[llvm] r265388 - Adds the ability to use an epilog remainder loop during loop unrolling and makes

Michael Zolotukhin via llvm-commits llvm-commits at lists.llvm.org
Mon Jul 25 15:53:51 PDT 2016


> On Jul 24, 2016, at 3:10 AM, Evgeny Stupachenko <evstupac at gmail.com> wrote:
> 
> Hi Michael,
Hi Evgeny,
> 
> Ok. I'm on vacation right now. With limit access to testing. I'll back
> in the middle of August, run the testing and revert to prologue.
> Should we get one more vote to revert this to prologue or I can do
> this right when I'm back from from vacation?
I can switch it to the previous value (prologue) for you, and then you fix the test/LSR and switch it back (to epilogue). Does it sound good?
> 
> Could you please point me to someone who is responsible for the
> performance tests you are running? I'll address the issue.
> Sorry for staying so long without addressing the issue. I've missed
> the importance of the test and its performance.
It’s not about that particular test, it’s about 90% regression.

> The regression is not compiler dependent its a "bad luck" caused by
> test structure. I can prove this to the person who is responsible for
> the test.
If the test is flaky, then I’m completely fine with fixing the test. But otherwise the “bad luck” argument doesn’t convince me - what if a user found a similar regression from a previous compiler version on his code?

> My LSR patch is fixing only static addresses in the loop. The
> regression stays unchanged. The root cause of the regression related
> to code alignment.

Thanks,
Michael

PS: Sorry to disrupt your vacation with this!
> 
> Thanks,
> Evgeny
> 
> 
> 
> On Thu, Jul 21, 2016 at 11:57 AM, Mikhail Zolotukhin
> <mzolotukhin at apple.com> wrote:
>> 
>>> On Jul 21, 2016, at 11:36 AM, Evgeny Stupachenko <evstupac at gmail.com> wrote:
>>> 
>>> Hi Michael,
>> Hi Evgeny,
>>> 
>>> Turning back to default will decrease LSR positive effect.
>> When the LSR changes are committed, we certainly can switch it back.
>>> As for the test itself. It does not represent a real case.
>> I won't argue that, though the "real case" is a very vague term. What matters is that this test is currently in the testsuite.
>>> Global arrays with big amount of data are not ok.
>>> If we switch to malloc instead, the regression disappears.
>> The problem here is that we have a big regression with this change, and it's not addressed so far. It might be a test issue or an LSR issue, but whatever it is, we need to address it, and if it takes too long, turn it back off until it's fixed.
>> 
>> Thanks,
>> Michael
>>> I'd better modify the test or exclude it.
>>> 
>>> Thanks,
>>> Evgeny
>>> 
>>> On Wed, Jul 20, 2016 at 1:06 PM, Michael Zolotukhin
>>> <mzolotukhin at apple.com> wrote:
>>>> Hi Evgeny,
>>>> 
>>>> Thanks for the detailed update! After a second thought - can we please switch the default to the previous value while you’re working on the patch? Generally, it’s bad to have such a big regression even though your original patch just exposed an issue in another place.
>>>> 
>>>> Thanks,
>>>> Michael
>>>>> On Jul 11, 2016, at 9:08 PM, Evgeny Stupachenko <evstupac at gmail.com> wrote:
>>>>> 
>>>>> Hi Michael,
>>>>> 
>>>>> The patch is under internal review. It changes a lot. I plan to send
>>>>> it here this month or in August.
>>>>> The patch fixes addressing, but not the regression.
>>>>> We looked into the regression itself on simulator. It appears that the
>>>>> big issue is branch misprediction.
>>>>> 
>>>>> Regarding addresses.
>>>>> When we have prolog (with unroll on 2):
>>>>> 
>>>>> for_body
>>>>> i = phi [i.next, i0]; //i0 is 0 or 1 depending on the prolog execution
>>>>> x = *(array + i);
>>>>> ...
>>>>> cmp i, N
>>>>> br for_body
>>>>> 
>>>>> LSR is trying to simplify ind vars to one.
>>>>> lsr.i = phi [lsr.i.next, 0];
>>>>> or
>>>>> lsr.i = phi [lsr.i.next, -N];
>>>>> That way array access will have base: “array + i0” or “array + i0 - N”
>>>>> which is not static even if array is static.
>>>>> 
>>>>> x = *((array + i0) + lsr.i);
>>>>> 
>>>>> So it will require a register inside loop. Right now number of
>>>>> registers has the highest priority in LSR when it chooses a solution.
>>>>> 
>>>>> When we have epilog, the same access is without “i0”
>>>>> 
>>>>> x = *(array + lsr.i);
>>>>> 
>>>>> If array is static we do not need an additional register.
>>>>> In the test where regression occurred the array is static and N is constant.
>>>>> 
>>>>> However if we have enough registers we can use register instead of
>>>>> constant address. The patch should address this.
>>>>> 
>>>>> Thanks,
>>>>> Evgeny
>>>>> 
>>>>> On Mon, Jul 11, 2016 at 6:04 PM, Michael Zolotukhin
>>>>> <mzolotukhin at apple.com> wrote:
>>>>>> 
>>>>>>> On Apr 22, 2016, at 11:35 AM, Michael Zolotukhin <mzolotukhin at apple.com> wrote:
>>>>>>> 
>>>>>>> 
>>>>>>>> On Apr 20, 2016, at 4:43 PM, Evgeny Stupachenko <evstupac at gmail.com> wrote:
>>>>>>>> 
>>>>>>>> Hi,
>>>>>>>> 
>>>>>>>> Yes if the test is that important. However I believe that the
>>>>>>>> regression caused randomly, but not by epilog unrolling.
>>>>>>>> On my Corei7 "I was able to reproduce it only in 32 bit mode, 64 bit
>>>>>>>> mode epilog is ~30% faster.".
>>>>>>>> The analysis showed no critical changes in the hottest loop.
>>>>>>>> 
>>>>>>>> As for LSR issue.
>>>>>>>> Sorry for missing your request for posting PR. I'm preparing LSR patch
>>>>>>>> fixing the issue. And issue itself is related to already filed PR23384
>>>>>>>> (on an inefficient x86 LSR transformation).
>>>>>> Hi Evgeny,
>>>>>> 
>>>>>> Is there any progress with the LSR patch? Or is there something blocking you?
>>>>>> 
>>>>>> Thanks,
>>>>>> Michael
>>>>>>> Hi Evgeny,
>>>>>>> 
>>>>>>> It’s fine with me to keep it on, I just want to make sure we address the regression. So, if you’re working on the patch, there are no concerns from my side.
>>>>>>> 
>>>>>>> Thanks,
>>>>>>> Michael
>>>>>>> 
>>>>>>>> 
>>>>>>>> Thanks,
>>>>>>>> Evgeny
>>>>>>>> 
>>>>>>>> On Wed, Apr 20, 2016 at 11:41 AM, Michael Zolotukhin
>>>>>>>> <mzolotukhin at apple.com> wrote:
>>>>>>>>> Hi,
>>>>>>>>> 
>>>>>>>>> Could we change the default value to the original one until this 90%
>>>>>>>>> regression is addressed?
>>>>>>>>> 
>>>>>>>>> Thanks,
>>>>>>>>> Michael
>>>>>>>>> 
>>>>>>>>> On Apr 15, 2016, at 12:37 PM, Mikhail Zolotukhin <mzolotukhin at apple.com>
>>>>>>>>> wrote:
>>>>>>>>> 
>>>>>>>>> 
>>>>>>>>> On Apr 8, 2016, at 5:39 PM, Evgeny Stupachenko <evstupac at gmail.com> wrote:
>>>>>>>>> 
>>>>>>>>> Investigation showed that the regression is most likely LSR related,
>>>>>>>>> but not loop unroll.
>>>>>>>>> I was able to reproduce it only in 32 bit mode, 64 bit mode epilog is
>>>>>>>>> ~30% faster.
>>>>>>>>> 
>>>>>>>>> Going back to the changes in the test. Epilog variant has 1 move more
>>>>>>>>> in the hottest loop (which is redundant and should be deleted) and use
>>>>>>>>> constant address in moves inside the loop. However manual deleting of
>>>>>>>>> the move does not give any significant performance gain.
>>>>>>>>> The different behavior of LSR comes from additional inductive variable
>>>>>>>>> in unrolled loop. For Epilog case we add "k" (supposed to be
>>>>>>>>> eliminated after LSR):
>>>>>>>>> 
>>>>>>>>> k = n - n % (unroll factor));
>>>>>>>>> ...
>>>>>>>>> access a[i];
>>>>>>>>> i++;
>>>>>>>>> k--;
>>>>>>>>> if (!k) break;
>>>>>>>>> 
>>>>>>>>> Moving code of the loop modifying "palign" before loop showed up to 2
>>>>>>>>> times perf difference. So most likely epilog unroll itself does not
>>>>>>>>> influence on performance here.
>>>>>>>>> However, the fact that LSR leave constant address inside the loop
>>>>>>>>> moves (making them much longer), should be addressed to LSR. I'll
>>>>>>>>> submit a bug report on this.
>>>>>>>>> 
>>>>>>>>> Hi Evgeny,
>>>>>>>>> 
>>>>>>>>> Could you please post the PR number here as well?
>>>>>>>>> 
>>>>>>>>> Michael
>>>>>>>>> 
>>>>>>>>> 
>>>>>>>>> 
>>>>>>>>> On Fri, Apr 8, 2016 at 2:09 PM, Evgeny Stupachenko <evstupac at gmail.com>
>>>>>>>>> wrote:
>>>>>>>>> 
>>>>>>>>> Hi Michael,
>>>>>>>>> 
>>>>>>>>> Yes I do have the data.
>>>>>>>>> There were ~10% improvements on some EEMBC tests; spec2000 performance
>>>>>>>>> was almost flat (within 2%).
>>>>>>>>> 
>>>>>>>>> Let me look into BubbleSort case and come back with analysis and
>>>>>>>>> possible improvement.
>>>>>>>>> 
>>>>>>>>> Thanks,
>>>>>>>>> Evgeny
>>>>>>>>> 
>>>>>>>>> 
>>>>>>>>> On Fri, Apr 8, 2016 at 1:23 PM, Michael Zolotukhin via llvm-commits
>>>>>>>>> <llvm-commits at lists.llvm.org> wrote:
>>>>>>>>> 
>>>>>>>>> Hi Evgeny,
>>>>>>>>> 
>>>>>>>>> We’ve found several performance regressions on LLVM testsuite caused by this
>>>>>>>>> patch. Do you have a data from your performance experiments to back-up the
>>>>>>>>> decision to make epilogues the default strategy?
>>>>>>>>> 
>>>>>>>>> One of the biggest regressions we see is 89% on
>>>>>>>>> SingleSource/Benchmarks/Stanford/Bubblesort (on x86), while the biggest gain
>>>>>>>>> is only 30%.
>>>>>>>>> 
>>>>>>>>> Thanks,
>>>>>>>>> Michael
>>>>>>>>> 
>>>>>>>>> 
>>>>>>>>> On Apr 5, 2016, at 5:19 AM, David L Kreitzer via llvm-commits
>>>>>>>>> <llvm-commits at lists.llvm.org> wrote:
>>>>>>>>> 
>>>>>>>>> Author: dlkreitz
>>>>>>>>> Date: Tue Apr  5 07:19:35 2016
>>>>>>>>> New Revision: 265388
>>>>>>>>> 
>>>>>>>>> URL: http://llvm.org/viewvc/llvm-project?rev=265388&view=rev
>>>>>>>>> Log:
>>>>>>>>> Adds the ability to use an epilog remainder loop during loop unrolling and
>>>>>>>>> makes
>>>>>>>>> this the default behavior.
>>>>>>>>> 
>>>>>>>>> Patch by Evgeny Stupachenko (evstupac at gmail.com).
>>>>>>>>> 
>>>>>>>>> Differential Revision: http://reviews.llvm.org/D18158
>>>>>>>>> 
>>>>>>>>> Modified:
>>>>>>>>> llvm/trunk/include/llvm/Transforms/Utils/UnrollLoop.h
>>>>>>>>> llvm/trunk/lib/Transforms/Utils/LoopUnroll.cpp
>>>>>>>>> llvm/trunk/lib/Transforms/Utils/LoopUnrollRuntime.cpp
>>>>>>>>> llvm/trunk/test/Transforms/LoopUnroll/AArch64/runtime-loop.ll
>>>>>>>>> llvm/trunk/test/Transforms/LoopUnroll/PowerPC/a2-unrolling.ll
>>>>>>>>> llvm/trunk/test/Transforms/LoopUnroll/X86/mmx.ll
>>>>>>>>> llvm/trunk/test/Transforms/LoopUnroll/high-cost-trip-count-computation.ll
>>>>>>>>> llvm/trunk/test/Transforms/LoopUnroll/runtime-loop.ll
>>>>>>>>> llvm/trunk/test/Transforms/LoopUnroll/runtime-loop1.ll
>>>>>>>>> llvm/trunk/test/Transforms/LoopUnroll/runtime-loop2.ll
>>>>>>>>> llvm/trunk/test/Transforms/LoopUnroll/runtime-loop4.ll
>>>>>>>>> llvm/trunk/test/Transforms/LoopUnroll/runtime-loop5.ll
>>>>>>>>> llvm/trunk/test/Transforms/LoopUnroll/tripcount-overflow.ll
>>>>>>>>> llvm/trunk/test/Transforms/LoopUnroll/unroll-cleanup.ll
>>>>>>>>> llvm/trunk/test/Transforms/LoopUnroll/unroll-pragmas.ll
>>>>>>>>> 
>>>>>>>>> Modified: llvm/trunk/include/llvm/Transforms/Utils/UnrollLoop.h
>>>>>>>>> URL:
>>>>>>>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Transforms/Utils/UnrollLoop.h?rev=265388&r1=265387&r2=265388&view=diff
>>>>>>>>> ==============================================================================
>>>>>>>>> --- llvm/trunk/include/llvm/Transforms/Utils/UnrollLoop.h (original)
>>>>>>>>> +++ llvm/trunk/include/llvm/Transforms/Utils/UnrollLoop.h Tue Apr  5
>>>>>>>>> 07:19:35 2016
>>>>>>>>> @@ -34,10 +34,11 @@ bool UnrollLoop(Loop *L, unsigned Count,
>>>>>>>>>          LoopInfo *LI, ScalarEvolution *SE, DominatorTree *DT,
>>>>>>>>>          AssumptionCache *AC, bool PreserveLCSSA);
>>>>>>>>> 
>>>>>>>>> -bool UnrollRuntimeLoopProlog(Loop *L, unsigned Count,
>>>>>>>>> -                             bool AllowExpensiveTripCount, LoopInfo *LI,
>>>>>>>>> -                             ScalarEvolution *SE, DominatorTree *DT,
>>>>>>>>> -                             bool PreserveLCSSA);
>>>>>>>>> +bool UnrollRuntimeLoopRemainder(Loop *L, unsigned Count,
>>>>>>>>> +                                bool AllowExpensiveTripCount,
>>>>>>>>> +                                bool UseEpilogRemainder, LoopInfo *LI,
>>>>>>>>> +                                ScalarEvolution *SE, DominatorTree *DT,
>>>>>>>>> +                                bool PreserveLCSSA);
>>>>>>>>> 
>>>>>>>>> MDNode *GetUnrollMetadata(MDNode *LoopID, StringRef Name);
>>>>>>>>> }
>>>>>>>>> 
>>>>>>>>> Modified: llvm/trunk/lib/Transforms/Utils/LoopUnroll.cpp
>>>>>>>>> URL:
>>>>>>>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/LoopUnroll.cpp?rev=265388&r1=265387&r2=265388&view=diff
>>>>>>>>> ==============================================================================
>>>>>>>>> --- llvm/trunk/lib/Transforms/Utils/LoopUnroll.cpp (original)
>>>>>>>>> +++ llvm/trunk/lib/Transforms/Utils/LoopUnroll.cpp Tue Apr  5 07:19:35 2016
>>>>>>>>> @@ -44,6 +44,11 @@ using namespace llvm;
>>>>>>>>> STATISTIC(NumCompletelyUnrolled, "Number of loops completely unrolled");
>>>>>>>>> STATISTIC(NumUnrolled, "Number of loops unrolled (completely or
>>>>>>>>> otherwise)");
>>>>>>>>> 
>>>>>>>>> +static cl::opt<bool>
>>>>>>>>> +UnrollRuntimeEpilog("unroll-runtime-epilog", cl::init(true), cl::Hidden,
>>>>>>>>> +                    cl::desc("Allow runtime unrolled loops to be unrolled "
>>>>>>>>> +                             "with epilog instead of prolog."));
>>>>>>>>> +
>>>>>>>>> /// Convert the instruction operands from referencing the current values
>>>>>>>>> into
>>>>>>>>> /// those specified by VMap.
>>>>>>>>> static inline void remapInstruction(Instruction *I,
>>>>>>>>> @@ -288,12 +293,13 @@ bool llvm::UnrollLoop(Loop *L, unsigned
>>>>>>>>>         "convergent "
>>>>>>>>>         "operation.");
>>>>>>>>> });
>>>>>>>>> -  // Don't output the runtime loop prolog if Count is a multiple of
>>>>>>>>> -  // TripMultiple.  Such a prolog is never needed, and is unsafe if the
>>>>>>>>> loop
>>>>>>>>> +  // Don't output the runtime loop remainder if Count is a multiple of
>>>>>>>>> +  // TripMultiple.  Such a remainder is never needed, and is unsafe if the
>>>>>>>>> loop
>>>>>>>>> // contains a convergent instruction.
>>>>>>>>> if (RuntimeTripCount && TripMultiple % Count != 0 &&
>>>>>>>>> -      !UnrollRuntimeLoopProlog(L, Count, AllowExpensiveTripCount, LI, SE,
>>>>>>>>> DT,
>>>>>>>>> -                               PreserveLCSSA))
>>>>>>>>> +      !UnrollRuntimeLoopRemainder(L, Count, AllowExpensiveTripCount,
>>>>>>>>> +                                  UnrollRuntimeEpilog, LI, SE, DT,
>>>>>>>>> +                                  PreserveLCSSA))
>>>>>>>>> return false;
>>>>>>>>> 
>>>>>>>>> // Notify ScalarEvolution that the loop will be substantially changed,
>>>>>>>>> 
>>>>>>>>> Modified: llvm/trunk/lib/Transforms/Utils/LoopUnrollRuntime.cpp
>>>>>>>>> URL:
>>>>>>>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/LoopUnrollRuntime.cpp?rev=265388&r1=265387&r2=265388&view=diff
>>>>>>>>> ==============================================================================
>>>>>>>>> --- llvm/trunk/lib/Transforms/Utils/LoopUnrollRuntime.cpp (original)
>>>>>>>>> +++ llvm/trunk/lib/Transforms/Utils/LoopUnrollRuntime.cpp Tue Apr  5
>>>>>>>>> 07:19:35 2016
>>>>>>>>> @@ -16,8 +16,8 @@
>>>>>>>>> // case, we need to generate code to execute these 'left over' iterations.
>>>>>>>>> //
>>>>>>>>> // The current strategy generates an if-then-else sequence prior to the
>>>>>>>>> -// unrolled loop to execute the 'left over' iterations.  Other strategies
>>>>>>>>> -// include generate a loop before or after the unrolled loop.
>>>>>>>>> +// unrolled loop to execute the 'left over' iterations before or after the
>>>>>>>>> +// unrolled loop.
>>>>>>>>> //
>>>>>>>>> //===----------------------------------------------------------------------===//
>>>>>>>>> 
>>>>>>>>> @@ -60,33 +60,35 @@ STATISTIC(NumRuntimeUnrolled,
>>>>>>>>> ///   than the unroll factor.
>>>>>>>>> ///
>>>>>>>>> static void ConnectProlog(Loop *L, Value *BECount, unsigned Count,
>>>>>>>>> -                          BasicBlock *LastPrologBB, BasicBlock *PrologEnd,
>>>>>>>>> -                          BasicBlock *OrigPH, BasicBlock *NewPH,
>>>>>>>>> -                          ValueToValueMapTy &VMap, DominatorTree *DT,
>>>>>>>>> -                          LoopInfo *LI, bool PreserveLCSSA) {
>>>>>>>>> +                          BasicBlock *PrologExit, BasicBlock *PreHeader,
>>>>>>>>> +                          BasicBlock *NewPreHeader, ValueToValueMapTy
>>>>>>>>> &VMap,
>>>>>>>>> +                          DominatorTree *DT, LoopInfo *LI, bool
>>>>>>>>> PreserveLCSSA) {
>>>>>>>>> BasicBlock *Latch = L->getLoopLatch();
>>>>>>>>> assert(Latch && "Loop must have a latch");
>>>>>>>>> +  BasicBlock *PrologLatch = cast<BasicBlock>(VMap[Latch]);
>>>>>>>>> 
>>>>>>>>> // Create a PHI node for each outgoing value from the original loop
>>>>>>>>> // (which means it is an outgoing value from the prolog code too).
>>>>>>>>> // The new PHI node is inserted in the prolog end basic block.
>>>>>>>>> -  // The new PHI name is added as an operand of a PHI node in either
>>>>>>>>> +  // The new PHI node value is added as an operand of a PHI node in either
>>>>>>>>> // the loop header or the loop exit block.
>>>>>>>>> -  for (succ_iterator SBI = succ_begin(Latch), SBE = succ_end(Latch);
>>>>>>>>> -       SBI != SBE; ++SBI) {
>>>>>>>>> -    for (BasicBlock::iterator BBI = (*SBI)->begin();
>>>>>>>>> -         PHINode *PN = dyn_cast<PHINode>(BBI); ++BBI) {
>>>>>>>>> -
>>>>>>>>> +  for (BasicBlock *Succ : successors(Latch)) {
>>>>>>>>> +    for (Instruction &BBI : *Succ) {
>>>>>>>>> +      PHINode *PN = dyn_cast<PHINode>(&BBI);
>>>>>>>>> +      // Exit when we passed all PHI nodes.
>>>>>>>>> +      if (!PN)
>>>>>>>>> +        break;
>>>>>>>>> // Add a new PHI node to the prolog end block and add the
>>>>>>>>> // appropriate incoming values.
>>>>>>>>> -      PHINode *NewPN = PHINode::Create(PN->getType(), 2,
>>>>>>>>> PN->getName()+".unr",
>>>>>>>>> -                                       PrologEnd->getTerminator());
>>>>>>>>> +      PHINode *NewPN = PHINode::Create(PN->getType(), 2, PN->getName() +
>>>>>>>>> ".unr",
>>>>>>>>> +                                       PrologExit->getFirstNonPHI());
>>>>>>>>> // Adding a value to the new PHI node from the original loop preheader.
>>>>>>>>> // This is the value that skips all the prolog code.
>>>>>>>>> if (L->contains(PN)) {
>>>>>>>>> -        NewPN->addIncoming(PN->getIncomingValueForBlock(NewPH), OrigPH);
>>>>>>>>> +        NewPN->addIncoming(PN->getIncomingValueForBlock(NewPreHeader),
>>>>>>>>> +                           PreHeader);
>>>>>>>>> } else {
>>>>>>>>> -        NewPN->addIncoming(UndefValue::get(PN->getType()), OrigPH);
>>>>>>>>> +        NewPN->addIncoming(UndefValue::get(PN->getType()), PreHeader);
>>>>>>>>> }
>>>>>>>>> 
>>>>>>>>> Value *V = PN->getIncomingValueForBlock(Latch);
>>>>>>>>> @@ -97,22 +99,22 @@ static void ConnectProlog(Loop *L, Value
>>>>>>>>> }
>>>>>>>>> // Adding a value to the new PHI node from the last prolog block
>>>>>>>>> // that was created.
>>>>>>>>> -      NewPN->addIncoming(V, LastPrologBB);
>>>>>>>>> +      NewPN->addIncoming(V, PrologLatch);
>>>>>>>>> 
>>>>>>>>> // Update the existing PHI node operand with the value from the
>>>>>>>>> // new PHI node.  How this is done depends on if the existing
>>>>>>>>> // PHI node is in the original loop block, or the exit block.
>>>>>>>>> if (L->contains(PN)) {
>>>>>>>>> -        PN->setIncomingValue(PN->getBasicBlockIndex(NewPH), NewPN);
>>>>>>>>> +        PN->setIncomingValue(PN->getBasicBlockIndex(NewPreHeader), NewPN);
>>>>>>>>> } else {
>>>>>>>>> -        PN->addIncoming(NewPN, PrologEnd);
>>>>>>>>> +        PN->addIncoming(NewPN, PrologExit);
>>>>>>>>> }
>>>>>>>>> }
>>>>>>>>> }
>>>>>>>>> 
>>>>>>>>> // Create a branch around the original loop, which is taken if there are no
>>>>>>>>> // iterations remaining to be executed after running the prologue.
>>>>>>>>> -  Instruction *InsertPt = PrologEnd->getTerminator();
>>>>>>>>> +  Instruction *InsertPt = PrologExit->getTerminator();
>>>>>>>>> IRBuilder<> B(InsertPt);
>>>>>>>>> 
>>>>>>>>> assert(Count != 0 && "nonsensical Count!");
>>>>>>>>> @@ -126,25 +128,152 @@ static void ConnectProlog(Loop *L, Value
>>>>>>>>> BasicBlock *Exit = L->getUniqueExitBlock();
>>>>>>>>> assert(Exit && "Loop must have a single exit block only");
>>>>>>>>> // Split the exit to maintain loop canonicalization guarantees
>>>>>>>>> -  SmallVector<BasicBlock*, 4> Preds(pred_begin(Exit), pred_end(Exit));
>>>>>>>>> +  SmallVector<BasicBlock*, 4> Preds(predecessors(Exit));
>>>>>>>>> SplitBlockPredecessors(Exit, Preds, ".unr-lcssa", DT, LI,
>>>>>>>>>                   PreserveLCSSA);
>>>>>>>>> // Add the branch to the exit block (around the unrolled loop)
>>>>>>>>> -  B.CreateCondBr(BrLoopExit, Exit, NewPH);
>>>>>>>>> +  B.CreateCondBr(BrLoopExit, Exit, NewPreHeader);
>>>>>>>>> +  InsertPt->eraseFromParent();
>>>>>>>>> +}
>>>>>>>>> +
>>>>>>>>> +/// Connect the unrolling epilog code to the original loop.
>>>>>>>>> +/// The unrolling epilog code contains code to execute the
>>>>>>>>> +/// 'extra' iterations if the run-time trip count modulo the
>>>>>>>>> +/// unroll count is non-zero.
>>>>>>>>> +///
>>>>>>>>> +/// This function performs the following:
>>>>>>>>> +/// - Update PHI nodes at the unrolling loop exit and epilog loop exit
>>>>>>>>> +/// - Create PHI nodes at the unrolling loop exit to combine
>>>>>>>>> +///   values that exit the unrolling loop code and jump around it.
>>>>>>>>> +/// - Update PHI operands in the epilog loop by the new PHI nodes
>>>>>>>>> +/// - Branch around the epilog loop if extra iters (ModVal) is zero.
>>>>>>>>> +///
>>>>>>>>> +static void ConnectEpilog(Loop *L, Value *ModVal, BasicBlock *NewExit,
>>>>>>>>> +                          BasicBlock *Exit, BasicBlock *PreHeader,
>>>>>>>>> +                          BasicBlock *EpilogPreHeader, BasicBlock
>>>>>>>>> *NewPreHeader,
>>>>>>>>> +                          ValueToValueMapTy &VMap, DominatorTree *DT,
>>>>>>>>> +                          LoopInfo *LI, bool PreserveLCSSA)  {
>>>>>>>>> +  BasicBlock *Latch = L->getLoopLatch();
>>>>>>>>> +  assert(Latch && "Loop must have a latch");
>>>>>>>>> +  BasicBlock *EpilogLatch = cast<BasicBlock>(VMap[Latch]);
>>>>>>>>> +
>>>>>>>>> +  // Loop structure should be the following:
>>>>>>>>> +  //
>>>>>>>>> +  // PreHeader
>>>>>>>>> +  // NewPreHeader
>>>>>>>>> +  //   Header
>>>>>>>>> +  //   ...
>>>>>>>>> +  //   Latch
>>>>>>>>> +  // NewExit (PN)
>>>>>>>>> +  // EpilogPreHeader
>>>>>>>>> +  //   EpilogHeader
>>>>>>>>> +  //   ...
>>>>>>>>> +  //   EpilogLatch
>>>>>>>>> +  // Exit (EpilogPN)
>>>>>>>>> +
>>>>>>>>> +  // Update PHI nodes at NewExit and Exit.
>>>>>>>>> +  for (Instruction &BBI : *NewExit) {
>>>>>>>>> +    PHINode *PN = dyn_cast<PHINode>(&BBI);
>>>>>>>>> +    // Exit when we passed all PHI nodes.
>>>>>>>>> +    if (!PN)
>>>>>>>>> +      break;
>>>>>>>>> +    // PN should be used in another PHI located in Exit block as
>>>>>>>>> +    // Exit was split by SplitBlockPredecessors into Exit and NewExit
>>>>>>>>> +    // Basicaly it should look like:
>>>>>>>>> +    // NewExit:
>>>>>>>>> +    //   PN = PHI [I, Latch]
>>>>>>>>> +    // ...
>>>>>>>>> +    // Exit:
>>>>>>>>> +    //   EpilogPN = PHI [PN, EpilogPreHeader]
>>>>>>>>> +    //
>>>>>>>>> +    // There is EpilogPreHeader incoming block instead of NewExit as
>>>>>>>>> +    // NewExit was spilt 1 more time to get EpilogPreHeader.
>>>>>>>>> +    assert(PN->hasOneUse() && "The phi should have 1 use");
>>>>>>>>> +    PHINode *EpilogPN = cast<PHINode> (PN->use_begin()->getUser());
>>>>>>>>> +    assert(EpilogPN->getParent() == Exit && "EpilogPN should be in Exit
>>>>>>>>> block");
>>>>>>>>> +
>>>>>>>>> +    // Add incoming PreHeader from branch around the Loop
>>>>>>>>> +    PN->addIncoming(UndefValue::get(PN->getType()), PreHeader);
>>>>>>>>> +
>>>>>>>>> +    Value *V = PN->getIncomingValueForBlock(Latch);
>>>>>>>>> +    Instruction *I = dyn_cast<Instruction>(V);
>>>>>>>>> +    if (I && L->contains(I))
>>>>>>>>> +      // If value comes from an instruction in the loop add VMap value.
>>>>>>>>> +      V = VMap[I];
>>>>>>>>> +    // For the instruction out of the loop, constant or undefined value
>>>>>>>>> +    // insert value itself.
>>>>>>>>> +    EpilogPN->addIncoming(V, EpilogLatch);
>>>>>>>>> +
>>>>>>>>> +    assert(EpilogPN->getBasicBlockIndex(EpilogPreHeader) >= 0 &&
>>>>>>>>> +          "EpilogPN should have EpilogPreHeader incoming block");
>>>>>>>>> +    // Change EpilogPreHeader incoming block to NewExit.
>>>>>>>>> +
>>>>>>>>> EpilogPN->setIncomingBlock(EpilogPN->getBasicBlockIndex(EpilogPreHeader),
>>>>>>>>> +                               NewExit);
>>>>>>>>> +    // Now PHIs should look like:
>>>>>>>>> +    // NewExit:
>>>>>>>>> +    //   PN = PHI [I, Latch], [undef, PreHeader]
>>>>>>>>> +    // ...
>>>>>>>>> +    // Exit:
>>>>>>>>> +    //   EpilogPN = PHI [PN, NewExit], [VMap[I], EpilogLatch]
>>>>>>>>> +  }
>>>>>>>>> +
>>>>>>>>> +  // Create PHI nodes at NewExit (from the unrolling loop Latch and
>>>>>>>>> PreHeader).
>>>>>>>>> +  // Update corresponding PHI nodes in epilog loop.
>>>>>>>>> +  for (BasicBlock *Succ : successors(Latch)) {
>>>>>>>>> +    // Skip this as we already updated phis in exit blocks.
>>>>>>>>> +    if (!L->contains(Succ))
>>>>>>>>> +      continue;
>>>>>>>>> +    for (Instruction &BBI : *Succ) {
>>>>>>>>> +      PHINode *PN = dyn_cast<PHINode>(&BBI);
>>>>>>>>> +      // Exit when we passed all PHI nodes.
>>>>>>>>> +      if (!PN)
>>>>>>>>> +        break;
>>>>>>>>> +      // Add new PHI nodes to the loop exit block and update epilog
>>>>>>>>> +      // PHIs with the new PHI values.
>>>>>>>>> +      PHINode *NewPN = PHINode::Create(PN->getType(), 2, PN->getName() +
>>>>>>>>> ".unr",
>>>>>>>>> +                                       NewExit->getFirstNonPHI());
>>>>>>>>> +      // Adding a value to the new PHI node from the unrolling loop
>>>>>>>>> preheader.
>>>>>>>>> +      NewPN->addIncoming(PN->getIncomingValueForBlock(NewPreHeader),
>>>>>>>>> PreHeader);
>>>>>>>>> +      // Adding a value to the new PHI node from the unrolling loop latch.
>>>>>>>>> +      NewPN->addIncoming(PN->getIncomingValueForBlock(Latch), Latch);
>>>>>>>>> +
>>>>>>>>> +      // Update the existing PHI node operand with the value from the new
>>>>>>>>> PHI
>>>>>>>>> +      // node.  Corresponding instruction in epilog loop should be PHI.
>>>>>>>>> +      PHINode *VPN = cast<PHINode>(VMap[&BBI]);
>>>>>>>>> +      VPN->setIncomingValue(VPN->getBasicBlockIndex(EpilogPreHeader),
>>>>>>>>> NewPN);
>>>>>>>>> +    }
>>>>>>>>> +  }
>>>>>>>>> +
>>>>>>>>> +  Instruction *InsertPt = NewExit->getTerminator();
>>>>>>>>> +  IRBuilder<> B(InsertPt);
>>>>>>>>> +  Value *BrLoopExit = B.CreateIsNotNull(ModVal);
>>>>>>>>> +  assert(Exit && "Loop must have a single exit block only");
>>>>>>>>> +  // Split the exit to maintain loop canonicalization guarantees
>>>>>>>>> +  SmallVector<BasicBlock*, 4> Preds(predecessors(Exit));
>>>>>>>>> +  SplitBlockPredecessors(Exit, Preds, ".epilog-lcssa", DT, LI,
>>>>>>>>> +                         PreserveLCSSA);
>>>>>>>>> +  // Add the branch to the exit block (around the unrolling loop)
>>>>>>>>> +  B.CreateCondBr(BrLoopExit, EpilogPreHeader, Exit);
>>>>>>>>> InsertPt->eraseFromParent();
>>>>>>>>> }
>>>>>>>>> 
>>>>>>>>> /// Create a clone of the blocks in a loop and connect them together.
>>>>>>>>> -/// If UnrollProlog is true, loop structure will not be cloned, otherwise a
>>>>>>>>> new
>>>>>>>>> -/// loop will be created including all cloned blocks, and the iterator of
>>>>>>>>> it
>>>>>>>>> -/// switches to count NewIter down to 0.
>>>>>>>>> +/// If CreateRemainderLoop is false, loop structure will not be cloned,
>>>>>>>>> +/// otherwise a new loop will be created including all cloned blocks, and
>>>>>>>>> the
>>>>>>>>> +/// iterator of it switches to count NewIter down to 0.
>>>>>>>>> +/// The cloned blocks should be inserted between InsertTop and InsertBot.
>>>>>>>>> +/// If loop structure is cloned InsertTop should be new preheader,
>>>>>>>>> InsertBot
>>>>>>>>> +/// new loop exit.
>>>>>>>>> ///
>>>>>>>>> -static void CloneLoopBlocks(Loop *L, Value *NewIter, const bool
>>>>>>>>> UnrollProlog,
>>>>>>>>> +static void CloneLoopBlocks(Loop *L, Value *NewIter,
>>>>>>>>> +                            const bool CreateRemainderLoop,
>>>>>>>>> +                            const bool UseEpilogRemainder,
>>>>>>>>>                      BasicBlock *InsertTop, BasicBlock *InsertBot,
>>>>>>>>> +                            BasicBlock *Preheader,
>>>>>>>>>                      std::vector<BasicBlock *> &NewBlocks,
>>>>>>>>>                      LoopBlocksDFS &LoopBlocks, ValueToValueMapTy
>>>>>>>>> &VMap,
>>>>>>>>>                      LoopInfo *LI) {
>>>>>>>>> -  BasicBlock *Preheader = L->getLoopPreheader();
>>>>>>>>> +  StringRef suffix = UseEpilogRemainder ? "epil" : "prol";
>>>>>>>>> BasicBlock *Header = L->getHeader();
>>>>>>>>> BasicBlock *Latch = L->getLoopLatch();
>>>>>>>>> Function *F = Header->getParent();
>>>>>>>>> @@ -152,7 +281,7 @@ static void CloneLoopBlocks(Loop *L, Val
>>>>>>>>> LoopBlocksDFS::RPOIterator BlockEnd = LoopBlocks.endRPO();
>>>>>>>>> Loop *NewLoop = nullptr;
>>>>>>>>> Loop *ParentLoop = L->getParentLoop();
>>>>>>>>> -  if (!UnrollProlog) {
>>>>>>>>> +  if (CreateRemainderLoop) {
>>>>>>>>> NewLoop = new Loop();
>>>>>>>>> if (ParentLoop)
>>>>>>>>> ParentLoop->addChildLoop(NewLoop);
>>>>>>>>> @@ -163,7 +292,7 @@ static void CloneLoopBlocks(Loop *L, Val
>>>>>>>>> // For each block in the original loop, create a new copy,
>>>>>>>>> // and update the value map with the newly created values.
>>>>>>>>> for (LoopBlocksDFS::RPOIterator BB = BlockBegin; BB != BlockEnd; ++BB) {
>>>>>>>>> -    BasicBlock *NewBB = CloneBasicBlock(*BB, VMap, ".prol", F);
>>>>>>>>> +    BasicBlock *NewBB = CloneBasicBlock(*BB, VMap, "." + suffix, F);
>>>>>>>>> NewBlocks.push_back(NewBB);
>>>>>>>>> 
>>>>>>>>> if (NewLoop)
>>>>>>>>> @@ -179,16 +308,17 @@ static void CloneLoopBlocks(Loop *L, Val
>>>>>>>>> }
>>>>>>>>> 
>>>>>>>>> if (Latch == *BB) {
>>>>>>>>> -      // For the last block, if UnrollProlog is true, create a direct jump
>>>>>>>>> to
>>>>>>>>> -      // InsertBot. If not, create a loop back to cloned head.
>>>>>>>>> +      // For the last block, if CreateRemainderLoop is false, create a
>>>>>>>>> direct
>>>>>>>>> +      // jump to InsertBot. If not, create a loop back to cloned head.
>>>>>>>>> VMap.erase((*BB)->getTerminator());
>>>>>>>>> BasicBlock *FirstLoopBB = cast<BasicBlock>(VMap[Header]);
>>>>>>>>> BranchInst *LatchBR = cast<BranchInst>(NewBB->getTerminator());
>>>>>>>>> IRBuilder<> Builder(LatchBR);
>>>>>>>>> -      if (UnrollProlog) {
>>>>>>>>> +      if (!CreateRemainderLoop) {
>>>>>>>>>  Builder.CreateBr(InsertBot);
>>>>>>>>> } else {
>>>>>>>>> -        PHINode *NewIdx = PHINode::Create(NewIter->getType(), 2,
>>>>>>>>> "prol.iter",
>>>>>>>>> +        PHINode *NewIdx = PHINode::Create(NewIter->getType(), 2,
>>>>>>>>> +                                          suffix + ".iter",
>>>>>>>>>                                    FirstLoopBB->getFirstNonPHI());
>>>>>>>>>  Value *IdxSub =
>>>>>>>>>      Builder.CreateSub(NewIdx, ConstantInt::get(NewIdx->getType(), 1),
>>>>>>>>> @@ -207,9 +337,15 @@ static void CloneLoopBlocks(Loop *L, Val
>>>>>>>>> // cloned loop.
>>>>>>>>> for (BasicBlock::iterator I = Header->begin(); isa<PHINode>(I); ++I) {
>>>>>>>>> PHINode *NewPHI = cast<PHINode>(VMap[&*I]);
>>>>>>>>> -    if (UnrollProlog) {
>>>>>>>>> -      VMap[&*I] = NewPHI->getIncomingValueForBlock(Preheader);
>>>>>>>>> -      cast<BasicBlock>(VMap[Header])->getInstList().erase(NewPHI);
>>>>>>>>> +    if (!CreateRemainderLoop) {
>>>>>>>>> +      if (UseEpilogRemainder) {
>>>>>>>>> +        unsigned idx = NewPHI->getBasicBlockIndex(Preheader);
>>>>>>>>> +        NewPHI->setIncomingBlock(idx, InsertTop);
>>>>>>>>> +        NewPHI->removeIncomingValue(Latch, false);
>>>>>>>>> +      } else {
>>>>>>>>> +        VMap[&*I] = NewPHI->getIncomingValueForBlock(Preheader);
>>>>>>>>> +        cast<BasicBlock>(VMap[Header])->getInstList().erase(NewPHI);
>>>>>>>>> +      }
>>>>>>>>> } else {
>>>>>>>>> unsigned idx = NewPHI->getBasicBlockIndex(Preheader);
>>>>>>>>> NewPHI->setIncomingBlock(idx, InsertTop);
>>>>>>>>> @@ -254,7 +390,7 @@ static void CloneLoopBlocks(Loop *L, Val
>>>>>>>>> }
>>>>>>>>> }
>>>>>>>>> 
>>>>>>>>> -/// Insert code in the prolog code when unrolling a loop with a
>>>>>>>>> +/// Insert code in the prolog/epilog code when unrolling a loop with a
>>>>>>>>> /// run-time trip-count.
>>>>>>>>> ///
>>>>>>>>> /// This method assumes that the loop unroll factor is total number
>>>>>>>>> @@ -266,6 +402,7 @@ static void CloneLoopBlocks(Loop *L, Val
>>>>>>>>> /// instruction in SimplifyCFG.cpp.  Then, the backend decides how code for
>>>>>>>>> /// the switch instruction is generated.
>>>>>>>>> ///
>>>>>>>>> +/// ***Prolog case***
>>>>>>>>> ///        extraiters = tripcount % loopfactor
>>>>>>>>> ///        if (extraiters == 0) jump Loop:
>>>>>>>>> ///        else jump Prol
>>>>>>>>> @@ -277,17 +414,35 @@ static void CloneLoopBlocks(Loop *L, Val
>>>>>>>>> /// ...
>>>>>>>>> /// End:
>>>>>>>>> ///
>>>>>>>>> -bool llvm::UnrollRuntimeLoopProlog(Loop *L, unsigned Count,
>>>>>>>>> -                                   bool AllowExpensiveTripCount, LoopInfo
>>>>>>>>> *LI,
>>>>>>>>> -                                   ScalarEvolution *SE, DominatorTree *DT,
>>>>>>>>> -                                   bool PreserveLCSSA) {
>>>>>>>>> -  // For now, only unroll loops that contain a single exit.
>>>>>>>>> +/// ***Epilog case***
>>>>>>>>> +///        extraiters = tripcount % loopfactor
>>>>>>>>> +///        if (extraiters == tripcount) jump LoopExit:
>>>>>>>>> +///        unroll_iters = tripcount - extraiters
>>>>>>>>> +/// Loop:  LoopBody; (executes unroll_iter times);
>>>>>>>>> +///        unroll_iter -= 1
>>>>>>>>> +///        if (unroll_iter != 0) jump Loop:
>>>>>>>>> +/// LoopExit:
>>>>>>>>> +///        if (extraiters == 0) jump EpilExit:
>>>>>>>>> +/// Epil:  LoopBody; (executes extraiters times)
>>>>>>>>> +///        extraiters -= 1                 // Omitted if unroll factor is
>>>>>>>>> 2.
>>>>>>>>> +///        if (extraiters != 0) jump Epil: // Omitted if unroll factor is
>>>>>>>>> 2.
>>>>>>>>> +/// EpilExit:
>>>>>>>>> +
>>>>>>>>> +bool llvm::UnrollRuntimeLoopRemainder(Loop *L, unsigned Count,
>>>>>>>>> +                                      bool AllowExpensiveTripCount,
>>>>>>>>> +                                      bool UseEpilogRemainder,
>>>>>>>>> +                                      LoopInfo *LI, ScalarEvolution *SE,
>>>>>>>>> +                                      DominatorTree *DT, bool
>>>>>>>>> PreserveLCSSA) {
>>>>>>>>> +  // for now, only unroll loops that contain a single exit
>>>>>>>>> if (!L->getExitingBlock())
>>>>>>>>> return false;
>>>>>>>>> 
>>>>>>>>> // Make sure the loop is in canonical form, and there is a single
>>>>>>>>> // exit block only.
>>>>>>>>> -  if (!L->isLoopSimplifyForm() || !L->getUniqueExitBlock())
>>>>>>>>> +  if (!L->isLoopSimplifyForm())
>>>>>>>>> +    return false;
>>>>>>>>> +  BasicBlock *Exit = L->getUniqueExitBlock(); // successor out of loop
>>>>>>>>> +  if (!Exit)
>>>>>>>>> return false;
>>>>>>>>> 
>>>>>>>>> // Use Scalar Evolution to compute the trip count. This allows more loops to
>>>>>>>>> @@ -311,8 +466,8 @@ bool llvm::UnrollRuntimeLoopProlog(Loop
>>>>>>>>> return false;
>>>>>>>>> 
>>>>>>>>> BasicBlock *Header = L->getHeader();
>>>>>>>>> -  BasicBlock *PH = L->getLoopPreheader();
>>>>>>>>> -  BranchInst *PreHeaderBR = cast<BranchInst>(PH->getTerminator());
>>>>>>>>> +  BasicBlock *PreHeader = L->getLoopPreheader();
>>>>>>>>> +  BranchInst *PreHeaderBR = cast<BranchInst>(PreHeader->getTerminator());
>>>>>>>>> const DataLayout &DL = Header->getModule()->getDataLayout();
>>>>>>>>> SCEVExpander Expander(*SE, DL, "loop-unroll");
>>>>>>>>> if (!AllowExpensiveTripCount &&
>>>>>>>>> @@ -330,26 +485,75 @@ bool llvm::UnrollRuntimeLoopProlog(Loop
>>>>>>>>> SE->forgetLoop(ParentLoop);
>>>>>>>>> 
>>>>>>>>> BasicBlock *Latch = L->getLoopLatch();
>>>>>>>>> -  // It helps to split the original preheader twice, one for the end of the
>>>>>>>>> -  // prolog code and one for a new loop preheader.
>>>>>>>>> -  BasicBlock *PEnd = SplitEdge(PH, Header, DT, LI);
>>>>>>>>> -  BasicBlock *NewPH = SplitBlock(PEnd, PEnd->getTerminator(), DT, LI);
>>>>>>>>> -  PreHeaderBR = cast<BranchInst>(PH->getTerminator());
>>>>>>>>> 
>>>>>>>>> +  // Loop structure is the following:
>>>>>>>>> +  //
>>>>>>>>> +  // PreHeader
>>>>>>>>> +  //   Header
>>>>>>>>> +  //   ...
>>>>>>>>> +  //   Latch
>>>>>>>>> +  // Exit
>>>>>>>>> +
>>>>>>>>> +  BasicBlock *NewPreHeader;
>>>>>>>>> +  BasicBlock *NewExit = nullptr;
>>>>>>>>> +  BasicBlock *PrologExit = nullptr;
>>>>>>>>> +  BasicBlock *EpilogPreHeader = nullptr;
>>>>>>>>> +  BasicBlock *PrologPreHeader = nullptr;
>>>>>>>>> +
>>>>>>>>> +  if (UseEpilogRemainder) {
>>>>>>>>> +    // If epilog remainder
>>>>>>>>> +    // Split PreHeader to insert a branch around loop for unrolling.
>>>>>>>>> +    NewPreHeader = SplitBlock(PreHeader, PreHeader->getTerminator(), DT,
>>>>>>>>> LI);
>>>>>>>>> +    NewPreHeader->setName(PreHeader->getName() + ".new");
>>>>>>>>> +    // Split Exit to create phi nodes from branch above.
>>>>>>>>> +    SmallVector<BasicBlock*, 4> Preds(predecessors(Exit));
>>>>>>>>> +    NewExit = SplitBlockPredecessors(Exit, Preds, ".unr-lcssa",
>>>>>>>>> +                                     DT, LI, PreserveLCSSA);
>>>>>>>>> +    // Split NewExit to insert epilog remainder loop.
>>>>>>>>> +    EpilogPreHeader = SplitBlock(NewExit, NewExit->getTerminator(), DT,
>>>>>>>>> LI);
>>>>>>>>> +    EpilogPreHeader->setName(Header->getName() + ".epil.preheader");
>>>>>>>>> +  } else {
>>>>>>>>> +    // If prolog remainder
>>>>>>>>> +    // Split the original preheader twice to insert prolog remainder loop
>>>>>>>>> +    PrologPreHeader = SplitEdge(PreHeader, Header, DT, LI);
>>>>>>>>> +    PrologPreHeader->setName(Header->getName() + ".prol.preheader");
>>>>>>>>> +    PrologExit = SplitBlock(PrologPreHeader,
>>>>>>>>> PrologPreHeader->getTerminator(),
>>>>>>>>> +                            DT, LI);
>>>>>>>>> +    PrologExit->setName(Header->getName() + ".prol.loopexit");
>>>>>>>>> +    // Split PrologExit to get NewPreHeader.
>>>>>>>>> +    NewPreHeader = SplitBlock(PrologExit, PrologExit->getTerminator(), DT,
>>>>>>>>> LI);
>>>>>>>>> +    NewPreHeader->setName(PreHeader->getName() + ".new");
>>>>>>>>> +  }
>>>>>>>>> +  // Loop structure should be the following:
>>>>>>>>> +  //  Epilog             Prolog
>>>>>>>>> +  //
>>>>>>>>> +  // PreHeader         PreHeader
>>>>>>>>> +  // *NewPreHeader     *PrologPreHeader
>>>>>>>>> +  //   Header          *PrologExit
>>>>>>>>> +  //   ...             *NewPreHeader
>>>>>>>>> +  //   Latch             Header
>>>>>>>>> +  // *NewExit            ...
>>>>>>>>> +  // *EpilogPreHeader    Latch
>>>>>>>>> +  // Exit              Exit
>>>>>>>>> +
>>>>>>>>> +  // Calculate conditions for branch around loop for unrolling
>>>>>>>>> +  // in epilog case and around prolog remainder loop in prolog case.
>>>>>>>>> // Compute the number of extra iterations required, which is:
>>>>>>>>> -  //  extra iterations = run-time trip count % (loop unroll factor + 1)
>>>>>>>>> +  //  extra iterations = run-time trip count % loop unroll factor
>>>>>>>>> +  PreHeaderBR = cast<BranchInst>(PreHeader->getTerminator());
>>>>>>>>> Value *TripCount = Expander.expandCodeFor(TripCountSC,
>>>>>>>>> TripCountSC->getType(),
>>>>>>>>>                                      PreHeaderBR);
>>>>>>>>> Value *BECount = Expander.expandCodeFor(BECountSC, BECountSC->getType(),
>>>>>>>>>                                    PreHeaderBR);
>>>>>>>>> -
>>>>>>>>> IRBuilder<> B(PreHeaderBR);
>>>>>>>>> Value *ModVal;
>>>>>>>>> // Calculate ModVal = (BECount + 1) % Count.
>>>>>>>>> // Note that TripCount is BECount + 1.
>>>>>>>>> if (isPowerOf2_32(Count)) {
>>>>>>>>> +    // When Count is power of 2 we don't BECount for epilog case, however
>>>>>>>>> we'll
>>>>>>>>> +    // need it for a branch around unrolling loop for prolog case.
>>>>>>>>> ModVal = B.CreateAnd(TripCount, Count - 1, "xtraiter");
>>>>>>>>> -    //  1. There are no iterations to be run in the prologue loop.
>>>>>>>>> +    //  1. There are no iterations to be run in the prolog/epilog loop.
>>>>>>>>> // OR
>>>>>>>>> //  2. The addition computing TripCount overflowed.
>>>>>>>>> //
>>>>>>>>> @@ -371,18 +575,18 @@ bool llvm::UnrollRuntimeLoopProlog(Loop
>>>>>>>>>                    ConstantInt::get(BECount->getType(), Count),
>>>>>>>>>                    "xtraiter");
>>>>>>>>> }
>>>>>>>>> -  Value *BranchVal = B.CreateIsNotNull(ModVal, "lcmp.mod");
>>>>>>>>> -
>>>>>>>>> -  // Branch to either the extra iterations or the cloned/unrolled loop.
>>>>>>>>> -  // We will fix up the true branch label when adding loop body copies.
>>>>>>>>> -  B.CreateCondBr(BranchVal, PEnd, PEnd);
>>>>>>>>> -  assert(PreHeaderBR->isUnconditional() &&
>>>>>>>>> -         PreHeaderBR->getSuccessor(0) == PEnd &&
>>>>>>>>> -         "CFG edges in Preheader are not correct");
>>>>>>>>> +  Value *CmpOperand =
>>>>>>>>> +      UseEpilogRemainder ? TripCount :
>>>>>>>>> +                           ConstantInt::get(TripCount->getType(), 0);
>>>>>>>>> +  Value *BranchVal = B.CreateICmpNE(ModVal, CmpOperand, "lcmp.mod");
>>>>>>>>> +  BasicBlock *FirstLoop = UseEpilogRemainder ? NewPreHeader :
>>>>>>>>> PrologPreHeader;
>>>>>>>>> +  BasicBlock *SecondLoop = UseEpilogRemainder ? NewExit : PrologExit;
>>>>>>>>> +  // Branch to either remainder (extra iterations) loop or unrolling loop.
>>>>>>>>> +  B.CreateCondBr(BranchVal, FirstLoop, SecondLoop);
>>>>>>>>> PreHeaderBR->eraseFromParent();
>>>>>>>>> Function *F = Header->getParent();
>>>>>>>>> // Get an ordered list of blocks in the loop to help with the ordering of
>>>>>>>>> the
>>>>>>>>> -  // cloned blocks in the prolog code.
>>>>>>>>> +  // cloned blocks in the prolog/epilog code
>>>>>>>>> LoopBlocksDFS LoopBlocks(L);
>>>>>>>>> LoopBlocks.perform(LI);
>>>>>>>>> 
>>>>>>>>> @@ -394,17 +598,38 @@ bool llvm::UnrollRuntimeLoopProlog(Loop
>>>>>>>>> std::vector<BasicBlock *> NewBlocks;
>>>>>>>>> ValueToValueMapTy VMap;
>>>>>>>>> 
>>>>>>>>> -  bool UnrollPrologue = Count == 2;
>>>>>>>>> +  // For unroll factor 2 remainder loop will have 1 iterations.
>>>>>>>>> +  // Do not create 1 iteration loop.
>>>>>>>>> +  bool CreateRemainderLoop = (Count != 2);
>>>>>>>>> 
>>>>>>>>> // Clone all the basic blocks in the loop. If Count is 2, we don't clone
>>>>>>>>> // the loop, otherwise we create a cloned loop to execute the extra
>>>>>>>>> // iterations. This function adds the appropriate CFG connections.
>>>>>>>>> -  CloneLoopBlocks(L, ModVal, UnrollPrologue, PH, PEnd, NewBlocks,
>>>>>>>>> LoopBlocks,
>>>>>>>>> -                  VMap, LI);
>>>>>>>>> +  BasicBlock *InsertBot = UseEpilogRemainder ? Exit : PrologExit;
>>>>>>>>> +  BasicBlock *InsertTop = UseEpilogRemainder ? EpilogPreHeader :
>>>>>>>>> PrologPreHeader;
>>>>>>>>> +  CloneLoopBlocks(L, ModVal, CreateRemainderLoop, UseEpilogRemainder,
>>>>>>>>> InsertTop,
>>>>>>>>> +                  InsertBot, NewPreHeader, NewBlocks, LoopBlocks, VMap,
>>>>>>>>> LI);
>>>>>>>>> +
>>>>>>>>> +  // Insert the cloned blocks into the function.
>>>>>>>>> +  F->getBasicBlockList().splice(InsertBot->getIterator(),
>>>>>>>>> +                                F->getBasicBlockList(),
>>>>>>>>> +                                NewBlocks[0]->getIterator(),
>>>>>>>>> +                                F->end());
>>>>>>>>> 
>>>>>>>>> -  // Insert the cloned blocks into the function just before the original
>>>>>>>>> loop.
>>>>>>>>> -  F->getBasicBlockList().splice(PEnd->getIterator(),
>>>>>>>>> F->getBasicBlockList(),
>>>>>>>>> -                                NewBlocks[0]->getIterator(), F->end());
>>>>>>>>> +  // Loop structure should be the following:
>>>>>>>>> +  //  Epilog             Prolog
>>>>>>>>> +  //
>>>>>>>>> +  // PreHeader         PreHeader
>>>>>>>>> +  // NewPreHeader      PrologPreHeader
>>>>>>>>> +  //   Header            PrologHeader
>>>>>>>>> +  //   ...               ...
>>>>>>>>> +  //   Latch             PrologLatch
>>>>>>>>> +  // NewExit           PrologExit
>>>>>>>>> +  // EpilogPreHeader   NewPreHeader
>>>>>>>>> +  //   EpilogHeader      Header
>>>>>>>>> +  //   ...               ...
>>>>>>>>> +  //   EpilogLatch       Latch
>>>>>>>>> +  // Exit              Exit
>>>>>>>>> 
>>>>>>>>> // Rewrite the cloned instruction operands to use the values created when
>>>>>>>>> the
>>>>>>>>> // clone is created.
>>>>>>>>> @@ -415,11 +640,38 @@ bool llvm::UnrollRuntimeLoopProlog(Loop
>>>>>>>>> }
>>>>>>>>> }
>>>>>>>>> 
>>>>>>>>> -  // Connect the prolog code to the original loop and update the
>>>>>>>>> -  // PHI functions.
>>>>>>>>> -  BasicBlock *LastLoopBB = cast<BasicBlock>(VMap[Latch]);
>>>>>>>>> -  ConnectProlog(L, BECount, Count, LastLoopBB, PEnd, PH, NewPH, VMap, DT,
>>>>>>>>> LI,
>>>>>>>>> -                PreserveLCSSA);
>>>>>>>>> +  if (UseEpilogRemainder) {
>>>>>>>>> +    // Connect the epilog code to the original loop and update the
>>>>>>>>> +    // PHI functions.
>>>>>>>>> +    ConnectEpilog(L, ModVal, NewExit, Exit, PreHeader,
>>>>>>>>> +                  EpilogPreHeader, NewPreHeader, VMap, DT, LI,
>>>>>>>>> +                  PreserveLCSSA);
>>>>>>>>> +
>>>>>>>>> +    // Update counter in loop for unrolling.
>>>>>>>>> +    // I should be multiply of Count.
>>>>>>>>> +    IRBuilder<> B2(NewPreHeader->getTerminator());
>>>>>>>>> +    Value *TestVal = B2.CreateSub(TripCount, ModVal, "unroll_iter");
>>>>>>>>> +    BranchInst *LatchBR = cast<BranchInst>(Latch->getTerminator());
>>>>>>>>> +    B2.SetInsertPoint(LatchBR);
>>>>>>>>> +    PHINode *NewIdx = PHINode::Create(TestVal->getType(), 2, "niter",
>>>>>>>>> +                                      Header->getFirstNonPHI());
>>>>>>>>> +    Value *IdxSub =
>>>>>>>>> +        B2.CreateSub(NewIdx, ConstantInt::get(NewIdx->getType(), 1),
>>>>>>>>> +                     NewIdx->getName() + ".nsub");
>>>>>>>>> +    Value *IdxCmp;
>>>>>>>>> +    if (LatchBR->getSuccessor(0) == Header)
>>>>>>>>> +      IdxCmp = B2.CreateIsNotNull(IdxSub, NewIdx->getName() + ".ncmp");
>>>>>>>>> +    else
>>>>>>>>> +      IdxCmp = B2.CreateIsNull(IdxSub, NewIdx->getName() + ".ncmp");
>>>>>>>>> +    NewIdx->addIncoming(TestVal, NewPreHeader);
>>>>>>>>> +    NewIdx->addIncoming(IdxSub, Latch);
>>>>>>>>> +    LatchBR->setCondition(IdxCmp);
>>>>>>>>> +  } else {
>>>>>>>>> +    // Connect the prolog code to the original loop and update the
>>>>>>>>> +    // PHI functions.
>>>>>>>>> +    ConnectProlog(L, BECount, Count, PrologExit, PreHeader, NewPreHeader,
>>>>>>>>> +                  VMap, DT, LI, PreserveLCSSA);
>>>>>>>>> +  }
>>>>>>>>> NumRuntimeUnrolled++;
>>>>>>>>> return true;
>>>>>>>>> }
>>>>>>>>> 
>>>>>>>>> Modified: llvm/trunk/test/Transforms/LoopUnroll/AArch64/runtime-loop.ll
>>>>>>>>> URL:
>>>>>>>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopUnroll/AArch64/runtime-loop.ll?rev=265388&r1=265387&r2=265388&view=diff
>>>>>>>>> ==============================================================================
>>>>>>>>> --- llvm/trunk/test/Transforms/LoopUnroll/AArch64/runtime-loop.ll (original)
>>>>>>>>> +++ llvm/trunk/test/Transforms/LoopUnroll/AArch64/runtime-loop.ll Tue Apr  5
>>>>>>>>> 07:19:35 2016
>>>>>>>>> @@ -1,13 +1,21 @@
>>>>>>>>> -; RUN: opt < %s -S -loop-unroll -mtriple aarch64 -mcpu=cortex-a57 |
>>>>>>>>> FileCheck %s
>>>>>>>>> +; RUN: opt < %s -S -loop-unroll -mtriple aarch64 -mcpu=cortex-a57 |
>>>>>>>>> FileCheck %s -check-prefix=EPILOG
>>>>>>>>> +; RUN: opt < %s -S -loop-unroll -mtriple aarch64 -mcpu=cortex-a57
>>>>>>>>> -unroll-runtime-epilog=false | FileCheck %s -check-prefix=PROLOG
>>>>>>>>> 
>>>>>>>>> ; Tests for unrolling loops with run-time trip counts
>>>>>>>>> 
>>>>>>>>> -; CHECK:  %xtraiter = and i32 %n
>>>>>>>>> -; CHECK:  %lcmp.mod = icmp ne i32 %xtraiter, 0
>>>>>>>>> -; CHECK:  br i1 %lcmp.mod, label %for.body.prol, label
>>>>>>>>> %for.body.preheader.split
>>>>>>>>> +; EPILOG:  %xtraiter = and i32 %n
>>>>>>>>> +; EPILOG:  %lcmp.mod = icmp ne i32 %xtraiter, %n
>>>>>>>>> +; EPILOG:  br i1 %lcmp.mod, label %for.body.preheader.new, label
>>>>>>>>> %for.end.loopexit.unr-lcssa
>>>>>>>>> 
>>>>>>>>> -; CHECK:  for.body.prol:
>>>>>>>>> -; CHECK:  for.body:
>>>>>>>>> +; PROLOG:  %xtraiter = and i32 %n
>>>>>>>>> +; PROLOG:  %lcmp.mod = icmp ne i32 %xtraiter, 0
>>>>>>>>> +; PROLOG:  br i1 %lcmp.mod, label %for.body.prol.preheader, label
>>>>>>>>> %for.body.prol.loopexit
>>>>>>>>> +
>>>>>>>>> +; EPILOG:  for.body:
>>>>>>>>> +; EPILOG:  for.body.epil:
>>>>>>>>> +
>>>>>>>>> +; PROLOG:  for.body.prol:
>>>>>>>>> +; PROLOG:  for.body:
>>>>>>>>> 
>>>>>>>>> define i32 @test(i32* nocapture %a, i32 %n) nounwind uwtable readonly {
>>>>>>>>> entry:
>>>>>>>>> 
>>>>>>>>> Modified: llvm/trunk/test/Transforms/LoopUnroll/PowerPC/a2-unrolling.ll
>>>>>>>>> URL:
>>>>>>>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopUnroll/PowerPC/a2-unrolling.ll?rev=265388&r1=265387&r2=265388&view=diff
>>>>>>>>> ==============================================================================
>>>>>>>>> --- llvm/trunk/test/Transforms/LoopUnroll/PowerPC/a2-unrolling.ll (original)
>>>>>>>>> +++ llvm/trunk/test/Transforms/LoopUnroll/PowerPC/a2-unrolling.ll Tue Apr  5
>>>>>>>>> 07:19:35 2016
>>>>>>>>> @@ -1,4 +1,5 @@
>>>>>>>>> -; RUN: opt < %s -S -mtriple=powerpc64-unknown-linux-gnu -mcpu=a2
>>>>>>>>> -loop-unroll | FileCheck %s
>>>>>>>>> +; RUN: opt < %s -S -mtriple=powerpc64-unknown-linux-gnu -mcpu=a2
>>>>>>>>> -loop-unroll | FileCheck %s -check-prefix=EPILOG
>>>>>>>>> +; RUN: opt < %s -S -mtriple=powerpc64-unknown-linux-gnu -mcpu=a2
>>>>>>>>> -loop-unroll -unroll-runtime-epilog=false | FileCheck %s
>>>>>>>>> -check-prefix=PROLOG
>>>>>>>>> define void @unroll_opt_for_size() nounwind optsize {
>>>>>>>>> entry:
>>>>>>>>> br label %loop
>>>>>>>>> @@ -13,11 +14,17 @@ exit:
>>>>>>>>> ret void
>>>>>>>>> }
>>>>>>>>> 
>>>>>>>>> -; CHECK-LABEL: @unroll_opt_for_size
>>>>>>>>> -; CHECK:      add
>>>>>>>>> -; CHECK-NEXT: add
>>>>>>>>> -; CHECK-NEXT: add
>>>>>>>>> -; CHECK: icmp
>>>>>>>>> +; EPILOG-LABEL: @unroll_opt_for_size
>>>>>>>>> +; EPILOG:      add
>>>>>>>>> +; EPILOG-NEXT: add
>>>>>>>>> +; EPILOG-NEXT: add
>>>>>>>>> +; EPILOG: icmp
>>>>>>>>> +
>>>>>>>>> +; PROLOG-LABEL: @unroll_opt_for_size
>>>>>>>>> +; PROLOG:      add
>>>>>>>>> +; PROLOG-NEXT: add
>>>>>>>>> +; PROLOG-NEXT: add
>>>>>>>>> +; PROLOG: icmp
>>>>>>>>> 
>>>>>>>>> define i32 @test(i32* nocapture %a, i32 %n) nounwind uwtable readonly {
>>>>>>>>> entry:
>>>>>>>>> @@ -40,8 +47,13 @@ for.end:
>>>>>>>>> ret i32 %sum.0.lcssa
>>>>>>>>> }
>>>>>>>>> 
>>>>>>>>> -; CHECK-LABEL: @test
>>>>>>>>> -; CHECK: for.body.prol{{.*}}:
>>>>>>>>> -; CHECK: for.body:
>>>>>>>>> -; CHECK: br i1 %exitcond.7, label %for.end.loopexit{{.*}}, label %for.body
>>>>>>>>> +; EPILOG-LABEL: @test
>>>>>>>>> +; EPILOG: for.body:
>>>>>>>>> +; EPILOG: br i1 %niter.ncmp.7, label %for.end.loopexit{{.*}}, label
>>>>>>>>> %for.body
>>>>>>>>> +; EPILOG: for.body.epil{{.*}}:
>>>>>>>>> +
>>>>>>>>> +; PROLOG-LABEL: @test
>>>>>>>>> +; PROLOG: for.body.prol{{.*}}:
>>>>>>>>> +; PROLOG: for.body:
>>>>>>>>> +; PROLOG: br i1 %exitcond.7, label %for.end.loopexit{{.*}}, label %for.body
>>>>>>>>> 
>>>>>>>>> 
>>>>>>>>> Modified: llvm/trunk/test/Transforms/LoopUnroll/X86/mmx.ll
>>>>>>>>> URL:
>>>>>>>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopUnroll/X86/mmx.ll?rev=265388&r1=265387&r2=265388&view=diff
>>>>>>>>> ==============================================================================
>>>>>>>>> --- llvm/trunk/test/Transforms/LoopUnroll/X86/mmx.ll (original)
>>>>>>>>> +++ llvm/trunk/test/Transforms/LoopUnroll/X86/mmx.ll Tue Apr  5 07:19:35
>>>>>>>>> 2016
>>>>>>>>> @@ -14,9 +14,9 @@ for.body:
>>>>>>>>> 
>>>>>>>>> exit:                                             ; preds = %for.body
>>>>>>>>> %ret = phi x86_mmx [ undef, %for.body ]
>>>>>>>>> -  ; CHECK: %[[ret_unr:.*]] = phi x86_mmx [ undef,
>>>>>>>>> -  ; CHECK: %[[ret_ph:.*]]  = phi x86_mmx [ undef,
>>>>>>>>> -  ; CHECK: %[[ret:.*]] = phi x86_mmx [ %[[ret_unr]], {{.*}} ], [
>>>>>>>>> %[[ret_ph]]
>>>>>>>>> +  ; CHECK: %[[ret_ph:.*]] = phi x86_mmx [ undef, %entry
>>>>>>>>> +  ; CHECK: %[[ret_ph1:.*]]  = phi x86_mmx [ undef,
>>>>>>>>> +  ; CHECK: %[[ret:.*]] = phi x86_mmx [ %[[ret_ph]], {{.*}} ], [
>>>>>>>>> %[[ret_ph1]],
>>>>>>>>> ; CHECK: ret x86_mmx %[[ret]]
>>>>>>>>> ret x86_mmx %ret
>>>>>>>>> }
>>>>>>>>> 
>>>>>>>>> Modified:
>>>>>>>>> llvm/trunk/test/Transforms/LoopUnroll/high-cost-trip-count-computation.ll
>>>>>>>>> URL:
>>>>>>>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopUnroll/high-cost-trip-count-computation.ll?rev=265388&r1=265387&r2=265388&view=diff
>>>>>>>>> ==============================================================================
>>>>>>>>> ---
>>>>>>>>> llvm/trunk/test/Transforms/LoopUnroll/high-cost-trip-count-computation.ll
>>>>>>>>> (original)
>>>>>>>>> +++
>>>>>>>>> llvm/trunk/test/Transforms/LoopUnroll/high-cost-trip-count-computation.ll
>>>>>>>>> Tue Apr  5 07:19:35 2016
>>>>>>>>> @@ -34,7 +34,7 @@ define i32 @test2(i64* %loc, i64 %conv7)
>>>>>>>>> ; CHECK: udiv
>>>>>>>>> ; CHECK: udiv
>>>>>>>>> ; CHECK-NOT: udiv
>>>>>>>>> -; CHECK-LABEL: for.body.prol
>>>>>>>>> +; CHECK-LABEL: for.body
>>>>>>>>> entry:
>>>>>>>>> %rem0 = load i64, i64* %loc, align 8
>>>>>>>>> %ExpensiveComputation = udiv i64 %rem0, 42 ; <<< Extra computations are
>>>>>>>>> added to the trip-count expression
>>>>>>>>> 
>>>>>>>>> Modified: llvm/trunk/test/Transforms/LoopUnroll/runtime-loop.ll
>>>>>>>>> URL:
>>>>>>>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopUnroll/runtime-loop.ll?rev=265388&r1=265387&r2=265388&view=diff
>>>>>>>>> ==============================================================================
>>>>>>>>> --- llvm/trunk/test/Transforms/LoopUnroll/runtime-loop.ll (original)
>>>>>>>>> +++ llvm/trunk/test/Transforms/LoopUnroll/runtime-loop.ll Tue Apr  5
>>>>>>>>> 07:19:35 2016
>>>>>>>>> @@ -1,18 +1,30 @@
>>>>>>>>> -; RUN: opt < %s -S -loop-unroll -unroll-runtime=true | FileCheck %s
>>>>>>>>> +; RUN: opt < %s -S -loop-unroll -unroll-runtime=true | FileCheck %s
>>>>>>>>> -check-prefix=EPILOG
>>>>>>>>> +; RUN: opt < %s -S -loop-unroll -unroll-runtime=true
>>>>>>>>> -unroll-runtime-epilog=false | FileCheck %s -check-prefix=PROLOG
>>>>>>>>> 
>>>>>>>>> target datalayout =
>>>>>>>>> "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
>>>>>>>>> 
>>>>>>>>> ; Tests for unrolling loops with run-time trip counts
>>>>>>>>> 
>>>>>>>>> -; CHECK: %xtraiter = and i32 %n
>>>>>>>>> -; CHECK:  %lcmp.mod = icmp ne i32 %xtraiter, 0
>>>>>>>>> -; CHECK:  br i1 %lcmp.mod, label %for.body.prol, label
>>>>>>>>> %for.body.preheader.split
>>>>>>>>> -
>>>>>>>>> -; CHECK: for.body.prol:
>>>>>>>>> -; CHECK: %indvars.iv.prol = phi i64 [ %indvars.iv.next.prol, %for.body.prol
>>>>>>>>> ], [ 0, %for.body.preheader ]
>>>>>>>>> -; CHECK:  %prol.iter.sub = sub i32 %prol.iter, 1
>>>>>>>>> -; CHECK:  %prol.iter.cmp = icmp ne i32 %prol.iter.sub, 0
>>>>>>>>> -; CHECK:  br i1 %prol.iter.cmp, label %for.body.prol, label
>>>>>>>>> %for.body.preheader.split, !llvm.loop !0
>>>>>>>>> +; EPILOG: %xtraiter = and i32 %n
>>>>>>>>> +; EPILOG:  %lcmp.mod = icmp ne i32 %xtraiter, %n
>>>>>>>>> +; EPILOG:  br i1 %lcmp.mod, label %for.body.preheader.new, label
>>>>>>>>> %for.end.loopexit.unr-lcssa
>>>>>>>>> +
>>>>>>>>> +; PROLOG: %xtraiter = and i32 %n
>>>>>>>>> +; PROLOG:  %lcmp.mod = icmp ne i32 %xtraiter, 0
>>>>>>>>> +; PROLOG:  br i1 %lcmp.mod, label %for.body.prol.preheader, label
>>>>>>>>> %for.body.prol.loopexit
>>>>>>>>> +
>>>>>>>>> +; EPILOG: for.body.epil:
>>>>>>>>> +; EPILOG: %indvars.iv.epil = phi i64 [ %indvars.iv.next.epil,
>>>>>>>>> %for.body.epil ],  [ %indvars.iv.unr, %for.body.epil.preheader ]
>>>>>>>>> +; EPILOG:  %epil.iter.sub = sub i32 %epil.iter, 1
>>>>>>>>> +; EPILOG:  %epil.iter.cmp = icmp ne i32 %epil.iter.sub, 0
>>>>>>>>> +; EPILOG:  br i1 %epil.iter.cmp, label %for.body.epil, label
>>>>>>>>> %for.end.loopexit.epilog-lcssa, !llvm.loop !0
>>>>>>>>> +
>>>>>>>>> +; PROLOG: for.body.prol:
>>>>>>>>> +; PROLOG: %indvars.iv.prol = phi i64 [ %indvars.iv.next.prol,
>>>>>>>>> %for.body.prol ], [ 0, %for.body.prol.preheader ]
>>>>>>>>> +; PROLOG:  %prol.iter.sub = sub i32 %prol.iter, 1
>>>>>>>>> +; PROLOG:  %prol.iter.cmp = icmp ne i32 %prol.iter.sub, 0
>>>>>>>>> +; PROLOG:  br i1 %prol.iter.cmp, label %for.body.prol, label
>>>>>>>>> %for.body.prol.loopexit, !llvm.loop !0
>>>>>>>>> +
>>>>>>>>> 
>>>>>>>>> define i32 @test(i32* nocapture %a, i32 %n) nounwind uwtable readonly {
>>>>>>>>> entry:
>>>>>>>>> @@ -39,8 +51,11 @@ for.end:
>>>>>>>>> ; Still try to completely unroll loops with compile-time trip counts
>>>>>>>>> ; even if the -unroll-runtime is specified
>>>>>>>>> 
>>>>>>>>> -; CHECK: for.body:
>>>>>>>>> -; CHECK-NOT: for.body.prol:
>>>>>>>>> +; EPILOG: for.body:
>>>>>>>>> +; EPILOG-NOT: for.body.epil:
>>>>>>>>> +
>>>>>>>>> +; PROLOG: for.body:
>>>>>>>>> +; PROLOG-NOT: for.body.prol:
>>>>>>>>> 
>>>>>>>>> define i32 @test1(i32* nocapture %a) nounwind uwtable readonly {
>>>>>>>>> entry:
>>>>>>>>> @@ -64,7 +79,8 @@ for.end:
>>>>>>>>> ; This is test 2007-05-09-UnknownTripCount.ll which can be unrolled now
>>>>>>>>> ; if the -unroll-runtime option is turned on
>>>>>>>>> 
>>>>>>>>> -; CHECK: bb72.2:
>>>>>>>>> +; EPILOG: bb72.2:
>>>>>>>>> +; PROLOG: bb72.2:
>>>>>>>>> 
>>>>>>>>> define void @foo(i32 %trips) {
>>>>>>>>> entry:
>>>>>>>>> @@ -86,8 +102,11 @@ cond_true138:
>>>>>>>>> 
>>>>>>>>> ; Test run-time unrolling for a loop that counts down by -2.
>>>>>>>>> 
>>>>>>>>> -; CHECK: for.body.prol:
>>>>>>>>> -; CHECK: br i1 %prol.iter.cmp, label %for.body.prol, label
>>>>>>>>> %for.body.preheader.split
>>>>>>>>> +; EPILOG: for.body.epil:
>>>>>>>>> +; EPILOG: br i1 %epil.iter.cmp, label %for.body.epil, label
>>>>>>>>> %for.cond.for.end_crit_edge.epilog-lcssa
>>>>>>>>> +
>>>>>>>>> +; PROLOG: for.body.prol:
>>>>>>>>> +; PROLOG: br i1 %prol.iter.cmp, label %for.body.prol, label
>>>>>>>>> %for.body.prol.loopexit
>>>>>>>>> 
>>>>>>>>> define zeroext i16 @down(i16* nocapture %p, i32 %len) nounwind uwtable
>>>>>>>>> readonly {
>>>>>>>>> entry:
>>>>>>>>> @@ -116,8 +135,11 @@ for.end:
>>>>>>>>> }
>>>>>>>>> 
>>>>>>>>> ; Test run-time unrolling disable metadata.
>>>>>>>>> -; CHECK: for.body:
>>>>>>>>> -; CHECK-NOT: for.body.prol:
>>>>>>>>> +; EPILOG: for.body:
>>>>>>>>> +; EPILOG-NOT: for.body.epil:
>>>>>>>>> +
>>>>>>>>> +; PROLOG: for.body:
>>>>>>>>> +; PROLOG-NOT: for.body.prol:
>>>>>>>>> 
>>>>>>>>> define zeroext i16 @test2(i16* nocapture %p, i32 %len) nounwind uwtable
>>>>>>>>> readonly {
>>>>>>>>> entry:
>>>>>>>>> @@ -148,6 +170,8 @@ for.end:
>>>>>>>>> !0 = distinct !{!0, !1}
>>>>>>>>> !1 = !{!"llvm.loop.unroll.runtime.disable"}
>>>>>>>>> 
>>>>>>>>> -; CHECK: !0 = distinct !{!0, !1}
>>>>>>>>> -; CHECK: !1 = !{!"llvm.loop.unroll.disable"}
>>>>>>>>> +; EPILOG: !0 = distinct !{!0, !1}
>>>>>>>>> +; EPILOG: !1 = !{!"llvm.loop.unroll.disable"}
>>>>>>>>> 
>>>>>>>>> +; PROLOG: !0 = distinct !{!0, !1}
>>>>>>>>> +; PROLOG: !1 = !{!"llvm.loop.unroll.disable"}
>>>>>>>>> 
>>>>>>>>> Modified: llvm/trunk/test/Transforms/LoopUnroll/runtime-loop1.ll
>>>>>>>>> URL:
>>>>>>>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopUnroll/runtime-loop1.ll?rev=265388&r1=265387&r2=265388&view=diff
>>>>>>>>> ==============================================================================
>>>>>>>>> --- llvm/trunk/test/Transforms/LoopUnroll/runtime-loop1.ll (original)
>>>>>>>>> +++ llvm/trunk/test/Transforms/LoopUnroll/runtime-loop1.ll Tue Apr  5
>>>>>>>>> 07:19:35 2016
>>>>>>>>> @@ -1,19 +1,35 @@
>>>>>>>>> -; RUN: opt < %s -S -loop-unroll -unroll-runtime -unroll-count=2 | FileCheck
>>>>>>>>> %s
>>>>>>>>> +; RUN: opt < %s -S -loop-unroll -unroll-runtime -unroll-count=2 | FileCheck
>>>>>>>>> %s -check-prefix=EPILOG
>>>>>>>>> +; RUN: opt < %s -S -loop-unroll -unroll-runtime -unroll-count=2
>>>>>>>>> -unroll-runtime-epilog=false | FileCheck %s -check-prefix=PROLOG
>>>>>>>>> 
>>>>>>>>> ; This tests that setting the unroll count works
>>>>>>>>> 
>>>>>>>>> -; CHECK: for.body.preheader:
>>>>>>>>> -; CHECK:   br {{.*}} label %for.body.prol, label %for.body.preheader.split,
>>>>>>>>> !dbg [[PH_LOC:![0-9]+]]
>>>>>>>>> -; CHECK: for.body.prol:
>>>>>>>>> -; CHECK:   br label %for.body.preheader.split, !dbg [[BODY_LOC:![0-9]+]]
>>>>>>>>> -; CHECK: for.body.preheader.split:
>>>>>>>>> -; CHECK:   br {{.*}} label %for.end.loopexit, label
>>>>>>>>> %for.body.preheader.split.split, !dbg [[PH_LOC]]
>>>>>>>>> -; CHECK: for.body:
>>>>>>>>> -; CHECK:   br i1 %exitcond.1, label %for.end.loopexit.unr-lcssa, label
>>>>>>>>> %for.body, !dbg [[BODY_LOC]]
>>>>>>>>> -; CHECK-NOT: br i1 %exitcond.4, label %for.end.loopexit{{.*}}, label
>>>>>>>>> %for.body
>>>>>>>>> 
>>>>>>>>> -; CHECK-DAG: [[PH_LOC]] = !DILocation(line: 101, column: 1, scope: !{{.*}})
>>>>>>>>> -; CHECK-DAG: [[BODY_LOC]] = !DILocation(line: 102, column: 1, scope:
>>>>>>>>> !{{.*}})
>>>>>>>>> +; EPILOG: for.body.preheader:
>>>>>>>>> +; EPILOG:   br i1 %lcmp.mod, label %for.body.preheader.new, label
>>>>>>>>> %for.end.loopexit.unr-lcssa, !dbg [[PH_LOC:![0-9]+]]
>>>>>>>>> +; EPILOG: for.body:
>>>>>>>>> +; EPILOG:   br i1 %niter.ncmp.1, label
>>>>>>>>> %for.end.loopexit.unr-lcssa.loopexit, label %for.body, !dbg
>>>>>>>>> [[BODY_LOC:![0-9]+]]
>>>>>>>>> +; EPILOG-NOT: br i1 %niter.ncmp.2, label %for.end.loopexit{{.*}}, label
>>>>>>>>> %for.body
>>>>>>>>> +; EPILOG: for.body.epil.preheader:
>>>>>>>>> +; EPILOG:   br label %for.body.epil, !dbg [[EXIT_LOC:![0-9]+]]
>>>>>>>>> +; EPILOG: for.body.epil:
>>>>>>>>> +; EPILOG:   br label %for.end.loopexit.epilog-lcssa, !dbg
>>>>>>>>> [[BODY_LOC:![0-9]+]]
>>>>>>>>> +
>>>>>>>>> +; EPILOG-DAG: [[PH_LOC]] = !DILocation(line: 101, column: 1, scope:
>>>>>>>>> !{{.*}})
>>>>>>>>> +; EPILOG-DAG: [[BODY_LOC]] = !DILocation(line: 102, column: 1, scope:
>>>>>>>>> !{{.*}})
>>>>>>>>> +; EPILOG-DAG: [[EXIT_LOC]] = !DILocation(line: 103, column: 1, scope:
>>>>>>>>> !{{.*}})
>>>>>>>>> +
>>>>>>>>> +; PROLOG: for.body.preheader:
>>>>>>>>> +; PROLOG:   br {{.*}} label %for.body.prol.preheader, label
>>>>>>>>> %for.body.prol.loopexit, !dbg [[PH_LOC:![0-9]+]]
>>>>>>>>> +; PROLOG: for.body.prol:
>>>>>>>>> +; PROLOG:   br label %for.body.prol.loopexit, !dbg [[BODY_LOC:![0-9]+]]
>>>>>>>>> +; PROLOG: for.body.prol.loopexit:
>>>>>>>>> +; PROLOG:   br {{.*}} label %for.end.loopexit, label
>>>>>>>>> %for.body.preheader.new, !dbg [[PH_LOC]]
>>>>>>>>> +; PROLOG: for.body:
>>>>>>>>> +; PROLOG:   br i1 %exitcond.1, label %for.end.loopexit.unr-lcssa, label
>>>>>>>>> %for.body, !dbg [[BODY_LOC]]
>>>>>>>>> +; PROLOG-NOT: br i1 %exitcond.4, label %for.end.loopexit{{.*}}, label
>>>>>>>>> %for.body
>>>>>>>>> +
>>>>>>>>> +; PROLOG-DAG: [[PH_LOC]] = !DILocation(line: 101, column: 1, scope:
>>>>>>>>> !{{.*}})
>>>>>>>>> +; PROLOG-DAG: [[BODY_LOC]] = !DILocation(line: 102, column: 1, scope:
>>>>>>>>> !{{.*}})
>>>>>>>>> 
>>>>>>>>> define i32 @test(i32* nocapture %a, i32 %n) nounwind uwtable readonly !dbg
>>>>>>>>> !6 {
>>>>>>>>> entry:
>>>>>>>>> 
>>>>>>>>> Modified: llvm/trunk/test/Transforms/LoopUnroll/runtime-loop2.ll
>>>>>>>>> URL:
>>>>>>>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopUnroll/runtime-loop2.ll?rev=265388&r1=265387&r2=265388&view=diff
>>>>>>>>> ==============================================================================
>>>>>>>>> --- llvm/trunk/test/Transforms/LoopUnroll/runtime-loop2.ll (original)
>>>>>>>>> +++ llvm/trunk/test/Transforms/LoopUnroll/runtime-loop2.ll Tue Apr  5
>>>>>>>>> 07:19:35 2016
>>>>>>>>> @@ -1,12 +1,18 @@
>>>>>>>>> -; RUN: opt < %s -S -loop-unroll -unroll-threshold=25 -unroll-runtime
>>>>>>>>> -unroll-count=8 | FileCheck %s
>>>>>>>>> +; RUN: opt < %s -S -loop-unroll -unroll-threshold=25 -unroll-runtime
>>>>>>>>> -unroll-count=8 | FileCheck %s  -check-prefix=EPILOG
>>>>>>>>> +; RUN: opt < %s -S -loop-unroll -unroll-threshold=25 -unroll-runtime
>>>>>>>>> -unroll-runtime-epilog=false | FileCheck %s -check-prefix=PROLOG
>>>>>>>>> 
>>>>>>>>> ; Choose a smaller, power-of-two, unroll count if the loop is too large.
>>>>>>>>> ; This test makes sure we're not unrolling 'odd' counts
>>>>>>>>> 
>>>>>>>>> -; CHECK: for.body.prol:
>>>>>>>>> -; CHECK: for.body:
>>>>>>>>> -; CHECK: br i1 %exitcond.3, label %for.end.loopexit{{.*}}, label %for.body
>>>>>>>>> -; CHECK-NOT: br i1 %exitcond.4, label %for.end.loopexit{{.*}}, label
>>>>>>>>> %for.body
>>>>>>>>> +; EPILOG: for.body:
>>>>>>>>> +; EPILOG: br i1 %niter.ncmp.3, label
>>>>>>>>> %for.end.loopexit.unr-lcssa.loopexit{{.*}}, label %for.body
>>>>>>>>> +; EPILOG-NOT: br i1 %niter.ncmp.4, label
>>>>>>>>> %for.end.loopexit.unr-lcssa.loopexit{{.*}}, label %for.body
>>>>>>>>> +; EPILOG: for.body.epil:
>>>>>>>>> +
>>>>>>>>> +; PROLOG: for.body.prol:
>>>>>>>>> +; PROLOG: for.body:
>>>>>>>>> +; PROLOG: br i1 %exitcond.3, label %for.end.loopexit{{.*}}, label %for.body
>>>>>>>>> +; PROLOG-NOT: br i1 %exitcond.4, label %for.end.loopexit{{.*}}, label
>>>>>>>>> %for.body
>>>>>>>>> 
>>>>>>>>> define i32 @test(i32* nocapture %a, i32 %n) nounwind uwtable readonly {
>>>>>>>>> entry:
>>>>>>>>> 
>>>>>>>>> Modified: llvm/trunk/test/Transforms/LoopUnroll/runtime-loop4.ll
>>>>>>>>> URL:
>>>>>>>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopUnroll/runtime-loop4.ll?rev=265388&r1=265387&r2=265388&view=diff
>>>>>>>>> ==============================================================================
>>>>>>>>> --- llvm/trunk/test/Transforms/LoopUnroll/runtime-loop4.ll (original)
>>>>>>>>> +++ llvm/trunk/test/Transforms/LoopUnroll/runtime-loop4.ll Tue Apr  5
>>>>>>>>> 07:19:35 2016
>>>>>>>>> @@ -1,13 +1,21 @@
>>>>>>>>> -; RUN: opt < %s -S -O2 -unroll-runtime=true | FileCheck %s
>>>>>>>>> +; RUN: opt < %s -S -O2 -unroll-runtime=true | FileCheck %s
>>>>>>>>> -check-prefix=EPILOG
>>>>>>>>> +; RUN: opt < %s -S -O2 -unroll-runtime=true -unroll-runtime-epilog=false |
>>>>>>>>> FileCheck %s -check-prefix=PROLOG
>>>>>>>>> 
>>>>>>>>> ; Check runtime unrolling prologue can be promoted by LICM pass.
>>>>>>>>> 
>>>>>>>>> -; CHECK: entry:
>>>>>>>>> -; CHECK: %xtraiter
>>>>>>>>> -; CHECK: %lcmp.mod
>>>>>>>>> -; CHECK: loop1:
>>>>>>>>> -; CHECK: br i1 %lcmp.mod
>>>>>>>>> -; CHECK: loop2.prol:
>>>>>>>>> +; EPILOG: entry:
>>>>>>>>> +; EPILOG: %xtraiter
>>>>>>>>> +; EPILOG: %lcmp.mod
>>>>>>>>> +; EPILOG: loop1:
>>>>>>>>> +; EPILOG: br i1 %lcmp.mod
>>>>>>>>> +; EPILOG: loop2.epil:
>>>>>>>>> +
>>>>>>>>> +; PROLOG: entry:
>>>>>>>>> +; PROLOG: %xtraiter
>>>>>>>>> +; PROLOG: %lcmp.mod
>>>>>>>>> +; PROLOG: loop1:
>>>>>>>>> +; PROLOG: br i1 %lcmp.mod
>>>>>>>>> +; PROLOG: loop2.prol:
>>>>>>>>> 
>>>>>>>>> define void @unroll(i32 %iter, i32* %addr1, i32* %addr2) nounwind {
>>>>>>>>> entry:
>>>>>>>>> 
>>>>>>>>> Modified: llvm/trunk/test/Transforms/LoopUnroll/runtime-loop5.ll
>>>>>>>>> URL:
>>>>>>>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopUnroll/runtime-loop5.ll?rev=265388&r1=265387&r2=265388&view=diff
>>>>>>>>> ==============================================================================
>>>>>>>>> --- llvm/trunk/test/Transforms/LoopUnroll/runtime-loop5.ll (original)
>>>>>>>>> +++ llvm/trunk/test/Transforms/LoopUnroll/runtime-loop5.ll Tue Apr  5
>>>>>>>>> 07:19:35 2016
>>>>>>>>> @@ -11,9 +11,6 @@ entry:
>>>>>>>>> %cmp1 = icmp eq i3 %n, 0
>>>>>>>>> br i1 %cmp1, label %for.end, label %for.body
>>>>>>>>> 
>>>>>>>>> -; UNROLL-16-NOT: for.body.prol:
>>>>>>>>> -; UNROLL-4: for.body.prol:
>>>>>>>>> -
>>>>>>>>> for.body:                                         ; preds = %for.body,
>>>>>>>>> %entry
>>>>>>>>> ; UNROLL-16-LABEL: for.body:
>>>>>>>>> ; UNROLL-4-LABEL: for.body:
>>>>>>>>> @@ -39,6 +36,10 @@ for.body:
>>>>>>>>> 
>>>>>>>>> ; UNROLL-16-LABEL: for.end
>>>>>>>>> ; UNROLL-4-LABEL: for.end
>>>>>>>>> +
>>>>>>>>> +; UNROLL-16-NOT: for.body.epil:
>>>>>>>>> +; UNROLL-4: for.body.epil:
>>>>>>>>> +
>>>>>>>>> for.end:                                          ; preds = %for.body,
>>>>>>>>> %entry
>>>>>>>>> %sum.0.lcssa = phi i3 [ 0, %entry ], [ %add, %for.body ]
>>>>>>>>> ret i3 %sum.0.lcssa
>>>>>>>>> 
>>>>>>>>> Modified: llvm/trunk/test/Transforms/LoopUnroll/tripcount-overflow.ll
>>>>>>>>> URL:
>>>>>>>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopUnroll/tripcount-overflow.ll?rev=265388&r1=265387&r2=265388&view=diff
>>>>>>>>> ==============================================================================
>>>>>>>>> --- llvm/trunk/test/Transforms/LoopUnroll/tripcount-overflow.ll (original)
>>>>>>>>> +++ llvm/trunk/test/Transforms/LoopUnroll/tripcount-overflow.ll Tue Apr  5
>>>>>>>>> 07:19:35 2016
>>>>>>>>> @@ -13,13 +13,13 @@ target datalayout = "e-m:o-i64:64-f80:12
>>>>>>>>> ; CHECK: entry:
>>>>>>>>> ; CHECK-NEXT: %0 = add i32 %N, 1
>>>>>>>>> ; CHECK-NEXT: %xtraiter = and i32 %0, 1
>>>>>>>>> -; CHECK-NEXT: %lcmp.mod = icmp ne i32 %xtraiter, 0
>>>>>>>>> -; CHECK-NEXT: br i1 %lcmp.mod, label %while.body.prol, label %entry.split
>>>>>>>>> +; CHECK-NEXT: %lcmp.mod = icmp ne i32 %xtraiter, %0
>>>>>>>>> +; CHECK-NEXT: br i1 %lcmp.mod, label %entry.new, label %while.end.unr-lcssa
>>>>>>>>> 
>>>>>>>>> -; CHECK: while.body.prol:
>>>>>>>>> -; CHECK: br label %entry.split
>>>>>>>>> +; CHECK: while.body.epil:
>>>>>>>>> +; CHECK: br label %while.end.epilog-lcssa
>>>>>>>>> 
>>>>>>>>> -; CHECK: entry.split:
>>>>>>>>> +; CHECK: while.end.epilog-lcssa:
>>>>>>>>> 
>>>>>>>>> ; Function Attrs: nounwind readnone ssp uwtable
>>>>>>>>> define i32 @foo(i32 %N) {
>>>>>>>>> 
>>>>>>>>> Modified: llvm/trunk/test/Transforms/LoopUnroll/unroll-cleanup.ll
>>>>>>>>> URL:
>>>>>>>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopUnroll/unroll-cleanup.ll?rev=265388&r1=265387&r2=265388&view=diff
>>>>>>>>> ==============================================================================
>>>>>>>>> --- llvm/trunk/test/Transforms/LoopUnroll/unroll-cleanup.ll (original)
>>>>>>>>> +++ llvm/trunk/test/Transforms/LoopUnroll/unroll-cleanup.ll Tue Apr  5
>>>>>>>>> 07:19:35 2016
>>>>>>>>> @@ -4,14 +4,14 @@
>>>>>>>>> ; RUN: opt < %s -O2 -S | FileCheck %s
>>>>>>>>> 
>>>>>>>>> ; After loop unroll:
>>>>>>>>> -;       %dec18 = add nsw i32 %dec18.in, -1
>>>>>>>>> +;       %niter.nsub = add nsw i32 %niter, -1
>>>>>>>>> ;       ...
>>>>>>>>> -;       %dec18.1 = add nsw i32 %dec18, -1
>>>>>>>>> +;       %niter.nsub.1 = add nsw i32 %niter.nsub, -1
>>>>>>>>> ; should be merged to:
>>>>>>>>> -;       %dec18.1 = add nsw i32 %dec18.in, -2
>>>>>>>>> +;       %dec18.1 = add nsw i32 %niter, -2
>>>>>>>>> ;
>>>>>>>>> ; CHECK-LABEL: @_Z3fn1v(
>>>>>>>>> -; CHECK: %dec18.1 = add nsw i32 %dec18.in, -2
>>>>>>>>> +; CHECK: %niter.nsub.1 = add i32 %niter, -2
>>>>>>>>> 
>>>>>>>>> ; ModuleID = '<stdin>'
>>>>>>>>> target triple = "x86_64-unknown-linux-gnu"
>>>>>>>>> 
>>>>>>>>> Modified: llvm/trunk/test/Transforms/LoopUnroll/unroll-pragmas.ll
>>>>>>>>> URL:
>>>>>>>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopUnroll/unroll-pragmas.ll?rev=265388&r1=265387&r2=265388&view=diff
>>>>>>>>> ==============================================================================
>>>>>>>>> --- llvm/trunk/test/Transforms/LoopUnroll/unroll-pragmas.ll (original)
>>>>>>>>> +++ llvm/trunk/test/Transforms/LoopUnroll/unroll-pragmas.ll Tue Apr  5
>>>>>>>>> 07:19:35 2016
>>>>>>>>> @@ -171,10 +171,6 @@ for.end:
>>>>>>>>> ; should be duplicated (original and 4x unrolled).
>>>>>>>>> ;
>>>>>>>>> ; CHECK-LABEL: @runtime_loop_with_count4(
>>>>>>>>> -; CHECK: for.body.prol:
>>>>>>>>> -; CHECK: store
>>>>>>>>> -; CHECK-NOT: store
>>>>>>>>> -; CHECK: br i1
>>>>>>>>> ; CHECK: for.body
>>>>>>>>> ; CHECK: store
>>>>>>>>> ; CHECK: store
>>>>>>>>> @@ -182,6 +178,10 @@ for.end:
>>>>>>>>> ; CHECK: store
>>>>>>>>> ; CHECK-NOT: store
>>>>>>>>> ; CHECK: br i1
>>>>>>>>> +; CHECK: for.body.epil:
>>>>>>>>> +; CHECK: store
>>>>>>>>> +; CHECK-NOT: store
>>>>>>>>> +; CHECK: br i1
>>>>>>>>> define void @runtime_loop_with_count4(i32* nocapture %a, i32 %b) {
>>>>>>>>> entry:
>>>>>>>>> %cmp3 = icmp sgt i32 %b, 0
>>>>>>>>> @@ -287,10 +287,6 @@ for.end:
>>>>>>>>> ; (original and 8x).
>>>>>>>>> ;
>>>>>>>>> ; CHECK-LABEL: @runtime_loop_with_enable(
>>>>>>>>> -; CHECK: for.body.prol:
>>>>>>>>> -; CHECK: store
>>>>>>>>> -; CHECK-NOT: store
>>>>>>>>> -; CHECK: br i1
>>>>>>>>> ; CHECK: for.body:
>>>>>>>>> ; CHECK: store i32
>>>>>>>>> ; CHECK: store i32
>>>>>>>>> @@ -302,6 +298,10 @@ for.end:
>>>>>>>>> ; CHECK: store i32
>>>>>>>>> ; CHECK-NOT: store i32
>>>>>>>>> ; CHECK: br i1
>>>>>>>>> +; CHECK: for.body.epil:
>>>>>>>>> +; CHECK: store
>>>>>>>>> +; CHECK-NOT: store
>>>>>>>>> +; CHECK: br i1
>>>>>>>>> define void @runtime_loop_with_enable(i32* nocapture %a, i32 %b) {
>>>>>>>>> entry:
>>>>>>>>> %cmp3 = icmp sgt i32 %b, 0
>>>>>>>>> @@ -328,16 +328,16 @@ for.end:
>>>>>>>>> ; should be duplicated (original and 3x unrolled).
>>>>>>>>> ;
>>>>>>>>> ; CHECK-LABEL: @runtime_loop_with_count3(
>>>>>>>>> -; CHECK: for.body.prol:
>>>>>>>>> -; CHECK: store
>>>>>>>>> -; CHECK-NOT: store
>>>>>>>>> -; CHECK: br i1
>>>>>>>>> ; CHECK: for.body
>>>>>>>>> ; CHECK: store
>>>>>>>>> ; CHECK: store
>>>>>>>>> ; CHECK: store
>>>>>>>>> ; CHECK-NOT: store
>>>>>>>>> ; CHECK: br i1
>>>>>>>>> +; CHECK: for.body.epil:
>>>>>>>>> +; CHECK: store
>>>>>>>>> +; CHECK-NOT: store
>>>>>>>>> +; CHECK: br i1
>>>>>>>>> define void @runtime_loop_with_count3(i32* nocapture %a, i32 %b) {
>>>>>>>>> entry:
>>>>>>>>> %cmp3 = icmp sgt i32 %b, 0
>>>>>>>>> 
>>>>>>>>> 
>>>>>>>>> _______________________________________________
>>>>>>>>> llvm-commits mailing list
>>>>>>>>> llvm-commits at lists.llvm.org
>>>>>>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>>>>>>>>> 
>>>>>>>>> 
>>>>>>>>> _______________________________________________
>>>>>>>>> llvm-commits mailing list
>>>>>>>>> llvm-commits at lists.llvm.org
>>>>>>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>>>>>>>>> 
>>>>>>>>> 
>>>>>>> 
>>>>>> 
>>>> 
>> 



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