Revert "Relax constraints for reduction vectorization"

This reverts commit r355868.  Breaks hexagon.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@355873 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Analysis/IVDescriptors.h

@@ -89,12 +89,10 @@ class RecurrenceDescriptor {
   RecurrenceDescriptor() = default;
 
   RecurrenceDescriptor(Value *Start, Instruction *Exit, RecurrenceKind K,
-                       FastMathFlags FMF, MinMaxRecurrenceKind MK,
-                       Instruction *UAI, Type *RT, bool Signed,
-                       SmallPtrSetImpl<Instruction *> &CI)
-      : StartValue(Start), LoopExitInstr(Exit), Kind(K), FMF(FMF),
-        MinMaxKind(MK), UnsafeAlgebraInst(UAI), RecurrenceType(RT),
-        IsSigned(Signed) {
+                       MinMaxRecurrenceKind MK, Instruction *UAI, Type *RT,
+                       bool Signed, SmallPtrSetImpl<Instruction *> &CI)
+      : StartValue(Start), LoopExitInstr(Exit), Kind(K), MinMaxKind(MK),
+        UnsafeAlgebraInst(UAI), RecurrenceType(RT), IsSigned(Signed) {
     CastInsts.insert(CI.begin(), CI.end());
   }
 
@@ -200,8 +198,6 @@ class RecurrenceDescriptor {
 
   MinMaxRecurrenceKind getMinMaxRecurrenceKind() { return MinMaxKind; }
 
-  FastMathFlags getFastMathFlags() { return FMF; }
-
   TrackingVH<Value> getRecurrenceStartValue() { return StartValue; }
 
   Instruction *getLoopExitInstr() { return LoopExitInstr; }
@@ -241,9 +237,6 @@ class RecurrenceDescriptor {
   Instruction *LoopExitInstr = nullptr;
   // The kind of the recurrence.
   RecurrenceKind Kind = RK_NoRecurrence;
-  // The fast-math flags on the recurrent instructions.  We propagate these
-  // fast-math flags into the vectorized FP instructions we generate.
-  FastMathFlags FMF;
   // If this a min/max recurrence the kind of recurrence.
   MinMaxRecurrenceKind MinMaxKind = MRK_Invalid;
   // First occurrence of unasfe algebra in the PHI's use-chain.

include/llvm/IR/Operator.h

@@ -187,12 +187,6 @@ class FastMathFlags {
 
   FastMathFlags() = default;
 
-  static FastMathFlags getFast() {
-    FastMathFlags FMF;
-    FMF.setFast();
-    return FMF;
-  }
-
   bool any() const { return Flags != 0; }
   bool none() const { return Flags == 0; }
   bool all() const { return Flags == ~0U; }

include/llvm/Transforms/Utils/LoopUtils.h

@@ -296,7 +296,6 @@ getOrderedReduction(IRBuilder<> &Builder, Value *Acc, Value *Src, unsigned Op,
 Value *getShuffleReduction(IRBuilder<> &Builder, Value *Src, unsigned Op,
                            RecurrenceDescriptor::MinMaxRecurrenceKind
                                MinMaxKind = RecurrenceDescriptor::MRK_Invalid,
-                           FastMathFlags FMF = FastMathFlags(),
                            ArrayRef<Value *> RedOps = None);
 
 /// Create a target reduction of the given vector. The reduction operation
@@ -309,7 +308,6 @@ Value *createSimpleTargetReduction(IRBuilder<> &B,
                                    unsigned Opcode, Value *Src,
                                    TargetTransformInfo::ReductionFlags Flags =
                                        TargetTransformInfo::ReductionFlags(),
-                                   FastMathFlags FMF = FastMathFlags(),
                                    ArrayRef<Value *> RedOps = None);
 
 /// Create a generic target reduction using a recurrence descriptor \p Desc

lib/Analysis/IVDescriptors.cpp

@@ -251,10 +251,6 @@ bool RecurrenceDescriptor::AddReductionVar(PHINode *Phi, RecurrenceKind Kind,
   Worklist.push_back(Start);
   VisitedInsts.insert(Start);
 
-  // Start with all flags set because we will intersect this with the reduction
-  // flags from all the reduction operations.
-  FastMathFlags FMF = FastMathFlags::getFast();
-
   // A value in the reduction can be used:
   //  - By the reduction:
   //      - Reduction operation:
@@ -300,8 +296,6 @@ bool RecurrenceDescriptor::AddReductionVar(PHINode *Phi, RecurrenceKind Kind,
       ReduxDesc = isRecurrenceInstr(Cur, Kind, ReduxDesc, HasFunNoNaNAttr);
       if (!ReduxDesc.isRecurrence())
         return false;
-      if (isa<FPMathOperator>(ReduxDesc.getPatternInst()))
-        FMF &= ReduxDesc.getPatternInst()->getFastMathFlags();
     }
 
     bool IsASelect = isa<SelectInst>(Cur);
@@ -447,7 +441,7 @@ bool RecurrenceDescriptor::AddReductionVar(PHINode *Phi, RecurrenceKind Kind,
 
   // Save the description of this reduction variable.
   RecurrenceDescriptor RD(
-      RdxStart, ExitInstruction, Kind, FMF, ReduxDesc.getMinMaxKind(),
+      RdxStart, ExitInstruction, Kind, ReduxDesc.getMinMaxKind(),
       ReduxDesc.getUnsafeAlgebraInst(), RecurrenceType, IsSigned, CastInsts);
   RedDes = RD;
 
@@ -556,7 +550,7 @@ RecurrenceDescriptor::InstDesc
 RecurrenceDescriptor::isRecurrenceInstr(Instruction *I, RecurrenceKind Kind,
                                         InstDesc &Prev, bool HasFunNoNaNAttr) {
   Instruction *UAI = Prev.getUnsafeAlgebraInst();
-  if (!UAI && isa<FPMathOperator>(I) && !I->hasAllowReassoc())
+  if (!UAI && isa<FPMathOperator>(I) && !I->isFast())
     UAI = I; // Found an unsafe (unvectorizable) algebra instruction.
 
   switch (I->getOpcode()) {

lib/CodeGen/ExpandReductions.cpp

@@ -118,11 +118,9 @@ bool expandReductions(Function &F, const TargetTransformInfo *TTI) {
     }
     if (!TTI->shouldExpandReduction(II))
       continue;
-    FastMathFlags FMF =
-        isa<FPMathOperator>(II) ? II->getFastMathFlags() : FastMathFlags{};
     Value *Rdx =
         IsOrdered ? getOrderedReduction(Builder, Acc, Vec, getOpcode(ID), MRK)
-                  : getShuffleReduction(Builder, Vec, getOpcode(ID), MRK, FMF);
+                  : getShuffleReduction(Builder, Vec, getOpcode(ID), MRK);
     II->replaceAllUsesWith(Rdx);
     II->eraseFromParent();
     Changed = true;

lib/Transforms/Utils/LoopUtils.cpp

@@ -671,9 +671,13 @@ bool llvm::hasIterationCountInvariantInParent(Loop *InnerLoop,
   return true;
 }
 
-static Value *addFastMathFlag(Value *V, FastMathFlags FMF) {
-  if (isa<FPMathOperator>(V))
-    cast<Instruction>(V)->setFastMathFlags(FMF);
+/// Adds a 'fast' flag to floating point operations.
+static Value *addFastMathFlag(Value *V) {
+  if (isa<FPMathOperator>(V)) {
+    FastMathFlags Flags;
+    Flags.setFast();
+    cast<Instruction>(V)->setFastMathFlags(Flags);
+  }
   return V;
 }
 
@@ -757,7 +761,7 @@ llvm::getOrderedReduction(IRBuilder<> &Builder, Value *Acc, Value *Src,
 Value *
 llvm::getShuffleReduction(IRBuilder<> &Builder, Value *Src, unsigned Op,
                           RecurrenceDescriptor::MinMaxRecurrenceKind MinMaxKind,
-                          FastMathFlags FMF, ArrayRef<Value *> RedOps) {
+                          ArrayRef<Value *> RedOps) {
   unsigned VF = Src->getType()->getVectorNumElements();
   // VF is a power of 2 so we can emit the reduction using log2(VF) shuffles
   // and vector ops, reducing the set of values being computed by half each
@@ -782,8 +786,7 @@ llvm::getShuffleReduction(IRBuilder<> &Builder, Value *Src, unsigned Op,
     if (Op != Instruction::ICmp && Op != Instruction::FCmp) {
       // Floating point operations had to be 'fast' to enable the reduction.
       TmpVec = addFastMathFlag(Builder.CreateBinOp((Instruction::BinaryOps)Op,
-                                                   TmpVec, Shuf, "bin.rdx"),
-                               FMF);
+                                                   TmpVec, Shuf, "bin.rdx"));
     } else {
       assert(MinMaxKind != RecurrenceDescriptor::MRK_Invalid &&
              "Invalid min/max");
@@ -800,7 +803,7 @@ llvm::getShuffleReduction(IRBuilder<> &Builder, Value *Src, unsigned Op,
 /// flags (if generating min/max reductions).
 Value *llvm::createSimpleTargetReduction(
     IRBuilder<> &Builder, const TargetTransformInfo *TTI, unsigned Opcode,
-    Value *Src, TargetTransformInfo::ReductionFlags Flags, FastMathFlags FMF,
+    Value *Src, TargetTransformInfo::ReductionFlags Flags,
     ArrayRef<Value *> RedOps) {
   assert(isa<VectorType>(Src->getType()) && "Type must be a vector");
 
@@ -870,7 +873,7 @@ Value *llvm::createSimpleTargetReduction(
   }
   if (TTI->useReductionIntrinsic(Opcode, Src->getType(), Flags))
     return BuildFunc();
-  return getShuffleReduction(Builder, Src, Opcode, MinMaxKind, FMF, RedOps);
+  return getShuffleReduction(Builder, Src, Opcode, MinMaxKind, RedOps);
 }
 
 /// Create a vector reduction using a given recurrence descriptor.
@@ -885,37 +888,28 @@ Value *llvm::createTargetReduction(IRBuilder<> &B,
   Flags.NoNaN = NoNaN;
   switch (RecKind) {
   case RD::RK_FloatAdd:
-    return createSimpleTargetReduction(B, TTI, Instruction::FAdd, Src, Flags,
-                                       Desc.getFastMathFlags());
+    return createSimpleTargetReduction(B, TTI, Instruction::FAdd, Src, Flags);
   case RD::RK_FloatMult:
-    return createSimpleTargetReduction(B, TTI, Instruction::FMul, Src, Flags,
-                                       Desc.getFastMathFlags());
+    return createSimpleTargetReduction(B, TTI, Instruction::FMul, Src, Flags);
   case RD::RK_IntegerAdd:
-    return createSimpleTargetReduction(B, TTI, Instruction::Add, Src, Flags,
-                                       Desc.getFastMathFlags());
+    return createSimpleTargetReduction(B, TTI, Instruction::Add, Src, Flags);
   case RD::RK_IntegerMult:
-    return createSimpleTargetReduction(B, TTI, Instruction::Mul, Src, Flags,
-                                       Desc.getFastMathFlags());
+    return createSimpleTargetReduction(B, TTI, Instruction::Mul, Src, Flags);
   case RD::RK_IntegerAnd:
-    return createSimpleTargetReduction(B, TTI, Instruction::And, Src, Flags,
-                                       Desc.getFastMathFlags());
+    return createSimpleTargetReduction(B, TTI, Instruction::And, Src, Flags);
   case RD::RK_IntegerOr:
-    return createSimpleTargetReduction(B, TTI, Instruction::Or, Src, Flags,
-                                       Desc.getFastMathFlags());
+    return createSimpleTargetReduction(B, TTI, Instruction::Or, Src, Flags);
   case RD::RK_IntegerXor:
-    return createSimpleTargetReduction(B, TTI, Instruction::Xor, Src, Flags,
-                                       Desc.getFastMathFlags());
+    return createSimpleTargetReduction(B, TTI, Instruction::Xor, Src, Flags);
   case RD::RK_IntegerMinMax: {
     RD::MinMaxRecurrenceKind MMKind = Desc.getMinMaxRecurrenceKind();
     Flags.IsMaxOp = (MMKind == RD::MRK_SIntMax || MMKind == RD::MRK_UIntMax);
     Flags.IsSigned = (MMKind == RD::MRK_SIntMax || MMKind == RD::MRK_SIntMin);
-    return createSimpleTargetReduction(B, TTI, Instruction::ICmp, Src, Flags,
-                                       Desc.getFastMathFlags());
+    return createSimpleTargetReduction(B, TTI, Instruction::ICmp, Src, Flags);
   }
   case RD::RK_FloatMinMax: {
     Flags.IsMaxOp = Desc.getMinMaxRecurrenceKind() == RD::MRK_FloatMax;
-    return createSimpleTargetReduction(B, TTI, Instruction::FCmp, Src, Flags,
-                                       Desc.getFastMathFlags());
+    return createSimpleTargetReduction(B, TTI, Instruction::FCmp, Src, Flags);
   }
   default:
     llvm_unreachable("Unhandled RecKind");

lib/Transforms/Vectorize/LoopVectorize.cpp

@@ -319,14 +319,11 @@ static unsigned getReciprocalPredBlockProb() { return 2; }
 
 /// A helper function that adds a 'fast' flag to floating-point operations.
 static Value *addFastMathFlag(Value *V) {
-  if (isa<FPMathOperator>(V))
-    cast<Instruction>(V)->setFastMathFlags(FastMathFlags::getFast());
-  return V;
-}
-
-static Value *addFastMathFlag(Value *V, FastMathFlags FMF) {
-  if (isa<FPMathOperator>(V))
-    cast<Instruction>(V)->setFastMathFlags(FMF);
+  if (isa<FPMathOperator>(V)) {
+    FastMathFlags Flags;
+    Flags.setFast();
+    cast<Instruction>(V)->setFastMathFlags(Flags);
+  }
   return V;
 }
 
@@ -3615,8 +3612,7 @@ void InnerLoopVectorizer::fixReduction(PHINode *Phi) {
       // Floating point operations had to be 'fast' to enable the reduction.
       ReducedPartRdx = addFastMathFlag(
           Builder.CreateBinOp((Instruction::BinaryOps)Op, RdxPart,
-                              ReducedPartRdx, "bin.rdx"),
-          RdxDesc.getFastMathFlags());
+                              ReducedPartRdx, "bin.rdx"));
     else
       ReducedPartRdx = createMinMaxOp(Builder, MinMaxKind, ReducedPartRdx,
                                       RdxPart);

lib/Transforms/Vectorize/SLPVectorizer.cpp

@@ -5929,8 +5929,7 @@ class HorizontalReduction {
     if (!IsPairwiseReduction)
       return createSimpleTargetReduction(
           Builder, TTI, ReductionData.getOpcode(), VectorizedValue,
-          ReductionData.getFlags(), FastMathFlags::getFast(),
-          ReductionOps.back());
+          ReductionData.getFlags(), ReductionOps.back());
 
     Value *TmpVec = VectorizedValue;
     for (unsigned i = ReduxWidth / 2; i != 0; i >>= 1) {