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

Mikhail Zolotukhin via llvm-commits llvm-commits at lists.llvm.org
Tue Aug 2 14:34:00 PDT 2016


> On Jul 25, 2016, at 5:15 PM, Gerolf Hoflehner <ghoflehner at apple.com> wrote:
> 
>> 
>> On Jul 25, 2016, at 3:53 PM, Michael Zolotukhin via llvm-commits <llvm-commits at lists.llvm.org <mailto:llvm-commits at lists.llvm.org>> wrote:
>> 
>> 
>>> On Jul 24, 2016, at 3:10 AM, Evgeny Stupachenko <evstupac at gmail.com <mailto: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?
> +1
> I think this is the right approach dealing with big regressions.
Hi Evgeny,

I switched the flag to 'false' in r277524 and adjusted the tests accordingly. Please feel free to reenable it back once the regression is addressed.

Thanks,
Michael
> 
>>> 
>>> 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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