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[SVE][LoopVectorize] Add support for scalable vectorization of first-order recurrences 

Adds support for scalable vectorization of loops containing first-order recurrences, e.g:
```
for(int i = 0; i < n; i++)
  b[i] =  a[i] + a[i - 1]
```
This patch changes fixFirstOrderRecurrence for scalable vectors to take vscale into
account when inserting into and extracting from the last lane of a vector.
CreateVectorSplice has been added to construct a vector for the recurrence, which
returns a splice intrinsic for scalable types. For fixed-width the behaviour
remains unchanged as CreateVectorSplice will return a shufflevector instead.

The tests included here are the same as test/Transform/LoopVectorize/first-order-recurrence.ll

Reviewed By: david-arm, fhahn

Differential Revision: https://reviews.llvm.org/D101076
This commit is contained in:
Kerry McLaughlin 2021-05-06 10:50:51 +01:00
parent cdf33962d9
commit 8c9742bd23
5 changed files with 439 additions and 26 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
llvm/include/llvm/IR/IRBuilder.h
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@ -2510,6 +2510,16 @@ public:
/// Return a vector value that contains the vector V reversed /// Return a vector value that contains the vector V reversed
Value *CreateVectorReverse(Value *V, const Twine &Name = ""); Value *CreateVectorReverse(Value *V, const Twine &Name = "");
/// Return a vector splice intrinsic if using scalable vectors, otherwise
/// return a shufflevector. If the immediate is positive, a vector is
/// extracted from concat(V1, V2), starting at Imm. If the immediate
/// is negative, we extract -Imm elements from V1 and the remaining
/// elements from V2. Imm is a signed integer in the range
/// -VL <= Imm < VL (where VL is the runtime vector length of the
/// source/result vector)
Value *CreateVectorSplice(Value *V1, Value *V2, int64_t Imm,
const Twine &Name = "");
/// Return a vector value that contains \arg V broadcasted to \p /// Return a vector value that contains \arg V broadcasted to \p
/// NumElts elements. /// NumElts elements.
Value *CreateVectorSplat(unsigned NumElts, Value *V, const Twine &Name = ""); Value *CreateVectorSplat(unsigned NumElts, Value *V, const Twine &Name = "");

28
llvm/lib/IR/IRBuilder.cpp
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@ -1027,6 +1027,34 @@ Value *IRBuilderBase::CreateVectorReverse(Value *V, const Twine &Name) {
return CreateShuffleVector(V, ShuffleMask, Name); return CreateShuffleVector(V, ShuffleMask, Name);
} }
Value *IRBuilderBase::CreateVectorSplice(Value *V1, Value *V2, int64_t Imm,
const Twine &Name) {
assert(isa<VectorType>(V1->getType()) && "Unexpected type");
assert(V1->getType() == V2->getType() &&
"Splice expects matching operand types!");
if (auto *VTy = dyn_cast<ScalableVectorType>(V1->getType())) {
Module *M = BB->getParent()->getParent();
Function *F = Intrinsic::getDeclaration(
M, Intrinsic::experimental_vector_splice, VTy);
Value *Ops[] = {V1, V2, getInt32(Imm)};
return Insert(CallInst::Create(F, Ops), Name);
}
unsigned NumElts = cast<FixedVectorType>(V1->getType())->getNumElements();
assert(((-Imm <= NumElts) || (Imm < NumElts)) &&
"Invalid immediate for vector splice!");
// Keep the original behaviour for fixed vector
unsigned Idx = (NumElts + Imm) % NumElts;
SmallVector<int, 8> Mask;
for (unsigned I = 0; I < NumElts; ++I)
Mask.push_back(Idx + I);
return CreateShuffleVector(V1, V2, Mask);
}
Value *IRBuilderBase::CreateVectorSplat(unsigned NumElts, Value *V, Value *IRBuilderBase::CreateVectorSplat(unsigned NumElts, Value *V,
const Twine &Name) { const Twine &Name) {
auto EC = ElementCount::getFixed(NumElts); auto EC = ElementCount::getFixed(NumElts);

43
llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
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@ -4173,14 +4173,18 @@ void InnerLoopVectorizer::fixFirstOrderRecurrence(PHINode *Phi,
auto *ScalarInit = Phi->getIncomingValueForBlock(Preheader); auto *ScalarInit = Phi->getIncomingValueForBlock(Preheader);
auto *Previous = Phi->getIncomingValueForBlock(Latch); auto *Previous = Phi->getIncomingValueForBlock(Latch);
auto *IdxTy = Builder.getInt32Ty();
auto *One = ConstantInt::get(IdxTy, 1);
// Create a vector from the initial value. // Create a vector from the initial value.
auto *VectorInit = ScalarInit; auto *VectorInit = ScalarInit;
if (VF.isVector()) { if (VF.isVector()) {
Builder.SetInsertPoint(LoopVectorPreHeader->getTerminator()); Builder.SetInsertPoint(LoopVectorPreHeader->getTerminator());
assert(!VF.isScalable() && "VF is assumed to be non scalable."); auto *RuntimeVF = getRuntimeVF(Builder, IdxTy, VF);
auto *LastIdx = Builder.CreateSub(RuntimeVF, One);
VectorInit = Builder.CreateInsertElement( VectorInit = Builder.CreateInsertElement(
PoisonValue::get(VectorType::get(VectorInit->getType(), VF)), VectorInit, PoisonValue::get(VectorType::get(VectorInit->getType(), VF)),
Builder.getInt32(VF.getKnownMinValue() - 1), "vector.recur.init"); VectorInit, LastIdx, "vector.recur.init");
} }
VPValue *PhiDef = State.Plan->getVPValue(Phi); VPValue *PhiDef = State.Plan->getVPValue(Phi);
@ -4220,14 +4224,6 @@ void InnerLoopVectorizer::fixFirstOrderRecurrence(PHINode *Phi,
} }
Builder.SetInsertPoint(&*InsertPt); Builder.SetInsertPoint(&*InsertPt);
// We will construct a vector for the recurrence by combining the values for
// the current and previous iterations. This is the required shuffle mask.
assert(!VF.isScalable());
SmallVector<int, 8> ShuffleMask(VF.getKnownMinValue());
ShuffleMask[0] = VF.getKnownMinValue() - 1;
for (unsigned I = 1; I < VF.getKnownMinValue(); ++I)
ShuffleMask[I] = I + VF.getKnownMinValue() - 1;
// The vector from which to take the initial value for the current iteration // The vector from which to take the initial value for the current iteration
// (actual or unrolled). Initially, this is the vector phi node. // (actual or unrolled). Initially, this is the vector phi node.
Value *Incoming = VecPhi; Value *Incoming = VecPhi;
@ -4236,9 +4232,8 @@ void InnerLoopVectorizer::fixFirstOrderRecurrence(PHINode *Phi,
for (unsigned Part = 0; Part < UF; ++Part) { for (unsigned Part = 0; Part < UF; ++Part) {
Value *PreviousPart = State.get(PreviousDef, Part); Value *PreviousPart = State.get(PreviousDef, Part);
Value *PhiPart = State.get(PhiDef, Part); Value *PhiPart = State.get(PhiDef, Part);
auto *Shuffle = auto *Shuffle = VF.isVector()
VF.isVector() ? Builder.CreateVectorSplice(Incoming, PreviousPart, -1)
? Builder.CreateShuffleVector(Incoming, PreviousPart, ShuffleMask)
: Incoming; : Incoming;
PhiPart->replaceAllUsesWith(Shuffle); PhiPart->replaceAllUsesWith(Shuffle);
cast<Instruction>(PhiPart)->eraseFromParent(); cast<Instruction>(PhiPart)->eraseFromParent();
@ -4254,8 +4249,9 @@ void InnerLoopVectorizer::fixFirstOrderRecurrence(PHINode *Phi,
auto *ExtractForScalar = Incoming; auto *ExtractForScalar = Incoming;
if (VF.isVector()) { if (VF.isVector()) {
Builder.SetInsertPoint(LoopMiddleBlock->getTerminator()); Builder.SetInsertPoint(LoopMiddleBlock->getTerminator());
ExtractForScalar = Builder.CreateExtractElement( auto *RuntimeVF = getRuntimeVF(Builder, IdxTy, VF);
ExtractForScalar, Builder.getInt32(VF.getKnownMinValue() - 1), auto *LastIdx = Builder.CreateSub(RuntimeVF, One);
ExtractForScalar = Builder.CreateExtractElement(ExtractForScalar, LastIdx,
"vector.recur.extract"); "vector.recur.extract");
} }
// Extract the second last element in the middle block if the // Extract the second last element in the middle block if the
@ -4264,15 +4260,16 @@ void InnerLoopVectorizer::fixFirstOrderRecurrence(PHINode *Phi,
// will be the value when jumping to the exit block from the LoopMiddleBlock, // will be the value when jumping to the exit block from the LoopMiddleBlock,
// when the scalar loop is not run at all. // when the scalar loop is not run at all.
Value *ExtractForPhiUsedOutsideLoop = nullptr; Value *ExtractForPhiUsedOutsideLoop = nullptr;
if (VF.isVector()) if (VF.isVector()) {
auto *RuntimeVF = getRuntimeVF(Builder, IdxTy, VF);
auto *Idx = Builder.CreateSub(RuntimeVF, ConstantInt::get(IdxTy, 2));
ExtractForPhiUsedOutsideLoop = Builder.CreateExtractElement( ExtractForPhiUsedOutsideLoop = Builder.CreateExtractElement(
Incoming, Builder.getInt32(VF.getKnownMinValue() - 2), Incoming, Idx, "vector.recur.extract.for.phi");
"vector.recur.extract.for.phi"); } else if (UF > 1)
// When loop is unrolled without vectorizing, initialize // When loop is unrolled without vectorizing, initialize
// ExtractForPhiUsedOutsideLoop with the value just prior to unrolled value of // ExtractForPhiUsedOutsideLoop with the value just prior to unrolled value
// `Incoming`. This is analogous to the vectorized case above: extracting the // of `Incoming`. This is analogous to the vectorized case above: extracting
// second last element when VF > 1. // the second last element when VF > 1.
else if (UF > 1)
ExtractForPhiUsedOutsideLoop = State.get(PreviousDef, UF - 2); ExtractForPhiUsedOutsideLoop = State.get(PreviousDef, UF - 2);
// Fix the initial value of the original recurrence in the scalar loop. // Fix the initial value of the original recurrence in the scalar loop.

104
llvm/test/Transforms/LoopVectorize/AArch64/first-order-recurrence.ll Normal file
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@ -0,0 +1,104 @@
; RUN: opt -loop-vectorize -force-vector-width=4 -force-vector-interleave=1 -mtriple aarch64-unknown-linux-gnu -mattr=+sve -S < %s | FileCheck %s --check-prefix=CHECK-VF4UF1
; RUN: opt -loop-vectorize -force-vector-width=4 -force-vector-interleave=2 -mtriple aarch64-unknown-linux-gnu -mattr=+sve -S < %s | FileCheck %s --check-prefix=CHECK-VF4UF2
; We vectorize this first order recurrence, with a set of insertelements for
; each unrolled part. Make sure these insertelements are generated in-order,
; because the shuffle of the first order recurrence will be added after the
; insertelement of the last part UF - 1, assuming the latter appears after the
; insertelements of all other parts.
;
; int PR33613(double *b, double j, int d) {
; int a = 0;
; for(int i = 0; i < 10240; i++, b+=25) {
; double f = b[d]; // Scalarize to form insertelements
; if (j * f)
; a++;
; j = f;
; }
; return a;
; }
;
define i32 @PR33613(double* %b, double %j, i32 %d) {
; CHECK-VF4UF2-LABEL: @PR33613
; CHECK-VF4UF2: vector.body
; CHECK-VF4UF2: %[[VEC_RECUR:.*]] = phi <vscale x 4 x double> [ {{.*}}, %vector.ph ], [ {{.*}}, %vector.body ]
; CHECK-VF4UF2: %[[SPLICE1:.*]] = call <vscale x 4 x double> @llvm.experimental.vector.splice.nxv4f64(<vscale x 4 x double> %[[VEC_RECUR]], <vscale x 4 x double> {{.*}}, i32 -1)
; CHECK-VF4UF2-NEXT: %[[SPLICE2:.*]] = call <vscale x 4 x double> @llvm.experimental.vector.splice.nxv4f64(<vscale x 4 x double> %{{.*}}, <vscale x 4 x double> %{{.*}}, i32 -1)
; CHECK-VF4UF2-NOT: insertelement <vscale x 4 x double>
; CHECK-VF4UF2: middle.block
entry:
%idxprom = sext i32 %d to i64
br label %for.body
for.cond.cleanup:
%a.1.lcssa = phi i32 [ %a.1, %for.body ]
ret i32 %a.1.lcssa
for.body:
%b.addr.012 = phi double* [ %b, %entry ], [ %add.ptr, %for.body ]
%i.011 = phi i32 [ 0, %entry ], [ %inc1, %for.body ]
%a.010 = phi i32 [ 0, %entry ], [ %a.1, %for.body ]
%j.addr.09 = phi double [ %j, %entry ], [ %0, %for.body ]
%arrayidx = getelementptr inbounds double, double* %b.addr.012, i64 %idxprom
%0 = load double, double* %arrayidx, align 8
%mul = fmul double %j.addr.09, %0
%tobool = fcmp une double %mul, 0.000000e+00
%inc = zext i1 %tobool to i32
%a.1 = add nsw i32 %a.010, %inc
%inc1 = add nuw nsw i32 %i.011, 1
%add.ptr = getelementptr inbounds double, double* %b.addr.012, i64 25
%exitcond = icmp eq i32 %inc1, 10240
br i1 %exitcond, label %for.cond.cleanup, label %for.body, !llvm.loop !0
}
; PR34711: given three consecutive instructions such that the first will be
; widened, the second is a cast that will be widened and needs to sink after the
; third, and the third is a first-order-recurring load that will be replicated
; instead of widened. Although the cast and the first instruction will both be
; widened, and are originally adjacent to each other, make sure the replicated
; load ends up appearing between them.
;
; void PR34711(short[2] *a, int *b, int *c, int n) {
; for(int i = 0; i < n; i++) {
; c[i] = 7;
; b[i] = (a[i][0] * a[i][1]);
; }
; }
;
; Check that the sext sank after the load in the vector loop.
define void @PR34711([2 x i16]* %a, i32* %b, i32* %c, i64 %n) {
; CHECK-VF4UF1-LABEL: @PR34711
; CHECK-VF4UF1: vector.body
; CHECK-VF4UF1: %[[VEC_RECUR:.*]] = phi <vscale x 4 x i16> [ %vector.recur.init, %vector.ph ], [ %[[MGATHER:.*]], %vector.body ]
; CHECK-VF4UF1: %[[MGATHER]] = call <vscale x 4 x i16> @llvm.masked.gather.nxv4i16.nxv4p0i16(<vscale x 4 x i16*> {{.*}}, i32 2, <vscale x 4 x i1> shufflevector (<vscale x 4 x i1> insertelement (<vscale x 4 x i1> undef, i1 true, i32 0), <vscale x 4 x i1> undef, <vscale x 4 x i32> zeroinitializer), <vscale x 4 x i16> undef)
; CHECK-VF4UF1-NEXT: %[[SPLICE:.*]] = call <vscale x 4 x i16> @llvm.experimental.vector.splice.nxv4i16(<vscale x 4 x i16> %[[VEC_RECUR]], <vscale x 4 x i16> %[[MGATHER]], i32 -1)
; CHECK-VF4UF1-NEXT: %[[SXT1:.*]] = sext <vscale x 4 x i16> %[[SPLICE]] to <vscale x 4 x i32>
; CHECK-VF4UF1-NEXT: %[[SXT2:.*]] = sext <vscale x 4 x i16> %[[MGATHER]] to <vscale x 4 x i32>
; CHECK-VF4UF1-NEXT: mul nsw <vscale x 4 x i32> %[[SXT2]], %[[SXT1]]
entry:
%pre.index = getelementptr inbounds [2 x i16], [2 x i16]* %a, i64 0, i64 0
%.pre = load i16, i16* %pre.index
br label %for.body
for.body:
%0 = phi i16 [ %.pre, %entry ], [ %1, %for.body ]
%indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
%arraycidx = getelementptr inbounds i32, i32* %c, i64 %indvars.iv
%cur.index = getelementptr inbounds [2 x i16], [2 x i16]* %a, i64 %indvars.iv, i64 1
store i32 7, i32* %arraycidx ; 1st instruction, to be widened.
%conv = sext i16 %0 to i32 ; 2nd, cast to sink after third.
%1 = load i16, i16* %cur.index ; 3rd, first-order-recurring load not widened.
%conv3 = sext i16 %1 to i32
%mul = mul nsw i32 %conv3, %conv
%arrayidx5 = getelementptr inbounds i32, i32* %b, i64 %indvars.iv
store i32 %mul, i32* %arrayidx5
%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
%exitcond = icmp eq i64 %indvars.iv.next, %n
br i1 %exitcond, label %for.end, label %for.body, !llvm.loop !0
for.end:
ret void
}
!0 = distinct !{!0, !1}
!1 = !{!"llvm.loop.vectorize.scalable.enable", i1 true}

274
llvm/test/Transforms/LoopVectorize/scalable-first-order-recurrence.ll Normal file
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@ -0,0 +1,274 @@
; RUN: opt -loop-vectorize -force-vector-width=4 -force-vector-interleave=1 -force-target-supports-scalable-vectors=true -S < %s | FileCheck %s --check-prefix=CHECK-VF4UF1
; RUN: opt -loop-vectorize -force-vector-width=4 -force-vector-interleave=2 -force-target-supports-scalable-vectors=true -S < %s | FileCheck %s --check-prefix=CHECK-VF4UF2
; void recurrence_1(int *a, int *b, int n) {
; for(int i = 0; i < n; i++)
; b[i] = a[i] + a[i - 1]
; }
;
define void @recurrence_1(i32* nocapture readonly %a, i32* nocapture %b, i32 %n) {
; CHECK-VF4UF1-LABEL: @recurrence_1
; CHECK-VF4UF1: for.preheader
; CHECK-VF4UF1: %[[SUB_1:.*]] = add i32 %n, -1
; CHECK-VF4UF1: %[[ZEXT:.*]] = zext i32 %[[SUB_1]] to i64
; CHECK-VF4UF1: %[[ADD:.*]] = add nuw nsw i64 %[[ZEXT]], 1
; CHECK-VF4UF1: vector.ph:
; CHECK-VF4UF1: %[[VSCALE1:.*]] = call i32 @llvm.vscale.i32()
; CHECK-VF4UF1: %[[MUL1:.*]] = mul i32 %[[VSCALE1]], 4
; CHECK-VF4UF1: %[[SUB1:.*]] = sub i32 %[[MUL1]], 1
; CHECK-VF4UF1: %[[VEC_RECUR_INIT:.*]] = insertelement <vscale x 4 x i32> poison, i32 %pre_load, i32 %[[SUB1]]
; CHECK-VF4UF1: vector.body:
; CHECK-VF4UF1: %[[INDEX:.*]] = phi i64 [ 0, %vector.ph ], [ %[[NEXT_IDX:.*]], %vector.body ]
; CHECK-VF4UF1: %[[VEC_RECUR:.*]] = phi <vscale x 4 x i32> [ %[[VEC_RECUR_INIT]], %vector.ph ], [ %[[LOAD:.*]], %vector.body ]
; CHECK-VF4UF1: %[[LOAD]] = load <vscale x 4 x i32>, <vscale x 4 x i32>*
; CHECK-VF4UF1: %[[SPLICE:.*]] = call <vscale x 4 x i32> @llvm.experimental.vector.splice.nxv4i32(<vscale x 4 x i32> %[[VEC_RECUR]], <vscale x 4 x i32> %[[LOAD]], i32 -1)
; CHECK-VF4UF1: middle.block:
; CHECK-VF4UF1: %[[VSCALE2:.*]] = call i32 @llvm.vscale.i32()
; CHECK-VF4UF1: %[[MUL2:.*]] = mul i32 %[[VSCALE2]], 4
; CHECK-VF4UF1: %[[SUB2:.*]] = sub i32 %[[MUL2]], 1
; CHECK-VF4UF1: %[[VEC_RECUR_EXT:.*]] = extractelement <vscale x 4 x i32> %[[LOAD]], i32 %[[SUB2]]
; CHECK-VF4UF1: %[[VSCALE3:.*]] = call i32 @llvm.vscale.i32()
; CHECK-VF4UF1: %[[MUL3:.*]] = mul i32 %[[VSCALE3]], 4
; CHECK-VF4UF1: %[[SUB3:.*]] = sub i32 %[[MUL3]], 2
; CHECK-VF4UF1: %[[VEC_RECUR_FOR_PHI:.*]] = extractelement <vscale x 4 x i32> %[[LOAD]], i32 %[[SUB3]]
entry:
br label %for.preheader
for.preheader:
%arrayidx.phi.trans.insert = getelementptr inbounds i32, i32* %a, i64 0
%pre_load = load i32, i32* %arrayidx.phi.trans.insert
br label %scalar.body
scalar.body:
%0 = phi i32 [ %pre_load, %for.preheader ], [ %1, %scalar.body ]
%indvars.iv = phi i64 [ 0, %for.preheader ], [ %indvars.iv.next, %scalar.body ]
%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
%arrayidx32 = getelementptr inbounds i32, i32* %a, i64 %indvars.iv.next
%1 = load i32, i32* %arrayidx32
%arrayidx34 = getelementptr inbounds i32, i32* %b, i64 %indvars.iv
%add35 = add i32 %1, %0
store i32 %add35, i32* %arrayidx34
%lftr.wideiv = trunc i64 %indvars.iv.next to i32
%exitcond = icmp eq i32 %lftr.wideiv, %n
br i1 %exitcond, label %for.exit, label %scalar.body, !llvm.loop !0
for.exit:
ret void
}
; int recurrence_2(int *a, int n) {
; int minmax;
; for (int i = 0; i < n; ++i)
; minmax = min(minmax, max(a[i] - a[i-1], 0));
; return minmax;
; }
;
define i32 @recurrence_2(i32* nocapture readonly %a, i32 %n) {
; CHECK-VF4UF1-LABEL: @recurrence_2
; CHECK-VF4UF1: vector.ph:
; CHECK-VF4UF1: %[[VSCALE1:.*]] = call i32 @llvm.vscale.i32()
; CHECK-VF4UF1: %[[MUL1:.*]] = mul i32 %[[VSCALE1]], 4
; CHECK-VF4UF1: %[[SUB1:.*]] = sub i32 %[[MUL1]], 1
; CHECK-VF4UF1: %[[VEC_RECUR_INIT:.*]] = insertelement <vscale x 4 x i32> poison, i32 %.pre, i32 %[[SUB1]]
; CHECK-VF4UF1: vector.body:
; CHECK-VF4UF1: %[[VEC_RECUR:.*]] = phi <vscale x 4 x i32> [ %[[VEC_RECUR_INIT]], %vector.ph ], [ %[[LOAD:.*]], %vector.body ]
; CHECK-VF4UF1: %[[LOAD]] = load <vscale x 4 x i32>, <vscale x 4 x i32>*
; CHECK-VF4UF1: %[[REVERSE:.*]] = call <vscale x 4 x i32> @llvm.experimental.vector.splice.nxv4i32(<vscale x 4 x i32> %[[VEC_RECUR]], <vscale x 4 x i32> %[[LOAD]], i32 -1)
; CHECK-VF4UF1: middle.block:
; CHECK-VF4UF1: %[[VSCALE2:.*]] = call i32 @llvm.vscale.i32()
; CHECK-VF4UF1: %[[MUL2:.*]] = mul i32 %[[VSCALE2]], 4
; CHECK-VF4UF1: %[[SUB2:.*]] = sub i32 %[[MUL2]], 1
; CHECK-VF4UF1: %[[VEC_RECUR_EXT:.*]] = extractelement <vscale x 4 x i32> %[[LOAD]], i32 %[[SUB2]]
entry:
%cmp27 = icmp sgt i32 %n, 0
br i1 %cmp27, label %for.preheader, label %for.cond.cleanup
for.preheader:
%arrayidx2.phi.trans.insert = getelementptr inbounds i32, i32* %a, i64 -1
%.pre = load i32, i32* %arrayidx2.phi.trans.insert, align 4
br label %scalar.body
for.cond.cleanup.loopexit:
%minmax.0.cond.lcssa = phi i32 [ %minmax.0.cond, %scalar.body ]
br label %for.cond.cleanup
for.cond.cleanup:
%minmax.0.lcssa = phi i32 [ undef, %entry ], [ %minmax.0.cond.lcssa, %for.cond.cleanup.loopexit ]
ret i32 %minmax.0.lcssa
scalar.body:
%0 = phi i32 [ %.pre, %for.preheader ], [ %1, %scalar.body ]
%indvars.iv = phi i64 [ 0, %for.preheader ], [ %indvars.iv.next, %scalar.body ]
%minmax.028 = phi i32 [ undef, %for.preheader ], [ %minmax.0.cond, %scalar.body ]
%arrayidx = getelementptr inbounds i32, i32* %a, i64 %indvars.iv
%1 = load i32, i32* %arrayidx, align 4
%sub3 = sub nsw i32 %1, %0
%cmp4 = icmp sgt i32 %sub3, 0
%cond = select i1 %cmp4, i32 %sub3, i32 0
%cmp5 = icmp slt i32 %minmax.028, %cond
%minmax.0.cond = select i1 %cmp5, i32 %minmax.028, i32 %cond
%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
%lftr.wideiv = trunc i64 %indvars.iv.next to i32
%exitcond = icmp eq i32 %lftr.wideiv, %n
br i1 %exitcond, label %for.cond.cleanup.loopexit, label %scalar.body, !llvm.loop !0
}
define void @recurrence_3(i16* nocapture readonly %a, double* nocapture %b, i32 %n, float %f, i16 %p) {
; CHECK-VF4UF1: vector.ph:
; CHECK-VF4UF1: %[[VSCALE1:.*]] = call i32 @llvm.vscale.i32()
; CHECK-VF4UF1: %[[MUL1:.*]] = mul i32 %[[VSCALE1]], 4
; CHECK-VF4UF1: %[[SUB1:.*]] = sub i32 %[[MUL1]], 1
; CHECK-VF4UF1: %vector.recur.init = insertelement <vscale x 4 x i16> poison, i16 %0, i32 %[[SUB1]]
; CHECK-VF4UF1: vector.body:
; CHECK-VF4UF1: %vector.recur = phi <vscale x 4 x i16> [ %vector.recur.init, %vector.ph ], [ %[[L1:.*]], %vector.body ]
; CHECK-VF4UF1: %[[L1]] = load <vscale x 4 x i16>, <vscale x 4 x i16>*
; CHECK-VF4UF1: %[[SPLICE:.*]] = call <vscale x 4 x i16> @llvm.experimental.vector.splice.nxv4i16(<vscale x 4 x i16> %vector.recur, <vscale x 4 x i16> %[[L1]], i32 -1)
; Check also that the casts were not moved needlessly.
; CHECK-VF4UF1: sitofp <vscale x 4 x i16> %[[L1]] to <vscale x 4 x double>
; CHECK-VF4UF1: sitofp <vscale x 4 x i16> %[[SPLICE]] to <vscale x 4 x double>
; CHECK-VF4UF1: middle.block:
; CHECK-VF4UF1: %[[VSCALE2:.*]] = call i32 @llvm.vscale.i32()
; CHECK-VF4UF1: %[[MUL2:.*]] = mul i32 %[[VSCALE2]], 4
; CHECK-VF4UF1: %[[SUB2:.*]] = sub i32 %[[MUL2]], 1
; CHECK-VF4UF1: %vector.recur.extract = extractelement <vscale x 4 x i16> %[[L1]], i32 %[[SUB2]]
entry:
%0 = load i16, i16* %a, align 2
%conv = sitofp i16 %0 to double
%conv1 = fpext float %f to double
%conv2 = sitofp i16 %p to double
%mul = fmul fast double %conv2, %conv1
%sub = fsub fast double %conv, %mul
store double %sub, double* %b, align 8
%cmp25 = icmp sgt i32 %n, 1
br i1 %cmp25, label %for.preheader, label %for.end
for.preheader:
br label %scalar.body
scalar.body:
%1 = phi i16 [ %0, %for.preheader ], [ %2, %scalar.body ]
%iv = phi i64 [ %iv.next, %scalar.body ], [ 1, %for.preheader ]
%arrayidx5 = getelementptr inbounds i16, i16* %a, i64 %iv
%2 = load i16, i16* %arrayidx5, align 2
%conv6 = sitofp i16 %2 to double
%conv11 = sitofp i16 %1 to double
%mul12 = fmul fast double %conv11, %conv1
%sub13 = fsub fast double %conv6, %mul12
%arrayidx15 = getelementptr inbounds double, double* %b, i64 %iv
store double %sub13, double* %arrayidx15, align 8
%iv.next = add nuw nsw i64 %iv, 1
%lftr.wideiv = trunc i64 %iv.next to i32
%exitcond = icmp eq i32 %lftr.wideiv, %n
br i1 %exitcond, label %for.end.loopexit, label %scalar.body, !llvm.loop !0
for.end.loopexit:
br label %for.end
for.end:
ret void
}
define void @constant_folded_previous_value() {
; CHECK-VF4UF2-LABEL: @constant_folded_previous_value
; CHECK-VF4UF2: vector.body
; CHECK-VF4UF2: %[[VECTOR_RECUR:.*]] = phi <vscale x 4 x i64> [ %vector.recur.init, %vector.ph ], [ shufflevector (<vscale x 4 x i64> insertelement (<vscale x 4 x i64> undef, i64 1, i32 0), <vscale x 4 x i64> undef, <vscale x 4 x i32> zeroinitializer), %vector.body ]
; CHECK-VF4UF2-NEXT: %[[SPLICE1:.*]] = call <vscale x 4 x i64> @llvm.experimental.vector.splice.nxv4i64(<vscale x 4 x i64> %vector.recur, <vscale x 4 x i64> shufflevector (<vscale x 4 x i64> insertelement (<vscale x 4 x i64> undef, i64 1, i32 0), <vscale x 4 x i64> undef, <vscale x 4 x i32> zeroinitializer), i32 -1)
; CHECK-VF4UF2: %[[SPLICE2:.*]] = call <vscale x 4 x i64> @llvm.experimental.vector.splice.nxv4i64(<vscale x 4 x i64> shufflevector (<vscale x 4 x i64> insertelement (<vscale x 4 x i64> undef, i64 1, i32 0), <vscale x 4 x i64> undef, <vscale x 4 x i32> zeroinitializer), <vscale x 4 x i64> shufflevector (<vscale x 4 x i64> insertelement (<vscale x 4 x i64> undef, i64 1, i32 0), <vscale x 4 x i64> undef, <vscale x 4 x i32> zeroinitializer), i32 -1)
entry:
br label %scalar.body
scalar.body:
%i = phi i64 [ 0, %entry ], [ %i.next, %scalar.body ]
%tmp2 = phi i64 [ 0, %entry ], [ %tmp3, %scalar.body ]
%tmp3 = add i64 0, 1
%i.next = add nuw nsw i64 %i, 1
%cond = icmp eq i64 %i.next, undef
br i1 %cond, label %for.end, label %scalar.body, !llvm.loop !0
for.end:
ret void
}
; We vectorize this first order recurrence, by generating two
; extracts for the phi `val.phi` - one at the last index and
; another at the second last index. We need these 2 extracts because
; the first order recurrence phi is used outside the loop, so we require the phi
; itself and not its update (addx).
define i32 @extract_second_last_iteration(i32* %cval, i32 %x) {
; CHECK-VF4UF2-LABEL: @extract_second_last_iteration
; CHECK-VF4UF2: vector.ph
; CHECK-VF4UF2: %[[SPLAT_INS1:.*]] = insertelement <vscale x 4 x i32> poison, i32 %x, i32 0
; CHECK-VF4UF2: %[[SPLAT1:.*]] = shufflevector <vscale x 4 x i32> %[[SPLAT_INS1]], <vscale x 4 x i32> poison, <vscale x 4 x i32> zeroinitializer
; CHECK-VF4UF2: %[[SPLAT_INS2:.*]] = insertelement <vscale x 4 x i32> poison, i32 %x, i32 0
; CHECK-VF4UF2: %[[SPLAT2:.*]] = shufflevector <vscale x 4 x i32> %[[SPLAT_INS2]], <vscale x 4 x i32> poison, <vscale x 4 x i32> zeroinitializer
; CHECK-VF4UF2: %[[VSCALE1:.*]] = call i32 @llvm.vscale.i32()
; CHECK-VF4UF2: %[[MUL1:.*]] = mul i32 %[[VSCALE1]], 4
; CHECK-VF4UF2: %[[SUB1:.*]] = sub i32 %[[MUL1]], 1
; CHECK-VF4UF2: %[[VEC_RECUR_INIT:.*]] = insertelement <vscale x 4 x i32> poison, i32 0, i32 %[[SUB1]]
; CHECK-VF4UF2: vector.body
; CHECK-VF4UF2: %[[VEC_RECUR:.*]] = phi <vscale x 4 x i32> [ %[[VEC_RECUR_INIT]], %vector.ph ], [ %[[ADD2:.*]], %vector.body ]
; CHECK-VF4UF2: %[[ADD1:.*]] = add <vscale x 4 x i32> %{{.*}}, %[[SPLAT1]]
; CHECK-VF4UF2: %[[ADD2]] = add <vscale x 4 x i32> %{{.*}}, %[[SPLAT2]]
; CHECK-VF4UF2: middle.block
; CHECK-VF4UF2: %[[VSCALE2:.*]] = call i32 @llvm.vscale.i32()
; CHECK-VF4UF2: %[[MUL2:.*]] = mul i32 %[[VSCALE2]], 4
; CHECK-VF4UF2: %[[SUB2:.*]] = sub i32 %[[MUL2]], 1
; CHECK-VF4UF2: %vector.recur.extract = extractelement <vscale x 4 x i32> %[[ADD2]], i32 %[[SUB2]]
; CHECK-VF4UF2: %[[VSCALE3:.*]] = call i32 @llvm.vscale.i32()
; CHECK-VF4UF2: %[[MUL3:.*]] = mul i32 %[[VSCALE3]], 4
; CHECK-VF4UF2: %[[SUB3:.*]] = sub i32 %[[MUL3]], 2
; CHECK-VF4UF2: %vector.recur.extract.for.phi = extractelement <vscale x 4 x i32> %[[ADD2]], i32 %[[SUB3]]
entry:
br label %for.body
for.body:
%inc.phi = phi i32 [ 0, %entry ], [ %inc, %for.body ]
%val.phi = phi i32 [ 0, %entry ], [ %addx, %for.body ]
%inc = add i32 %inc.phi, 1
%bc = zext i32 %inc.phi to i64
%addx = add i32 %inc.phi, %x
%cmp = icmp eq i32 %inc.phi, 95
br i1 %cmp, label %for.end, label %for.body, !llvm.loop !0
for.end:
ret i32 %val.phi
}
; void sink_after(short *a, int n, int *b) {
; for(int i = 0; i < n; i++)
; b[i] = (a[i] * a[i + 1]);
; }
; Check that the sext sank after the load in the vector loop.
define void @sink_after(i16* %a, i32* %b, i64 %n) {
; CHECK-VF4UF1-LABEL: @sink_after
; CHECK-VF4UF1: vector.body
; CHECK-VF4UF1: %[[VEC_RECUR:.*]] = phi <vscale x 4 x i16> [ %vector.recur.init, %vector.ph ], [ %[[LOAD:.*]], %vector.body ]
; CHECK-VF4UF1: %[[LOAD]] = load <vscale x 4 x i16>, <vscale x 4 x i16>*
; CHECK-VF4UF1-NEXT: %[[SPLICE:.*]] = call <vscale x 4 x i16> @llvm.experimental.vector.splice.nxv4i16(<vscale x 4 x i16> %[[VEC_RECUR]], <vscale x 4 x i16> %[[LOAD]], i32 -1)
; CHECK-VF4UF1-NEXT: sext <vscale x 4 x i16> %[[SPLICE]] to <vscale x 4 x i32>
; CHECK-VF4UF1-NEXT: sext <vscale x 4 x i16> %[[LOAD]] to <vscale x 4 x i32>
entry:
%.pre = load i16, i16* %a
br label %for.body
for.body:
%0 = phi i16 [ %.pre, %entry ], [ %1, %for.body ]
%indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
%conv = sext i16 %0 to i32
%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
%arrayidx2 = getelementptr inbounds i16, i16* %a, i64 %indvars.iv.next
%1 = load i16, i16* %arrayidx2
%conv3 = sext i16 %1 to i32
%mul = mul nsw i32 %conv3, %conv
%arrayidx5 = getelementptr inbounds i32, i32* %b, i64 %indvars.iv
store i32 %mul, i32* %arrayidx5
%exitcond = icmp eq i64 %indvars.iv.next, %n
br i1 %exitcond, label %for.end, label %for.body, !llvm.loop !0
for.end:
ret void
}
!0 = distinct !{!0, !1}
!1 = !{!"llvm.loop.vectorize.scalable.enable", i1 true}