > +
>>>> > +declare i32 @llvm.ctlz.i32(i32 %x) readnone
>>>> > +declare i32 @llvm.cttz.i32(i32 %x) readnone
>>>> > +
>>>> > +; CHECK-LABEL: test12
>>>> > +; CHECK: call i32 @llvm.ctlz
>>>> > +; CHECK: call i32 @llvm.cttz
>>>> > +
>>>> > +; The TBAA metadata should be properly combined.
>>>> > +define i32 @test13(i1 zeroext %flag, i32 %x, i32* %y) {
>>>> > +entry:
>>>> > + br i1 %flag, label %if.then, label %if.else
>>>> > +
>>>> > +if.then:
>>>> > + %z = load volatile i32, i32* %y
>>>> > + %a = add i32 %z, 5
>>>> > + store volatile i32 %a, i32* %y, !tbaa !3
>>>> > + br label %if.end
>>>> > +
>>>> > +if.else:
>>>> > + %w = load volatile i32, i32* %y
>>>> > + %b = add i32 %w, 7
>>>> > + store volatile i32 %b, i32* %y, !tbaa !4
>>>> > + br label %if.end
>>>> > +
>>>> > +if.end:
>>>> > + ret i32 1
>>>> > +}
>>>> > +
>>>> > +!0 = !{ !"an example type tree" }
>>>> > +!1 = !{ !"int", !0 }
>>>> > +!2 = !{ !"float", !0 }
>>>> > +!3 = !{ !"const float", !2, i64 0 }
>>>> > +!4 = !{ !"special float", !2, i64 1 }
>>>> > +
>>>> > +; CHECK-LABEL: test13
>>>> > +; CHECK-DAG: select
>>>> > +; CHECK-DAG: load volatile
>>>> > +; CHECK: store volatile {{.*}}, !tbaa !0
>>>> > +; CHECK-NOT: load
>>>> > +; CHECK-NOT: store
>>>> > +
>>>> > +; The call should be commoned.
>>>> > +define i32 @test13a(i1 zeroext %flag, i32 %w, i32 %x, i32 %y) {
>>>> > +entry:
>>>> > + br i1 %flag, label %if.then, label %if.else
>>>> > +
>>>> > +if.then:
>>>> > + %sv1 = call i32 @bar(i32 %x)
>>>> > + br label %if.end
>>>> > +
>>>> > +if.else:
>>>> > + %sv2 = call i32 @bar(i32 %y)
>>>> > + br label %if.end
>>>> > +
>>>> > +if.end:
>>>> > + %p = phi i32 [ %sv1, %if.then ], [ %sv2, %if.else ]
>>>> > + ret i32 1
>>>> > +}
>>>> > +declare i32 @bar(i32)
>>>> > +
>>>> > +; CHECK-LABEL: test13a
>>>> > +; CHECK: %[[x:.*]] = select i1 %flag
>>>> > +; CHECK: call i32 @bar(i32 %[[x]])
>>>> > +
>>>> > +; The load should be commoned.
>>>> > +define i32 @test14(i1 zeroext %flag, i32 %w, i32 %x, i32 %y,
>>>> > %struct.anon* %s) {
>>>> > +entry:
>>>> > + br i1 %flag, label %if.then, label %if.else
>>>> > +
>>>> > +if.then:
>>>> > + %dummy = add i32 %x, 1
>>>> > + %gepa = getelementptr inbounds %struct.anon, %struct.anon* %s, i32
>>>> > 0, i32 1
>>>> > + %sv1 = load i32, i32* %gepa
>>>> > + %cmp1 = icmp eq i32 %sv1, 56
>>>> > + br label %if.end
>>>> > +
>>>> > +if.else:
>>>> > + %dummy2 = add i32 %x, 4
>>>> > + %gepb = getelementptr inbounds %struct.anon, %struct.anon* %s, i32
>>>> > 0, i32 1
>>>> > + %sv2 = load i32, i32* %gepb
>>>> > + %cmp2 = icmp eq i32 %sv2, 57
>>>> > + br label %if.end
>>>> > +
>>>> > +if.end:
>>>> > + %p = phi i1 [ %cmp1, %if.then ], [ %cmp2, %if.else ]
>>>> > + ret i32 1
>>>> > +}
>>>> > +
>>>> > +; CHECK-LABEL: test14
>>>> > +; CHECK: getelementptr
>>>> > +; CHECK: load
>>>> > +; CHECK-NOT: load
>>>> > +
>>>> > +; The load should be commoned.
>>>> > +define i32 @test15(i1 zeroext %flag, i32 %w, i32 %x, i32 %y,
>>>> > %struct.anon* %s) {
>>>> > +entry:
>>>> > + br i1 %flag, label %if.then, label %if.else
>>>> > +
>>>> > +if.then:
>>>> > + %dummy = add i32 %x, 1
>>>> > + %gepa = getelementptr inbounds %struct.anon, %struct.anon* %s, i32
>>>> > 0, i32 0
>>>> > + %sv1 = load i32, i32* %gepa
>>>> > + %ext1 = zext i32 %sv1 to i64
>>>> > + %cmp1 = icmp eq i64 %ext1, 56
>>>> > + br label %if.end
>>>> > +
>>>> > +if.else:
>>>> > + %dummy2 = add i32 %x, 4
>>>> > + %gepb = getelementptr inbounds %struct.anon, %struct.anon* %s, i32
>>>> > 0, i32 1
>>>> > + %sv2 = load i32, i32* %gepb
>>>> > + %ext2 = zext i32 %sv2 to i64
>>>> > + %cmp2 = icmp eq i64 %ext2, 56
>>>> > + br label %if.end
>>>> > +
>>>> > +if.end:
>>>> > + %p = phi i1 [ %cmp1, %if.then ], [ %cmp2, %if.else ]
>>>> > + ret i32 1
>>>> > +}
>>>> > +
>>>> > +; CHECK-LABEL: test15
>>>> > +; CHECK: getelementptr
>>>> > +; CHECK: load
>>>> > +; CHECK-NOT: load
>>>> > +
>>>> > +define zeroext i1 @test_crash(i1 zeroext %flag, i32* %i4, i32* %m,
>>>> > i32* %n) {
>>>> > +entry:
>>>> > + br i1 %flag, label %if.then, label %if.else
>>>> > +
>>>> > +if.then:
>>>> > + %tmp1 = load i32, i32* %i4
>>>> > + %tmp2 = add i32 %tmp1, -1
>>>> > + store i32 %tmp2, i32* %i4
>>>> > + br label %if.end
>>>> > +
>>>> > +if.else:
>>>> > + %tmp3 = load i32, i32* %m
>>>> > + %tmp4 = load i32, i32* %n
>>>> > + %tmp5 = add i32 %tmp3, %tmp4
>>>> > + store i32 %tmp5, i32* %i4
>>>> > + br label %if.end
>>>> > +
>>>> > +if.end:
>>>> > + ret i1 true
>>>> > +}
>>>> > +
>>>> > +; CHECK-LABEL: test_crash
>>>> > +; No checks for test_crash - just ensure it doesn't crash!
>>>> > +
>>>> > +define zeroext i1 @test16(i1 zeroext %flag, i1 zeroext %flag2, i32
>>>> > %blksA, i32 %blksB, i32 %nblks) {
>>>> > +
>>>> > +entry:
>>>> > + br i1 %flag, label %if.then, label %if.else
>>>> > +
>>>> > +if.then:
>>>> > + %cmp = icmp uge i32 %blksA, %nblks
>>>> > + %frombool1 = zext i1 %cmp to i8
>>>> > + br label %if.end
>>>> > +
>>>> > +if.else:
>>>> > + br i1 %flag2, label %if.then2, label %if.end
>>>> > +
>>>> > +if.then2:
>>>> > + %add = add i32 %nblks, %blksB
>>>> > + %cmp2 = icmp ule i32 %add, %blksA
>>>> > + %frombool3 = zext i1 %cmp2 to i8
>>>> > + br label %if.end
>>>> > +
>>>> > +if.end:
>>>> > + %obeys.0 = phi i8 [ %frombool1, %if.then ], [ %frombool3, %if.then2
>>>> > ], [ 0, %if.else ]
>>>> > + %tobool4 = icmp ne i8 %obeys.0, 0
>>>> > + ret i1 %tobool4
>>>> > +}
>>>> > +
>>>> > +; CHECK-LABEL: test16
>>>> > +; CHECK: zext
>>>> > +; CHECK: zext
>>>> > +
>>>> > +define zeroext i1 @test16a(i1 zeroext %flag, i1 zeroext %flag2, i32
>>>> > %blksA, i32 %blksB, i32 %nblks, i8* %p) {
>>>> > +
>>>> > +entry:
>>>> > + br i1 %flag, label %if.then, label %if.else
>>>> > +
>>>> > +if.then:
>>>> > + %cmp = icmp uge i32 %blksA, %nblks
>>>> > + %frombool1 = zext i1 %cmp to i8
>>>> > + %b1 = sext i8 %frombool1 to i32
>>>> > + %b2 = trunc i32 %b1 to i8
>>>> > + store i8 %b2, i8* %p
>>>> > + br label %if.end
>>>> > +
>>>> > +if.else:
>>>> > + br i1 %flag2, label %if.then2, label %if.end
>>>> > +
>>>> > +if.then2:
>>>> > + %add = add i32 %nblks, %blksB
>>>> > + %cmp2 = icmp ule i32 %add, %blksA
>>>> > + %frombool3 = zext i1 %cmp2 to i8
>>>> > + %a1 = sext i8 %frombool3 to i32
>>>> > + %a2 = trunc i32 %a1 to i8
>>>> > + store i8 %a2, i8* %p
>>>> > + br label %if.end
>>>> > +
>>>> > +if.end:
>>>> > + ret i1 true
>>>> > +}
>>>> > +
>>>> > +; CHECK-LABEL: test16a
>>>> > +; CHECK: zext
>>>> > +; CHECK-NOT: zext
>>>> > +
>>>> > +define zeroext i1 @test17(i32 %flag, i32 %blksA, i32 %blksB, i32
>>>> > %nblks) {
>>>> > +entry:
>>>> > + switch i32 %flag, label %if.end [
>>>> > + i32 0, label %if.then
>>>> > + i32 1, label %if.then2
>>>> > + ]
>>>> > +
>>>> > +if.then:
>>>> > + %cmp = icmp uge i32 %blksA, %nblks
>>>> > + %frombool1 = call i8 @i1toi8(i1 %cmp)
>>>> > + %a1 = sext i8 %frombool1 to i32
>>>> > + %a2 = trunc i32 %a1 to i8
>>>> > + br label %if.end
>>>> > +
>>>> > +if.then2:
>>>> > + %add = add i32 %nblks, %blksB
>>>> > + %cmp2 = icmp ule i32 %add, %blksA
>>>> > + %frombool3 = call i8 @i1toi8(i1 %cmp2)
>>>> > + %b1 = sext i8 %frombool3 to i32
>>>> > + %b2 = trunc i32 %b1 to i8
>>>> > + br label %if.end
>>>> > +
>>>> > +if.end:
>>>> > + %obeys.0 = phi i8 [ %a2, %if.then ], [ %b2, %if.then2 ], [ 0,
>>>> > %entry ]
>>>> > + %tobool4 = icmp ne i8 %obeys.0, 0
>>>> > + ret i1 %tobool4
>>>> > +}
>>>> > +declare i8 @i1toi8(i1)
>>>> > +
>>>> > +; FIXME: DISABLED - we don't consider this profitable. We should
>>>> > +; - Consider argument setup/return mov'ing for calls, like
>>>> > InlineCost does.
>>>> > +; - Consider the removal of the %obeys.0 PHI (zero PHI movement
>>>> > overall)
>>>> > +
>>>> > +; DISABLED-CHECK-LABEL: test17
>>>> > +; DISABLED-CHECK: if.then:
>>>> > +; DISABLED-CHECK-NEXT: icmp uge
>>>> > +; DISABLED-CHECK-NEXT: br label %[[x:.*]]
>>>> > +
>>>> > +; DISABLED-CHECK: if.then2:
>>>> > +; DISABLED-CHECK-NEXT: add
>>>> > +; DISABLED-CHECK-NEXT: icmp ule
>>>> > +; DISABLED-CHECK-NEXT: br label %[[x]]
>>>> > +
>>>> > +; DISABLED-CHECK: [[x]]:
>>>> > +; DISABLED-CHECK-NEXT: %[[y:.*]] = phi i1 [ %cmp
>>>> > +; DISABLED-CHECK-NEXT: %[[z:.*]] = call i8 @i1toi8(i1 %[[y]])
>>>> > +; DISABLED-CHECK-NEXT: br label %if.end
>>>> > +
>>>> > +; DISABLED-CHECK: if.end:
>>>> > +; DISABLED-CHECK-NEXT: phi i8
>>>> > +; DISABLED-CHECK-DAG: [ %[[z]], %[[x]] ]
>>>> > +; DISABLED-CHECK-DAG: [ 0, %entry ]
>>>> > +
>>>> > +define zeroext i1 @test18(i32 %flag, i32 %blksA, i32 %blksB, i32
>>>> > %nblks) {
>>>> > +entry:
>>>> > + switch i32 %flag, label %if.then3 [
>>>> > + i32 0, label %if.then
>>>> > + i32 1, label %if.then2
>>>> > + ]
>>>> > +
>>>> > +if.then:
>>>> > + %cmp = icmp uge i32 %blksA, %nblks
>>>> > + %frombool1 = zext i1 %cmp to i8
>>>> > + br label %if.end
>>>> > +
>>>> > +if.then2:
>>>> > + %add = add i32 %nblks, %blksB
>>>> > + %cmp2 = icmp ule i32 %add, %blksA
>>>> > + %frombool3 = zext i1 %cmp2 to i8
>>>> > + br label %if.end
>>>> > +
>>>> > +if.then3:
>>>> > + %add2 = add i32 %nblks, %blksA
>>>> > + %cmp3 = icmp ule i32 %add2, %blksA
>>>> > + %frombool4 = zext i1 %cmp3 to i8
>>>> > + br label %if.end
>>>> > +
>>>> > +if.end:
>>>> > + %obeys.0 = phi i8 [ %frombool1, %if.then ], [ %frombool3, %if.then2
>>>> > ], [ %frombool4, %if.then3 ]
>>>> > + %tobool4 = icmp ne i8 %obeys.0, 0
>>>> > + ret i1 %tobool4
>>>> > +}
>>>> > +
>>>> > +; CHECK-LABEL: test18
>>>> > +; CHECK: if.end:
>>>> > +; CHECK-NEXT: %[[x:.*]] = phi i1
>>>> > +; CHECK-DAG: [ %cmp, %if.then ]
>>>> > +; CHECK-DAG: [ %cmp2, %if.then2 ]
>>>> > +; CHECK-DAG: [ %cmp3, %if.then3 ]
>>>> > +; CHECK-NEXT: zext i1 %[[x]] to i8
>>>> > +
>>>> > +; The phi is confusing - both add instructions are used by it, but
>>>> > +; not on their respective unconditional arcs. It should not be
>>>> > +; optimized.
>>>> > +define void @test_pr30292(i1 %cond, i1 %cond2, i32 %a, i32 %b) {
>>>> > +entry:
>>>> > + %add1 = add i32 %a, 1
>>>> > + br label %succ
>>>> > +
>>>> > +one:
>>>> > + br i1 %cond, label %two, label %succ
>>>> > +
>>>> > +two:
>>>> > + call void @g()
>>>> > + %add2 = add i32 %a, 1
>>>> > + br label %succ
>>>> > +
>>>> > +succ:
>>>> > + %p = phi i32 [ 0, %entry ], [ %add1, %one ], [ %add2, %two ]
>>>> > + br label %one
>>>> > +}
>>>> > +declare void @g()
>>>> > +
>>>> > +; CHECK-LABEL: test_pr30292
>>>> > +; CHECK: phi i32 [ 0, %entry ], [ %add1, %succ ], [ %add2, %two ]
>>>> > +
>>>> > +define zeroext i1 @test_pr30244(i1 zeroext %flag, i1 zeroext %flag2,
>>>> > i32 %blksA, i32 %blksB, i32 %nblks) {
>>>> > +
>>>> > +entry:
>>>> > + %p = alloca i8
>>>> > + br i1 %flag, label %if.then, label %if.else
>>>> > +
>>>> > +if.then:
>>>> > + %cmp = icmp uge i32 %blksA, %nblks
>>>> > + %frombool1 = zext i1 %cmp to i8
>>>> > + store i8 %frombool1, i8* %p
>>>> > + br label %if.end
>>>> > +
>>>> > +if.else:
>>>> > + br i1 %flag2, label %if.then2, label %if.end
>>>> > +
>>>> > +if.then2:
>>>> > + %add = add i32 %nblks, %blksB
>>>> > + %cmp2 = icmp ule i32 %add, %blksA
>>>> > + %frombool3 = zext i1 %cmp2 to i8
>>>> > + store i8 %frombool3, i8* %p
>>>> > + br label %if.end
>>>> > +
>>>> > +if.end:
>>>> > + ret i1 tr
>>>
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--
Davide
"There are no solved problems; there are only problems that are more
or less solved" -- Henri Poincare
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