[llvm] r268254 - [SimplifyCFG] Extend TryToSimplifyUncondBranchFromEmptyBlock for empty block including lifetime intrinsics
Mehdi Amini via llvm-commits
llvm-commits at lists.llvm.org
Mon May 2 14:55:09 PDT 2016
I believe it also broke our LTO bootstrap: http://lab.llvm.org:8080/green/job/clang-stage2-configure-Rlto/8740/
--
Mehdi
> On May 2, 2016, at 12:49 PM, Hans Wennborg via llvm-commits <llvm-commits at lists.llvm.org> wrote:
>
> Sounds good, thanks.
>
> On Mon, May 2, 2016 at 12:44 PM, Reid Kleckner via llvm-commits
> <llvm-commits at lists.llvm.org> wrote:
>> We are seeing assertion failures while building Chromium related to this
>> change:
>> https://build.chromium.org/p/chromium.fyi/builders/ClangToTLinuxASan/builds/4019/steps/compile/logs/stdio
>>
>> The uses related to lifetime start / end make me suspect this change, as
>> well as TryToSimplifyUncondBranchFromEmptyBlock, so I'm going to
>> speculatively revert for now while I look for a test case.
>>
>> FAILED: obj/base/files/base.file_posix.o
>> ...
>> While deleting: i8* %
>> Use still stuck around after Def is destroyed: call void
>> @llvm.lifetime.end(i64 4, i8* <badref>) #11, !dbg !129
>> Use still stuck around after Def is destroyed: call void
>> @llvm.lifetime.end(i64 4, i8* <badref>) #11, !dbg !129
>> clang-3.9:
>> /b/build/slave/ClangToTLinuxASan/build/src/third_party/llvm/lib/IR/Value.cpp:85:
>> virtual llvm::Value::~Value(): Assertion `use_empty() && "Uses remain when a
>> value is destroyed!"' failed.
>> 0 clang-3.9 0x0000000001a1c945
>> llvm::sys::PrintStackTrace(llvm::raw_ostream&) + 37
>> 1 clang-3.9 0x0000000001a1a6d6 llvm::sys::RunSignalHandlers() + 54
>> 2 clang-3.9 0x0000000001a1a901
>> 3 libpthread.so.0 0x00007f753c5c2cb0
>> 4 libc.so.6 0x00007f753b7ff0d5 gsignal + 53
>> 5 libc.so.6 0x00007f753b80283b abort + 379
>> 6 libc.so.6 0x00007f753b7f7d9e
>> 7 libc.so.6 0x00007f753b7f7e42
>> 8 clang-3.9 0x00000000016d6d0f
>> 9 clang-3.9 0x0000000001679437
>> 10 clang-3.9 0x00000000016161fc llvm::BasicBlock::~BasicBlock() + 140
>> 11 clang-3.9 0x00000000016163b9 llvm::BasicBlock::~BasicBlock() + 9
>> 12 clang-3.9 0x0000000001616722 llvm::BasicBlock::eraseFromParent() +
>> 114
>> 13 clang-3.9 0x0000000001a6b0d3
>> llvm::TryToSimplifyUncondBranchFromEmptyBlock(llvm::BasicBlock*) + 3923
>> 14 clang-3.9 0x0000000001ab74ea llvm::SimplifyCFG(llvm::BasicBlock*,
>> llvm::TargetTransformInfo const&, unsigned int, llvm::AssumptionCache*,
>> llvm::SmallPtrSetImpl<llvm::BasicBlock*>*) + 7914
>> 15 clang-3.9 0x0000000001994c2d
>>
>> On Mon, May 2, 2016 at 10:22 AM, Hans Wennborg via llvm-commits
>> <llvm-commits at lists.llvm.org> wrote:
>>>
>>> Author: hans
>>> Date: Mon May 2 12:22:54 2016
>>> New Revision: 268254
>>>
>>> URL: http://llvm.org/viewvc/llvm-project?rev=268254&view=rev
>>> Log:
>>> [SimplifyCFG] Extend TryToSimplifyUncondBranchFromEmptyBlock for empty
>>> block including lifetime intrinsics
>>>
>>> Make it possible that TryToSimplifyUncondBranchFromEmptyBlock merges empty
>>> basic block including lifetime intrinsics as well as phi nodes and
>>> unconditional branch into its successor or predecessor(s).
>>>
>>> If successor of empty block has single predecessor, all contents including
>>> lifetime intrinsics are sinked into the successor. Otherwise, they are
>>> hoisted into its predecessor(s) and then merged into the predecessor(s).
>>>
>>> Patch by Josh Yoon <josh.yoon at samsung.com>!
>>>
>>> Differential Revision: http://reviews.llvm.org/D19257
>>>
>>> Modified:
>>> llvm/trunk/include/llvm/IR/BasicBlock.h
>>> llvm/trunk/lib/IR/BasicBlock.cpp
>>> llvm/trunk/lib/Transforms/Utils/Local.cpp
>>> llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp
>>> llvm/trunk/test/Transforms/SimplifyCFG/lifetime.ll
>>>
>>> Modified: llvm/trunk/include/llvm/IR/BasicBlock.h
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/IR/BasicBlock.h?rev=268254&r1=268253&r2=268254&view=diff
>>>
>>> ==============================================================================
>>> --- llvm/trunk/include/llvm/IR/BasicBlock.h (original)
>>> +++ llvm/trunk/include/llvm/IR/BasicBlock.h Mon May 2 12:22:54 2016
>>> @@ -152,6 +152,15 @@ public:
>>> return
>>> const_cast<BasicBlock*>(this)->getFirstNonPHIOrDbgOrLifetime();
>>> }
>>>
>>> + /// \brief Returns a pointer to the first instruction in this block
>>> that is
>>> + /// not a PHINode, a debug intrinsic, a lifetime intrinsic, or a
>>> bitcast
>>> + /// instruction coupled with the following lifetime intrinsic.
>>> + Instruction *getFirstNonPHIOrDbgOrLifetimeOrBitCast();
>>> + const Instruction *getFirstNonPHIOrDbgOrLifetimeOrBitCast() const {
>>> + return const_cast<BasicBlock *>(this)
>>> + ->getFirstNonPHIOrDbgOrLifetimeOrBitCast();
>>> + }
>>> +
>>> /// \brief Returns an iterator to the first instruction in this block
>>> that is
>>> /// suitable for inserting a non-PHI instruction.
>>> ///
>>>
>>> Modified: llvm/trunk/lib/IR/BasicBlock.cpp
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/BasicBlock.cpp?rev=268254&r1=268253&r2=268254&view=diff
>>>
>>> ==============================================================================
>>> --- llvm/trunk/lib/IR/BasicBlock.cpp (original)
>>> +++ llvm/trunk/lib/IR/BasicBlock.cpp Mon May 2 12:22:54 2016
>>> @@ -206,6 +206,30 @@ Instruction* BasicBlock::getFirstNonPHIO
>>> return nullptr;
>>> }
>>>
>>> +Instruction *BasicBlock::getFirstNonPHIOrDbgOrLifetimeOrBitCast() {
>>> + for (Instruction &I : *this) {
>>> + if (isa<PHINode>(I) || isa<DbgInfoIntrinsic>(I))
>>> + continue;
>>> +
>>> + if (auto *II = dyn_cast<IntrinsicInst>(&I))
>>> + if (II->getIntrinsicID() == Intrinsic::lifetime_start ||
>>> + II->getIntrinsicID() == Intrinsic::lifetime_end)
>>> + continue;
>>> +
>>> + if (auto *BCI = dyn_cast<BitCastInst>(&I)) {
>>> + if (auto *II = dyn_cast<IntrinsicInst>(++I.getIterator())) {
>>> + if ((II->getIntrinsicID() == Intrinsic::lifetime_start ||
>>> + II->getIntrinsicID() == Intrinsic::lifetime_end) &&
>>> + II->getOperand(1) == BCI) {
>>> + continue;
>>> + }
>>> + }
>>> + }
>>> + return &I;
>>> + }
>>> + return nullptr;
>>> +}
>>> +
>>> BasicBlock::iterator BasicBlock::getFirstInsertionPt() {
>>> Instruction *FirstNonPHI = getFirstNonPHI();
>>> if (!FirstNonPHI)
>>>
>>> Modified: llvm/trunk/lib/Transforms/Utils/Local.cpp
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/Local.cpp?rev=268254&r1=268253&r2=268254&view=diff
>>>
>>> ==============================================================================
>>> --- llvm/trunk/lib/Transforms/Utils/Local.cpp (original)
>>> +++ llvm/trunk/lib/Transforms/Utils/Local.cpp Mon May 2 12:22:54 2016
>>> @@ -800,6 +800,55 @@ static void redirectValuesFromPredecesso
>>> replaceUndefValuesInPhi(PN, IncomingValues);
>>> }
>>>
>>> +/// Return true if BB has lifetime.end intrinsic.
>>> +///
>>> +static bool hasLifetime(BasicBlock *BB) {
>>> + for (auto &I : *BB) {
>>> + if (const IntrinsicInst *II = dyn_cast<IntrinsicInst>(&I)) {
>>> + if (II->getIntrinsicID() == Intrinsic::lifetime_end ||
>>> + II->getIntrinsicID() == Intrinsic::lifetime_start) {
>>> + return true;
>>> + }
>>> + }
>>> + }
>>> + return false;
>>> +}
>>> +
>>> +/// hoistLifetimeFromEmptyBlockToPred - Hoist lifetime.end intrinsics and
>>> +/// related bitcast instructions from BB to predecessors of BB.
>>> +///
>>> +static bool hoistLifetimeFromEmptyBlockToPred(BasicBlock *BB) {
>>> + // Check to see if all Preds have single successor and if not, we
>>> cannot
>>> + // hoist lifetime intrinsics because it would change semantics.
>>> + for (auto Pred : predecessors(BB))
>>> + if (!Pred->getSingleSuccessor())
>>> + return false;
>>> +
>>> + // Hoist all lifetime.end intrinsics and related bitcast instrunctions
>>> + // in BB to Preds.
>>> + for (auto &I : *BB) {
>>> + if (auto *II = dyn_cast<IntrinsicInst>(&I)) {
>>> + if (II->getIntrinsicID() == Intrinsic::lifetime_end ||
>>> + II->getIntrinsicID() == Intrinsic::lifetime_start) {
>>> + for (auto Pred : predecessors(BB)) {
>>> + Instruction *NewII = I.clone();
>>> + NewII->insertBefore(Pred->getTerminator());
>>> +
>>> + if (I.getIterator() != BB->begin()) {
>>> + if (auto BC = dyn_cast<BitCastInst>(--I.getIterator())) {
>>> + assert(BC == I.getOperand(1));
>>> + auto NewBC = BC->clone();
>>> + NewBC->insertBefore(NewII);
>>> + NewII->setOperand(1, NewBC);
>>> + }
>>> + }
>>> + }
>>> + }
>>> + }
>>> + }
>>> + return true;
>>> +}
>>> +
>>> /// TryToSimplifyUncondBranchFromEmptyBlock - BB is known to contain an
>>> /// unconditional branch, and contains no instructions other than PHI
>>> nodes,
>>> /// potential side-effect free intrinsics and the branch. If possible,
>>> @@ -813,74 +862,118 @@ bool llvm::TryToSimplifyUncondBranchFrom
>>> BasicBlock *Succ =
>>> cast<BranchInst>(BB->getTerminator())->getSuccessor(0);
>>> if (BB == Succ) return false;
>>>
>>> - // Check to see if merging these blocks would cause conflicts for any
>>> of the
>>> - // phi nodes in BB or Succ. If not, we can safely merge.
>>> - if (!CanPropagatePredecessorsForPHIs(BB, Succ)) return false;
>>> -
>>> - // Check for cases where Succ has multiple predecessors and a PHI node
>>> in BB
>>> - // has uses which will not disappear when the PHI nodes are merged. It
>>> is
>>> - // possible to handle such cases, but difficult: it requires checking
>>> whether
>>> - // BB dominates Succ, which is non-trivial to calculate in the case
>>> where
>>> - // Succ has multiple predecessors. Also, it requires checking whether
>>> - // constructing the necessary self-referential PHI node doesn't
>>> introduce any
>>> - // conflicts; this isn't too difficult, but the previous code for doing
>>> this
>>> - // was incorrect.
>>> - //
>>> - // Note that if this check finds a live use, BB dominates Succ, so BB
>>> is
>>> - // something like a loop pre-header (or rarely, a part of an
>>> irreducible CFG);
>>> - // folding the branch isn't profitable in that case anyway.
>>> - if (!Succ->getSinglePredecessor()) {
>>> - BasicBlock::iterator BBI = BB->begin();
>>> - while (isa<PHINode>(*BBI)) {
>>> - for (Use &U : BBI->uses()) {
>>> - if (PHINode* PN = dyn_cast<PHINode>(U.getUser())) {
>>> - if (PN->getIncomingBlock(U) != BB)
>>> - return false;
>>> - } else {
>>> - return false;
>>> - }
>>> + // If BB has lifetime.end intrinsics, simplify BB under more
>>> constraints.
>>> + if (hasLifetime(BB)) {
>>> + // Check to see if BB and its predecessors and successors have PHI.
>>> + if (isa<PHINode>(BB->begin()))
>>> + return false;
>>> +
>>> + for (auto Pred : predecessors(BB))
>>> + if (isa<PHINode>(Pred->begin()))
>>> + return false;
>>> +
>>> + for (auto Succ : successors(BB))
>>> + if (isa<PHINode>(Succ->begin()))
>>> + return false;
>>> +
>>> + if (Succ->getSinglePredecessor()) {
>>> + // BB is the only predecessor of Succ, so Succ will end up with
>>> exactly
>>> + // the same predecessors BB had.
>>> +
>>> + // Copy over any debug or lifetime instruction.
>>> + BB->getTerminator()->eraseFromParent();
>>> + Succ->getInstList().splice(Succ->getFirstNonPHI()->getIterator(),
>>> + BB->getInstList());
>>> +
>>> + } else {
>>> + // Unless BB is the only predecessor of Succ, hoist lifetime
>>> intrinsics
>>> + // to predecessors of BB and simplify BB.
>>> + if (!hoistLifetimeFromEmptyBlockToPred(BB)) {
>>> + return false;
>>> }
>>> - ++BBI;
>>> }
>>> - }
>>>
>>> - DEBUG(dbgs() << "Killing Trivial BB: \n" << *BB);
>>> + DEBUG(dbgs() << "Killing Trivial BB: \n" << *BB);
>>>
>>> - if (isa<PHINode>(Succ->begin())) {
>>> - // If there is more than one pred of succ, and there are PHI nodes in
>>> - // the successor, then we need to add incoming edges for the PHI
>>> nodes
>>> + // Everything that jumped to BB now goes to Succ.
>>> + BB->replaceAllUsesWith(Succ);
>>> + if (!Succ->hasName())
>>> + Succ->takeName(BB);
>>> + BB->eraseFromParent(); // Delete the old basic block.
>>> + return true;
>>> + } else {
>>> + // Check to see if merging these blocks would cause conflicts for any
>>> of the
>>> + // phi nodes in BB or Succ. If not, we can safely merge.
>>> + if (!CanPropagatePredecessorsForPHIs(BB, Succ))
>>> + return false;
>>> +
>>> + // Check for cases where Succ has multiple predecessors and a PHI
>>> node in BB
>>> + // has uses which will not disappear when the PHI nodes are merged.
>>> It is
>>> + // possible to handle such cases, but difficult: it requires checking
>>> + // whether BB dominates Succ, which is non-trivial to calculate in
>>> the
>>> + // case where Succ has multiple predecessors. Also, it requires
>>> checking
>>> + // whether constructing the necessary self-referential PHI node
>>> doesn't
>>> + // introduce any conflicts; this isn't too difficult, but the
>>> previous code
>>> + // for doing this was incorrect.
>>> //
>>> - const PredBlockVector BBPreds(pred_begin(BB), pred_end(BB));
>>> + // Note that if this check finds a live use, BB dominates Succ, so BB
>>> is
>>> + // something like a loop pre-header (or rarely, a part of an
>>> irreducible
>>> + // CFG);
>>> + // folding the branch isn't profitable in that case anyway.
>>> + if (!Succ->getSinglePredecessor()) {
>>> + BasicBlock::iterator BBI = BB->begin();
>>> + while (isa<PHINode>(*BBI)) {
>>> + for (Use &U : BBI->uses()) {
>>> + if (PHINode *PN = dyn_cast<PHINode>(U.getUser())) {
>>> + if (PN->getIncomingBlock(U) != BB)
>>> + return false;
>>> + } else {
>>> + return false;
>>> + }
>>> + }
>>> + ++BBI;
>>> + }
>>> + }
>>> +
>>> + DEBUG(dbgs() << "Killing Trivial BB: \n" << *BB);
>>>
>>> - // Loop over all of the PHI nodes in the successor of BB.
>>> - for (BasicBlock::iterator I = Succ->begin(); isa<PHINode>(I); ++I) {
>>> - PHINode *PN = cast<PHINode>(I);
>>> + if (isa<PHINode>(Succ->begin())) {
>>> + // If there is more than one pred of succ, and there are PHI nodes
>>> in
>>> + // the successor, then we need to add incoming edges for the PHI
>>> nodes
>>> + //
>>> + const PredBlockVector BBPreds(pred_begin(BB), pred_end(BB));
>>> +
>>> + // Loop over all of the PHI nodes in the successor of BB.
>>> + for (BasicBlock::iterator I = Succ->begin(); isa<PHINode>(I); ++I)
>>> {
>>> + PHINode *PN = cast<PHINode>(I);
>>>
>>> - redirectValuesFromPredecessorsToPhi(BB, BBPreds, PN);
>>> + redirectValuesFromPredecessorsToPhi(BB, BBPreds, PN);
>>> + }
>>> }
>>> - }
>>>
>>> - if (Succ->getSinglePredecessor()) {
>>> - // BB is the only predecessor of Succ, so Succ will end up with
>>> exactly
>>> - // the same predecessors BB had.
>>> -
>>> - // Copy over any phi, debug or lifetime instruction.
>>> - BB->getTerminator()->eraseFromParent();
>>> - Succ->getInstList().splice(Succ->getFirstNonPHI()->getIterator(),
>>> - BB->getInstList());
>>> - } else {
>>> - while (PHINode *PN = dyn_cast<PHINode>(&BB->front())) {
>>> - // We explicitly check for such uses in
>>> CanPropagatePredecessorsForPHIs.
>>> - assert(PN->use_empty() && "There shouldn't be any uses here!");
>>> - PN->eraseFromParent();
>>> + if (Succ->getSinglePredecessor()) {
>>> + // BB is the only predecessor of Succ, so Succ will end up with
>>> exactly
>>> + // the same predecessors BB had.
>>> +
>>> + // Copy over any phi, debug or lifetime instruction.
>>> + BB->getTerminator()->eraseFromParent();
>>> + Succ->getInstList().splice(Succ->getFirstNonPHI()->getIterator(),
>>> + BB->getInstList());
>>> + } else {
>>> + while (PHINode *PN = dyn_cast<PHINode>(&BB->front())) {
>>> + // We explicitly check for such uses in
>>> CanPropagatePredecessorsForPHIs.
>>> + assert(PN->use_empty() && "There shouldn't be any uses here!");
>>> + PN->eraseFromParent();
>>> + }
>>> }
>>> - }
>>>
>>> - // Everything that jumped to BB now goes to Succ.
>>> - BB->replaceAllUsesWith(Succ);
>>> - if (!Succ->hasName()) Succ->takeName(BB);
>>> - BB->eraseFromParent(); // Delete the old basic block.
>>> - return true;
>>> + // Everything that jumped to BB now goes to Succ.
>>> + BB->replaceAllUsesWith(Succ);
>>> + if (!Succ->hasName())
>>> + Succ->takeName(BB);
>>> + BB->eraseFromParent(); // Delete the old basic block.
>>> + return true;
>>> + }
>>> }
>>>
>>> /// EliminateDuplicatePHINodes - Check for and eliminate duplicate PHI
>>>
>>> Modified: llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp?rev=268254&r1=268253&r2=268254&view=diff
>>>
>>> ==============================================================================
>>> --- llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp (original)
>>> +++ llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp Mon May 2 12:22:54
>>> 2016
>>> @@ -5056,14 +5056,15 @@ bool SimplifyCFGOpt::SimplifyUncondBranc
>>>
>>> if (SinkCommon && SinkThenElseCodeToEnd(BI))
>>> return true;
>>> -
>>> - // If the Terminator is the only non-phi instruction, simplify the
>>> block.
>>> - // if LoopHeader is provided, check if the block is a loop header
>>> + // If the Terminator is the only non-phi instruction except for bitcast
>>> + // instruction coupled with the following lifetime intrinsic, simplify
>>> the
>>> + // block. If LoopHeader is provided, check if the block is a loop
>>> header
>>> // (This is for early invocations before loop simplify and
>>> vectorization
>>> // to keep canonical loop forms for nested loops.
>>> // These blocks can be eliminated when the pass is invoked later
>>> // in the back-end.)
>>> - BasicBlock::iterator I = BB->getFirstNonPHIOrDbg()->getIterator();
>>> + BasicBlock::iterator I =
>>> + BB->getFirstNonPHIOrDbgOrLifetimeOrBitCast()->getIterator();
>>> if (I->isTerminator() && BB != &BB->getParent()->getEntryBlock() &&
>>> (!LoopHeaders || !LoopHeaders->count(BB)) &&
>>> TryToSimplifyUncondBranchFromEmptyBlock(BB))
>>>
>>> Modified: llvm/trunk/test/Transforms/SimplifyCFG/lifetime.ll
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/SimplifyCFG/lifetime.ll?rev=268254&r1=268253&r2=268254&view=diff
>>>
>>> ==============================================================================
>>> --- llvm/trunk/test/Transforms/SimplifyCFG/lifetime.ll (original)
>>> +++ llvm/trunk/test/Transforms/SimplifyCFG/lifetime.ll Mon May 2 12:22:54
>>> 2016
>>> @@ -1,6 +1,9 @@
>>> ; RUN: opt < %s -simplifycfg -S | FileCheck %s
>>>
>>> ; Test that a lifetime intrinsic isn't removed because that would change
>>> semantics
>>> +; This case is that predecessor(s) of the target empty block (bb0) has
>>> multiple
>>> +; successors (bb0 and bb1) and its successor has multiple predecessors
>>> (entry and
>>> +; bb0).
>>>
>>> ; CHECK: foo
>>> ; CHECK: entry:
>>> @@ -27,3 +30,232 @@ declare void @f()
>>> declare void @llvm.lifetime.start(i64, i8* nocapture) nounwind
>>>
>>> declare void @llvm.lifetime.end(i64, i8* nocapture) nounwind
>>> +
>>> +; Test that empty block including lifetime intrinsic and not related
>>> bitcast
>>> +; instruction cannot be removed. It is because the block is not empty.
>>> +
>>> +; CHECK-LABEL: coo
>>> +; CHECK-LABEL: entry:
>>> +; CHECK-LABEL: if.then:
>>> +; CHECK-LABEL: if.else:
>>> +; CHECK-LABEL: if.end:
>>> +; CHECK-LABEL: bb:
>>> +; CHECK: ret
>>> +
>>> +define void @coo(i1 %x, i1 %y) {
>>> +entry:
>>> + %a = alloca i8, align 4
>>> + %b = alloca i32, align 4
>>> + br label %while.cond
>>> +
>>> +while.cond: ; preds = %if.end,
>>> %entry
>>> + br i1 %y, label %while.body, label %bb
>>> +
>>> +while.body: ; preds = %while.cond
>>> + call void @llvm.lifetime.start(i64 4, i8* %a)
>>> + %c = load i8, i8* %a, align 4
>>> + br i1 %x, label %if.then, label %if.else
>>> +
>>> +if.then: ; preds = %while.body
>>> + %d = add i8 %c, 1
>>> + br label %if.end
>>> +
>>> +if.else: ; preds = %while.body
>>> + %e = sub i8 %c, 1
>>> + br label %if.end
>>> +
>>> +if.end: ; preds = %if.else,
>>> %if.then
>>> + %f = bitcast i32* %b to i8*
>>> + call void @llvm.lifetime.end(i64 4, i8* %a)
>>> + br label %while.cond
>>> +
>>> +bb: ; preds = %while.cond
>>> + ret void
>>> +}
>>> +
>>> +; Test that empty block including lifetime intrinsic can be removed.
>>> +; Lifetime.end intrinsic is moved to predecessors because successor has
>>> +; multiple predecessors.
>>> +
>>> +; CHECK-LABEL: soo
>>> +; CHECK-LABEL: entry:
>>> +; CHECK-LABEL: if.then:
>>> +; CHECK-NEXT: %e
>>> +; CHECK-NEXT: call void @llvm.lifetime.end
>>> +; CHECK-LABEL: if.else:
>>> +; CHECK-NEXT: %g
>>> +; CHECK-NEXT: call void @llvm.lifetime.end
>>> +; CHECK-NEXT: br label %while.cond
>>> +; CHECK-NOT: if.end:
>>> +; CHECK: ret
>>> +
>>> +define void @soo(i1 %x, i1 %y) {
>>> +entry:
>>> + %a = alloca i8, align 4
>>> + br label %while.cond
>>> +
>>> +while.cond: ; preds = %if.end,
>>> %entry
>>> + br i1 %y, label %while.body, label %bb
>>> +
>>> +while.body: ; preds = %while.cond
>>> + call void @llvm.lifetime.start(i64 4, i8* %a)
>>> + %d = load i8, i8* %a, align 4
>>> + br i1 %x, label %if.then, label %if.else
>>> +
>>> +if.then: ; preds = %while.body
>>> + %e = add i8 %d, 1
>>> + br label %if.end
>>> +
>>> +if.else: ; preds = %while.body
>>> + %g = sub i8 %d, 1
>>> + br label %if.end
>>> +
>>> +if.end: ; preds = %if.else,
>>> %if.then
>>> + call void @llvm.lifetime.end(i64 4, i8* %a)
>>> + br label %while.cond
>>> +
>>> +bb: ; preds = %while.cond
>>> + ret void
>>> +}
>>> +
>>> +; Test that empty block including lifetime intrinsic and related bitcast
>>> +; instruction can be removed. Lifetime.end intrinsic and related bitcast
>>> +; instruction are moved to predecessors because successor has multiple
>>> +; predecessors.
>>> +
>>> +; CHECK-LABEL: boo
>>> +; CHECK-LABEL: entry:
>>> +; CHECK-LABEL: if.then:
>>> +; CHECK-NEXT: %e
>>> +; CHECK-NEXT: %[[T:[^ ]+]] = bitcast
>>> +; CHECK-NEXT: call void @llvm.lifetime.end(i64 4, i8* %[[T]])
>>> +; CHECK-LABEL: if.else:
>>> +; CHECK-NEXT: %g
>>> +; CHECK-NEXT: %[[B:[^ ]+]] = bitcast
>>> +; CHECK-NEXT: call void @llvm.lifetime.end(i64 4, i8* %[[B]])
>>> +; CHECK-NEXT: br label %while.cond
>>> +; CHECK-NOT: if.end:
>>> +; CHECK: ret
>>> +
>>> +define void @boo(i1 %x, i1 %y) {
>>> +entry:
>>> + %a = alloca i32, align 4
>>> + br label %while.cond
>>> +
>>> +while.cond: ; preds = %if.end,
>>> %entry
>>> + br i1 %y, label %while.body, label %bb
>>> +
>>> +while.body: ; preds = %while.cond
>>> + %b = bitcast i32* %a to i8*
>>> + call void @llvm.lifetime.start(i64 4, i8* %b)
>>> + %d = load i32, i32* %a, align 4
>>> + br i1 %x, label %if.then, label %if.else
>>> +
>>> +if.then: ; preds = %while.body
>>> + %e = add i32 %d, 1
>>> + br label %if.end
>>> +
>>> +if.else: ; preds = %while.body
>>> + %g = sub i32 %d, 1
>>> + br label %if.end
>>> +
>>> +if.end: ; preds = %if.else,
>>> %if.then
>>> + %c = bitcast i32* %a to i8*
>>> + call void @llvm.lifetime.end(i64 4, i8* %c)
>>> + br label %while.cond
>>> +
>>> +bb: ; preds = %while.cond
>>> + ret void
>>> +}
>>> +
>>> +; Test that empty block including lifetime intrinsic can be removed.
>>> +; Lifetime.start intrinsic is moved to predecessors because successor has
>>> +; multiple predecessors.
>>> +
>>> +; CHECK-LABEL: koo
>>> +; CHECK-LABEL: entry:
>>> +; CHECK-LABEL: if.then:
>>> +; CHECK-NEXT: call void @f
>>> +; CHECK-NEXT: call void @llvm.lifetime.start
>>> +; CHECK-LABEL: if.else:
>>> +; CHECK-NEXT: call void @g
>>> +; CHECK-NEXT: call void @llvm.lifetime.start
>>> +; CHECK-NEXT: br label %bb
>>> +; CHECK-NOT: if.end:
>>> +; CHECK: ret
>>> +
>>> +define void @koo(i1 %x, i1 %y, i1 %z) {
>>> +entry:
>>> + %a = alloca i8, align 4
>>> + br i1 %z, label %bb, label %bb0
>>> +
>>> +bb0: ; preds = %entry
>>> + br i1 %x, label %if.then, label %if.else
>>> +
>>> +if.then: ; preds = %bb0
>>> + call void @f()
>>> + br label %if.end
>>> +
>>> +if.else: ; preds = %bb0
>>> + call void @g()
>>> + br label %if.end
>>> +
>>> +if.end: ; preds = %if.else,
>>> %if.then
>>> + call void @llvm.lifetime.start(i64 4, i8* %a)
>>> + br label %bb
>>> +
>>> +bb: ; preds = %if.end,
>>> %entry
>>> + %d = load i8, i8* %a, align 4
>>> + call void @llvm.lifetime.end(i64 4, i8* %a)
>>> + ret void
>>> +}
>>> +
>>> +declare void @g()
>>> +
>>> +; Test that empty block including lifetime intrinsic and related bitcast
>>> +; instruction can be removed. Lifetime.start intrinsic and related
>>> bitcast
>>> +; instruction are moved to predecessors because successor has multiple
>>> +; predecessors.
>>> +
>>> +
>>> +; CHECK-LABEL: goo
>>> +; CHECK-LABEL: entry:
>>> +; CHECK-LABEL: if.then:
>>> +; CHECK-NEXT: call void @f
>>> +; CHECK-NEXT: %[[T:[^ ]+]] = bitcast
>>> +; CHECK-NEXT: call void @llvm.lifetime.start(i64 4, i8* %[[T]])
>>> +; CHECK-LABEL: if.else:
>>> +; CHECK-NEXT: call void @g
>>> +; CHECK-NEXT: %[[B:[^ ]+]] = bitcast
>>> +; CHECK-NEXT: call void @llvm.lifetime.start(i64 4, i8* %[[B]])
>>> +; CHECK-NEXT: br label %bb
>>> +; CHECK-NOT: if.end:
>>> +; CHECK: ret
>>> +
>>> +define void @goo(i1 %x, i1 %y, i1 %z) {
>>> +entry:
>>> + %a = alloca i32, align 4
>>> + br i1 %z, label %bb, label %bb0
>>> +
>>> +bb0: ; preds = %entry
>>> + br i1 %x, label %if.then, label %if.else
>>> +
>>> +if.then: ; preds = %bb0
>>> + call void @f()
>>> + br label %if.end
>>> +
>>> +if.else: ; preds = %bb0
>>> + call void @g()
>>> + br label %if.end
>>> +
>>> +if.end: ; preds = %if.else,
>>> %if.then
>>> + %b = bitcast i32* %a to i8*
>>> + call void @llvm.lifetime.start(i64 4, i8* %b)
>>> + br label %bb
>>> +
>>> +bb: ; preds = %if.end,
>>> %entry
>>> + %d = load i32, i32* %a, align 4
>>> + %c = bitcast i32* %a to i8*
>>> + call void @llvm.lifetime.end(i64 4, i8* %c)
>>> + ret void
>>> +}
>>>
>>>
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