<div dir="ltr"><div dir="ltr">Sounds good to me, and thanks for sending the heads up :)</div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, May 5, 2021 at 10:01 PM Philip Reames <<a href="mailto:listmail@philipreames.com">listmail@philipreames.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">FYI, I'm going to try recommitting this without changes in a day or so.<br>
<br>
I never heard back from a PPC bot owner, and I don't have enough <br>
information to really debug anything from the builtbot log. I did run <br>
across a latent issue which this patch may very well have exposed at <br>
much higher frequency; the previous patch in this series (which is much <br>
more restrictive) does appear to have increased frequency. That was <br>
worked around in 80e80250. My educated guess is that same issue <br>
triggered the miscompile seen on the ppc bot, but that is more of a <br>
guess than I'd really prefer.<br>
<br>
I'm going to submit this during off hours, and watch the bots fairly <br>
closely after submit. Hopefully this either cycles clean or I get a <br>
better clue as to what the root issue is.<br>
<br>
Philip<br>
<br>
On 2/8/21 9:09 PM, Philip Reames via llvm-commits wrote:<br>
> Ben,<br>
><br>
> Thanks for the clarification. The log does not make the fact this is <br>
> an execution failure obvious.<br>
><br>
> No, I don't have access to a PPC machine.<br>
><br>
> I am going to need some assistance from the bot owner on this. At a <br>
> minimum, IR for the test in question (before optimization, but on <br>
> target platform) seems like a reasonable ask.<br>
><br>
> I strongly suspect this change is simply exposing another latent <br>
> issue. Or at least, I've reviewed the change and don't see anything <br>
> likely to cause runtime crashes w/o also tripping compiler asserts.<br>
><br>
> Philip<br>
><br>
><br>
> On 2/8/21 5:21 AM, Benjamin Kramer wrote:<br>
>> `execution_time` failures mean that the bot succeeded building a test<br>
>> but it failed when running it. I'm relatively certain that this is the<br>
>> same issue Adrian is seeing -- binaries segfaulting early on PPC.<br>
>><br>
>> The bot log output isn't helpful at all for investigating why this is<br>
>> happening. Do you happen to have access to a PPC machine?<br>
>><br>
>> On Fri, Feb 5, 2021 at 6:05 PM Philip Reames via llvm-commits<br>
>> <<a href="mailto:llvm-commits@lists.llvm.org" target="_blank">llvm-commits@lists.llvm.org</a>> wrote:<br>
>>> Adrian,<br>
>>><br>
>>> I'm going to need you to provide a bit more information here. The test<br>
>>> failure in stage1 was fixed at the time you reverted this patch. The<br>
>>> remaining failure in the bot is very unclear. What is a execution_time<br>
>>> failure? From the log output, the "failing" run finished in 0.5 <br>
>>> seconds,<br>
>>> whereas the previous "succeeding" run finished in 11 seconds. Without<br>
>>> further context, I'd say that's no failure.<br>
>>><br>
>>> I'll also note that I did not receive email from this bot. I received<br>
>>> notice from the various other bots and fixed the ARM test issue, but<br>
>>> unless I missed it in with the others, this bot is not notifying.<br>
>>><br>
>>> In general, I'm a fan of fast reverts, but I have to admit, this one<br>
>>> appears borderline at the moment.<br>
>>><br>
>>> Philip<br>
>>><br>
>>> On 2/5/21 3:53 AM, Adrian Kuegel via llvm-commits wrote:<br>
>>>> Author: Adrian Kuegel<br>
>>>> Date: 2021-02-05T12:51:03+01:00<br>
>>>> New Revision: 7fe41ac3dff2d44c3d2c31b28554fbe4a86eaa6c<br>
>>>><br>
>>>> URL: <br>
>>>> <a href="https://github.com/llvm/llvm-project/commit/7fe41ac3dff2d44c3d2c31b28554fbe4a86eaa6c" rel="noreferrer" target="_blank">https://github.com/llvm/llvm-project/commit/7fe41ac3dff2d44c3d2c31b28554fbe4a86eaa6c</a><br>
>>>> DIFF: <br>
>>>> <a href="https://github.com/llvm/llvm-project/commit/7fe41ac3dff2d44c3d2c31b28554fbe4a86eaa6c.diff" rel="noreferrer" target="_blank">https://github.com/llvm/llvm-project/commit/7fe41ac3dff2d44c3d2c31b28554fbe4a86eaa6c.diff</a><br>
>>>><br>
>>>> LOG: Revert "[LV] Unconditionally branch from middle to scalar <br>
>>>> preheader if the scalar loop must execute"<br>
>>>><br>
>>>> This reverts commit 3e5ce49e5371ce4feadbf97dd5c2b652d9db3d1d.<br>
>>>><br>
>>>> Tests started failing on PPC, for example:<br>
>>>> <a href="http://lab.llvm.org:8011/#/builders/105/builds/5569" rel="noreferrer" target="_blank">http://lab.llvm.org:8011/#/builders/105/builds/5569</a><br>
>>>><br>
>>>> Added:<br>
>>>><br>
>>>><br>
>>>> Modified:<br>
>>>> llvm/lib/Transforms/Utils/LoopVersioning.cpp<br>
>>>> llvm/lib/Transforms/Vectorize/LoopVectorize.cpp<br>
>>>> llvm/test/Transforms/LoopVectorize/first-order-recurrence-complex.ll<br>
>>>> llvm/test/Transforms/LoopVectorize/interleaved-accesses.ll<br>
>>>> llvm/test/Transforms/LoopVectorize/loop-form.ll<br>
>>>><br>
>>>> Removed:<br>
>>>><br>
>>>><br>
>>>><br>
>>>> ################################################################################ <br>
>>>><br>
>>>> diff --git a/llvm/lib/Transforms/Utils/LoopVersioning.cpp <br>
>>>> b/llvm/lib/Transforms/Utils/LoopVersioning.cpp<br>
>>>> index 8a89158788cf..de4fb446fdf2 100644<br>
>>>> --- a/llvm/lib/Transforms/Utils/LoopVersioning.cpp<br>
>>>> +++ b/llvm/lib/Transforms/Utils/LoopVersioning.cpp<br>
>>>> @@ -44,11 +44,11 @@ LoopVersioning::LoopVersioning(const <br>
>>>> LoopAccessInfo &LAI,<br>
>>>> AliasChecks(Checks.begin(), Checks.end()),<br>
>>>> Preds(LAI.getPSE().getUnionPredicate()), LAI(LAI), LI(LI), <br>
>>>> DT(DT),<br>
>>>> SE(SE) {<br>
>>>> + assert(L->getUniqueExitBlock() && "No single exit block");<br>
>>>> }<br>
>>>><br>
>>>> void LoopVersioning::versionLoop(<br>
>>>> const SmallVectorImpl<Instruction *> &DefsUsedOutside) {<br>
>>>> - assert(VersionedLoop->getUniqueExitBlock() && "No single exit <br>
>>>> block");<br>
>>>> assert(VersionedLoop->isLoopSimplifyForm() &&<br>
>>>> "Loop is not in loop-simplify form");<br>
>>>><br>
>>>><br>
>>>> diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp <br>
>>>> b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp<br>
>>>> index 3277842edbfe..6bce0caeb36f 100644<br>
>>>> --- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp<br>
>>>> +++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp<br>
>>>> @@ -852,7 +852,7 @@ class InnerLoopVectorizer {<br>
>>>> /// Middle Block between the vector and the scalar.<br>
>>>> BasicBlock *LoopMiddleBlock;<br>
>>>><br>
>>>> - /// The unique ExitBlock of the scalar loop if one exists. Note <br>
>>>> that<br>
>>>> + /// The (unique) ExitBlock of the scalar loop. Note that<br>
>>>> /// there can be multiple exiting edges reaching this block.<br>
>>>> BasicBlock *LoopExitBlock;<br>
>>>><br>
>>>> @@ -3147,13 +3147,9 @@ void <br>
>>>> InnerLoopVectorizer::emitMinimumIterationCountCheck(Loop *L,<br>
>>>> DT->getNode(Bypass)->getIDom()) &&<br>
>>>> "TC check is expected to dominate Bypass");<br>
>>>><br>
>>>> - // Update dominator for Bypass & LoopExit (if needed).<br>
>>>> + // Update dominator for Bypass & LoopExit.<br>
>>>> DT->changeImmediateDominator(Bypass, TCCheckBlock);<br>
>>>> - if (!Cost->requiresScalarEpilogue())<br>
>>>> - // If there is an epilogue which must run, there's no edge <br>
>>>> from the<br>
>>>> - // middle block to exit blocks and thus no need to update the <br>
>>>> immediate<br>
>>>> - // dominator of the exit blocks.<br>
>>>> - DT->changeImmediateDominator(LoopExitBlock, TCCheckBlock);<br>
>>>> + DT->changeImmediateDominator(LoopExitBlock, TCCheckBlock);<br>
>>>><br>
>>>> ReplaceInstWithInst(<br>
>>>> TCCheckBlock->getTerminator(),<br>
>>>> @@ -3192,11 +3188,7 @@ void <br>
>>>> InnerLoopVectorizer::emitSCEVChecks(Loop *L, BasicBlock *Bypass) {<br>
>>>> // Update dominator only if this is first RT check.<br>
>>>> if (LoopBypassBlocks.empty()) {<br>
>>>> DT->changeImmediateDominator(Bypass, SCEVCheckBlock);<br>
>>>> - if (!Cost->requiresScalarEpilogue())<br>
>>>> - // If there is an epilogue which must run, there's no edge <br>
>>>> from the<br>
>>>> - // middle block to exit blocks and thus no need to update <br>
>>>> the immediate<br>
>>>> - // dominator of the exit blocks.<br>
>>>> - DT->changeImmediateDominator(LoopExitBlock, SCEVCheckBlock);<br>
>>>> + DT->changeImmediateDominator(LoopExitBlock, SCEVCheckBlock);<br>
>>>> }<br>
>>>><br>
>>>> ReplaceInstWithInst(<br>
>>>> @@ -3252,11 +3244,7 @@ void <br>
>>>> InnerLoopVectorizer::emitMemRuntimeChecks(Loop *L, BasicBlock <br>
>>>> *Bypass) {<br>
>>>> // Update dominator only if this is first RT check.<br>
>>>> if (LoopBypassBlocks.empty()) {<br>
>>>> DT->changeImmediateDominator(Bypass, MemCheckBlock);<br>
>>>> - if (!Cost->requiresScalarEpilogue())<br>
>>>> - // If there is an epilogue which must run, there's no edge <br>
>>>> from the<br>
>>>> - // middle block to exit blocks and thus no need to update <br>
>>>> the immediate<br>
>>>> - // dominator of the exit blocks.<br>
>>>> - DT->changeImmediateDominator(LoopExitBlock, MemCheckBlock);<br>
>>>> + DT->changeImmediateDominator(LoopExitBlock, MemCheckBlock);<br>
>>>> }<br>
>>>><br>
>>>> Instruction *FirstCheckInst;<br>
>>>> @@ -3381,10 +3369,9 @@ Value <br>
>>>> *InnerLoopVectorizer::emitTransformedIndex(<br>
>>>> Loop *InnerLoopVectorizer::createVectorLoopSkeleton(StringRef <br>
>>>> Prefix) {<br>
>>>> LoopScalarBody = OrigLoop->getHeader();<br>
>>>> LoopVectorPreHeader = OrigLoop->getLoopPreheader();<br>
>>>> + LoopExitBlock = OrigLoop->getUniqueExitBlock();<br>
>>>> + assert(LoopExitBlock && "Must have an exit block");<br>
>>>> assert(LoopVectorPreHeader && "Invalid loop structure");<br>
>>>> - LoopExitBlock = OrigLoop->getUniqueExitBlock(); // may be nullptr<br>
>>>> - assert((LoopExitBlock || Cost->requiresScalarEpilogue()) &&<br>
>>>> - "multiple exit loop without required epilogue?");<br>
>>>><br>
>>>> LoopMiddleBlock =<br>
>>>> SplitBlock(LoopVectorPreHeader, <br>
>>>> LoopVectorPreHeader->getTerminator(), DT,<br>
>>>> @@ -3393,20 +3380,12 @@ Loop <br>
>>>> *InnerLoopVectorizer::createVectorLoopSkeleton(StringRef Prefix) {<br>
>>>> SplitBlock(LoopMiddleBlock, <br>
>>>> LoopMiddleBlock->getTerminator(), DT, LI,<br>
>>>> nullptr, Twine(Prefix) + "<a href="http://scalar.ph" rel="noreferrer" target="_blank">scalar.ph</a>");<br>
>>>><br>
>>>> + // Set up branch from middle block to the exit and scalar <br>
>>>> preheader blocks.<br>
>>>> + // completeLoopSkeleton will update the condition to use an <br>
>>>> iteration check,<br>
>>>> + // if required to decide whether to execute the remainder.<br>
>>>> + BranchInst *BrInst =<br>
>>>> + BranchInst::Create(LoopExitBlock, LoopScalarPreHeader, <br>
>>>> Builder.getTrue());<br>
>>>> auto *ScalarLatchTerm = <br>
>>>> OrigLoop->getLoopLatch()->getTerminator();<br>
>>>> -<br>
>>>> - // Set up the middle block terminator. Two cases:<br>
>>>> - // 1) If we know that we must execute the scalar epilogue, emit an<br>
>>>> - // unconditional branch.<br>
>>>> - // 2) Otherwise, we must have a single unique exit block (due to <br>
>>>> how we<br>
>>>> - // implement the multiple exit case). In this case, set up a <br>
>>>> conditonal<br>
>>>> - // branch from the middle block to the loop scalar preheader, <br>
>>>> and the<br>
>>>> - // exit block. completeLoopSkeleton will update the <br>
>>>> condition to use an<br>
>>>> - // iteration check, if required to decide whether to execute <br>
>>>> the remainder.<br>
>>>> - BranchInst *BrInst = Cost->requiresScalarEpilogue() ?<br>
>>>> - BranchInst::Create(LoopScalarPreHeader) :<br>
>>>> - BranchInst::Create(LoopExitBlock, LoopScalarPreHeader,<br>
>>>> - Builder.getTrue());<br>
>>>> BrInst->setDebugLoc(ScalarLatchTerm->getDebugLoc());<br>
>>>> ReplaceInstWithInst(LoopMiddleBlock->getTerminator(), BrInst);<br>
>>>><br>
>>>> @@ -3418,11 +3397,7 @@ Loop <br>
>>>> *InnerLoopVectorizer::createVectorLoopSkeleton(StringRef Prefix) {<br>
>>>> nullptr, nullptr, Twine(Prefix) + "vector.body");<br>
>>>><br>
>>>> // Update dominator for loop exit.<br>
>>>> - if (!Cost->requiresScalarEpilogue())<br>
>>>> - // If there is an epilogue which must run, there's no edge <br>
>>>> from the<br>
>>>> - // middle block to exit blocks and thus no need to update the <br>
>>>> immediate<br>
>>>> - // dominator of the exit blocks.<br>
>>>> - DT->changeImmediateDominator(LoopExitBlock, LoopMiddleBlock);<br>
>>>> + DT->changeImmediateDominator(LoopExitBlock, LoopMiddleBlock);<br>
>>>><br>
>>>> // Create and register the new vector loop.<br>
>>>> Loop *Lp = LI->AllocateLoop();<br>
>>>> @@ -3519,14 +3494,10 @@ BasicBlock <br>
>>>> *InnerLoopVectorizer::completeLoopSkeleton(Loop *L,<br>
>>>> auto *ScalarLatchTerm = <br>
>>>> OrigLoop->getLoopLatch()->getTerminator();<br>
>>>><br>
>>>> // Add a check in the middle block to see if we have completed<br>
>>>> - // all of the iterations in the first vector loop. Three cases:<br>
>>>> - // 1) If we require a scalar epilogue, there is no conditional <br>
>>>> branch as<br>
>>>> - // we unconditionally branch to the scalar preheader. Do <br>
>>>> nothing.<br>
>>>> - // 2) If (N - N%VF) == N, then we *don't* need to run the <br>
>>>> remainder.<br>
>>>> - // Thus if tail is to be folded, we know we don't need to run <br>
>>>> the<br>
>>>> - // remainder and we can use the previous value for the <br>
>>>> condition (true).<br>
>>>> - // 3) Otherwise, construct a runtime check.<br>
>>>> - if (!Cost->requiresScalarEpilogue() && <br>
>>>> !Cost->foldTailByMasking()) {<br>
>>>> + // all of the iterations in the first vector loop.<br>
>>>> + // If (N - N%VF) == N, then we *don't* need to run the remainder.<br>
>>>> + // If tail is to be folded, we know we don't need to run the <br>
>>>> remainder.<br>
>>>> + if (!Cost->foldTailByMasking()) {<br>
>>>> Instruction *CmpN = CmpInst::Create(Instruction::ICmp, <br>
>>>> CmpInst::ICMP_EQ,<br>
>>>> Count, VectorTripCount, <br>
>>>> "cmp.n",<br>
>>>> LoopMiddleBlock->getTerminator());<br>
>>>> @@ -3590,17 +3561,17 @@ BasicBlock <br>
>>>> *InnerLoopVectorizer::createVectorizedLoopSkeleton() {<br>
>>>> | [ ]_| <-- vector loop.<br>
>>>> | |<br>
>>>> | v<br>
>>>> - \ -[ ] <--- middle-block.<br>
>>>> - \/ |<br>
>>>> - /\ v<br>
>>>> - | ->[ ] <--- new preheader.<br>
>>>> + | -[ ] <--- middle-block.<br>
>>>> + | / |<br>
>>>> + | / v<br>
>>>> + -|- >[ ] <--- new preheader.<br>
>>>> | |<br>
>>>> - (opt) v <-- edge from middle to exit iff epilogue is not <br>
>>>> required.<br>
>>>> + | v<br>
>>>> | [ ] \<br>
>>>> - | [ ]_| <-- old scalar loop to handle remainder (scalar <br>
>>>> epilogue).<br>
>>>> + | [ ]_| <-- old scalar loop to handle remainder.<br>
>>>> \ |<br>
>>>> \ v<br>
>>>> - >[ ] <-- exit block(s).<br>
>>>> + >[ ] <-- exit block.<br>
>>>> ...<br>
>>>> */<br>
>>>><br>
>>>> @@ -4021,18 +3992,13 @@ void <br>
>>>> InnerLoopVectorizer::fixVectorizedLoop() {<br>
>>>> // Forget the original basic block.<br>
>>>> PSE.getSE()->forgetLoop(OrigLoop);<br>
>>>><br>
>>>> - // If we inserted an edge from the middle block to the unique <br>
>>>> exit block,<br>
>>>> - // update uses outside the loop (phis) to account for the newly <br>
>>>> inserted<br>
>>>> - // edge.<br>
>>>> - if (!Cost->requiresScalarEpilogue()) {<br>
>>>> - // Fix-up external users of the induction variables.<br>
>>>> - for (auto &Entry : Legal->getInductionVars())<br>
>>>> - fixupIVUsers(Entry.first, Entry.second,<br>
>>>> - getOrCreateVectorTripCount(LI->getLoopFor(LoopVectorBody)),<br>
>>>> - IVEndValues[Entry.first], LoopMiddleBlock);<br>
>>>> + // Fix-up external users of the induction variables.<br>
>>>> + for (auto &Entry : Legal->getInductionVars())<br>
>>>> + fixupIVUsers(Entry.first, Entry.second,<br>
>>>> + getOrCreateVectorTripCount(LI->getLoopFor(LoopVectorBody)),<br>
>>>> + IVEndValues[Entry.first], LoopMiddleBlock);<br>
>>>><br>
>>>> - fixLCSSAPHIs();<br>
>>>> - }<br>
>>>> + fixLCSSAPHIs();<br>
>>>> for (Instruction *PI : PredicatedInstructions)<br>
>>>> sinkScalarOperands(&*PI);<br>
>>>><br>
>>>> @@ -4250,13 +4216,12 @@ void <br>
>>>> InnerLoopVectorizer::fixFirstOrderRecurrence(PHINode *Phi) {<br>
>>>> // recurrence in the exit block, and then add an edge for the <br>
>>>> middle block.<br>
>>>> // Note that LCSSA does not imply single entry when the <br>
>>>> original scalar loop<br>
>>>> // had multiple exiting edges (as we always run the last <br>
>>>> iteration in the<br>
>>>> - // scalar epilogue); in that case, there is no edge from middle <br>
>>>> to exit and<br>
>>>> - // and thus no phis which needed updated.<br>
>>>> - if (!Cost->requiresScalarEpilogue())<br>
>>>> - for (PHINode &LCSSAPhi : LoopExitBlock->phis())<br>
>>>> - if (any_of(LCSSAPhi.incoming_values(),<br>
>>>> - [Phi](Value *V) { return V == Phi; }))<br>
>>>> - LCSSAPhi.addIncoming(ExtractForPhiUsedOutsideLoop, <br>
>>>> LoopMiddleBlock);<br>
>>>> + // scalar epilogue); in that case, the exiting path through <br>
>>>> middle will be<br>
>>>> + // dynamically dead and the value picked for the phi doesn't <br>
>>>> matter.<br>
>>>> + for (PHINode &LCSSAPhi : LoopExitBlock->phis())<br>
>>>> + if (any_of(LCSSAPhi.incoming_values(),<br>
>>>> + [Phi](Value *V) { return V == Phi; }))<br>
>>>> + LCSSAPhi.addIncoming(ExtractForPhiUsedOutsideLoop, <br>
>>>> LoopMiddleBlock);<br>
>>>> }<br>
>>>><br>
>>>> void InnerLoopVectorizer::fixReduction(PHINode *Phi) {<br>
>>>> @@ -4421,11 +4386,10 @@ void <br>
>>>> InnerLoopVectorizer::fixReduction(PHINode *Phi) {<br>
>>>> // We know that the loop is in LCSSA form. We need to update <br>
>>>> the PHI nodes<br>
>>>> // in the exit blocks. See comment on analogous loop in<br>
>>>> // fixFirstOrderRecurrence for a more complete explaination of <br>
>>>> the logic.<br>
>>>> - if (!Cost->requiresScalarEpilogue())<br>
>>>> - for (PHINode &LCSSAPhi : LoopExitBlock->phis())<br>
>>>> - if (any_of(LCSSAPhi.incoming_values(),<br>
>>>> - [LoopExitInst](Value *V) { return V == <br>
>>>> LoopExitInst; }))<br>
>>>> - LCSSAPhi.addIncoming(ReducedPartRdx, LoopMiddleBlock);<br>
>>>> + for (PHINode &LCSSAPhi : LoopExitBlock->phis())<br>
>>>> + if (any_of(LCSSAPhi.incoming_values(),<br>
>>>> + [LoopExitInst](Value *V) { return V == <br>
>>>> LoopExitInst; }))<br>
>>>> + LCSSAPhi.addIncoming(ReducedPartRdx, LoopMiddleBlock);<br>
>>>><br>
>>>> // Fix the scalar loop reduction variable with the incoming <br>
>>>> reduction sum<br>
>>>> // from the vector body and from the backedge value.<br>
>>>> @@ -8074,11 +8038,7 @@ BasicBlock <br>
>>>> *EpilogueVectorizerMainLoop::emitMinimumIterationCountCheck(<br>
>>>><br>
>>>> // Update dominator for Bypass & LoopExit.<br>
>>>> DT->changeImmediateDominator(Bypass, TCCheckBlock);<br>
>>>> - if (!Cost->requiresScalarEpilogue())<br>
>>>> - // For loops with multiple exits, there's no edge from the <br>
>>>> middle block<br>
>>>> - // to exit blocks (as the epilogue must run) and thus no <br>
>>>> need to update<br>
>>>> - // the immediate dominator of the exit blocks.<br>
>>>> - DT->changeImmediateDominator(LoopExitBlock, TCCheckBlock);<br>
>>>> + DT->changeImmediateDominator(LoopExitBlock, TCCheckBlock);<br>
>>>><br>
>>>> LoopBypassBlocks.push_back(TCCheckBlock);<br>
>>>><br>
>>>> @@ -8142,12 +8102,7 @@ <br>
>>>> EpilogueVectorizerEpilogueLoop::createEpilogueVectorizedLoopSkeleton() <br>
>>>> {<br>
>>>><br>
>>>> DT->changeImmediateDominator(LoopScalarPreHeader,<br>
>>>> EPI.EpilogueIterationCountCheck);<br>
>>>> - if (!Cost->requiresScalarEpilogue())<br>
>>>> - // If there is an epilogue which must run, there's no edge <br>
>>>> from the<br>
>>>> - // middle block to exit blocks and thus no need to update the <br>
>>>> immediate<br>
>>>> - // dominator of the exit blocks.<br>
>>>> - DT->changeImmediateDominator(LoopExitBlock,<br>
>>>> - EPI.EpilogueIterationCountCheck);<br>
>>>> + DT->changeImmediateDominator(LoopExitBlock, <br>
>>>> EPI.EpilogueIterationCountCheck);<br>
>>>><br>
>>>> // Keep track of bypass blocks, as they feed start values to <br>
>>>> the induction<br>
>>>> // phis in the scalar loop preheader.<br>
>>>><br>
>>>> diff --git <br>
>>>> a/llvm/test/Transforms/LoopVectorize/first-order-recurrence-complex.ll <br>
>>>> b/llvm/test/Transforms/LoopVectorize/first-order-recurrence-complex.ll<br>
>>>> index ec280bf5d5e4..7d4a3c5c9935 100644<br>
>>>> --- <br>
>>>> a/llvm/test/Transforms/LoopVectorize/first-order-recurrence-complex.ll<br>
>>>> +++ <br>
>>>> b/llvm/test/Transforms/LoopVectorize/first-order-recurrence-complex.ll<br>
>>>> @@ -471,9 +471,10 @@ define i16 @multiple_exit(i16* %p, i32 %n) {<br>
>>>> ; CHECK-NEXT: [[TMP15:%.*]] = icmp eq i32 [[INDEX_NEXT]], <br>
>>>> [[N_VEC]]<br>
>>>> ; CHECK-NEXT: br i1 [[TMP15]], label [[MIDDLE_BLOCK:%.*]], <br>
>>>> label [[VECTOR_BODY]], [[LOOP6:!llvm.loop !.*]]<br>
>>>> ; CHECK: middle.block:<br>
>>>> +; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i32 [[TMP2]], [[N_VEC]]<br>
>>>> ; CHECK-NEXT: [[VECTOR_RECUR_EXTRACT:%.*]] = extractelement <br>
>>>> <4 x i16> [[WIDE_LOAD]], i32 3<br>
>>>> ; CHECK-NEXT: [[VECTOR_RECUR_EXTRACT_FOR_PHI:%.*]] = <br>
>>>> extractelement <4 x i16> [[WIDE_LOAD]], i32 2<br>
>>>> -; CHECK-NEXT: br label [[SCALAR_PH]]<br>
>>>> +; CHECK-NEXT: br i1 [[CMP_N]], label [[IF_END:%.*]], label <br>
>>>> [[SCALAR_PH]]<br>
>>>> ; CHECK: <a href="http://scalar.ph" rel="noreferrer" target="_blank">scalar.ph</a>:<br>
>>>> ; CHECK-NEXT: [[SCALAR_RECUR_INIT:%.*]] = phi i16 [ 0, <br>
>>>> [[ENTRY:%.*]] ], [ [[VECTOR_RECUR_EXTRACT]], [[MIDDLE_BLOCK]] ]<br>
>>>> ; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i32 [ [[N_VEC]], <br>
>>>> [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY]] ]<br>
>>>> @@ -485,14 +486,14 @@ define i16 @multiple_exit(i16* %p, i32 %n) {<br>
>>>> ; CHECK-NEXT: [[B:%.*]] = getelementptr inbounds i16, i16* <br>
>>>> [[P]], i64 [[IPROM]]<br>
>>>> ; CHECK-NEXT: [[REC_NEXT]] = load i16, i16* [[B]], align 2<br>
>>>> ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i32 [[I]], [[N]]<br>
>>>> -; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label <br>
>>>> [[IF_END:%.*]]<br>
>>>> +; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label [[IF_END]]<br>
>>>> ; CHECK: for.body:<br>
>>>> ; CHECK-NEXT: store i16 [[SCALAR_RECUR]], i16* [[B]], align 4<br>
>>>> ; CHECK-NEXT: [[INC]] = add nsw i32 [[I]], 1<br>
>>>> ; CHECK-NEXT: [[CMP2:%.*]] = icmp slt i32 [[I]], 2096<br>
>>>> ; CHECK-NEXT: br i1 [[CMP2]], label [[FOR_COND]], label <br>
>>>> [[IF_END]], [[LOOP7:!llvm.loop !.*]]<br>
>>>> ; CHECK: if.end:<br>
>>>> -; CHECK-NEXT: [[REC_LCSSA:%.*]] = phi i16 [ [[SCALAR_RECUR]], <br>
>>>> [[FOR_BODY]] ], [ [[SCALAR_RECUR]], [[FOR_COND]] ]<br>
>>>> +; CHECK-NEXT: [[REC_LCSSA:%.*]] = phi i16 [ [[SCALAR_RECUR]], <br>
>>>> [[FOR_BODY]] ], [ [[SCALAR_RECUR]], [[FOR_COND]] ], [ <br>
>>>> [[VECTOR_RECUR_EXTRACT_FOR_PHI]], [[MIDDLE_BLOCK]] ]<br>
>>>> ; CHECK-NEXT: ret i16 [[REC_LCSSA]]<br>
>>>> ;<br>
>>>> entry:<br>
>>>> @@ -557,9 +558,10 @@ define i16 @multiple_exit2(i16* %p, i32 %n) {<br>
>>>> ; CHECK-NEXT: [[TMP15:%.*]] = icmp eq i32 [[INDEX_NEXT]], <br>
>>>> [[N_VEC]]<br>
>>>> ; CHECK-NEXT: br i1 [[TMP15]], label [[MIDDLE_BLOCK:%.*]], <br>
>>>> label [[VECTOR_BODY]], [[LOOP8:!llvm.loop !.*]]<br>
>>>> ; CHECK: middle.block:<br>
>>>> +; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i32 [[TMP2]], [[N_VEC]]<br>
>>>> ; CHECK-NEXT: [[VECTOR_RECUR_EXTRACT:%.*]] = extractelement <br>
>>>> <4 x i16> [[WIDE_LOAD]], i32 3<br>
>>>> ; CHECK-NEXT: [[VECTOR_RECUR_EXTRACT_FOR_PHI:%.*]] = <br>
>>>> extractelement <4 x i16> [[WIDE_LOAD]], i32 2<br>
>>>> -; CHECK-NEXT: br label [[SCALAR_PH]]<br>
>>>> +; CHECK-NEXT: br i1 [[CMP_N]], label [[IF_END:%.*]], label <br>
>>>> [[SCALAR_PH]]<br>
>>>> ; CHECK: <a href="http://scalar.ph" rel="noreferrer" target="_blank">scalar.ph</a>:<br>
>>>> ; CHECK-NEXT: [[SCALAR_RECUR_INIT:%.*]] = phi i16 [ 0, <br>
>>>> [[ENTRY:%.*]] ], [ [[VECTOR_RECUR_EXTRACT]], [[MIDDLE_BLOCK]] ]<br>
>>>> ; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i32 [ [[N_VEC]], <br>
>>>> [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY]] ]<br>
>>>> @@ -571,14 +573,14 @@ define i16 @multiple_exit2(i16* %p, i32 %n) {<br>
>>>> ; CHECK-NEXT: [[B:%.*]] = getelementptr inbounds i16, i16* <br>
>>>> [[P]], i64 [[IPROM]]<br>
>>>> ; CHECK-NEXT: [[REC_NEXT]] = load i16, i16* [[B]], align 2<br>
>>>> ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i32 [[I]], [[N]]<br>
>>>> -; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label <br>
>>>> [[IF_END:%.*]]<br>
>>>> +; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label [[IF_END]]<br>
>>>> ; CHECK: for.body:<br>
>>>> ; CHECK-NEXT: store i16 [[SCALAR_RECUR]], i16* [[B]], align 4<br>
>>>> ; CHECK-NEXT: [[INC]] = add nsw i32 [[I]], 1<br>
>>>> ; CHECK-NEXT: [[CMP2:%.*]] = icmp slt i32 [[I]], 2096<br>
>>>> ; CHECK-NEXT: br i1 [[CMP2]], label [[FOR_COND]], label <br>
>>>> [[IF_END]], [[LOOP9:!llvm.loop !.*]]<br>
>>>> ; CHECK: if.end:<br>
>>>> -; CHECK-NEXT: [[REC_LCSSA:%.*]] = phi i16 [ [[SCALAR_RECUR]], <br>
>>>> [[FOR_COND]] ], [ 10, [[FOR_BODY]] ]<br>
>>>> +; CHECK-NEXT: [[REC_LCSSA:%.*]] = phi i16 [ [[SCALAR_RECUR]], <br>
>>>> [[FOR_COND]] ], [ 10, [[FOR_BODY]] ], [ <br>
>>>> [[VECTOR_RECUR_EXTRACT_FOR_PHI]], [[MIDDLE_BLOCK]] ]<br>
>>>> ; CHECK-NEXT: ret i16 [[REC_LCSSA]]<br>
>>>> ;<br>
>>>> entry:<br>
>>>><br>
>>>> diff --git <br>
>>>> a/llvm/test/Transforms/LoopVectorize/interleaved-accesses.ll <br>
>>>> b/llvm/test/Transforms/LoopVectorize/interleaved-accesses.ll<br>
>>>> index f0ba677348ab..0d4bdf0ecac3 100644<br>
>>>> --- a/llvm/test/Transforms/LoopVectorize/interleaved-accesses.ll<br>
>>>> +++ b/llvm/test/Transforms/LoopVectorize/interleaved-accesses.ll<br>
>>>> @@ -447,7 +447,7 @@ define void @even_load_static_tc(i32* noalias <br>
>>>> nocapture readonly %A, i32* noalia<br>
>>>> ; CHECK-NEXT: [[TMP6:%.*]] = icmp eq i64 [[INDEX_NEXT]], 508<br>
>>>> ; CHECK-NEXT: br i1 [[TMP6]], label [[MIDDLE_BLOCK:%.*]], <br>
>>>> label [[VECTOR_BODY]], [[LOOP12:!llvm.loop !.*]]<br>
>>>> ; CHECK: middle.block:<br>
>>>> -; CHECK-NEXT: br label [[SCALAR_PH]]<br>
>>>> +; CHECK-NEXT: br i1 false, label [[FOR_COND_CLEANUP:%.*]], <br>
>>>> label [[SCALAR_PH]]<br>
>>>> ; CHECK: <a href="http://scalar.ph" rel="noreferrer" target="_blank">scalar.ph</a>:<br>
>>>> ; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i64 [ 1016, <br>
>>>> [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]<br>
>>>> ; CHECK-NEXT: br label [[FOR_BODY:%.*]]<br>
>>>> @@ -463,7 +463,7 @@ define void @even_load_static_tc(i32* noalias <br>
>>>> nocapture readonly %A, i32* noalia<br>
>>>> ; CHECK-NEXT: store i32 [[MUL]], i32* [[ARRAYIDX2]], align 4<br>
>>>> ; CHECK-NEXT: [[INDVARS_IV_NEXT]] = add nuw nsw i64 <br>
>>>> [[INDVARS_IV]], 2<br>
>>>> ; CHECK-NEXT: [[CMP:%.*]] = icmp ult i64 [[INDVARS_IV]], 1022<br>
>>>> -; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label <br>
>>>> [[FOR_COND_CLEANUP:%.*]], [[LOOP13:!llvm.loop !.*]]<br>
>>>> +; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label <br>
>>>> [[FOR_COND_CLEANUP]], [[LOOP13:!llvm.loop !.*]]<br>
>>>> ;<br>
>>>> entry:<br>
>>>> br label %for.body<br>
>>>> @@ -528,7 +528,7 @@ define void @even_load_dynamic_tc(i32* noalias <br>
>>>> nocapture readonly %A, i32* noali<br>
>>>> ; CHECK-NEXT: [[TMP12:%.*]] = icmp eq i64 [[INDEX_NEXT]], <br>
>>>> [[N_VEC]]<br>
>>>> ; CHECK-NEXT: br i1 [[TMP12]], label [[MIDDLE_BLOCK:%.*]], <br>
>>>> label [[VECTOR_BODY]], [[LOOP14:!llvm.loop !.*]]<br>
>>>> ; CHECK: middle.block:<br>
>>>> -; CHECK-NEXT: br label [[SCALAR_PH]]<br>
>>>> +; CHECK-NEXT: br i1 false, label [[FOR_COND_CLEANUP:%.*]], <br>
>>>> label [[SCALAR_PH]]<br>
>>>> ; CHECK: <a href="http://scalar.ph" rel="noreferrer" target="_blank">scalar.ph</a>:<br>
>>>> ; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i64 [ [[IND_END]], <br>
>>>> [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]<br>
>>>> ; CHECK-NEXT: br label [[FOR_BODY:%.*]]<br>
>>>> @@ -544,7 +544,7 @@ define void @even_load_dynamic_tc(i32* noalias <br>
>>>> nocapture readonly %A, i32* noali<br>
>>>> ; CHECK-NEXT: store i32 [[MUL]], i32* [[ARRAYIDX2]], align 4<br>
>>>> ; CHECK-NEXT: [[INDVARS_IV_NEXT]] = add nuw nsw i64 <br>
>>>> [[INDVARS_IV]], 2<br>
>>>> ; CHECK-NEXT: [[CMP:%.*]] = icmp ult i64 [[INDVARS_IV_NEXT]], <br>
>>>> [[N]]<br>
>>>> -; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label <br>
>>>> [[FOR_COND_CLEANUP:%.*]], [[LOOP15:!llvm.loop !.*]]<br>
>>>> +; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label <br>
>>>> [[FOR_COND_CLEANUP]], [[LOOP15:!llvm.loop !.*]]<br>
>>>> ;<br>
>>>> entry:<br>
>>>> br label %for.body<br>
>>>> @@ -973,7 +973,7 @@ define void @PR27626_0(%pair.i32 *%p, i32 %z, <br>
>>>> i64 %n) {<br>
>>>> ; CHECK-NEXT: [[TMP19:%.*]] = icmp eq i64 [[INDEX_NEXT]], <br>
>>>> [[N_VEC]]<br>
>>>> ; CHECK-NEXT: br i1 [[TMP19]], label [[MIDDLE_BLOCK:%.*]], <br>
>>>> label [[VECTOR_BODY]], [[LOOP24:!llvm.loop !.*]]<br>
>>>> ; CHECK: middle.block:<br>
>>>> -; CHECK-NEXT: br label [[SCALAR_PH]]<br>
>>>> +; CHECK-NEXT: br i1 false, label [[FOR_END:%.*]], label <br>
>>>> [[SCALAR_PH]]<br>
>>>> ; CHECK: <a href="http://scalar.ph" rel="noreferrer" target="_blank">scalar.ph</a>:<br>
>>>> ; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], <br>
>>>> [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]<br>
>>>> ; CHECK-NEXT: br label [[FOR_BODY:%.*]]<br>
>>>> @@ -985,7 +985,7 @@ define void @PR27626_0(%pair.i32 *%p, i32 %z, <br>
>>>> i64 %n) {<br>
>>>> ; CHECK-NEXT: store i32 [[Z]], i32* [[P_I_Y]], align 4<br>
>>>> ; CHECK-NEXT: [[I_NEXT]] = add nuw nsw i64 [[I]], 1<br>
>>>> ; CHECK-NEXT: [[COND:%.*]] = icmp slt i64 [[I_NEXT]], [[N]]<br>
>>>> -; CHECK-NEXT: br i1 [[COND]], label [[FOR_BODY]], label <br>
>>>> [[FOR_END:%.*]], [[LOOP25:!llvm.loop !.*]]<br>
>>>> +; CHECK-NEXT: br i1 [[COND]], label [[FOR_BODY]], label <br>
>>>> [[FOR_END]], [[LOOP25:!llvm.loop !.*]]<br>
>>>> ; CHECK: for.end:<br>
>>>> ; CHECK-NEXT: ret void<br>
>>>> ;<br>
>>>> @@ -1066,7 +1066,7 @@ define i32 @PR27626_1(%pair.i32 *%p, i64 %n) {<br>
>>>> ; CHECK-NEXT: [[RDX_SHUF3:%.*]] = shufflevector <4 x i32> <br>
>>>> [[BIN_RDX]], <4 x i32> poison, <4 x i32> <i32 1, i32 undef, i32 <br>
>>>> undef, i32 undef><br>
>>>> ; CHECK-NEXT: [[BIN_RDX4:%.*]] = add <4 x i32> [[BIN_RDX]], <br>
>>>> [[RDX_SHUF3]]<br>
>>>> ; CHECK-NEXT: [[TMP19:%.*]] = extractelement <4 x i32> <br>
>>>> [[BIN_RDX4]], i32 0<br>
>>>> -; CHECK-NEXT: br label [[SCALAR_PH]]<br>
>>>> +; CHECK-NEXT: br i1 false, label [[FOR_END:%.*]], label <br>
>>>> [[SCALAR_PH]]<br>
>>>> ; CHECK: <a href="http://scalar.ph" rel="noreferrer" target="_blank">scalar.ph</a>:<br>
>>>> ; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], <br>
>>>> [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]<br>
>>>> ; CHECK-NEXT: [[BC_MERGE_RDX:%.*]] = phi i32 [ [[TMP19]], <br>
>>>> [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY]] ]<br>
>>>> @@ -1081,9 +1081,10 @@ define i32 @PR27626_1(%pair.i32 *%p, i64 %n) {<br>
>>>> ; CHECK-NEXT: [[TMP21]] = add nsw i32 [[TMP20]], [[S]]<br>
>>>> ; CHECK-NEXT: [[I_NEXT]] = add nuw nsw i64 [[I]], 1<br>
>>>> ; CHECK-NEXT: [[COND:%.*]] = icmp slt i64 [[I_NEXT]], [[N]]<br>
>>>> -; CHECK-NEXT: br i1 [[COND]], label [[FOR_BODY]], label <br>
>>>> [[FOR_END:%.*]], [[LOOP27:!llvm.loop !.*]]<br>
>>>> +; CHECK-NEXT: br i1 [[COND]], label [[FOR_BODY]], label <br>
>>>> [[FOR_END]], [[LOOP27:!llvm.loop !.*]]<br>
>>>> ; CHECK: for.end:<br>
>>>> -; CHECK-NEXT: ret i32 [[TMP21]]<br>
>>>> +; CHECK-NEXT: [[TMP22:%.*]] = phi i32 [ [[TMP21]], [[FOR_BODY]] <br>
>>>> ], [ [[TMP19]], [[MIDDLE_BLOCK]] ]<br>
>>>> +; CHECK-NEXT: ret i32 [[TMP22]]<br>
>>>> ;<br>
>>>> entry:<br>
>>>> br label %for.body<br>
>>>> @@ -1162,7 +1163,7 @@ define void @PR27626_2(%pair.i32 *%p, i64 %n, <br>
>>>> i32 %z) {<br>
>>>> ; CHECK-NEXT: [[TMP20:%.*]] = icmp eq i64 [[INDEX_NEXT]], <br>
>>>> [[N_VEC]]<br>
>>>> ; CHECK-NEXT: br i1 [[TMP20]], label [[MIDDLE_BLOCK:%.*]], <br>
>>>> label [[VECTOR_BODY]], [[LOOP28:!llvm.loop !.*]]<br>
>>>> ; CHECK: middle.block:<br>
>>>> -; CHECK-NEXT: br label [[SCALAR_PH]]<br>
>>>> +; CHECK-NEXT: br i1 false, label [[FOR_END:%.*]], label <br>
>>>> [[SCALAR_PH]]<br>
>>>> ; CHECK: <a href="http://scalar.ph" rel="noreferrer" target="_blank">scalar.ph</a>:<br>
>>>> ; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], <br>
>>>> [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]<br>
>>>> ; CHECK-NEXT: br label [[FOR_BODY:%.*]]<br>
>>>> @@ -1176,7 +1177,7 @@ define void @PR27626_2(%pair.i32 *%p, i64 %n, <br>
>>>> i32 %z) {<br>
>>>> ; CHECK-NEXT: store i32 [[TMP21]], i32* [[P_I_Y]], align 4<br>
>>>> ; CHECK-NEXT: [[I_NEXT]] = add nuw nsw i64 [[I]], 1<br>
>>>> ; CHECK-NEXT: [[COND:%.*]] = icmp slt i64 [[I_NEXT]], [[N]]<br>
>>>> -; CHECK-NEXT: br i1 [[COND]], label [[FOR_BODY]], label <br>
>>>> [[FOR_END:%.*]], [[LOOP29:!llvm.loop !.*]]<br>
>>>> +; CHECK-NEXT: br i1 [[COND]], label [[FOR_BODY]], label <br>
>>>> [[FOR_END]], [[LOOP29:!llvm.loop !.*]]<br>
>>>> ; CHECK: for.end:<br>
>>>> ; CHECK-NEXT: ret void<br>
>>>> ;<br>
>>>> @@ -1263,7 +1264,7 @@ define i32 @PR27626_3(%pair.i32 *%p, i64 %n, <br>
>>>> i32 %z) {<br>
>>>> ; CHECK-NEXT: [[RDX_SHUF3:%.*]] = shufflevector <4 x i32> <br>
>>>> [[BIN_RDX]], <4 x i32> poison, <4 x i32> <i32 1, i32 undef, i32 <br>
>>>> undef, i32 undef><br>
>>>> ; CHECK-NEXT: [[BIN_RDX4:%.*]] = add <4 x i32> [[BIN_RDX]], <br>
>>>> [[RDX_SHUF3]]<br>
>>>> ; CHECK-NEXT: [[TMP22:%.*]] = extractelement <4 x i32> <br>
>>>> [[BIN_RDX4]], i32 0<br>
>>>> -; CHECK-NEXT: br label [[SCALAR_PH]]<br>
>>>> +; CHECK-NEXT: br i1 false, label [[FOR_END:%.*]], label <br>
>>>> [[SCALAR_PH]]<br>
>>>> ; CHECK: <a href="http://scalar.ph" rel="noreferrer" target="_blank">scalar.ph</a>:<br>
>>>> ; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], <br>
>>>> [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]<br>
>>>> ; CHECK-NEXT: [[BC_MERGE_RDX:%.*]] = phi i32 [ [[TMP22]], <br>
>>>> [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY]] ]<br>
>>>> @@ -1281,9 +1282,10 @@ define i32 @PR27626_3(%pair.i32 *%p, i64 %n, <br>
>>>> i32 %z) {<br>
>>>> ; CHECK-NEXT: [[TMP25]] = add nsw i32 [[TMP24]], [[S]]<br>
>>>> ; CHECK-NEXT: [[I_NEXT]] = add nuw nsw i64 [[I]], 1<br>
>>>> ; CHECK-NEXT: [[COND:%.*]] = icmp slt i64 [[I_NEXT]], [[N]]<br>
>>>> -; CHECK-NEXT: br i1 [[COND]], label [[FOR_BODY]], label <br>
>>>> [[FOR_END:%.*]], [[LOOP31:!llvm.loop !.*]]<br>
>>>> +; CHECK-NEXT: br i1 [[COND]], label [[FOR_BODY]], label <br>
>>>> [[FOR_END]], [[LOOP31:!llvm.loop !.*]]<br>
>>>> ; CHECK: for.end:<br>
>>>> -; CHECK-NEXT: ret i32 [[TMP25]]<br>
>>>> +; CHECK-NEXT: [[TMP26:%.*]] = phi i32 [ [[TMP25]], [[FOR_BODY]] <br>
>>>> ], [ [[TMP22]], [[MIDDLE_BLOCK]] ]<br>
>>>> +; CHECK-NEXT: ret i32 [[TMP26]]<br>
>>>> ;<br>
>>>> entry:<br>
>>>> br label %for.body<br>
>>>><br>
>>>> diff --git a/llvm/test/Transforms/LoopVectorize/loop-form.ll <br>
>>>> b/llvm/test/Transforms/LoopVectorize/loop-form.ll<br>
>>>> index f32002fae2b6..91780789088b 100644<br>
>>>> --- a/llvm/test/Transforms/LoopVectorize/loop-form.ll<br>
>>>> +++ b/llvm/test/Transforms/LoopVectorize/loop-form.ll<br>
>>>> @@ -146,14 +146,15 @@ define void @early_exit(i16* %p, i32 %n) {<br>
>>>> ; CHECK-NEXT: [[TMP10:%.*]] = icmp eq i32 [[INDEX_NEXT]], <br>
>>>> [[N_VEC]]<br>
>>>> ; CHECK-NEXT: br i1 [[TMP10]], label [[MIDDLE_BLOCK:%.*]], <br>
>>>> label [[VECTOR_BODY]], [[LOOP4:!llvm.loop !.*]]<br>
>>>> ; CHECK: middle.block:<br>
>>>> -; CHECK-NEXT: br label [[SCALAR_PH]]<br>
>>>> +; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i32 [[TMP1]], [[N_VEC]]<br>
>>>> +; CHECK-NEXT: br i1 [[CMP_N]], label [[IF_END:%.*]], label <br>
>>>> [[SCALAR_PH]]<br>
>>>> ; CHECK: <a href="http://scalar.ph" rel="noreferrer" target="_blank">scalar.ph</a>:<br>
>>>> ; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i32 [ [[N_VEC]], <br>
>>>> [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]<br>
>>>> ; CHECK-NEXT: br label [[FOR_COND:%.*]]<br>
>>>> ; CHECK: for.cond:<br>
>>>> ; CHECK-NEXT: [[I:%.*]] = phi i32 [ [[BC_RESUME_VAL]], <br>
>>>> [[SCALAR_PH]] ], [ [[INC:%.*]], [[FOR_BODY:%.*]] ]<br>
>>>> ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i32 [[I]], [[N]]<br>
>>>> -; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label <br>
>>>> [[IF_END:%.*]]<br>
>>>> +; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label [[IF_END]]<br>
>>>> ; CHECK: for.body:<br>
>>>> ; CHECK-NEXT: [[IPROM:%.*]] = sext i32 [[I]] to i64<br>
>>>> ; CHECK-NEXT: [[B:%.*]] = getelementptr inbounds i16, i16* <br>
>>>> [[P]], i64 [[IPROM]]<br>
>>>> @@ -285,14 +286,15 @@ define void @multiple_unique_exit(i16* %p, <br>
>>>> i32 %n) {<br>
>>>> ; CHECK-NEXT: [[TMP11:%.*]] = icmp eq i32 [[INDEX_NEXT]], <br>
>>>> [[N_VEC]]<br>
>>>> ; CHECK-NEXT: br i1 [[TMP11]], label [[MIDDLE_BLOCK:%.*]], <br>
>>>> label [[VECTOR_BODY]], [[LOOP6:!llvm.loop !.*]]<br>
>>>> ; CHECK: middle.block:<br>
>>>> -; CHECK-NEXT: br label [[SCALAR_PH]]<br>
>>>> +; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i32 [[TMP2]], [[N_VEC]]<br>
>>>> +; CHECK-NEXT: br i1 [[CMP_N]], label [[IF_END:%.*]], label <br>
>>>> [[SCALAR_PH]]<br>
>>>> ; CHECK: <a href="http://scalar.ph" rel="noreferrer" target="_blank">scalar.ph</a>:<br>
>>>> ; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i32 [ [[N_VEC]], <br>
>>>> [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]<br>
>>>> ; CHECK-NEXT: br label [[FOR_COND:%.*]]<br>
>>>> ; CHECK: for.cond:<br>
>>>> ; CHECK-NEXT: [[I:%.*]] = phi i32 [ [[BC_RESUME_VAL]], <br>
>>>> [[SCALAR_PH]] ], [ [[INC:%.*]], [[FOR_BODY:%.*]] ]<br>
>>>> ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i32 [[I]], [[N]]<br>
>>>> -; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label <br>
>>>> [[IF_END:%.*]]<br>
>>>> +; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label [[IF_END]]<br>
>>>> ; CHECK: for.body:<br>
>>>> ; CHECK-NEXT: [[IPROM:%.*]] = sext i32 [[I]] to i64<br>
>>>> ; CHECK-NEXT: [[B:%.*]] = getelementptr inbounds i16, i16* <br>
>>>> [[P]], i64 [[IPROM]]<br>
>>>> @@ -372,14 +374,17 @@ define i32 @multiple_unique_exit2(i16* %p, <br>
>>>> i32 %n) {<br>
>>>> ; CHECK-NEXT: [[TMP11:%.*]] = icmp eq i32 [[INDEX_NEXT]], <br>
>>>> [[N_VEC]]<br>
>>>> ; CHECK-NEXT: br i1 [[TMP11]], label [[MIDDLE_BLOCK:%.*]], <br>
>>>> label [[VECTOR_BODY]], [[LOOP8:!llvm.loop !.*]]<br>
>>>> ; CHECK: middle.block:<br>
>>>> -; CHECK-NEXT: br label [[SCALAR_PH]]<br>
>>>> +; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i32 [[TMP2]], [[N_VEC]]<br>
>>>> +; CHECK-NEXT: [[IND_ESCAPE:%.*]] = sub i32 [[N_VEC]], 1<br>
>>>> +; CHECK-NEXT: [[IND_ESCAPE1:%.*]] = sub i32 [[N_VEC]], 1<br>
>>>> +; CHECK-NEXT: br i1 [[CMP_N]], label [[IF_END:%.*]], label <br>
>>>> [[SCALAR_PH]]<br>
>>>> ; CHECK: <a href="http://scalar.ph" rel="noreferrer" target="_blank">scalar.ph</a>:<br>
>>>> ; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i32 [ [[N_VEC]], <br>
>>>> [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]<br>
>>>> ; CHECK-NEXT: br label [[FOR_COND:%.*]]<br>
>>>> ; CHECK: for.cond:<br>
>>>> ; CHECK-NEXT: [[I:%.*]] = phi i32 [ [[BC_RESUME_VAL]], <br>
>>>> [[SCALAR_PH]] ], [ [[INC:%.*]], [[FOR_BODY:%.*]] ]<br>
>>>> ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i32 [[I]], [[N]]<br>
>>>> -; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label <br>
>>>> [[IF_END:%.*]]<br>
>>>> +; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label [[IF_END]]<br>
>>>> ; CHECK: for.body:<br>
>>>> ; CHECK-NEXT: [[IPROM:%.*]] = sext i32 [[I]] to i64<br>
>>>> ; CHECK-NEXT: [[B:%.*]] = getelementptr inbounds i16, i16* <br>
>>>> [[P]], i64 [[IPROM]]<br>
>>>> @@ -388,7 +393,7 @@ define i32 @multiple_unique_exit2(i16* %p, i32 <br>
>>>> %n) {<br>
>>>> ; CHECK-NEXT: [[CMP2:%.*]] = icmp slt i32 [[I]], 2096<br>
>>>> ; CHECK-NEXT: br i1 [[CMP2]], label [[FOR_COND]], label <br>
>>>> [[IF_END]], [[LOOP9:!llvm.loop !.*]]<br>
>>>> ; CHECK: if.end:<br>
>>>> -; CHECK-NEXT: [[I_LCSSA:%.*]] = phi i32 [ [[I]], [[FOR_BODY]] <br>
>>>> ], [ [[I]], [[FOR_COND]] ]<br>
>>>> +; CHECK-NEXT: [[I_LCSSA:%.*]] = phi i32 [ [[I]], [[FOR_BODY]] <br>
>>>> ], [ [[I]], [[FOR_COND]] ], [ [[IND_ESCAPE1]], [[MIDDLE_BLOCK]] ]<br>
>>>> ; CHECK-NEXT: ret i32 [[I_LCSSA]]<br>
>>>> ;<br>
>>>> ; TAILFOLD-LABEL: @multiple_unique_exit2(<br>
>>>> @@ -461,14 +466,15 @@ define i32 @multiple_unique_exit3(i16* %p, <br>
>>>> i32 %n) {<br>
>>>> ; CHECK-NEXT: [[TMP11:%.*]] = icmp eq i32 [[INDEX_NEXT]], <br>
>>>> [[N_VEC]]<br>
>>>> ; CHECK-NEXT: br i1 [[TMP11]], label [[MIDDLE_BLOCK:%.*]], <br>
>>>> label [[VECTOR_BODY]], [[LOOP10:!llvm.loop !.*]]<br>
>>>> ; CHECK: middle.block:<br>
>>>> -; CHECK-NEXT: br label [[SCALAR_PH]]<br>
>>>> +; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i32 [[TMP2]], [[N_VEC]]<br>
>>>> +; CHECK-NEXT: br i1 [[CMP_N]], label [[IF_END:%.*]], label <br>
>>>> [[SCALAR_PH]]<br>
>>>> ; CHECK: <a href="http://scalar.ph" rel="noreferrer" target="_blank">scalar.ph</a>:<br>
>>>> ; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i32 [ [[N_VEC]], <br>
>>>> [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]<br>
>>>> ; CHECK-NEXT: br label [[FOR_COND:%.*]]<br>
>>>> ; CHECK: for.cond:<br>
>>>> ; CHECK-NEXT: [[I:%.*]] = phi i32 [ [[BC_RESUME_VAL]], <br>
>>>> [[SCALAR_PH]] ], [ [[INC:%.*]], [[FOR_BODY:%.*]] ]<br>
>>>> ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i32 [[I]], [[N]]<br>
>>>> -; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label <br>
>>>> [[IF_END:%.*]]<br>
>>>> +; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label [[IF_END]]<br>
>>>> ; CHECK: for.body:<br>
>>>> ; CHECK-NEXT: [[IPROM:%.*]] = sext i32 [[I]] to i64<br>
>>>> ; CHECK-NEXT: [[B:%.*]] = getelementptr inbounds i16, i16* <br>
>>>> [[P]], i64 [[IPROM]]<br>
>>>> @@ -477,7 +483,7 @@ define i32 @multiple_unique_exit3(i16* %p, i32 <br>
>>>> %n) {<br>
>>>> ; CHECK-NEXT: [[CMP2:%.*]] = icmp slt i32 [[I]], 2096<br>
>>>> ; CHECK-NEXT: br i1 [[CMP2]], label [[FOR_COND]], label <br>
>>>> [[IF_END]], [[LOOP11:!llvm.loop !.*]]<br>
>>>> ; CHECK: if.end:<br>
>>>> -; CHECK-NEXT: [[EXIT:%.*]] = phi i32 [ 0, [[FOR_COND]] ], [ 1, <br>
>>>> [[FOR_BODY]] ]<br>
>>>> +; CHECK-NEXT: [[EXIT:%.*]] = phi i32 [ 0, [[FOR_COND]] ], [ 1, <br>
>>>> [[FOR_BODY]] ], [ 0, [[MIDDLE_BLOCK]] ]<br>
>>>> ; CHECK-NEXT: ret i32 [[EXIT]]<br>
>>>> ;<br>
>>>> ; TAILFOLD-LABEL: @multiple_unique_exit3(<br>
>>>> @@ -994,7 +1000,8 @@ define void @scalar_predication(float* %addr) {<br>
>>>> ; CHECK-NEXT: [[TMP10:%.*]] = icmp eq i64 [[INDEX_NEXT]], 200<br>
>>>> ; CHECK-NEXT: br i1 [[TMP10]], label [[MIDDLE_BLOCK:%.*]], <br>
>>>> label [[VECTOR_BODY]], [[LOOP12:!llvm.loop !.*]]<br>
>>>> ; CHECK: middle.block:<br>
>>>> -; CHECK-NEXT: br label [[SCALAR_PH]]<br>
>>>> +; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i64 201, 200<br>
>>>> +; CHECK-NEXT: br i1 [[CMP_N]], label [[EXIT:%.*]], label <br>
>>>> [[SCALAR_PH]]<br>
>>>> ; CHECK: <a href="http://scalar.ph" rel="noreferrer" target="_blank">scalar.ph</a>:<br>
>>>> ; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i64 [ 200, <br>
>>>> [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]<br>
>>>> ; CHECK-NEXT: br label [[LOOP_HEADER:%.*]]<br>
>>>> @@ -1002,7 +1009,7 @@ define void @scalar_predication(float* %addr) {<br>
>>>> ; CHECK-NEXT: [[IV:%.*]] = phi i64 [ [[BC_RESUME_VAL]], <br>
>>>> [[SCALAR_PH]] ], [ [[IV_NEXT:%.*]], [[LOOP_LATCH:%.*]] ]<br>
>>>> ; CHECK-NEXT: [[GEP:%.*]] = getelementptr float, float* <br>
>>>> [[ADDR]], i64 [[IV]]<br>
>>>> ; CHECK-NEXT: [[EXITCOND_NOT:%.*]] = icmp eq i64 [[IV]], 200<br>
>>>> -; CHECK-NEXT: br i1 [[EXITCOND_NOT]], label [[EXIT:%.*]], label <br>
>>>> [[LOOP_BODY:%.*]]<br>
>>>> +; CHECK-NEXT: br i1 [[EXITCOND_NOT]], label [[EXIT]], label <br>
>>>> [[LOOP_BODY:%.*]]<br>
>>>> ; CHECK: loop.body:<br>
>>>> ; CHECK-NEXT: [[TMP11:%.*]] = load float, float* [[GEP]], <br>
>>>> align 4<br>
>>>> ; CHECK-NEXT: [[PRED:%.*]] = fcmp oeq float [[TMP11]], <br>
>>>> 0.000000e+00<br>
>>>> @@ -1088,7 +1095,8 @@ define i32 @me_reduction(i32* %addr) {<br>
>>>> ; CHECK-NEXT: [[RDX_SHUF:%.*]] = shufflevector <2 x i32> <br>
>>>> [[TMP5]], <2 x i32> poison, <2 x i32> <i32 1, i32 undef><br>
>>>> ; CHECK-NEXT: [[BIN_RDX:%.*]] = add <2 x i32> [[TMP5]], <br>
>>>> [[RDX_SHUF]]<br>
>>>> ; CHECK-NEXT: [[TMP7:%.*]] = extractelement <2 x i32> <br>
>>>> [[BIN_RDX]], i32 0<br>
>>>> -; CHECK-NEXT: br label [[SCALAR_PH]]<br>
>>>> +; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i64 201, 200<br>
>>>> +; CHECK-NEXT: br i1 [[CMP_N]], label [[EXIT:%.*]], label <br>
>>>> [[SCALAR_PH]]<br>
>>>> ; CHECK: <a href="http://scalar.ph" rel="noreferrer" target="_blank">scalar.ph</a>:<br>
>>>> ; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i64 [ 200, <br>
>>>> [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]<br>
>>>> ; CHECK-NEXT: [[BC_MERGE_RDX:%.*]] = phi i32 [ 0, [[ENTRY]] <br>
>>>> ], [ [[TMP7]], [[MIDDLE_BLOCK]] ]<br>
>>>> @@ -1098,7 +1106,7 @@ define i32 @me_reduction(i32* %addr) {<br>
>>>> ; CHECK-NEXT: [[ACCUM:%.*]] = phi i32 [ [[BC_MERGE_RDX]], <br>
>>>> [[SCALAR_PH]] ], [ [[ACCUM_NEXT:%.*]], [[LOOP_LATCH]] ]<br>
>>>> ; CHECK-NEXT: [[GEP:%.*]] = getelementptr i32, i32* [[ADDR]], <br>
>>>> i64 [[IV]]<br>
>>>> ; CHECK-NEXT: [[EXITCOND_NOT:%.*]] = icmp eq i64 [[IV]], 200<br>
>>>> -; CHECK-NEXT: br i1 [[EXITCOND_NOT]], label [[EXIT:%.*]], label <br>
>>>> [[LOOP_LATCH]]<br>
>>>> +; CHECK-NEXT: br i1 [[EXITCOND_NOT]], label [[EXIT]], label <br>
>>>> [[LOOP_LATCH]]<br>
>>>> ; CHECK: loop.latch:<br>
>>>> ; CHECK-NEXT: [[TMP8:%.*]] = load i32, i32* [[GEP]], align 4<br>
>>>> ; CHECK-NEXT: [[ACCUM_NEXT]] = add i32 [[ACCUM]], [[TMP8]]<br>
>>>> @@ -1106,7 +1114,7 @@ define i32 @me_reduction(i32* %addr) {<br>
>>>> ; CHECK-NEXT: [[EXITCOND2_NOT:%.*]] = icmp eq i64 [[IV]], 400<br>
>>>> ; CHECK-NEXT: br i1 [[EXITCOND2_NOT]], label [[EXIT]], label <br>
>>>> [[LOOP_HEADER]], [[LOOP15:!llvm.loop !.*]]<br>
>>>> ; CHECK: exit:<br>
>>>> -; CHECK-NEXT: [[LCSSA:%.*]] = phi i32 [ 0, [[LOOP_HEADER]] ], [ <br>
>>>> [[ACCUM_NEXT]], [[LOOP_LATCH]] ]<br>
>>>> +; CHECK-NEXT: [[LCSSA:%.*]] = phi i32 [ 0, [[LOOP_HEADER]] ], [ <br>
>>>> [[ACCUM_NEXT]], [[LOOP_LATCH]] ], [ [[TMP7]], [[MIDDLE_BLOCK]] ]<br>
>>>> ; CHECK-NEXT: ret i32 [[LCSSA]]<br>
>>>> ;<br>
>>>> ; TAILFOLD-LABEL: @me_reduction(<br>
>>>><br>
>>>><br>
>>>><br>
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