[SCEV][reland] More precise trip multiples

[caojoshua]

Summary

We currently have getMinTrailingZeros(), from which we can get a SCEV's
multiple by computing 1 << MinTrailingZeroes. However, this only gets us
multiples that are a power of 2. This patch introduces a way to get max
constant multiples that are not just a power of 2. The logic is similar
to that of getMinTrailingZeros. getMinTrailingZerosImpl is replaced by
computing the max constant multiple, and counting the number of trailing
bits.

I have so far found this useful in two places:

1. Computing unsigned constant ranges. For example, if we have i8 {10,+,10}<nuw>, we know the max constant it can be is 250.

2. My original intent was to use this in getSmallConstantTripMultiples, but it has no effect right now due to change from D110587. For example, if we have backedge count (6 * %N) - 1, the trip count becomes 1 + zext((6 * %N) - 1), and we cannot say that 6 is a multiple of the SCEV. I plan to look further into this separately.

The implementation assumes the value is unsigned. It can probably be
extended to handle signed values as well.

If the code sees that a SCEV does not have <nuw>, it will fall back to
finding the max multiple that is a power of 2. Multiples that are a
power of 2 will still be a multiple even after the SCEV overflows. This
does not apply to other values. This is the 1st commit message:

---

This relands https://reviews.llvm.org/D141823. The verification fails
when expensive checks are turned on. This can occur when:

1. SCEV S's multiple is cached
2. SCEV S's no wrap flags are strengthened, and the multiple changes
3. SCEV verifier finds that S's cached and recomputed multiple are different

We eliminate most cases by forgetting SCEVAddRecExpr's cached values
when the flags are modified, but there are still cases for other SCEV
types. We relax the check by making sure the cached multiple divides the
recomputed multiple, ensuring the cached multiple is correct,
conservative multiple.

[caojoshua]

An interesting non-SCEVAddRecExpr case that failures the verification is IndVarSimplify/udiv.ll. In verification, we try to compute the multiple of (8193 smax {6,+,3}<nuw><%for.body15>), which is 3. When originally caching the value for the SCEV, we had (8193 smax {6,+,3}<%for.body15>), which due to the lack of nuw, has a multiple of 1.

The only write operation to a SCEV that can affect its multiple is its wrap flags, or the wrap flags of its operands. The operands themselves never change. If only the flags change, the originally cached multiple should divide the recomputed multiple.

These cases are rare, and I'd say its ok for the cached multiple to not always be the best answer, and sometimes be a conservative answer.

[caojoshua]

fix typo

[mkazantsev]

Do we know if we can forget smth when strenghtening flags without harming the compile time to get the more precise resutlt in these cases?

[caojoshua]

In D149529#4320986, @mkazantsev wrote:

Do we know if we can forget smth when strenghtening flags without harming the compile time to get the more precise resutlt in these cases?

In this patch we forget it specifically for getRecAddExpr's, which accounts for most use cases and should not be expensive. For other less common use cases, forgetting would be too expensive. In the example I have above:

An interesting non-SCEVAddRecExpr case that failures the verification is IndVarSimplify/udiv.ll. In verification, we try to compute the multiple of (8193 smax {6,+,3}<nuw><%for.body15>), which is 3. When originally caching the value for the SCEV, we had (8193 smax {6,+,3}<%for.body15>), which due to the lack of nuw, has a multiple of 1.

When we add the addition, we would need to forget the addition and all uses of the addition as well, which is the smax in this case. In worse case, there can be long chains of SCEV users that would need to be forgotten. I'd say its too compile-time expensive for very little benefit.

[uabelho]

Hello,

The following starts crashing with this commit:

opt -disable-loop-unrolling -verify-scev -passes="module(default<Os>)" bbi-83087.ll -o /dev/null

It crashes with

opt: ../lib/Support/APInt.cpp:1667: llvm::APInt llvm::APInt::urem(const llvm::APInt &) const: Assertion `RHS.U.VAL != 0 && "Remainder by zero?"' failed.
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0.	Program arguments: ../../main-github/llvm/build-all/bin/opt -disable-loop-unrolling -verify-scev -passes=module(default<Os>) bbi-83087.ll -o /dev/null
 #0 0x0000561a0f6c6ec7 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (../../main-github/llvm/build-all/bin/opt+0x2d8eec7)
 #1 0x0000561a0f6c4bee llvm::sys::RunSignalHandlers() (../../main-github/llvm/build-all/bin/opt+0x2d8cbee)
 #2 0x0000561a0f6c755f SignalHandler(int) (../../main-github/llvm/build-all/bin/opt+0x2d8f55f)
 #3 0x00007f0da7660630 __restore_rt (/lib64/libpthread.so.0+0xf630)
 #4 0x00007f0da4da7387 raise (/lib64/libc.so.6+0x36387)
 #5 0x00007f0da4da8a78 abort (/lib64/libc.so.6+0x37a78)
 #6 0x00007f0da4da01a6 __assert_fail_base (/lib64/libc.so.6+0x2f1a6)
 #7 0x00007f0da4da0252 (/lib64/libc.so.6+0x2f252)
 #8 0x0000561a0f61d076 llvm::APInt::urem(llvm::APInt const&) const (../../main-github/llvm/build-all/bin/opt+0x2ce5076)
 #9 0x0000561a0e87bcb8 llvm::ScalarEvolution::verify() const (../../main-github/llvm/build-all/bin/opt+0x1f43cb8)
#10 0x0000561a101f6d06 llvm::FunctionToLoopPassAdaptor::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (../../main-github/llvm/build-all/bin/opt+0x38bed06)
#11 0x0000561a0f8e7d5d llvm::detail::PassModel<llvm::Function, llvm::FunctionToLoopPassAdaptor, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::Function> >::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (../../main-github/llvm/build-all/bin/opt+0x2fafd5d)
#12 0x0000561a0f0a5e84 llvm::PassManager<llvm::Function, llvm::AnalysisManager<llvm::Function> >::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (../../main-github/llvm/build-all/bin/opt+0x276de84)
#13 0x0000561a0d55aa3d llvm::detail::PassModel<llvm::Function, llvm::PassManager<llvm::Function, llvm::AnalysisManager<llvm::Function> >, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::Function> >::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (../../main-github/llvm/build-all/bin/opt+0xc22a3d)
#14 0x0000561a0e677c0f llvm::CGSCCToFunctionPassAdaptor::run(llvm::LazyCallGraph::SCC&, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>&, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&) (../../main-github/llvm/build-all/bin/opt+0x1d3fc0f)
#15 0x0000561a0d55c5cd llvm::detail::PassModel<llvm::LazyCallGraph::SCC, llvm::CGSCCToFunctionPassAdaptor, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&>::run(llvm::LazyCallGraph::SCC&, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>&, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&) (../../main-github/llvm/build-all/bin/opt+0xc245cd)
#16 0x0000561a0e6724be llvm::PassManager<llvm::LazyCallGraph::SCC, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&>::run(llvm::LazyCallGraph::SCC&, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>&, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&) (../../main-github/llvm/build-all/bin/opt+0x1d3a4be)
#17 0x0000561a0f8d032d llvm::detail::PassModel<llvm::LazyCallGraph::SCC, llvm::PassManager<llvm::LazyCallGraph::SCC, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&>, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&>::run(llvm::LazyCallGraph::SCC&, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>&, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&) (../../main-github/llvm/build-all/bin/opt+0x2f9832d)
#18 0x0000561a0e675dd5 llvm::DevirtSCCRepeatedPass::run(llvm::LazyCallGraph::SCC&, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>&, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&) (../../main-github/llvm/build-all/bin/opt+0x1d3ddd5)
#19 0x0000561a0f8e9d5d llvm::detail::PassModel<llvm::LazyCallGraph::SCC, llvm::DevirtSCCRepeatedPass, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&>::run(llvm::LazyCallGraph::SCC&, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>&, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&) (../../main-github/llvm/build-all/bin/opt+0x2fb1d5d)
#20 0x0000561a0e6744ca llvm::ModuleToPostOrderCGSCCPassAdaptor::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (../../main-github/llvm/build-all/bin/opt+0x1d3c4ca)
#21 0x0000561a0f8d05cd llvm::detail::PassModel<llvm::Module, llvm::ModuleToPostOrderCGSCCPassAdaptor, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::Module> >::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (../../main-github/llvm/build-all/bin/opt+0x2f985cd)
#22 0x0000561a0f0a5014 llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module> >::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (../../main-github/llvm/build-all/bin/opt+0x276d014)
#23 0x0000561a0f9f437d llvm::ModuleInlinerWrapperPass::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (../../main-github/llvm/build-all/bin/opt+0x30bc37d)
#24 0x0000561a0f8d6e8d llvm::detail::PassModel<llvm::Module, llvm::ModuleInlinerWrapperPass, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::Module> >::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (../../main-github/llvm/build-all/bin/opt+0x2f9ee8d)
#25 0x0000561a0f0a5014 llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module> >::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (../../main-github/llvm/build-all/bin/opt+0x276d014)
#26 0x0000561a0d196e8e llvm::runPassPipeline(llvm::StringRef, llvm::Module&, llvm::TargetMachine*, llvm::TargetLibraryInfoImpl*, llvm::ToolOutputFile*, llvm::ToolOutputFile*, llvm::ToolOutputFile*, llvm::StringRef, llvm::ArrayRef<llvm::PassPlugin>, llvm::opt_tool::OutputKind, llvm::opt_tool::VerifierKind, bool, bool, bool, bool, bool, bool) (../../main-github/llvm/build-all/bin/opt+0x85ee8e)
#27 0x0000561a0d1a555e main (../../main-github/llvm/build-all/bin/opt+0x86d55e)
#28 0x00007f0da4d93555 __libc_start_main (/lib64/libc.so.6+0x22555)
#29 0x0000561a0d1915e0 _start (../../main-github/llvm/build-all/bin/opt+0x8595e0)
Abort (core dumped)

bbi-83087.ll3 KBDownload

[uabelho]

Ping @caojoshua

llvm/lib/Analysis/ScalarEvolution.cpp

14326

It's this urem call that crashes in the comment I made yesterday.

Multiple is 0 and doing urem with RHS being 0 hits the assertion since dividing by 0 isn't good.

Are we perhaps missing a negation of the condition

(Multiple == 0 || RecomputedMultiple == 0)

?
Now we do the urem(Multiple) specifically if Multiple is 0, which we should avoid.

[caojoshua]

llvm/lib/Analysis/ScalarEvolution.cpp

14326

Its due to returning a zero from too many trailing zeros. I am going to rewrite this a bit, it should be verifying on getNonZeroConstantMultiple().

I am going to run this through expensive checks.

[caojoshua]

llvm/lib/Analysis/ScalarEvolution.cpp

14326

Correction: I looked at things wrong. The current verification requires that recomputed multiples are stronger than previous multiples, but that is not the case here. It turns out a multiple can become weaker if due to dependence on ComputeKnownBits(). As the IR transforms, its possible that ComputeKnownBits() becomes weaker due to limitations in depth.

I have local changes that relaxes the verification and passes the provided test case. Testing with expensive checks takes a long time on my machine and I won't be able to push today.

[caojoshua]

llvm/lib/Analysis/ScalarEvolution.cpp

14326

Issue fixed by https://github.com/llvm/llvm-project/commit/ff471dcf7669b1ad7903a44d0773bef4eb175eb9

llvm/include/llvm/Analysis/ScalarEvolution.h

public:
   void forgetBlockAndLoopDispositions(Value *V = nullptr);
 
   /// Determine the minimum number of zero bits that S is guaranteed to end in
   /// (at every loop iteration).  It is, at the same time, the minimum number
   /// of times S is divisible by 2.  For example, given {4,+,8} it returns 2.
   /// If S is guaranteed to be 0, it returns the bitwidth of S.
   uint32_t getMinTrailingZeros(const SCEV *S);
 
+  /// Returns the max constant multiple of S.
+  APInt getConstantMultiple(const SCEV *S);
+
+  // Returns the max constant multiple of S. If S is exactly 0, return 1.
+  APInt getNonZeroConstantMultiple(const SCEV *S);
+
   /// Determine the unsigned range for a particular SCEV.
   /// NOTE: This returns a copy of the reference returned by getRangeRef.
   ConstantRange getUnsignedRange(const SCEV *S) {
     return getRangeRef(S, HINT_RANGE_UNSIGNED);
   }
 
   /// Determine the min of the unsigned range for a particular SCEV.
   APInt getUnsignedRangeMin(const SCEV *S) {
private:
   /// Set to true by isLoopBackedgeGuardedByCond when we're walking the set of
   /// conditions dominating the backedge of a loop.
   bool WalkingBEDominatingConds = false;
 
   /// Set to true by isKnownPredicateViaSplitting when we're trying to prove a
   /// predicate by splitting it into a set of independent predicates.
   bool ProvingSplitPredicate = false;
 
-  /// Memoized values for the GetMinTrailingZeros
-  DenseMap<const SCEV *, uint32_t> MinTrailingZerosCache;
+  /// Memoized values for the getConstantMultiple
+  DenseMap<const SCEV *, APInt> ConstantMultipleCache;
 
   /// Return the Value set from which the SCEV expr is generated.
   ArrayRef<Value *> getSCEVValues(const SCEV *S);
 
-  /// Private helper method for the GetMinTrailingZeros method
-  uint32_t getMinTrailingZerosImpl(const SCEV *S);
+  /// Private helper method for the getConstantMultiple method.
+  APInt getConstantMultipleImpl(const SCEV *S);
 
   /// Information about the number of times a particular loop exit may be
   /// reached before exiting the loop.
   struct ExitNotTakenInfo {
     PoisoningVH<BasicBlock> ExitingBlock;
     const SCEV *ExactNotTaken;
     const SCEV *ConstantMaxNotTaken;
     const SCEV *SymbolicMaxNotTaken;

llvm/lib/Analysis/ScalarEvolution.cpp

assert(GEP->getSourceElementType()->isSized() &&
          "GEP source element type must be sized");
 
   SmallVector<const SCEV *, 4> IndexExprs;
   for (Value *Index : GEP->indices())
     IndexExprs.push_back(getSCEV(Index));
   return getGEPExpr(GEP, IndexExprs);
 }
 
-uint32_t ScalarEvolution::getMinTrailingZerosImpl(const SCEV *S) {
+APInt ScalarEvolution::getConstantMultipleImpl(const SCEV *S) {
+  uint64_t BitWidth = getTypeSizeInBits(S->getType());
+  auto GetShiftedByZeros = [BitWidth](uint32_t TrailingZeros) {
+    return TrailingZeros >= BitWidth
+               ? APInt::getZero(BitWidth)
+               : APInt::getOneBitSet(BitWidth, TrailingZeros);
+  };
+  auto GetGCDMultiple = [this](const SCEVNAryExpr *N) {
+    // The result is GCD of all operands results.
+    APInt Res = getConstantMultiple(N->getOperand(0));
+    for (unsigned I = 1, E = N->getNumOperands(); I < E && Res != 1; ++I)
+      Res = APIntOps::GreatestCommonDivisor(
+          Res, getConstantMultiple(N->getOperand(I)));
+    return Res;
+  };
+
   switch (S->getSCEVType()) {
   case scConstant:
-    return cast<SCEVConstant>(S)->getAPInt().countr_zero();
+    return cast<SCEVConstant>(S)->getAPInt();
+  case scPtrToInt:
+    return getConstantMultiple(cast<SCEVPtrToIntExpr>(S)->getOperand());
+  case scUDivExpr:
+  case scVScale:
+    return APInt(BitWidth, 1);
   case scTruncate: {
+    // Only multiples that are a power of 2 will hold after truncation.
     const SCEVTruncateExpr *T = cast<SCEVTruncateExpr>(S);
-    return std::min(getMinTrailingZeros(T->getOperand()),
-                    (uint32_t)getTypeSizeInBits(T->getType()));
+    uint32_t TZ = getMinTrailingZeros(T->getOperand());
+    return GetShiftedByZeros(TZ);
+  }
+  case scZeroExtend: {
+    const SCEVZeroExtendExpr *Z = cast<SCEVZeroExtendExpr>(S);
+    return getConstantMultiple(Z->getOperand()).zext(BitWidth);
   }
-  case scZeroExtend:
   case scSignExtend: {
-    const SCEVIntegralCastExpr *E = cast<SCEVIntegralCastExpr>(S);
-    uint32_t OpRes = getMinTrailingZeros(E->getOperand());
-    return OpRes == getTypeSizeInBits(E->getOperand()->getType())
-               ? getTypeSizeInBits(E->getType())
-               : OpRes;
+    const SCEVSignExtendExpr *E = cast<SCEVSignExtendExpr>(S);
+    return getConstantMultiple(E->getOperand()).sext(BitWidth);
   }
   case scMulExpr: {
     const SCEVMulExpr *M = cast<SCEVMulExpr>(S);
-    // The result is the sum of all operands results.
-    uint32_t SumOpRes = getMinTrailingZeros(M->getOperand(0));
-    uint32_t BitWidth = getTypeSizeInBits(M->getType());
-    for (unsigned I = 1, E = M->getNumOperands();
-         SumOpRes != BitWidth && I != E; ++I)
-      SumOpRes =
-          std::min(SumOpRes + getMinTrailingZeros(M->getOperand(I)), BitWidth);
-    return SumOpRes;
+    if (M->hasNoUnsignedWrap()) {
+      // The result is the product of all operand results.
+      APInt Res = getConstantMultiple(M->getOperand(0));
+      for (const SCEV *Operand : M->operands().drop_front())
+        Res = Res * getConstantMultiple(Operand);
+      return Res;
+    }
+
+    // If there are no wrap guarentees, find the trailing zeros, which is the
+    // sum of trailing zeros for all its operands.
+    uint32_t TZ = 0;
+    for (const SCEV *Operand : M->operands())
+      TZ += getMinTrailingZeros(Operand);
+    return GetShiftedByZeros(TZ);
   }
-  case scVScale:
-    return 0;
-  case scUDivExpr:
-    return 0;
-  case scPtrToInt:
   case scAddExpr:
-  case scAddRecExpr:
+  case scAddRecExpr: {
+    const SCEVNAryExpr *N = cast<SCEVNAryExpr>(S);
+    if (N->hasNoUnsignedWrap())
+        return GetGCDMultiple(N);
+    // Find the trailing bits, which is the minimum of its operands.
+    uint32_t TZ = getMinTrailingZeros(N->getOperand(0));
+    for (const SCEV *Operand : N->operands().drop_front())
+      TZ = std::min(TZ, getMinTrailingZeros(Operand));
+    return GetShiftedByZeros(TZ);
+  }
   case scUMaxExpr:
   case scSMaxExpr:
   case scUMinExpr:
   case scSMinExpr:
-  case scSequentialUMinExpr: {
-    // The result is the min of all operands results.
-    ArrayRef<const SCEV *> Ops = S->operands();
-    uint32_t MinOpRes = getMinTrailingZeros(Ops[0]);
-    for (unsigned I = 1, E = Ops.size(); MinOpRes && I != E; ++I)
-      MinOpRes = std::min(MinOpRes, getMinTrailingZeros(Ops[I]));
-    return MinOpRes;
-  }
+  case scSequentialUMinExpr:
+    return GetGCDMultiple(cast<SCEVNAryExpr>(S));
   case scUnknown: {
+    // ask ValueTracking for known bits
     const SCEVUnknown *U = cast<SCEVUnknown>(S);
-    // For a SCEVUnknown, ask ValueTracking.
-    KnownBits Known =
-        computeKnownBits(U->getValue(), getDataLayout(), 0, &AC, nullptr, &DT);
-    return Known.countMinTrailingZeros();
+    unsigned Known =
+        computeKnownBits(U->getValue(), getDataLayout(), 0, &AC, nullptr, &DT)
+            .countMinTrailingZeros();
+    return GetShiftedByZeros(Known);
   }
   case scCouldNotCompute:
     llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!");
   }
   llvm_unreachable("Unknown SCEV kind!");
 }
 
-uint32_t ScalarEvolution::getMinTrailingZeros(const SCEV *S) {
-  auto I = MinTrailingZerosCache.find(S);
-  if (I != MinTrailingZerosCache.end())
+APInt ScalarEvolution::getConstantMultiple(const SCEV *S) {
+  auto I = ConstantMultipleCache.find(S);
+  if (I != ConstantMultipleCache.end())
     return I->second;
 
-  uint32_t Result = getMinTrailingZerosImpl(S);
-  auto InsertPair = MinTrailingZerosCache.insert({S, Result});
+  APInt Result = getConstantMultipleImpl(S);
+  auto InsertPair = ConstantMultipleCache.insert({S, Result});
   assert(InsertPair.second && "Should insert a new key");
   return InsertPair.first->second;
 }
 
+APInt ScalarEvolution::getNonZeroConstantMultiple(const SCEV *S) {
+  APInt Multiple = getConstantMultiple(S);
+  return Multiple == 0 ? APInt(Multiple.getBitWidth(), 1) : Multiple;
+}
+
+uint32_t ScalarEvolution::getMinTrailingZeros(const SCEV *S) {
+  return std::min(getConstantMultiple(S).countTrailingZeros(),
+                  (unsigned)getTypeSizeInBits(S->getType()));
+}
+
 /// Helper method to assign a range to V from metadata present in the IR.
 static std::optional<ConstantRange> GetRangeFromMetadata(Value *V) {
   if (Instruction *I = dyn_cast<Instruction>(V))
     if (MDNode *MD = I->getMetadata(LLVMContext::MD_range))
       return getConstantRangeFromMetadata(*MD);
 
   return std::nullopt;
 }
 
 void ScalarEvolution::setNoWrapFlags(SCEVAddRecExpr *AddRec,
                                      SCEV::NoWrapFlags Flags) {
   if (AddRec->getNoWrapFlags(Flags) != Flags) {
     AddRec->setNoWrapFlags(Flags);
     UnsignedRanges.erase(AddRec);
     SignedRanges.erase(AddRec);
+    ConstantMultipleCache.erase(AddRec);
   }
 }
 
 ConstantRange ScalarEvolution::
 getRangeForUnknownRecurrence(const SCEVUnknown *U) {
   const DataLayout &DL = getDataLayout();
 
   unsigned BitWidth = getTypeSizeInBits(U->getType());
if (Depth > RangeIterThreshold)
     return getRangeRefIter(S, SignHint);
 
   unsigned BitWidth = getTypeSizeInBits(S->getType());
   ConstantRange ConservativeResult(BitWidth, /*isFullSet=*/true);
   using OBO = OverflowingBinaryOperator;
 
   // If the value has known zeros, the maximum value will have those known zeros
   // as well.
-  uint32_t TZ = getMinTrailingZeros(S);
-  if (TZ != 0) {
-    if (SignHint == ScalarEvolution::HINT_RANGE_UNSIGNED)
+  if (SignHint == ScalarEvolution::HINT_RANGE_UNSIGNED) {
+    APInt Multiple = getNonZeroConstantMultiple(S);
+    APInt Remainder = APInt::getMaxValue(BitWidth).urem(Multiple);
+    if (!Remainder.isZero())
       ConservativeResult =
           ConstantRange(APInt::getMinValue(BitWidth),
-                        APInt::getMaxValue(BitWidth).lshr(TZ).shl(TZ) + 1);
-    else
+                        APInt::getMaxValue(BitWidth) - Remainder + 1);
+  }
+  else {
+    uint32_t TZ = getMinTrailingZeros(S);
+    if (TZ != 0) {
       ConservativeResult = ConstantRange(
           APInt::getSignedMinValue(BitWidth),
           APInt::getSignedMaxValue(BitWidth).ashr(TZ).shl(TZ) + 1);
     }
+  }
 
   switch (S->getSCEVType()) {
   case scConstant:
     llvm_unreachable("Already handled above.");
   case scVScale:
     return setRange(S, SignHint, getVScaleRange(&F, BitWidth));
   case scTruncate: {
     const SCEVTruncateExpr *Trunc = cast<SCEVTruncateExpr>(S);
unsigned ScalarEvolution::getSmallConstantTripMultiple(const Loop *L,
 
   // If a trip multiple is huge (>=2^32), the trip count is still divisible by
   // the greatest power of 2 divisor less than 2^32.
   auto GetSmallMultiple = [](unsigned TrailingZeros) {
     return 1U << std::min((uint32_t)31, TrailingZeros);
   };
 
   const SCEVConstant *TC = dyn_cast<SCEVConstant>(TCExpr);
-  if (!TC)
-    // Attempt to factor more general cases. Returns the greatest power of
-    // two divisor.
-    return GetSmallMultiple(getMinTrailingZeros(TCExpr));
+  if (!TC) {
+    APInt Multiple = getNonZeroConstantMultiple(TCExpr);
+    return Multiple.getActiveBits() > 32
+               ? 1
+               : Multiple.zextOrTrunc(32).getZExtValue();
+  }
 
   ConstantInt *Result = TC->getValue();
   assert(Result && "SCEVConstant expected to have non-null ConstantInt");
   assert(Result->getValue() != 0 && "trip count should never be zero");
 
   // Guard against huge trip multiples.
   if (Result->getValue().getActiveBits() > 32)
     return GetSmallMultiple(Result->getValue().countTrailingZeros());
void ScalarEvolution::forgetAllLoops() {
   ValuesAtScopes.clear();
   ValuesAtScopesUsers.clear();
   LoopDispositions.clear();
   BlockDispositions.clear();
   UnsignedRanges.clear();
   SignedRanges.clear();
   ExprValueMap.clear();
   HasRecMap.clear();
-  MinTrailingZerosCache.clear();
+  ConstantMultipleCache.clear();
   PredicatedSCEVRewrites.clear();
   FoldCache.clear();
   FoldCacheUser.clear();
 }
 void ScalarEvolution::visitAndClearUsers(
     SmallVectorImpl<Instruction *> &Worklist,
     SmallPtrSetImpl<Instruction *> &Visited,
     SmallVectorImpl<const SCEV *> &ToForget) {

 
 ScalarEvolution::ScalarEvolution(ScalarEvolution &&Arg)
     : F(Arg.F), HasGuards(Arg.HasGuards), TLI(Arg.TLI), AC(Arg.AC), DT(Arg.DT),
       LI(Arg.LI), CouldNotCompute(std::move(Arg.CouldNotCompute)),
       ValueExprMap(std::move(Arg.ValueExprMap)),
       PendingLoopPredicates(std::move(Arg.PendingLoopPredicates)),
       PendingPhiRanges(std::move(Arg.PendingPhiRanges)),
       PendingMerges(std::move(Arg.PendingMerges)),
-      MinTrailingZerosCache(std::move(Arg.MinTrailingZerosCache)),
+      ConstantMultipleCache(std::move(Arg.ConstantMultipleCache)),
       BackedgeTakenCounts(std::move(Arg.BackedgeTakenCounts)),
       PredicatedBackedgeTakenCounts(
           std::move(Arg.PredicatedBackedgeTakenCounts)),
       BECountUsers(std::move(Arg.BECountUsers)),
       ConstantEvolutionLoopExitValue(
           std::move(Arg.ConstantEvolutionLoopExitValue)),
       ValuesAtScopes(std::move(Arg.ValuesAtScopes)),
       ValuesAtScopesUsers(std::move(Arg.ValuesAtScopesUsers)),

 }
 
 void ScalarEvolution::forgetMemoizedResultsImpl(const SCEV *S) {
   LoopDispositions.erase(S);
   BlockDispositions.erase(S);
   UnsignedRanges.erase(S);
   SignedRanges.erase(S);
   HasRecMap.erase(S);
-  MinTrailingZerosCache.erase(S);
+  ConstantMultipleCache.erase(S);
 
   if (auto *AR = dyn_cast<SCEVAddRecExpr>(S)) {
     UnsignedWrapViaInductionTried.erase(AR);
     SignedWrapViaInductionTried.erase(AR);
   }
 
   auto ExprIt = ExprValueMap.find(S);
   if (ExprIt != ExprValueMap.end()) {
for (auto &FoldID : IDs) {
       }
       if (I->second != Expr) {
         dbgs() << "Entry in FoldCache doesn't match FoldCacheUser: "
                << *I->second << " != " << *Expr << "!\n";
         std::abort();
       }
     }
   }
+
+  // Verify that ConstantMultipleCache computations are correct. It is possible
+  // that a recomputed multiple has a higher multiple than the cached multiple
+  // due to strengthened wrap flags. In this case, the cached multiple is a
+  // conservative, but still correct if it divides the recomputed multiple. As
+  // a special case, if if one multiple is zero, the other must also be zero.
+  for (auto [S, Multiple] : ConstantMultipleCache) {
+    APInt RecomputedMultiple = SE2.getConstantMultipleImpl(S);
+    if ((Multiple != RecomputedMultiple &&
+         (Multiple == 0 || RecomputedMultiple == 0)) &&
+        RecomputedMultiple.urem(Multiple) != 0) {
+      dbgs() << "Incorrect cached computation in ConstantMultipleCache for "
+             << *S << " : Computed " << RecomputedMultiple
+             << " but cache contains " << Multiple << "!\n";
+      std::abort();
+    }
+  }
 }
 
 bool ScalarEvolution::invalidate(
     Function &F, const PreservedAnalyses &PA,
     FunctionAnalysisManager::Invalidator &Inv) {
   // Invalidate the ScalarEvolution object whenever it isn't preserved or one
   // of its dependencies is invalidated.
   auto PAC = PA.getChecker<ScalarEvolutionAnalysis>();

llvm/test/Analysis/ScalarEvolution/nsw.ll

 
 
 define void @bad_postinc_nsw_a(i32 %n) {
 ; CHECK-LABEL: 'bad_postinc_nsw_a'
 ; CHECK-NEXT:  Classifying expressions for: @bad_postinc_nsw_a
 ; CHECK-NEXT:    %iv = phi i32 [ 0, %entry ], [ %iv.inc, %loop ]
 ; CHECK-NEXT:    --> {0,+,7}<nuw><nsw><%loop> U: [0,-2147483648) S: [0,-2147483648) Exits: (7 * ((((-1 * (1 umin %n))<nuw><nsw> + %n) /u 7) + (1 umin %n))) LoopDispositions: { %loop: Computable }
 ; CHECK-NEXT:    %iv.inc = add nsw i32 %iv, 7
-; CHECK-NEXT:    --> {7,+,7}<nuw><%loop> U: [7,0) S: [7,0) Exits: (7 + (7 * ((((-1 * (1 umin %n))<nuw><nsw> + %n) /u 7) + (1 umin %n)))) LoopDispositions: { %loop: Computable }
+; CHECK-NEXT:    --> {7,+,7}<nuw><%loop> U: [7,-3) S: [7,0) Exits: (7 + (7 * ((((-1 * (1 umin %n))<nuw><nsw> + %n) /u 7) + (1 umin %n)))) LoopDispositions: { %loop: Computable }
 ; CHECK-NEXT:  Determining loop execution counts for: @bad_postinc_nsw_a
 ; CHECK-NEXT:  Loop %loop: backedge-taken count is ((((-1 * (1 umin %n))<nuw><nsw> + %n) /u 7) + (1 umin %n))
 ; CHECK-NEXT:  Loop %loop: constant max backedge-taken count is 613566756
 ; CHECK-NEXT:  Loop %loop: symbolic max backedge-taken count is ((((-1 * (1 umin %n))<nuw><nsw> + %n) /u 7) + (1 umin %n))
 ; CHECK-NEXT:  Loop %loop: Predicated backedge-taken count is ((((-1 * (1 umin %n))<nuw><nsw> + %n) /u 7) + (1 umin %n))
 ; CHECK-NEXT:   Predicates:
 ; CHECK:       Loop %loop: Trip multiple is 1
 ;

llvm/test/Analysis/ScalarEvolution/ranges.ll

 ; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py
- ; RUN: opt < %s -disable-output "-passes=print<scalar-evolution>" 2>&1 | FileCheck %s
- ; RUN: opt < %s -disable-output "-passes=print<scalar-evolution>" -scev-range-iter-threshold=1 2>&1 | FileCheck %s
+ ; RUN: opt < %s -disable-output "-passes=print<scalar-evolution>,verify<scalar-evolution>" 2>&1 | FileCheck %s
+ ; RUN: opt < %s -disable-output "-passes=print<scalar-evolution>,verify<scalar-evolution>" -scev-range-iter-threshold=1 2>&1 | FileCheck %s
 
 target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64"
 
 ; Collection of cases exercising range logic, mostly (but not exclusively)
 ; involving SCEVUnknowns.
 
 declare void @llvm.assume(i1)
 

 }
 
 define void @add_6(i32 %n) {
 ; CHECK-LABEL: 'add_6'
 ; CHECK-NEXT:  Classifying expressions for: @add_6
 ; CHECK-NEXT:    %iv = phi i32 [ 0, %entry ], [ %iv.inc, %loop ]
 ; CHECK-NEXT:    --> {0,+,6}<nuw><nsw><%loop> U: [0,-2147483648) S: [0,2147483647) Exits: (6 * ((((-1 * (1 umin %n))<nuw><nsw> + %n) /u 6) + (1 umin %n))) LoopDispositions: { %loop: Computable }
 ; CHECK-NEXT:    %iv.inc = add nsw i32 %iv, 6
-; CHECK-NEXT:    --> {6,+,6}<nuw><%loop> U: [6,-1) S: [-2147483648,2147483647) Exits: (6 + (6 * ((((-1 * (1 umin %n))<nuw><nsw> + %n) /u 6) + (1 umin %n)))) LoopDispositions: { %loop: Computable }
+; CHECK-NEXT:    --> {6,+,6}<nuw><%loop> U: [6,-3) S: [-2147483648,2147483647) Exits: (6 + (6 * ((((-1 * (1 umin %n))<nuw><nsw> + %n) /u 6) + (1 umin %n)))) LoopDispositions: { %loop: Computable }
 ; CHECK-NEXT:  Determining loop execution counts for: @add_6
 ; CHECK-NEXT:  Loop %loop: backedge-taken count is ((((-1 * (1 umin %n))<nuw><nsw> + %n) /u 6) + (1 umin %n))
 ; CHECK-NEXT:  Loop %loop: constant max backedge-taken count is 715827882
 ; CHECK-NEXT:  Loop %loop: symbolic max backedge-taken count is ((((-1 * (1 umin %n))<nuw><nsw> + %n) /u 6) + (1 umin %n))
 ; CHECK-NEXT:  Loop %loop: Predicated backedge-taken count is ((((-1 * (1 umin %n))<nuw><nsw> + %n) /u 6) + (1 umin %n))
 ; CHECK-NEXT:   Predicates:
 ; CHECK:       Loop %loop: Trip multiple is 1
 ;
leave:
   ret void
 }
 define void @add_7(i32 %n) {
 ; CHECK-LABEL: 'add_7'
 ; CHECK-NEXT:  Classifying expressions for: @add_7
 ; CHECK-NEXT:    %iv = phi i32 [ 0, %entry ], [ %iv.inc, %loop ]
 ; CHECK-NEXT:    --> {0,+,7}<nuw><nsw><%loop> U: [0,-2147483648) S: [0,-2147483648) Exits: (7 * ((((-1 * (1 umin %n))<nuw><nsw> + %n) /u 7) + (1 umin %n))) LoopDispositions: { %loop: Computable }
 ; CHECK-NEXT:    %iv.inc = add nsw i32 %iv, 7
-; CHECK-NEXT:    --> {7,+,7}<nuw><%loop> U: [7,0) S: [7,0) Exits: (7 + (7 * ((((-1 * (1 umin %n))<nuw><nsw> + %n) /u 7) + (1 umin %n)))) LoopDispositions: { %loop: Computable }
+; CHECK-NEXT:    --> {7,+,7}<nuw><%loop> U: [7,-3) S: [7,0) Exits: (7 + (7 * ((((-1 * (1 umin %n))<nuw><nsw> + %n) /u 7) + (1 umin %n)))) LoopDispositions: { %loop: Computable }
 ; CHECK-NEXT:  Determining loop execution counts for: @add_7
 ; CHECK-NEXT:  Loop %loop: backedge-taken count is ((((-1 * (1 umin %n))<nuw><nsw> + %n) /u 7) + (1 umin %n))
 ; CHECK-NEXT:  Loop %loop: constant max backedge-taken count is 613566756
 ; CHECK-NEXT:  Loop %loop: symbolic max backedge-taken count is ((((-1 * (1 umin %n))<nuw><nsw> + %n) /u 7) + (1 umin %n))
 ; CHECK-NEXT:  Loop %loop: Predicated backedge-taken count is ((((-1 * (1 umin %n))<nuw><nsw> + %n) /u 7) + (1 umin %n))
 ; CHECK-NEXT:   Predicates:
 ; CHECK:       Loop %loop: Trip multiple is 1
 ;

 }
 
 define void @add_9(i32 %n) {
 ; CHECK-LABEL: 'add_9'
 ; CHECK-NEXT:  Classifying expressions for: @add_9
 ; CHECK-NEXT:    %iv = phi i32 [ 0, %entry ], [ %iv.inc, %loop ]
 ; CHECK-NEXT:    --> {0,+,9}<nuw><nsw><%loop> U: [0,-2147483648) S: [0,-2147483648) Exits: (9 * ((((-1 * (1 umin %n))<nuw><nsw> + %n) /u 9) + (1 umin %n))) LoopDispositions: { %loop: Computable }
 ; CHECK-NEXT:    %iv.inc = add nsw i32 %iv, 9
-; CHECK-NEXT:    --> {9,+,9}<nuw><%loop> U: [9,0) S: [9,0) Exits: (9 + (9 * ((((-1 * (1 umin %n))<nuw><nsw> + %n) /u 9) + (1 umin %n)))) LoopDispositions: { %loop: Computable }
+; CHECK-NEXT:    --> {9,+,9}<nuw><%loop> U: [9,-3) S: [9,0) Exits: (9 + (9 * ((((-1 * (1 umin %n))<nuw><nsw> + %n) /u 9) + (1 umin %n)))) LoopDispositions: { %loop: Computable }
 ; CHECK-NEXT:  Determining loop execution counts for: @add_9
 ; CHECK-NEXT:  Loop %loop: backedge-taken count is ((((-1 * (1 umin %n))<nuw><nsw> + %n) /u 9) + (1 umin %n))
 ; CHECK-NEXT:  Loop %loop: constant max backedge-taken count is 477218588
 ; CHECK-NEXT:  Loop %loop: symbolic max backedge-taken count is ((((-1 * (1 umin %n))<nuw><nsw> + %n) /u 9) + (1 umin %n))
 ; CHECK-NEXT:  Loop %loop: Predicated backedge-taken count is ((((-1 * (1 umin %n))<nuw><nsw> + %n) /u 9) + (1 umin %n))
 ; CHECK-NEXT:   Predicates:
 ; CHECK:       Loop %loop: Trip multiple is 1
 ;

 }
 
 define void @add_10(i32 %n) {
 ; CHECK-LABEL: 'add_10'
 ; CHECK-NEXT:  Classifying expressions for: @add_10
 ; CHECK-NEXT:    %iv = phi i32 [ 0, %entry ], [ %iv.inc, %loop ]
 ; CHECK-NEXT:    --> {0,+,10}<nuw><nsw><%loop> U: [0,-2147483648) S: [0,2147483647) Exits: (10 * ((((-1 * (1 umin %n))<nuw><nsw> + %n) /u 10) + (1 umin %n))) LoopDispositions: { %loop: Computable }
 ; CHECK-NEXT:    %iv.inc = add nsw i32 %iv, 10
-; CHECK-NEXT:    --> {10,+,10}<nuw><%loop> U: [10,-1) S: [-2147483648,2147483647) Exits: (10 + (10 * ((((-1 * (1 umin %n))<nuw><nsw> + %n) /u 10) + (1 umin %n)))) LoopDispositions: { %loop: Computable }
+; CHECK-NEXT:    --> {10,+,10}<nuw><%loop> U: [10,-5) S: [-2147483648,2147483647) Exits: (10 + (10 * ((((-1 * (1 umin %n))<nuw><nsw> + %n) /u 10) + (1 umin %n)))) LoopDispositions: { %loop: Computable }
 ; CHECK-NEXT:  Determining loop execution counts for: @add_10
 ; CHECK-NEXT:  Loop %loop: backedge-taken count is ((((-1 * (1 umin %n))<nuw><nsw> + %n) /u 10) + (1 umin %n))
 ; CHECK-NEXT:  Loop %loop: constant max backedge-taken count is 429496729
 ; CHECK-NEXT:  Loop %loop: symbolic max backedge-taken count is ((((-1 * (1 umin %n))<nuw><nsw> + %n) /u 10) + (1 umin %n))
 ; CHECK-NEXT:  Loop %loop: Predicated backedge-taken count is ((((-1 * (1 umin %n))<nuw><nsw> + %n) /u 10) + (1 umin %n))
 ; CHECK-NEXT:   Predicates:
 ; CHECK:       Loop %loop: Trip multiple is 1
 ;

llvm/test/Analysis/ScalarEvolution/trip-multiple-guard-info.ll

 ; CHECK-NEXT:    %inc = add nuw nsw i32 %i.010, 1
 ; CHECK-NEXT:    --> {1,+,1}<nuw><nsw><%for.body> U: [1,-2147483648) S: [1,-2147483648) Exits: %num LoopDispositions: { %for.body: Computable }
 ; CHECK-NEXT:  Determining loop execution counts for: @test_trip_multiple_5
 ; CHECK-NEXT:  Loop %for.body: backedge-taken count is (-1 + %num)
 ; CHECK-NEXT:  Loop %for.body: constant max backedge-taken count is -2
 ; CHECK-NEXT:  Loop %for.body: symbolic max backedge-taken count is (-1 + %num)
 ; CHECK-NEXT:  Loop %for.body: Predicated backedge-taken count is (-1 + %num)
 ; CHECK-NEXT:   Predicates:
-; CHECK:       Loop %for.body: Trip multiple is 1
+; CHECK:       Loop %for.body: Trip multiple is 5
 ;
 entry:
   %u = urem i32 %num, 5
   %cmp = icmp eq i32 %u, 0
   tail call void @llvm.assume(i1 %cmp)
   %cmp.1 = icmp uge i32 %num, 5
   tail call void @llvm.assume(i1 %cmp.1)
   br label %for.body

llvm/test/Analysis/ScalarEvolution/trip-multiple.ll

 ; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py
-; RUN: opt -passes='print<scalar-evolution>' -disable-output %s 2>&1 | FileCheck %s
+; RUN: opt -passes='print<scalar-evolution>,verify<scalar-evolution>' -disable-output %s 2>&1 | FileCheck %s
 
 ; Test trip multiples with functions that look like:
 
 ; void foo();
 ; void square(unsigned num) {
 ;     if (num % 5 == 0)
 ;     for (unsigned i = 0; i < num; ++i)
 ;         foo();

 ; CHECK-NEXT:    %inc = add nuw i32 %i.05, 1
 ; CHECK-NEXT:    --> {1,+,1}<nuw><%for.body> U: [1,0) S: [1,0) Exits: %num LoopDispositions: { %for.body: Computable }
 ; CHECK-NEXT:  Determining loop execution counts for: @trip_multiple_3
 ; CHECK-NEXT:  Loop %for.body: backedge-taken count is (-1 + %num)
 ; CHECK-NEXT:  Loop %for.body: constant max backedge-taken count is -2
 ; CHECK-NEXT:  Loop %for.body: symbolic max backedge-taken count is (-1 + %num)
 ; CHECK-NEXT:  Loop %for.body: Predicated backedge-taken count is (-1 + %num)
 ; CHECK-NEXT:   Predicates:
-; CHECK:       Loop %for.body: Trip multiple is 1
+; CHECK:       Loop %for.body: Trip multiple is 3
 ;
 entry:
   %rem = urem i32 %num, 3
   %cmp = icmp eq i32 %rem, 0
   %cmp14 = icmp ne i32 %num, 0
   %or.cond = and i1 %cmp, %cmp14
   br i1 %or.cond, label %for.body, label %if.end
 

 ; CHECK-NEXT:    %inc = add nuw i32 %i.05, 1
 ; CHECK-NEXT:    --> {1,+,1}<nuw><%for.body> U: [1,0) S: [1,0) Exits: %num LoopDispositions: { %for.body: Computable }
 ; CHECK-NEXT:  Determining loop execution counts for: @trip_multiple_5
 ; CHECK-NEXT:  Loop %for.body: backedge-taken count is (-1 + %num)
 ; CHECK-NEXT:  Loop %for.body: constant max backedge-taken count is -2
 ; CHECK-NEXT:  Loop %for.body: symbolic max backedge-taken count is (-1 + %num)
 ; CHECK-NEXT:  Loop %for.body: Predicated backedge-taken count is (-1 + %num)
 ; CHECK-NEXT:   Predicates:
-; CHECK:       Loop %for.body: Trip multiple is 1
+; CHECK:       Loop %for.body: Trip multiple is 5
 ;
 entry:
   %rem = urem i32 %num, 5
   %cmp = icmp eq i32 %rem, 0
   %cmp14 = icmp ne i32 %num, 0
   %or.cond = and i1 %cmp, %cmp14
   br i1 %or.cond, label %for.body, label %if.end
 

 ; CHECK-NEXT:    %inc = add nuw i32 %i.05, 1
 ; CHECK-NEXT:    --> {1,+,1}<nuw><%for.body> U: [1,-3) S: [1,-3) Exits: %num LoopDispositions: { %for.body: Computable }
 ; CHECK-NEXT:  Determining loop execution counts for: @trip_multiple_6
 ; CHECK-NEXT:  Loop %for.body: backedge-taken count is (-1 + %num)
 ; CHECK-NEXT:  Loop %for.body: constant max backedge-taken count is -5
 ; CHECK-NEXT:  Loop %for.body: symbolic max backedge-taken count is (-1 + %num)
 ; CHECK-NEXT:  Loop %for.body: Predicated backedge-taken count is (-1 + %num)
 ; CHECK-NEXT:   Predicates:
-; CHECK:       Loop %for.body: Trip multiple is 2
+; CHECK:       Loop %for.body: Trip multiple is 6
 ;
 entry:
   %rem = urem i32 %num, 6
   %cmp = icmp eq i32 %rem, 0
   %cmp14 = icmp ne i32 %num, 0
   %or.cond = and i1 %cmp, %cmp14
   br i1 %or.cond, label %for.body, label %if.end
 

 ; CHECK-NEXT:    %inc = add nuw i32 %i.05, 1
 ; CHECK-NEXT:    --> {1,+,1}<nuw><%for.body> U: [1,-3) S: [1,-3) Exits: %num LoopDispositions: { %for.body: Computable }
 ; CHECK-NEXT:  Determining loop execution counts for: @trip_multiple_7
 ; CHECK-NEXT:  Loop %for.body: backedge-taken count is (-1 + %num)
 ; CHECK-NEXT:  Loop %for.body: constant max backedge-taken count is -5
 ; CHECK-NEXT:  Loop %for.body: symbolic max backedge-taken count is (-1 + %num)
 ; CHECK-NEXT:  Loop %for.body: Predicated backedge-taken count is (-1 + %num)
 ; CHECK-NEXT:   Predicates:
-; CHECK:       Loop %for.body: Trip multiple is 1
+; CHECK:       Loop %for.body: Trip multiple is 7
 ;
 entry:
   %rem = urem i32 %num, 7
   %cmp = icmp eq i32 %rem, 0
   %cmp14 = icmp ne i32 %num, 0
   %or.cond = and i1 %cmp, %cmp14
   br i1 %or.cond, label %for.body, label %if.end
 

 ; CHECK-NEXT:    %inc = add nuw i32 %i.05, 1
 ; CHECK-NEXT:    --> {1,+,1}<nuw><%for.body> U: [1,-3) S: [1,-3) Exits: %num LoopDispositions: { %for.body: Computable }
 ; CHECK-NEXT:  Determining loop execution counts for: @trip_multiple_9
 ; CHECK-NEXT:  Loop %for.body: backedge-taken count is (-1 + %num)
 ; CHECK-NEXT:  Loop %for.body: constant max backedge-taken count is -5
 ; CHECK-NEXT:  Loop %for.body: symbolic max backedge-taken count is (-1 + %num)
 ; CHECK-NEXT:  Loop %for.body: Predicated backedge-taken count is (-1 + %num)
 ; CHECK-NEXT:   Predicates:
-; CHECK:       Loop %for.body: Trip multiple is 1
+; CHECK:       Loop %for.body: Trip multiple is 9
 ;
 entry:
   %rem = urem i32 %num, 9
   %cmp = icmp eq i32 %rem, 0
   %cmp14 = icmp ne i32 %num, 0
   %or.cond = and i1 %cmp, %cmp14
   br i1 %or.cond, label %for.body, label %if.end
 

 ; CHECK-NEXT:    %inc = add nuw i32 %i.05, 1
 ; CHECK-NEXT:    --> {1,+,1}<nuw><%for.body> U: [1,-5) S: [1,-5) Exits: %num LoopDispositions: { %for.body: Computable }
 ; CHECK-NEXT:  Determining loop execution counts for: @trip_multiple_10
 ; CHECK-NEXT:  Loop %for.body: backedge-taken count is (-1 + %num)
 ; CHECK-NEXT:  Loop %for.body: constant max backedge-taken count is -7
 ; CHECK-NEXT:  Loop %for.body: symbolic max backedge-taken count is (-1 + %num)
 ; CHECK-NEXT:  Loop %for.body: Predicated backedge-taken count is (-1 + %num)
 ; CHECK-NEXT:   Predicates:
-; CHECK:       Loop %for.body: Trip multiple is 2
+; CHECK:       Loop %for.body: Trip multiple is 10
 ;
 entry:
   %rem = urem i32 %num, 10
   %cmp = icmp eq i32 %rem, 0
   %cmp14 = icmp ne i32 %num, 0
   %or.cond = and i1 %cmp, %cmp14
   br i1 %or.cond, label %for.body, label %if.end