[llvm] 7fe41ac - Revert "[LV] Unconditionally branch from middle to scalar preheader if the scalar loop must execute"
Philip Reames via llvm-commits
llvm-commits at lists.llvm.org
Mon May 17 20:59:02 PDT 2021
I tried another cycle to see if this had been resolved, but am still
seeing build bot failures, nearly exclusively on PPC. (And one arm self
host bot.)
@PPC Bot Owner - I need help reducing a test case for the failure seen
here: https://lab.llvm.org/buildbot#builders/100/builds/5762. I am
stuck, and unable to make progress for nearly 3 months now. I would
greatly appreciate help.
Philip
On 5/5/21 11:59 PM, Adrian Kuegel wrote:
> Sounds good to me, and thanks for sending the heads up :)
>
> On Wed, May 5, 2021 at 10:01 PM Philip Reames
> <listmail at philipreames.com <mailto:listmail at philipreames.com>> wrote:
>
> FYI, I'm going to try recommitting this without changes in a day
> or so.
>
> I never heard back from a PPC bot owner, and I don't have enough
> information to really debug anything from the builtbot log. I did run
> across a latent issue which this patch may very well have exposed at
> much higher frequency; the previous patch in this series (which is
> much
> more restrictive) does appear to have increased frequency. That was
> worked around in 80e80250. My educated guess is that same issue
> triggered the miscompile seen on the ppc bot, but that is more of a
> guess than I'd really prefer.
>
> I'm going to submit this during off hours, and watch the bots fairly
> closely after submit. Hopefully this either cycles clean or I get a
> better clue as to what the root issue is.
>
> Philip
>
> On 2/8/21 9:09 PM, Philip Reames via llvm-commits wrote:
> > Ben,
> >
> > Thanks for the clarification. The log does not make the fact
> this is
> > an execution failure obvious.
> >
> > No, I don't have access to a PPC machine.
> >
> > I am going to need some assistance from the bot owner on this. At a
> > minimum, IR for the test in question (before optimization, but on
> > target platform) seems like a reasonable ask.
> >
> > I strongly suspect this change is simply exposing another latent
> > issue. Or at least, I've reviewed the change and don't see
> anything
> > likely to cause runtime crashes w/o also tripping compiler asserts.
> >
> > Philip
> >
> >
> > On 2/8/21 5:21 AM, Benjamin Kramer wrote:
> >> `execution_time` failures mean that the bot succeeded building
> a test
> >> but it failed when running it. I'm relatively certain that this
> is the
> >> same issue Adrian is seeing -- binaries segfaulting early on PPC.
> >>
> >> The bot log output isn't helpful at all for investigating why
> this is
> >> happening. Do you happen to have access to a PPC machine?
> >>
> >> On Fri, Feb 5, 2021 at 6:05 PM Philip Reames via llvm-commits
> >> <llvm-commits at lists.llvm.org
> <mailto:llvm-commits at lists.llvm.org>> wrote:
> >>> Adrian,
> >>>
> >>> I'm going to need you to provide a bit more information here.
> The test
> >>> failure in stage1 was fixed at the time you reverted this
> patch. The
> >>> remaining failure in the bot is very unclear. What is a
> execution_time
> >>> failure? From the log output, the "failing" run finished in 0.5
> >>> seconds,
> >>> whereas the previous "succeeding" run finished in 11 seconds.
> Without
> >>> further context, I'd say that's no failure.
> >>>
> >>> I'll also note that I did not receive email from this bot. I
> received
> >>> notice from the various other bots and fixed the ARM test
> issue, but
> >>> unless I missed it in with the others, this bot is not notifying.
> >>>
> >>> In general, I'm a fan of fast reverts, but I have to admit,
> this one
> >>> appears borderline at the moment.
> >>>
> >>> Philip
> >>>
> >>> On 2/5/21 3:53 AM, Adrian Kuegel via llvm-commits wrote:
> >>>> Author: Adrian Kuegel
> >>>> Date: 2021-02-05T12:51:03+01:00
> >>>> New Revision: 7fe41ac3dff2d44c3d2c31b28554fbe4a86eaa6c
> >>>>
> >>>> URL:
> >>>>
> https://github.com/llvm/llvm-project/commit/7fe41ac3dff2d44c3d2c31b28554fbe4a86eaa6c
> <https://github.com/llvm/llvm-project/commit/7fe41ac3dff2d44c3d2c31b28554fbe4a86eaa6c>
> >>>> DIFF:
> >>>>
> https://github.com/llvm/llvm-project/commit/7fe41ac3dff2d44c3d2c31b28554fbe4a86eaa6c.diff
> <https://github.com/llvm/llvm-project/commit/7fe41ac3dff2d44c3d2c31b28554fbe4a86eaa6c.diff>
> >>>>
> >>>> LOG: Revert "[LV] Unconditionally branch from middle to scalar
> >>>> preheader if the scalar loop must execute"
> >>>>
> >>>> This reverts commit 3e5ce49e5371ce4feadbf97dd5c2b652d9db3d1d.
> >>>>
> >>>> Tests started failing on PPC, for example:
> >>>> http://lab.llvm.org:8011/#/builders/105/builds/5569
> <http://lab.llvm.org:8011/#/builders/105/builds/5569>
> >>>>
> >>>> Added:
> >>>>
> >>>>
> >>>> Modified:
> >>>> llvm/lib/Transforms/Utils/LoopVersioning.cpp
> >>>> llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
> >>>>
> llvm/test/Transforms/LoopVectorize/first-order-recurrence-complex.ll
> >>>> llvm/test/Transforms/LoopVectorize/interleaved-accesses.ll
> >>>> llvm/test/Transforms/LoopVectorize/loop-form.ll
> >>>>
> >>>> Removed:
> >>>>
> >>>>
> >>>>
> >>>>
> ################################################################################
>
> >>>>
> >>>> diff --git a/llvm/lib/Transforms/Utils/LoopVersioning.cpp
> >>>> b/llvm/lib/Transforms/Utils/LoopVersioning.cpp
> >>>> index 8a89158788cf..de4fb446fdf2 100644
> >>>> --- a/llvm/lib/Transforms/Utils/LoopVersioning.cpp
> >>>> +++ b/llvm/lib/Transforms/Utils/LoopVersioning.cpp
> >>>> @@ -44,11 +44,11 @@ LoopVersioning::LoopVersioning(const
> >>>> LoopAccessInfo &LAI,
> >>>> AliasChecks(Checks.begin(), Checks.end()),
> >>>> Preds(LAI.getPSE().getUnionPredicate()), LAI(LAI), LI(LI),
> >>>> DT(DT),
> >>>> SE(SE) {
> >>>> + assert(L->getUniqueExitBlock() && "No single exit block");
> >>>> }
> >>>>
> >>>> void LoopVersioning::versionLoop(
> >>>> const SmallVectorImpl<Instruction *> &DefsUsedOutside) {
> >>>> - assert(VersionedLoop->getUniqueExitBlock() && "No single exit
> >>>> block");
> >>>> assert(VersionedLoop->isLoopSimplifyForm() &&
> >>>> "Loop is not in loop-simplify form");
> >>>>
> >>>>
> >>>> diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
> >>>> b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
> >>>> index 3277842edbfe..6bce0caeb36f 100644
> >>>> --- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
> >>>> +++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
> >>>> @@ -852,7 +852,7 @@ class InnerLoopVectorizer {
> >>>> /// Middle Block between the vector and the scalar.
> >>>> BasicBlock *LoopMiddleBlock;
> >>>>
> >>>> - /// The unique ExitBlock of the scalar loop if one
> exists. Note
> >>>> that
> >>>> + /// The (unique) ExitBlock of the scalar loop. Note that
> >>>> /// there can be multiple exiting edges reaching this block.
> >>>> BasicBlock *LoopExitBlock;
> >>>>
> >>>> @@ -3147,13 +3147,9 @@ void
> >>>> InnerLoopVectorizer::emitMinimumIterationCountCheck(Loop *L,
> >>>> DT->getNode(Bypass)->getIDom()) &&
> >>>> "TC check is expected to dominate Bypass");
> >>>>
> >>>> - // Update dominator for Bypass & LoopExit (if needed).
> >>>> + // Update dominator for Bypass & LoopExit.
> >>>> DT->changeImmediateDominator(Bypass, TCCheckBlock);
> >>>> - if (!Cost->requiresScalarEpilogue())
> >>>> - // If there is an epilogue which must run, there's no edge
> >>>> from the
> >>>> - // middle block to exit blocks and thus no need to
> update the
> >>>> immediate
> >>>> - // dominator of the exit blocks.
> >>>> - DT->changeImmediateDominator(LoopExitBlock, TCCheckBlock);
> >>>> + DT->changeImmediateDominator(LoopExitBlock, TCCheckBlock);
> >>>>
> >>>> ReplaceInstWithInst(
> >>>> TCCheckBlock->getTerminator(),
> >>>> @@ -3192,11 +3188,7 @@ void
> >>>> InnerLoopVectorizer::emitSCEVChecks(Loop *L, BasicBlock
> *Bypass) {
> >>>> // Update dominator only if this is first RT check.
> >>>> if (LoopBypassBlocks.empty()) {
> >>>> DT->changeImmediateDominator(Bypass, SCEVCheckBlock);
> >>>> - if (!Cost->requiresScalarEpilogue())
> >>>> - // If there is an epilogue which must run, there's no
> edge
> >>>> from the
> >>>> - // middle block to exit blocks and thus no need to
> update
> >>>> the immediate
> >>>> - // dominator of the exit blocks.
> >>>> - DT->changeImmediateDominator(LoopExitBlock, SCEVCheckBlock);
> >>>> + DT->changeImmediateDominator(LoopExitBlock, SCEVCheckBlock);
> >>>> }
> >>>>
> >>>> ReplaceInstWithInst(
> >>>> @@ -3252,11 +3244,7 @@ void
> >>>> InnerLoopVectorizer::emitMemRuntimeChecks(Loop *L, BasicBlock
> >>>> *Bypass) {
> >>>> // Update dominator only if this is first RT check.
> >>>> if (LoopBypassBlocks.empty()) {
> >>>> DT->changeImmediateDominator(Bypass, MemCheckBlock);
> >>>> - if (!Cost->requiresScalarEpilogue())
> >>>> - // If there is an epilogue which must run, there's no
> edge
> >>>> from the
> >>>> - // middle block to exit blocks and thus no need to
> update
> >>>> the immediate
> >>>> - // dominator of the exit blocks.
> >>>> - DT->changeImmediateDominator(LoopExitBlock, MemCheckBlock);
> >>>> + DT->changeImmediateDominator(LoopExitBlock, MemCheckBlock);
> >>>> }
> >>>>
> >>>> Instruction *FirstCheckInst;
> >>>> @@ -3381,10 +3369,9 @@ Value
> >>>> *InnerLoopVectorizer::emitTransformedIndex(
> >>>> Loop *InnerLoopVectorizer::createVectorLoopSkeleton(StringRef
> >>>> Prefix) {
> >>>> LoopScalarBody = OrigLoop->getHeader();
> >>>> LoopVectorPreHeader = OrigLoop->getLoopPreheader();
> >>>> + LoopExitBlock = OrigLoop->getUniqueExitBlock();
> >>>> + assert(LoopExitBlock && "Must have an exit block");
> >>>> assert(LoopVectorPreHeader && "Invalid loop structure");
> >>>> - LoopExitBlock = OrigLoop->getUniqueExitBlock(); // may be
> nullptr
> >>>> - assert((LoopExitBlock || Cost->requiresScalarEpilogue()) &&
> >>>> - "multiple exit loop without required epilogue?");
> >>>>
> >>>> LoopMiddleBlock =
> >>>> SplitBlock(LoopVectorPreHeader,
> >>>> LoopVectorPreHeader->getTerminator(), DT,
> >>>> @@ -3393,20 +3380,12 @@ Loop
> >>>> *InnerLoopVectorizer::createVectorLoopSkeleton(StringRef
> Prefix) {
> >>>> SplitBlock(LoopMiddleBlock,
> >>>> LoopMiddleBlock->getTerminator(), DT, LI,
> >>>> nullptr, Twine(Prefix) + "scalar.ph
> <http://scalar.ph>");
> >>>>
> >>>> + // Set up branch from middle block to the exit and scalar
> >>>> preheader blocks.
> >>>> + // completeLoopSkeleton will update the condition to use an
> >>>> iteration check,
> >>>> + // if required to decide whether to execute the remainder.
> >>>> + BranchInst *BrInst =
> >>>> + BranchInst::Create(LoopExitBlock, LoopScalarPreHeader,
> >>>> Builder.getTrue());
> >>>> auto *ScalarLatchTerm =
> >>>> OrigLoop->getLoopLatch()->getTerminator();
> >>>> -
> >>>> - // Set up the middle block terminator. Two cases:
> >>>> - // 1) If we know that we must execute the scalar epilogue,
> emit an
> >>>> - // unconditional branch.
> >>>> - // 2) Otherwise, we must have a single unique exit block
> (due to
> >>>> how we
> >>>> - // implement the multiple exit case). In this case,
> set up a
> >>>> conditonal
> >>>> - // branch from the middle block to the loop scalar
> preheader,
> >>>> and the
> >>>> - // exit block. completeLoopSkeleton will update the
> >>>> condition to use an
> >>>> - // iteration check, if required to decide whether to
> execute
> >>>> the remainder.
> >>>> - BranchInst *BrInst = Cost->requiresScalarEpilogue() ?
> >>>> - BranchInst::Create(LoopScalarPreHeader) :
> >>>> - BranchInst::Create(LoopExitBlock, LoopScalarPreHeader,
> >>>> - Builder.getTrue());
> >>>> BrInst->setDebugLoc(ScalarLatchTerm->getDebugLoc());
> >>>> ReplaceInstWithInst(LoopMiddleBlock->getTerminator(), BrInst);
> >>>>
> >>>> @@ -3418,11 +3397,7 @@ Loop
> >>>> *InnerLoopVectorizer::createVectorLoopSkeleton(StringRef
> Prefix) {
> >>>> nullptr, nullptr, Twine(Prefix) +
> "vector.body");
> >>>>
> >>>> // Update dominator for loop exit.
> >>>> - if (!Cost->requiresScalarEpilogue())
> >>>> - // If there is an epilogue which must run, there's no edge
> >>>> from the
> >>>> - // middle block to exit blocks and thus no need to
> update the
> >>>> immediate
> >>>> - // dominator of the exit blocks.
> >>>> - DT->changeImmediateDominator(LoopExitBlock, LoopMiddleBlock);
> >>>> + DT->changeImmediateDominator(LoopExitBlock, LoopMiddleBlock);
> >>>>
> >>>> // Create and register the new vector loop.
> >>>> Loop *Lp = LI->AllocateLoop();
> >>>> @@ -3519,14 +3494,10 @@ BasicBlock
> >>>> *InnerLoopVectorizer::completeLoopSkeleton(Loop *L,
> >>>> auto *ScalarLatchTerm =
> >>>> OrigLoop->getLoopLatch()->getTerminator();
> >>>>
> >>>> // Add a check in the middle block to see if we have
> completed
> >>>> - // all of the iterations in the first vector loop. Three
> cases:
> >>>> - // 1) If we require a scalar epilogue, there is no
> conditional
> >>>> branch as
> >>>> - // we unconditionally branch to the scalar preheader. Do
> >>>> nothing.
> >>>> - // 2) If (N - N%VF) == N, then we *don't* need to run the
> >>>> remainder.
> >>>> - // Thus if tail is to be folded, we know we don't need
> to run
> >>>> the
> >>>> - // remainder and we can use the previous value for the
> >>>> condition (true).
> >>>> - // 3) Otherwise, construct a runtime check.
> >>>> - if (!Cost->requiresScalarEpilogue() &&
> >>>> !Cost->foldTailByMasking()) {
> >>>> + // all of the iterations in the first vector loop.
> >>>> + // If (N - N%VF) == N, then we *don't* need to run the
> remainder.
> >>>> + // If tail is to be folded, we know we don't need to run the
> >>>> remainder.
> >>>> + if (!Cost->foldTailByMasking()) {
> >>>> Instruction *CmpN = CmpInst::Create(Instruction::ICmp,
> >>>> CmpInst::ICMP_EQ,
> >>>> Count, VectorTripCount,
> >>>> "cmp.n",
> >>>> LoopMiddleBlock->getTerminator());
> >>>> @@ -3590,17 +3561,17 @@ BasicBlock
> >>>> *InnerLoopVectorizer::createVectorizedLoopSkeleton() {
> >>>> | [ ]_| <-- vector loop.
> >>>> | |
> >>>> | v
> >>>> - \ -[ ] <--- middle-block.
> >>>> - \/ |
> >>>> - /\ v
> >>>> - | ->[ ] <--- new preheader.
> >>>> + | -[ ] <--- middle-block.
> >>>> + | / |
> >>>> + | / v
> >>>> + -|- >[ ] <--- new preheader.
> >>>> | |
> >>>> - (opt) v <-- edge from middle to exit iff epilogue is not
> >>>> required.
> >>>> + | v
> >>>> | [ ] \
> >>>> - | [ ]_| <-- old scalar loop to handle remainder (scalar
> >>>> epilogue).
> >>>> + | [ ]_| <-- old scalar loop to handle remainder.
> >>>> \ |
> >>>> \ v
> >>>> - >[ ] <-- exit block(s).
> >>>> + >[ ] <-- exit block.
> >>>> ...
> >>>> */
> >>>>
> >>>> @@ -4021,18 +3992,13 @@ void
> >>>> InnerLoopVectorizer::fixVectorizedLoop() {
> >>>> // Forget the original basic block.
> >>>> PSE.getSE()->forgetLoop(OrigLoop);
> >>>>
> >>>> - // If we inserted an edge from the middle block to the unique
> >>>> exit block,
> >>>> - // update uses outside the loop (phis) to account for the
> newly
> >>>> inserted
> >>>> - // edge.
> >>>> - if (!Cost->requiresScalarEpilogue()) {
> >>>> - // Fix-up external users of the induction variables.
> >>>> - for (auto &Entry : Legal->getInductionVars())
> >>>> - fixupIVUsers(Entry.first, Entry.second,
> >>>> - getOrCreateVectorTripCount(LI->getLoopFor(LoopVectorBody)),
> >>>> - IVEndValues[Entry.first], LoopMiddleBlock);
> >>>> + // Fix-up external users of the induction variables.
> >>>> + for (auto &Entry : Legal->getInductionVars())
> >>>> + fixupIVUsers(Entry.first, Entry.second,
> >>>> + getOrCreateVectorTripCount(LI->getLoopFor(LoopVectorBody)),
> >>>> + IVEndValues[Entry.first], LoopMiddleBlock);
> >>>>
> >>>> - fixLCSSAPHIs();
> >>>> - }
> >>>> + fixLCSSAPHIs();
> >>>> for (Instruction *PI : PredicatedInstructions)
> >>>> sinkScalarOperands(&*PI);
> >>>>
> >>>> @@ -4250,13 +4216,12 @@ void
> >>>> InnerLoopVectorizer::fixFirstOrderRecurrence(PHINode *Phi) {
> >>>> // recurrence in the exit block, and then add an edge
> for the
> >>>> middle block.
> >>>> // Note that LCSSA does not imply single entry when the
> >>>> original scalar loop
> >>>> // had multiple exiting edges (as we always run the last
> >>>> iteration in the
> >>>> - // scalar epilogue); in that case, there is no edge from
> middle
> >>>> to exit and
> >>>> - // and thus no phis which needed updated.
> >>>> - if (!Cost->requiresScalarEpilogue())
> >>>> - for (PHINode &LCSSAPhi : LoopExitBlock->phis())
> >>>> - if (any_of(LCSSAPhi.incoming_values(),
> >>>> - [Phi](Value *V) { return V == Phi; }))
> >>>> - LCSSAPhi.addIncoming(ExtractForPhiUsedOutsideLoop,
> >>>> LoopMiddleBlock);
> >>>> + // scalar epilogue); in that case, the exiting path through
> >>>> middle will be
> >>>> + // dynamically dead and the value picked for the phi doesn't
> >>>> matter.
> >>>> + for (PHINode &LCSSAPhi : LoopExitBlock->phis())
> >>>> + if (any_of(LCSSAPhi.incoming_values(),
> >>>> + [Phi](Value *V) { return V == Phi; }))
> >>>> + LCSSAPhi.addIncoming(ExtractForPhiUsedOutsideLoop,
> >>>> LoopMiddleBlock);
> >>>> }
> >>>>
> >>>> void InnerLoopVectorizer::fixReduction(PHINode *Phi) {
> >>>> @@ -4421,11 +4386,10 @@ void
> >>>> InnerLoopVectorizer::fixReduction(PHINode *Phi) {
> >>>> // We know that the loop is in LCSSA form. We need to
> update
> >>>> the PHI nodes
> >>>> // in the exit blocks. See comment on analogous loop in
> >>>> // fixFirstOrderRecurrence for a more complete
> explaination of
> >>>> the logic.
> >>>> - if (!Cost->requiresScalarEpilogue())
> >>>> - for (PHINode &LCSSAPhi : LoopExitBlock->phis())
> >>>> - if (any_of(LCSSAPhi.incoming_values(),
> >>>> - [LoopExitInst](Value *V) { return V ==
> >>>> LoopExitInst; }))
> >>>> - LCSSAPhi.addIncoming(ReducedPartRdx, LoopMiddleBlock);
> >>>> + for (PHINode &LCSSAPhi : LoopExitBlock->phis())
> >>>> + if (any_of(LCSSAPhi.incoming_values(),
> >>>> + [LoopExitInst](Value *V) { return V ==
> >>>> LoopExitInst; }))
> >>>> + LCSSAPhi.addIncoming(ReducedPartRdx, LoopMiddleBlock);
> >>>>
> >>>> // Fix the scalar loop reduction variable with the incoming
> >>>> reduction sum
> >>>> // from the vector body and from the backedge value.
> >>>> @@ -8074,11 +8038,7 @@ BasicBlock
> >>>> *EpilogueVectorizerMainLoop::emitMinimumIterationCountCheck(
> >>>>
> >>>> // Update dominator for Bypass & LoopExit.
> >>>> DT->changeImmediateDominator(Bypass, TCCheckBlock);
> >>>> - if (!Cost->requiresScalarEpilogue())
> >>>> - // For loops with multiple exits, there's no edge from
> the
> >>>> middle block
> >>>> - // to exit blocks (as the epilogue must run) and thus no
> >>>> need to update
> >>>> - // the immediate dominator of the exit blocks.
> >>>> - DT->changeImmediateDominator(LoopExitBlock, TCCheckBlock);
> >>>> + DT->changeImmediateDominator(LoopExitBlock, TCCheckBlock);
> >>>>
> >>>> LoopBypassBlocks.push_back(TCCheckBlock);
> >>>>
> >>>> @@ -8142,12 +8102,7 @@
> >>>>
> EpilogueVectorizerEpilogueLoop::createEpilogueVectorizedLoopSkeleton()
>
> >>>> {
> >>>>
> >>>> DT->changeImmediateDominator(LoopScalarPreHeader,
> >>>> EPI.EpilogueIterationCountCheck);
> >>>> - if (!Cost->requiresScalarEpilogue())
> >>>> - // If there is an epilogue which must run, there's no edge
> >>>> from the
> >>>> - // middle block to exit blocks and thus no need to
> update the
> >>>> immediate
> >>>> - // dominator of the exit blocks.
> >>>> - DT->changeImmediateDominator(LoopExitBlock,
> >>>> - EPI.EpilogueIterationCountCheck);
> >>>> + DT->changeImmediateDominator(LoopExitBlock,
> >>>> EPI.EpilogueIterationCountCheck);
> >>>>
> >>>> // Keep track of bypass blocks, as they feed start
> values to
> >>>> the induction
> >>>> // phis in the scalar loop preheader.
> >>>>
> >>>> diff --git
> >>>>
> a/llvm/test/Transforms/LoopVectorize/first-order-recurrence-complex.ll
>
> >>>>
> b/llvm/test/Transforms/LoopVectorize/first-order-recurrence-complex.ll
> >>>> index ec280bf5d5e4..7d4a3c5c9935 100644
> >>>> ---
> >>>>
> a/llvm/test/Transforms/LoopVectorize/first-order-recurrence-complex.ll
> >>>> +++
> >>>>
> b/llvm/test/Transforms/LoopVectorize/first-order-recurrence-complex.ll
> >>>> @@ -471,9 +471,10 @@ define i16 @multiple_exit(i16* %p, i32 %n) {
> >>>> ; CHECK-NEXT: [[TMP15:%.*]] = icmp eq i32 [[INDEX_NEXT]],
> >>>> [[N_VEC]]
> >>>> ; CHECK-NEXT: br i1 [[TMP15]], label [[MIDDLE_BLOCK:%.*]],
> >>>> label [[VECTOR_BODY]], [[LOOP6:!llvm.loop !.*]]
> >>>> ; CHECK: middle.block:
> >>>> +; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i32 [[TMP2]], [[N_VEC]]
> >>>> ; CHECK-NEXT: [[VECTOR_RECUR_EXTRACT:%.*]] = extractelement
> >>>> <4 x i16> [[WIDE_LOAD]], i32 3
> >>>> ; CHECK-NEXT: [[VECTOR_RECUR_EXTRACT_FOR_PHI:%.*]] =
> >>>> extractelement <4 x i16> [[WIDE_LOAD]], i32 2
> >>>> -; CHECK-NEXT: br label [[SCALAR_PH]]
> >>>> +; CHECK-NEXT: br i1 [[CMP_N]], label [[IF_END:%.*]], label
> >>>> [[SCALAR_PH]]
> >>>> ; CHECK: scalar.ph <http://scalar.ph>:
> >>>> ; CHECK-NEXT: [[SCALAR_RECUR_INIT:%.*]] = phi i16 [ 0,
> >>>> [[ENTRY:%.*]] ], [ [[VECTOR_RECUR_EXTRACT]], [[MIDDLE_BLOCK]] ]
> >>>> ; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i32 [ [[N_VEC]],
> >>>> [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY]] ]
> >>>> @@ -485,14 +486,14 @@ define i16 @multiple_exit(i16* %p, i32
> %n) {
> >>>> ; CHECK-NEXT: [[B:%.*]] = getelementptr inbounds i16, i16*
> >>>> [[P]], i64 [[IPROM]]
> >>>> ; CHECK-NEXT: [[REC_NEXT]] = load i16, i16* [[B]], align 2
> >>>> ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i32 [[I]], [[N]]
> >>>> -; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label
> >>>> [[IF_END:%.*]]
> >>>> +; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label
> [[IF_END]]
> >>>> ; CHECK: for.body:
> >>>> ; CHECK-NEXT: store i16 [[SCALAR_RECUR]], i16* [[B]],
> align 4
> >>>> ; CHECK-NEXT: [[INC]] = add nsw i32 [[I]], 1
> >>>> ; CHECK-NEXT: [[CMP2:%.*]] = icmp slt i32 [[I]], 2096
> >>>> ; CHECK-NEXT: br i1 [[CMP2]], label [[FOR_COND]], label
> >>>> [[IF_END]], [[LOOP7:!llvm.loop !.*]]
> >>>> ; CHECK: if.end:
> >>>> -; CHECK-NEXT: [[REC_LCSSA:%.*]] = phi i16 [
> [[SCALAR_RECUR]],
> >>>> [[FOR_BODY]] ], [ [[SCALAR_RECUR]], [[FOR_COND]] ]
> >>>> +; CHECK-NEXT: [[REC_LCSSA:%.*]] = phi i16 [
> [[SCALAR_RECUR]],
> >>>> [[FOR_BODY]] ], [ [[SCALAR_RECUR]], [[FOR_COND]] ], [
> >>>> [[VECTOR_RECUR_EXTRACT_FOR_PHI]], [[MIDDLE_BLOCK]] ]
> >>>> ; CHECK-NEXT: ret i16 [[REC_LCSSA]]
> >>>> ;
> >>>> entry:
> >>>> @@ -557,9 +558,10 @@ define i16 @multiple_exit2(i16* %p, i32
> %n) {
> >>>> ; CHECK-NEXT: [[TMP15:%.*]] = icmp eq i32 [[INDEX_NEXT]],
> >>>> [[N_VEC]]
> >>>> ; CHECK-NEXT: br i1 [[TMP15]], label [[MIDDLE_BLOCK:%.*]],
> >>>> label [[VECTOR_BODY]], [[LOOP8:!llvm.loop !.*]]
> >>>> ; CHECK: middle.block:
> >>>> +; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i32 [[TMP2]], [[N_VEC]]
> >>>> ; CHECK-NEXT: [[VECTOR_RECUR_EXTRACT:%.*]] = extractelement
> >>>> <4 x i16> [[WIDE_LOAD]], i32 3
> >>>> ; CHECK-NEXT: [[VECTOR_RECUR_EXTRACT_FOR_PHI:%.*]] =
> >>>> extractelement <4 x i16> [[WIDE_LOAD]], i32 2
> >>>> -; CHECK-NEXT: br label [[SCALAR_PH]]
> >>>> +; CHECK-NEXT: br i1 [[CMP_N]], label [[IF_END:%.*]], label
> >>>> [[SCALAR_PH]]
> >>>> ; CHECK: scalar.ph <http://scalar.ph>:
> >>>> ; CHECK-NEXT: [[SCALAR_RECUR_INIT:%.*]] = phi i16 [ 0,
> >>>> [[ENTRY:%.*]] ], [ [[VECTOR_RECUR_EXTRACT]], [[MIDDLE_BLOCK]] ]
> >>>> ; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i32 [ [[N_VEC]],
> >>>> [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY]] ]
> >>>> @@ -571,14 +573,14 @@ define i16 @multiple_exit2(i16* %p, i32
> %n) {
> >>>> ; CHECK-NEXT: [[B:%.*]] = getelementptr inbounds i16, i16*
> >>>> [[P]], i64 [[IPROM]]
> >>>> ; CHECK-NEXT: [[REC_NEXT]] = load i16, i16* [[B]], align 2
> >>>> ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i32 [[I]], [[N]]
> >>>> -; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label
> >>>> [[IF_END:%.*]]
> >>>> +; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label
> [[IF_END]]
> >>>> ; CHECK: for.body:
> >>>> ; CHECK-NEXT: store i16 [[SCALAR_RECUR]], i16* [[B]],
> align 4
> >>>> ; CHECK-NEXT: [[INC]] = add nsw i32 [[I]], 1
> >>>> ; CHECK-NEXT: [[CMP2:%.*]] = icmp slt i32 [[I]], 2096
> >>>> ; CHECK-NEXT: br i1 [[CMP2]], label [[FOR_COND]], label
> >>>> [[IF_END]], [[LOOP9:!llvm.loop !.*]]
> >>>> ; CHECK: if.end:
> >>>> -; CHECK-NEXT: [[REC_LCSSA:%.*]] = phi i16 [
> [[SCALAR_RECUR]],
> >>>> [[FOR_COND]] ], [ 10, [[FOR_BODY]] ]
> >>>> +; CHECK-NEXT: [[REC_LCSSA:%.*]] = phi i16 [
> [[SCALAR_RECUR]],
> >>>> [[FOR_COND]] ], [ 10, [[FOR_BODY]] ], [
> >>>> [[VECTOR_RECUR_EXTRACT_FOR_PHI]], [[MIDDLE_BLOCK]] ]
> >>>> ; CHECK-NEXT: ret i16 [[REC_LCSSA]]
> >>>> ;
> >>>> entry:
> >>>>
> >>>> diff --git
> >>>> a/llvm/test/Transforms/LoopVectorize/interleaved-accesses.ll
> >>>> b/llvm/test/Transforms/LoopVectorize/interleaved-accesses.ll
> >>>> index f0ba677348ab..0d4bdf0ecac3 100644
> >>>> --- a/llvm/test/Transforms/LoopVectorize/interleaved-accesses.ll
> >>>> +++ b/llvm/test/Transforms/LoopVectorize/interleaved-accesses.ll
> >>>> @@ -447,7 +447,7 @@ define void @even_load_static_tc(i32*
> noalias
> >>>> nocapture readonly %A, i32* noalia
> >>>> ; CHECK-NEXT: [[TMP6:%.*]] = icmp eq i64
> [[INDEX_NEXT]], 508
> >>>> ; CHECK-NEXT: br i1 [[TMP6]], label [[MIDDLE_BLOCK:%.*]],
> >>>> label [[VECTOR_BODY]], [[LOOP12:!llvm.loop !.*]]
> >>>> ; CHECK: middle.block:
> >>>> -; CHECK-NEXT: br label [[SCALAR_PH]]
> >>>> +; CHECK-NEXT: br i1 false, label [[FOR_COND_CLEANUP:%.*]],
> >>>> label [[SCALAR_PH]]
> >>>> ; CHECK: scalar.ph <http://scalar.ph>:
> >>>> ; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i64 [ 1016,
> >>>> [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]
> >>>> ; CHECK-NEXT: br label [[FOR_BODY:%.*]]
> >>>> @@ -463,7 +463,7 @@ define void @even_load_static_tc(i32*
> noalias
> >>>> nocapture readonly %A, i32* noalia
> >>>> ; CHECK-NEXT: store i32 [[MUL]], i32* [[ARRAYIDX2]],
> align 4
> >>>> ; CHECK-NEXT: [[INDVARS_IV_NEXT]] = add nuw nsw i64
> >>>> [[INDVARS_IV]], 2
> >>>> ; CHECK-NEXT: [[CMP:%.*]] = icmp ult i64
> [[INDVARS_IV]], 1022
> >>>> -; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label
> >>>> [[FOR_COND_CLEANUP:%.*]], [[LOOP13:!llvm.loop !.*]]
> >>>> +; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label
> >>>> [[FOR_COND_CLEANUP]], [[LOOP13:!llvm.loop !.*]]
> >>>> ;
> >>>> entry:
> >>>> br label %for.body
> >>>> @@ -528,7 +528,7 @@ define void @even_load_dynamic_tc(i32*
> noalias
> >>>> nocapture readonly %A, i32* noali
> >>>> ; CHECK-NEXT: [[TMP12:%.*]] = icmp eq i64 [[INDEX_NEXT]],
> >>>> [[N_VEC]]
> >>>> ; CHECK-NEXT: br i1 [[TMP12]], label [[MIDDLE_BLOCK:%.*]],
> >>>> label [[VECTOR_BODY]], [[LOOP14:!llvm.loop !.*]]
> >>>> ; CHECK: middle.block:
> >>>> -; CHECK-NEXT: br label [[SCALAR_PH]]
> >>>> +; CHECK-NEXT: br i1 false, label [[FOR_COND_CLEANUP:%.*]],
> >>>> label [[SCALAR_PH]]
> >>>> ; CHECK: scalar.ph <http://scalar.ph>:
> >>>> ; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i64 [
> [[IND_END]],
> >>>> [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]
> >>>> ; CHECK-NEXT: br label [[FOR_BODY:%.*]]
> >>>> @@ -544,7 +544,7 @@ define void @even_load_dynamic_tc(i32*
> noalias
> >>>> nocapture readonly %A, i32* noali
> >>>> ; CHECK-NEXT: store i32 [[MUL]], i32* [[ARRAYIDX2]],
> align 4
> >>>> ; CHECK-NEXT: [[INDVARS_IV_NEXT]] = add nuw nsw i64
> >>>> [[INDVARS_IV]], 2
> >>>> ; CHECK-NEXT: [[CMP:%.*]] = icmp ult i64
> [[INDVARS_IV_NEXT]],
> >>>> [[N]]
> >>>> -; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label
> >>>> [[FOR_COND_CLEANUP:%.*]], [[LOOP15:!llvm.loop !.*]]
> >>>> +; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label
> >>>> [[FOR_COND_CLEANUP]], [[LOOP15:!llvm.loop !.*]]
> >>>> ;
> >>>> entry:
> >>>> br label %for.body
> >>>> @@ -973,7 +973,7 @@ define void @PR27626_0(%pair.i32 *%p, i32
> %z,
> >>>> i64 %n) {
> >>>> ; CHECK-NEXT: [[TMP19:%.*]] = icmp eq i64 [[INDEX_NEXT]],
> >>>> [[N_VEC]]
> >>>> ; CHECK-NEXT: br i1 [[TMP19]], label [[MIDDLE_BLOCK:%.*]],
> >>>> label [[VECTOR_BODY]], [[LOOP24:!llvm.loop !.*]]
> >>>> ; CHECK: middle.block:
> >>>> -; CHECK-NEXT: br label [[SCALAR_PH]]
> >>>> +; CHECK-NEXT: br i1 false, label [[FOR_END:%.*]], label
> >>>> [[SCALAR_PH]]
> >>>> ; CHECK: scalar.ph <http://scalar.ph>:
> >>>> ; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]],
> >>>> [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]
> >>>> ; CHECK-NEXT: br label [[FOR_BODY:%.*]]
> >>>> @@ -985,7 +985,7 @@ define void @PR27626_0(%pair.i32 *%p, i32
> %z,
> >>>> i64 %n) {
> >>>> ; CHECK-NEXT: store i32 [[Z]], i32* [[P_I_Y]], align 4
> >>>> ; CHECK-NEXT: [[I_NEXT]] = add nuw nsw i64 [[I]], 1
> >>>> ; CHECK-NEXT: [[COND:%.*]] = icmp slt i64 [[I_NEXT]], [[N]]
> >>>> -; CHECK-NEXT: br i1 [[COND]], label [[FOR_BODY]], label
> >>>> [[FOR_END:%.*]], [[LOOP25:!llvm.loop !.*]]
> >>>> +; CHECK-NEXT: br i1 [[COND]], label [[FOR_BODY]], label
> >>>> [[FOR_END]], [[LOOP25:!llvm.loop !.*]]
> >>>> ; CHECK: for.end:
> >>>> ; CHECK-NEXT: ret void
> >>>> ;
> >>>> @@ -1066,7 +1066,7 @@ define i32 @PR27626_1(%pair.i32 *%p,
> i64 %n) {
> >>>> ; CHECK-NEXT: [[RDX_SHUF3:%.*]] = shufflevector <4 x i32>
> >>>> [[BIN_RDX]], <4 x i32> poison, <4 x i32> <i32 1, i32 undef, i32
> >>>> undef, i32 undef>
> >>>> ; CHECK-NEXT: [[BIN_RDX4:%.*]] = add <4 x i32>
> [[BIN_RDX]],
> >>>> [[RDX_SHUF3]]
> >>>> ; CHECK-NEXT: [[TMP19:%.*]] = extractelement <4 x i32>
> >>>> [[BIN_RDX4]], i32 0
> >>>> -; CHECK-NEXT: br label [[SCALAR_PH]]
> >>>> +; CHECK-NEXT: br i1 false, label [[FOR_END:%.*]], label
> >>>> [[SCALAR_PH]]
> >>>> ; CHECK: scalar.ph <http://scalar.ph>:
> >>>> ; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]],
> >>>> [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]
> >>>> ; CHECK-NEXT: [[BC_MERGE_RDX:%.*]] = phi i32 [ [[TMP19]],
> >>>> [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY]] ]
> >>>> @@ -1081,9 +1081,10 @@ define i32 @PR27626_1(%pair.i32 *%p,
> i64 %n) {
> >>>> ; CHECK-NEXT: [[TMP21]] = add nsw i32 [[TMP20]], [[S]]
> >>>> ; CHECK-NEXT: [[I_NEXT]] = add nuw nsw i64 [[I]], 1
> >>>> ; CHECK-NEXT: [[COND:%.*]] = icmp slt i64 [[I_NEXT]], [[N]]
> >>>> -; CHECK-NEXT: br i1 [[COND]], label [[FOR_BODY]], label
> >>>> [[FOR_END:%.*]], [[LOOP27:!llvm.loop !.*]]
> >>>> +; CHECK-NEXT: br i1 [[COND]], label [[FOR_BODY]], label
> >>>> [[FOR_END]], [[LOOP27:!llvm.loop !.*]]
> >>>> ; CHECK: for.end:
> >>>> -; CHECK-NEXT: ret i32 [[TMP21]]
> >>>> +; CHECK-NEXT: [[TMP22:%.*]] = phi i32 [ [[TMP21]],
> [[FOR_BODY]]
> >>>> ], [ [[TMP19]], [[MIDDLE_BLOCK]] ]
> >>>> +; CHECK-NEXT: ret i32 [[TMP22]]
> >>>> ;
> >>>> entry:
> >>>> br label %for.body
> >>>> @@ -1162,7 +1163,7 @@ define void @PR27626_2(%pair.i32 *%p,
> i64 %n,
> >>>> i32 %z) {
> >>>> ; CHECK-NEXT: [[TMP20:%.*]] = icmp eq i64 [[INDEX_NEXT]],
> >>>> [[N_VEC]]
> >>>> ; CHECK-NEXT: br i1 [[TMP20]], label [[MIDDLE_BLOCK:%.*]],
> >>>> label [[VECTOR_BODY]], [[LOOP28:!llvm.loop !.*]]
> >>>> ; CHECK: middle.block:
> >>>> -; CHECK-NEXT: br label [[SCALAR_PH]]
> >>>> +; CHECK-NEXT: br i1 false, label [[FOR_END:%.*]], label
> >>>> [[SCALAR_PH]]
> >>>> ; CHECK: scalar.ph <http://scalar.ph>:
> >>>> ; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]],
> >>>> [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]
> >>>> ; CHECK-NEXT: br label [[FOR_BODY:%.*]]
> >>>> @@ -1176,7 +1177,7 @@ define void @PR27626_2(%pair.i32 *%p,
> i64 %n,
> >>>> i32 %z) {
> >>>> ; CHECK-NEXT: store i32 [[TMP21]], i32* [[P_I_Y]], align 4
> >>>> ; CHECK-NEXT: [[I_NEXT]] = add nuw nsw i64 [[I]], 1
> >>>> ; CHECK-NEXT: [[COND:%.*]] = icmp slt i64 [[I_NEXT]], [[N]]
> >>>> -; CHECK-NEXT: br i1 [[COND]], label [[FOR_BODY]], label
> >>>> [[FOR_END:%.*]], [[LOOP29:!llvm.loop !.*]]
> >>>> +; CHECK-NEXT: br i1 [[COND]], label [[FOR_BODY]], label
> >>>> [[FOR_END]], [[LOOP29:!llvm.loop !.*]]
> >>>> ; CHECK: for.end:
> >>>> ; CHECK-NEXT: ret void
> >>>> ;
> >>>> @@ -1263,7 +1264,7 @@ define i32 @PR27626_3(%pair.i32 *%p,
> i64 %n,
> >>>> i32 %z) {
> >>>> ; CHECK-NEXT: [[RDX_SHUF3:%.*]] = shufflevector <4 x i32>
> >>>> [[BIN_RDX]], <4 x i32> poison, <4 x i32> <i32 1, i32 undef, i32
> >>>> undef, i32 undef>
> >>>> ; CHECK-NEXT: [[BIN_RDX4:%.*]] = add <4 x i32>
> [[BIN_RDX]],
> >>>> [[RDX_SHUF3]]
> >>>> ; CHECK-NEXT: [[TMP22:%.*]] = extractelement <4 x i32>
> >>>> [[BIN_RDX4]], i32 0
> >>>> -; CHECK-NEXT: br label [[SCALAR_PH]]
> >>>> +; CHECK-NEXT: br i1 false, label [[FOR_END:%.*]], label
> >>>> [[SCALAR_PH]]
> >>>> ; CHECK: scalar.ph <http://scalar.ph>:
> >>>> ; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]],
> >>>> [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]
> >>>> ; CHECK-NEXT: [[BC_MERGE_RDX:%.*]] = phi i32 [ [[TMP22]],
> >>>> [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY]] ]
> >>>> @@ -1281,9 +1282,10 @@ define i32 @PR27626_3(%pair.i32 *%p,
> i64 %n,
> >>>> i32 %z) {
> >>>> ; CHECK-NEXT: [[TMP25]] = add nsw i32 [[TMP24]], [[S]]
> >>>> ; CHECK-NEXT: [[I_NEXT]] = add nuw nsw i64 [[I]], 1
> >>>> ; CHECK-NEXT: [[COND:%.*]] = icmp slt i64 [[I_NEXT]], [[N]]
> >>>> -; CHECK-NEXT: br i1 [[COND]], label [[FOR_BODY]], label
> >>>> [[FOR_END:%.*]], [[LOOP31:!llvm.loop !.*]]
> >>>> +; CHECK-NEXT: br i1 [[COND]], label [[FOR_BODY]], label
> >>>> [[FOR_END]], [[LOOP31:!llvm.loop !.*]]
> >>>> ; CHECK: for.end:
> >>>> -; CHECK-NEXT: ret i32 [[TMP25]]
> >>>> +; CHECK-NEXT: [[TMP26:%.*]] = phi i32 [ [[TMP25]],
> [[FOR_BODY]]
> >>>> ], [ [[TMP22]], [[MIDDLE_BLOCK]] ]
> >>>> +; CHECK-NEXT: ret i32 [[TMP26]]
> >>>> ;
> >>>> entry:
> >>>> br label %for.body
> >>>>
> >>>> diff --git a/llvm/test/Transforms/LoopVectorize/loop-form.ll
> >>>> b/llvm/test/Transforms/LoopVectorize/loop-form.ll
> >>>> index f32002fae2b6..91780789088b 100644
> >>>> --- a/llvm/test/Transforms/LoopVectorize/loop-form.ll
> >>>> +++ b/llvm/test/Transforms/LoopVectorize/loop-form.ll
> >>>> @@ -146,14 +146,15 @@ define void @early_exit(i16* %p, i32 %n) {
> >>>> ; CHECK-NEXT: [[TMP10:%.*]] = icmp eq i32 [[INDEX_NEXT]],
> >>>> [[N_VEC]]
> >>>> ; CHECK-NEXT: br i1 [[TMP10]], label [[MIDDLE_BLOCK:%.*]],
> >>>> label [[VECTOR_BODY]], [[LOOP4:!llvm.loop !.*]]
> >>>> ; CHECK: middle.block:
> >>>> -; CHECK-NEXT: br label [[SCALAR_PH]]
> >>>> +; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i32 [[TMP1]], [[N_VEC]]
> >>>> +; CHECK-NEXT: br i1 [[CMP_N]], label [[IF_END:%.*]], label
> >>>> [[SCALAR_PH]]
> >>>> ; CHECK: scalar.ph <http://scalar.ph>:
> >>>> ; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i32 [ [[N_VEC]],
> >>>> [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]
> >>>> ; CHECK-NEXT: br label [[FOR_COND:%.*]]
> >>>> ; CHECK: for.cond:
> >>>> ; CHECK-NEXT: [[I:%.*]] = phi i32 [ [[BC_RESUME_VAL]],
> >>>> [[SCALAR_PH]] ], [ [[INC:%.*]], [[FOR_BODY:%.*]] ]
> >>>> ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i32 [[I]], [[N]]
> >>>> -; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label
> >>>> [[IF_END:%.*]]
> >>>> +; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label
> [[IF_END]]
> >>>> ; CHECK: for.body:
> >>>> ; CHECK-NEXT: [[IPROM:%.*]] = sext i32 [[I]] to i64
> >>>> ; CHECK-NEXT: [[B:%.*]] = getelementptr inbounds i16, i16*
> >>>> [[P]], i64 [[IPROM]]
> >>>> @@ -285,14 +286,15 @@ define void @multiple_unique_exit(i16* %p,
> >>>> i32 %n) {
> >>>> ; CHECK-NEXT: [[TMP11:%.*]] = icmp eq i32 [[INDEX_NEXT]],
> >>>> [[N_VEC]]
> >>>> ; CHECK-NEXT: br i1 [[TMP11]], label [[MIDDLE_BLOCK:%.*]],
> >>>> label [[VECTOR_BODY]], [[LOOP6:!llvm.loop !.*]]
> >>>> ; CHECK: middle.block:
> >>>> -; CHECK-NEXT: br label [[SCALAR_PH]]
> >>>> +; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i32 [[TMP2]], [[N_VEC]]
> >>>> +; CHECK-NEXT: br i1 [[CMP_N]], label [[IF_END:%.*]], label
> >>>> [[SCALAR_PH]]
> >>>> ; CHECK: scalar.ph <http://scalar.ph>:
> >>>> ; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i32 [ [[N_VEC]],
> >>>> [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]
> >>>> ; CHECK-NEXT: br label [[FOR_COND:%.*]]
> >>>> ; CHECK: for.cond:
> >>>> ; CHECK-NEXT: [[I:%.*]] = phi i32 [ [[BC_RESUME_VAL]],
> >>>> [[SCALAR_PH]] ], [ [[INC:%.*]], [[FOR_BODY:%.*]] ]
> >>>> ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i32 [[I]], [[N]]
> >>>> -; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label
> >>>> [[IF_END:%.*]]
> >>>> +; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label
> [[IF_END]]
> >>>> ; CHECK: for.body:
> >>>> ; CHECK-NEXT: [[IPROM:%.*]] = sext i32 [[I]] to i64
> >>>> ; CHECK-NEXT: [[B:%.*]] = getelementptr inbounds i16, i16*
> >>>> [[P]], i64 [[IPROM]]
> >>>> @@ -372,14 +374,17 @@ define i32 @multiple_unique_exit2(i16* %p,
> >>>> i32 %n) {
> >>>> ; CHECK-NEXT: [[TMP11:%.*]] = icmp eq i32 [[INDEX_NEXT]],
> >>>> [[N_VEC]]
> >>>> ; CHECK-NEXT: br i1 [[TMP11]], label [[MIDDLE_BLOCK:%.*]],
> >>>> label [[VECTOR_BODY]], [[LOOP8:!llvm.loop !.*]]
> >>>> ; CHECK: middle.block:
> >>>> -; CHECK-NEXT: br label [[SCALAR_PH]]
> >>>> +; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i32 [[TMP2]], [[N_VEC]]
> >>>> +; CHECK-NEXT: [[IND_ESCAPE:%.*]] = sub i32 [[N_VEC]], 1
> >>>> +; CHECK-NEXT: [[IND_ESCAPE1:%.*]] = sub i32 [[N_VEC]], 1
> >>>> +; CHECK-NEXT: br i1 [[CMP_N]], label [[IF_END:%.*]], label
> >>>> [[SCALAR_PH]]
> >>>> ; CHECK: scalar.ph <http://scalar.ph>:
> >>>> ; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i32 [ [[N_VEC]],
> >>>> [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]
> >>>> ; CHECK-NEXT: br label [[FOR_COND:%.*]]
> >>>> ; CHECK: for.cond:
> >>>> ; CHECK-NEXT: [[I:%.*]] = phi i32 [ [[BC_RESUME_VAL]],
> >>>> [[SCALAR_PH]] ], [ [[INC:%.*]], [[FOR_BODY:%.*]] ]
> >>>> ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i32 [[I]], [[N]]
> >>>> -; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label
> >>>> [[IF_END:%.*]]
> >>>> +; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label
> [[IF_END]]
> >>>> ; CHECK: for.body:
> >>>> ; CHECK-NEXT: [[IPROM:%.*]] = sext i32 [[I]] to i64
> >>>> ; CHECK-NEXT: [[B:%.*]] = getelementptr inbounds i16, i16*
> >>>> [[P]], i64 [[IPROM]]
> >>>> @@ -388,7 +393,7 @@ define i32 @multiple_unique_exit2(i16*
> %p, i32
> >>>> %n) {
> >>>> ; CHECK-NEXT: [[CMP2:%.*]] = icmp slt i32 [[I]], 2096
> >>>> ; CHECK-NEXT: br i1 [[CMP2]], label [[FOR_COND]], label
> >>>> [[IF_END]], [[LOOP9:!llvm.loop !.*]]
> >>>> ; CHECK: if.end:
> >>>> -; CHECK-NEXT: [[I_LCSSA:%.*]] = phi i32 [ [[I]],
> [[FOR_BODY]]
> >>>> ], [ [[I]], [[FOR_COND]] ]
> >>>> +; CHECK-NEXT: [[I_LCSSA:%.*]] = phi i32 [ [[I]],
> [[FOR_BODY]]
> >>>> ], [ [[I]], [[FOR_COND]] ], [ [[IND_ESCAPE1]], [[MIDDLE_BLOCK]] ]
> >>>> ; CHECK-NEXT: ret i32 [[I_LCSSA]]
> >>>> ;
> >>>> ; TAILFOLD-LABEL: @multiple_unique_exit2(
> >>>> @@ -461,14 +466,15 @@ define i32 @multiple_unique_exit3(i16* %p,
> >>>> i32 %n) {
> >>>> ; CHECK-NEXT: [[TMP11:%.*]] = icmp eq i32 [[INDEX_NEXT]],
> >>>> [[N_VEC]]
> >>>> ; CHECK-NEXT: br i1 [[TMP11]], label [[MIDDLE_BLOCK:%.*]],
> >>>> label [[VECTOR_BODY]], [[LOOP10:!llvm.loop !.*]]
> >>>> ; CHECK: middle.block:
> >>>> -; CHECK-NEXT: br label [[SCALAR_PH]]
> >>>> +; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i32 [[TMP2]], [[N_VEC]]
> >>>> +; CHECK-NEXT: br i1 [[CMP_N]], label [[IF_END:%.*]], label
> >>>> [[SCALAR_PH]]
> >>>> ; CHECK: scalar.ph <http://scalar.ph>:
> >>>> ; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i32 [ [[N_VEC]],
> >>>> [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]
> >>>> ; CHECK-NEXT: br label [[FOR_COND:%.*]]
> >>>> ; CHECK: for.cond:
> >>>> ; CHECK-NEXT: [[I:%.*]] = phi i32 [ [[BC_RESUME_VAL]],
> >>>> [[SCALAR_PH]] ], [ [[INC:%.*]], [[FOR_BODY:%.*]] ]
> >>>> ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i32 [[I]], [[N]]
> >>>> -; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label
> >>>> [[IF_END:%.*]]
> >>>> +; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label
> [[IF_END]]
> >>>> ; CHECK: for.body:
> >>>> ; CHECK-NEXT: [[IPROM:%.*]] = sext i32 [[I]] to i64
> >>>> ; CHECK-NEXT: [[B:%.*]] = getelementptr inbounds i16, i16*
> >>>> [[P]], i64 [[IPROM]]
> >>>> @@ -477,7 +483,7 @@ define i32 @multiple_unique_exit3(i16*
> %p, i32
> >>>> %n) {
> >>>> ; CHECK-NEXT: [[CMP2:%.*]] = icmp slt i32 [[I]], 2096
> >>>> ; CHECK-NEXT: br i1 [[CMP2]], label [[FOR_COND]], label
> >>>> [[IF_END]], [[LOOP11:!llvm.loop !.*]]
> >>>> ; CHECK: if.end:
> >>>> -; CHECK-NEXT: [[EXIT:%.*]] = phi i32 [ 0, [[FOR_COND]] ],
> [ 1,
> >>>> [[FOR_BODY]] ]
> >>>> +; CHECK-NEXT: [[EXIT:%.*]] = phi i32 [ 0, [[FOR_COND]] ],
> [ 1,
> >>>> [[FOR_BODY]] ], [ 0, [[MIDDLE_BLOCK]] ]
> >>>> ; CHECK-NEXT: ret i32 [[EXIT]]
> >>>> ;
> >>>> ; TAILFOLD-LABEL: @multiple_unique_exit3(
> >>>> @@ -994,7 +1000,8 @@ define void @scalar_predication(float*
> %addr) {
> >>>> ; CHECK-NEXT: [[TMP10:%.*]] = icmp eq i64
> [[INDEX_NEXT]], 200
> >>>> ; CHECK-NEXT: br i1 [[TMP10]], label [[MIDDLE_BLOCK:%.*]],
> >>>> label [[VECTOR_BODY]], [[LOOP12:!llvm.loop !.*]]
> >>>> ; CHECK: middle.block:
> >>>> -; CHECK-NEXT: br label [[SCALAR_PH]]
> >>>> +; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i64 201, 200
> >>>> +; CHECK-NEXT: br i1 [[CMP_N]], label [[EXIT:%.*]], label
> >>>> [[SCALAR_PH]]
> >>>> ; CHECK: scalar.ph <http://scalar.ph>:
> >>>> ; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i64 [ 200,
> >>>> [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]
> >>>> ; CHECK-NEXT: br label [[LOOP_HEADER:%.*]]
> >>>> @@ -1002,7 +1009,7 @@ define void @scalar_predication(float*
> %addr) {
> >>>> ; CHECK-NEXT: [[IV:%.*]] = phi i64 [ [[BC_RESUME_VAL]],
> >>>> [[SCALAR_PH]] ], [ [[IV_NEXT:%.*]], [[LOOP_LATCH:%.*]] ]
> >>>> ; CHECK-NEXT: [[GEP:%.*]] = getelementptr float, float*
> >>>> [[ADDR]], i64 [[IV]]
> >>>> ; CHECK-NEXT: [[EXITCOND_NOT:%.*]] = icmp eq i64
> [[IV]], 200
> >>>> -; CHECK-NEXT: br i1 [[EXITCOND_NOT]], label [[EXIT:%.*]],
> label
> >>>> [[LOOP_BODY:%.*]]
> >>>> +; CHECK-NEXT: br i1 [[EXITCOND_NOT]], label [[EXIT]], label
> >>>> [[LOOP_BODY:%.*]]
> >>>> ; CHECK: loop.body:
> >>>> ; CHECK-NEXT: [[TMP11:%.*]] = load float, float* [[GEP]],
> >>>> align 4
> >>>> ; CHECK-NEXT: [[PRED:%.*]] = fcmp oeq float [[TMP11]],
> >>>> 0.000000e+00
> >>>> @@ -1088,7 +1095,8 @@ define i32 @me_reduction(i32* %addr) {
> >>>> ; CHECK-NEXT: [[RDX_SHUF:%.*]] = shufflevector <2 x i32>
> >>>> [[TMP5]], <2 x i32> poison, <2 x i32> <i32 1, i32 undef>
> >>>> ; CHECK-NEXT: [[BIN_RDX:%.*]] = add <2 x i32> [[TMP5]],
> >>>> [[RDX_SHUF]]
> >>>> ; CHECK-NEXT: [[TMP7:%.*]] = extractelement <2 x i32>
> >>>> [[BIN_RDX]], i32 0
> >>>> -; CHECK-NEXT: br label [[SCALAR_PH]]
> >>>> +; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i64 201, 200
> >>>> +; CHECK-NEXT: br i1 [[CMP_N]], label [[EXIT:%.*]], label
> >>>> [[SCALAR_PH]]
> >>>> ; CHECK: scalar.ph <http://scalar.ph>:
> >>>> ; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i64 [ 200,
> >>>> [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]
> >>>> ; CHECK-NEXT: [[BC_MERGE_RDX:%.*]] = phi i32 [ 0,
> [[ENTRY]]
> >>>> ], [ [[TMP7]], [[MIDDLE_BLOCK]] ]
> >>>> @@ -1098,7 +1106,7 @@ define i32 @me_reduction(i32* %addr) {
> >>>> ; CHECK-NEXT: [[ACCUM:%.*]] = phi i32 [ [[BC_MERGE_RDX]],
> >>>> [[SCALAR_PH]] ], [ [[ACCUM_NEXT:%.*]], [[LOOP_LATCH]] ]
> >>>> ; CHECK-NEXT: [[GEP:%.*]] = getelementptr i32, i32*
> [[ADDR]],
> >>>> i64 [[IV]]
> >>>> ; CHECK-NEXT: [[EXITCOND_NOT:%.*]] = icmp eq i64
> [[IV]], 200
> >>>> -; CHECK-NEXT: br i1 [[EXITCOND_NOT]], label [[EXIT:%.*]],
> label
> >>>> [[LOOP_LATCH]]
> >>>> +; CHECK-NEXT: br i1 [[EXITCOND_NOT]], label [[EXIT]], label
> >>>> [[LOOP_LATCH]]
> >>>> ; CHECK: loop.latch:
> >>>> ; CHECK-NEXT: [[TMP8:%.*]] = load i32, i32* [[GEP]],
> align 4
> >>>> ; CHECK-NEXT: [[ACCUM_NEXT]] = add i32 [[ACCUM]], [[TMP8]]
> >>>> @@ -1106,7 +1114,7 @@ define i32 @me_reduction(i32* %addr) {
> >>>> ; CHECK-NEXT: [[EXITCOND2_NOT:%.*]] = icmp eq i64
> [[IV]], 400
> >>>> ; CHECK-NEXT: br i1 [[EXITCOND2_NOT]], label [[EXIT]],
> label
> >>>> [[LOOP_HEADER]], [[LOOP15:!llvm.loop !.*]]
> >>>> ; CHECK: exit:
> >>>> -; CHECK-NEXT: [[LCSSA:%.*]] = phi i32 [ 0,
> [[LOOP_HEADER]] ], [
> >>>> [[ACCUM_NEXT]], [[LOOP_LATCH]] ]
> >>>> +; CHECK-NEXT: [[LCSSA:%.*]] = phi i32 [ 0,
> [[LOOP_HEADER]] ], [
> >>>> [[ACCUM_NEXT]], [[LOOP_LATCH]] ], [ [[TMP7]], [[MIDDLE_BLOCK]] ]
> >>>> ; CHECK-NEXT: ret i32 [[LCSSA]]
> >>>> ;
> >>>> ; TAILFOLD-LABEL: @me_reduction(
> >>>>
> >>>>
> >>>>
> >>>> _______________________________________________
> >>>> llvm-commits mailing list
> >>>> llvm-commits at lists.llvm.org <mailto:llvm-commits at lists.llvm.org>
> >>>> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
> <https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits>
> >>> _______________________________________________
> >>> llvm-commits mailing list
> >>> llvm-commits at lists.llvm.org <mailto:llvm-commits at lists.llvm.org>
> >>> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
> <https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits>
> > _______________________________________________
> > llvm-commits mailing list
> > llvm-commits at lists.llvm.org <mailto:llvm-commits at lists.llvm.org>
> > https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
> <https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits>
>
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