[llvm] r281853 - [Loop Vectorizer] Consecutive memory access - fixed and simplified
Elena Demikhovsky via llvm-commits
llvm-commits at lists.llvm.org
Sun Sep 18 06:56:10 PDT 2016
Author: delena
Date: Sun Sep 18 08:56:08 2016
New Revision: 281853
URL: http://llvm.org/viewvc/llvm-project?rev=281853&view=rev
Log:
[Loop Vectorizer] Consecutive memory access - fixed and simplified
Amended consecutive memory access detection in Loop Vectorizer.
Load/Store were not handled properly without preceding GEP instruction.
Differential Revision: https://reviews.llvm.org/D20789
Added:
llvm/trunk/test/Transforms/LoopVectorize/consec_no_gep.ll
Modified:
llvm/trunk/include/llvm/Analysis/LoopAccessAnalysis.h
llvm/trunk/lib/Analysis/LoopAccessAnalysis.cpp
llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp
Modified: llvm/trunk/include/llvm/Analysis/LoopAccessAnalysis.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/LoopAccessAnalysis.h?rev=281853&r1=281852&r2=281853&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Analysis/LoopAccessAnalysis.h (original)
+++ llvm/trunk/include/llvm/Analysis/LoopAccessAnalysis.h Sun Sep 18 08:56:08 2016
@@ -713,7 +713,7 @@ const SCEV *replaceSymbolicStrideSCEV(Pr
/// run-time assumptions.
int64_t getPtrStride(PredicatedScalarEvolution &PSE, Value *Ptr, const Loop *Lp,
const ValueToValueMap &StridesMap = ValueToValueMap(),
- bool Assume = false);
+ bool Assume = false, bool ShouldCheckWrap = true);
/// \brief Returns true if the memory operations \p A and \p B are consecutive.
/// This is a simple API that does not depend on the analysis pass.
Modified: llvm/trunk/lib/Analysis/LoopAccessAnalysis.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/LoopAccessAnalysis.cpp?rev=281853&r1=281852&r2=281853&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/LoopAccessAnalysis.cpp (original)
+++ llvm/trunk/lib/Analysis/LoopAccessAnalysis.cpp Sun Sep 18 08:56:08 2016
@@ -887,7 +887,7 @@ static bool isNoWrapAddRec(Value *Ptr, c
/// \brief Check whether the access through \p Ptr has a constant stride.
int64_t llvm::getPtrStride(PredicatedScalarEvolution &PSE, Value *Ptr,
const Loop *Lp, const ValueToValueMap &StridesMap,
- bool Assume) {
+ bool Assume, bool ShouldCheckWrap) {
Type *Ty = Ptr->getType();
assert(Ty->isPointerTy() && "Unexpected non-ptr");
@@ -926,9 +926,9 @@ int64_t llvm::getPtrStride(PredicatedSca
// to access the pointer value "0" which is undefined behavior in address
// space 0, therefore we can also vectorize this case.
bool IsInBoundsGEP = isInBoundsGep(Ptr);
- bool IsNoWrapAddRec =
- PSE.hasNoOverflow(Ptr, SCEVWrapPredicate::IncrementNUSW) ||
- isNoWrapAddRec(Ptr, AR, PSE, Lp);
+ bool IsNoWrapAddRec = !ShouldCheckWrap ||
+ PSE.hasNoOverflow(Ptr, SCEVWrapPredicate::IncrementNUSW) ||
+ isNoWrapAddRec(Ptr, AR, PSE, Lp);
bool IsInAddressSpaceZero = PtrTy->getAddressSpace() == 0;
if (!IsNoWrapAddRec && !IsInBoundsGEP && !IsInAddressSpaceZero) {
if (Assume) {
Modified: llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp?rev=281853&r1=281852&r2=281853&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp (original)
+++ llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp Sun Sep 18 08:56:08 2016
@@ -2296,87 +2296,13 @@ void InnerLoopVectorizer::buildScalarSte
}
int LoopVectorizationLegality::isConsecutivePtr(Value *Ptr) {
- assert(Ptr->getType()->isPointerTy() && "Unexpected non-ptr");
- auto *SE = PSE.getSE();
- // Make sure that the pointer does not point to structs.
- if (Ptr->getType()->getPointerElementType()->isAggregateType())
- return 0;
-
- // If this value is a pointer induction variable, we know it is consecutive.
- PHINode *Phi = dyn_cast_or_null<PHINode>(Ptr);
- if (Phi && Inductions.count(Phi)) {
- InductionDescriptor II = Inductions[Phi];
- return II.getConsecutiveDirection();
- }
-
- GetElementPtrInst *Gep = getGEPInstruction(Ptr);
- if (!Gep)
- return 0;
-
- unsigned NumOperands = Gep->getNumOperands();
- Value *GpPtr = Gep->getPointerOperand();
- // If this GEP value is a consecutive pointer induction variable and all of
- // the indices are constant, then we know it is consecutive.
- Phi = dyn_cast<PHINode>(GpPtr);
- if (Phi && Inductions.count(Phi)) {
-
- // Make sure that the pointer does not point to structs.
- PointerType *GepPtrType = cast<PointerType>(GpPtr->getType());
- if (GepPtrType->getElementType()->isAggregateType())
- return 0;
-
- // Make sure that all of the index operands are loop invariant.
- for (unsigned i = 1; i < NumOperands; ++i)
- if (!SE->isLoopInvariant(PSE.getSCEV(Gep->getOperand(i)), TheLoop))
- return 0;
-
- InductionDescriptor II = Inductions[Phi];
- return II.getConsecutiveDirection();
- }
- unsigned InductionOperand = getGEPInductionOperand(Gep);
-
- // Check that all of the gep indices are uniform except for our induction
- // operand.
- for (unsigned i = 0; i != NumOperands; ++i)
- if (i != InductionOperand &&
- !SE->isLoopInvariant(PSE.getSCEV(Gep->getOperand(i)), TheLoop))
- return 0;
-
- // We can emit wide load/stores only if the last non-zero index is the
- // induction variable.
- const SCEV *Last = nullptr;
- if (!getSymbolicStrides() || !getSymbolicStrides()->count(Gep))
- Last = PSE.getSCEV(Gep->getOperand(InductionOperand));
- else {
- // Because of the multiplication by a stride we can have a s/zext cast.
- // We are going to replace this stride by 1 so the cast is safe to ignore.
- //
- // %indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
- // %0 = trunc i64 %indvars.iv to i32
- // %mul = mul i32 %0, %Stride1
- // %idxprom = zext i32 %mul to i64 << Safe cast.
- // %arrayidx = getelementptr inbounds i32* %B, i64 %idxprom
- //
- Last = replaceSymbolicStrideSCEV(PSE, *getSymbolicStrides(),
- Gep->getOperand(InductionOperand), Gep);
- if (const SCEVCastExpr *C = dyn_cast<SCEVCastExpr>(Last))
- Last =
- (C->getSCEVType() == scSignExtend || C->getSCEVType() == scZeroExtend)
- ? C->getOperand()
- : Last;
- }
- if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Last)) {
- const SCEV *Step = AR->getStepRecurrence(*SE);
-
- // The memory is consecutive because the last index is consecutive
- // and all other indices are loop invariant.
- if (Step->isOne())
- return 1;
- if (Step->isAllOnesValue())
- return -1;
- }
+ const ValueToValueMap &Strides = getSymbolicStrides() ? *getSymbolicStrides() :
+ ValueToValueMap();
+ int Stride = getPtrStride(PSE, Ptr, TheLoop, Strides, true, false);
+ if (Stride == 1 || Stride == -1)
+ return Stride;
return 0;
}
@@ -2813,8 +2739,6 @@ void InnerLoopVectorizer::vectorizeMemor
Ptr = Builder.Insert(Gep2);
} else { // No GEP
- // Use the induction element ptr.
- assert(isa<PHINode>(Ptr) && "Invalid induction ptr");
setDebugLocFromInst(Builder, Ptr);
Ptr = getScalarValue(Ptr, 0, 0);
}
Added: llvm/trunk/test/Transforms/LoopVectorize/consec_no_gep.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopVectorize/consec_no_gep.ll?rev=281853&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/LoopVectorize/consec_no_gep.ll (added)
+++ llvm/trunk/test/Transforms/LoopVectorize/consec_no_gep.ll Sun Sep 18 08:56:08 2016
@@ -0,0 +1,43 @@
+;RUN: opt < %s -loop-vectorize -force-vector-width=4 -force-vector-interleave=1 -instcombine -S | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+;; Check consecutive memory access without preceding GEP instruction
+
+; for (int i=0; i<len; i++) {
+; *to++ = *from++;
+; }
+
+; CHECK-LABEL: @consecutive_no_gep(
+; CHECK: vector.body
+; CHECK: %[[index:.*]] = phi i64 [ 0, %vector.ph ]
+; CHECK: getelementptr float, float* %{{.*}}, i64 %[[index]]
+; CHECK: load <4 x float>
+
+define void @consecutive_no_gep(float* noalias nocapture readonly %from, float* noalias nocapture %to, i32 %len) #0 {
+entry:
+ %cmp2 = icmp sgt i32 %len, 0
+ br i1 %cmp2, label %for.body.preheader, label %for.end
+
+for.body.preheader: ; preds = %entry
+ br label %for.body
+
+for.body: ; preds = %for.body.preheader, %for.body
+ %i.05 = phi i32 [ %inc, %for.body ], [ 0, %for.body.preheader ]
+ %from.addr.04 = phi float* [ %incdec.ptr, %for.body ], [ %from, %for.body.preheader ]
+ %to.addr.03 = phi float* [ %incdec.ptr1, %for.body ], [ %to, %for.body.preheader ]
+ %incdec.ptr = getelementptr inbounds float, float* %from.addr.04, i64 1
+ %val = load float, float* %from.addr.04, align 4
+ %incdec.ptr1 = getelementptr inbounds float, float* %to.addr.03, i64 1
+ store float %val, float* %to.addr.03, align 4
+ %inc = add nsw i32 %i.05, 1
+ %cmp = icmp slt i32 %inc, %len
+ br i1 %cmp, label %for.body, label %for.end.loopexit
+
+for.end.loopexit: ; preds = %for.body
+ br label %for.end
+
+for.end: ; preds = %for.end.loopexit, %entry
+ ret void
+}
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