[llvm] r258700 - Differential Revision: http://reviews.llvm.org/D13151
Sanjoy Das via llvm-commits
llvm-commits at lists.llvm.org
Mon Jan 25 11:18:18 PST 2016
On Mon, Jan 25, 2016 at 10:53 AM, Lawrence Hu via llvm-commits
<llvm-commits at lists.llvm.org> wrote:
> Author: lawrence
> Date: Mon Jan 25 12:53:39 2016
> New Revision: 258700
>
> URL: http://llvm.org/viewvc/llvm-project?rev=258700&view=rev
> Log:
>
> Differential Revision: http://reviews.llvm.org/D13151
>
> Added:
> llvm/trunk/test/Transforms/LoopReroll/ptrindvar.ll
> Modified:
> llvm/trunk/lib/Transforms/Scalar/LoopRerollPass.cpp
>
> Modified: llvm/trunk/lib/Transforms/Scalar/LoopRerollPass.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/LoopRerollPass.cpp?rev=258700&r1=258699&r2=258700&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Transforms/Scalar/LoopRerollPass.cpp (original)
> +++ llvm/trunk/lib/Transforms/Scalar/LoopRerollPass.cpp Mon Jan 25 12:53:39 2016
> @@ -396,6 +396,7 @@ namespace {
> bool instrDependsOn(Instruction *I,
> UsesTy::iterator Start,
> UsesTy::iterator End);
> + void replaceIV(Instruction *Inst, Instruction *IV, const SCEV *IterCount);
>
> LoopReroll *Parent;
>
> @@ -460,6 +461,48 @@ static bool hasUsesOutsideLoop(Instructi
> return false;
> }
>
> +static const SCEVConstant *getIncrmentFactorSCEV(ScalarEvolution *SE,
> + const SCEV *SCEVExpr,
> + Instruction &IV) {
Should this be named getIncrementFactorSCEV ?
> + const SCEVMulExpr *MulSCEV = dyn_cast<SCEVMulExpr>(SCEVExpr);
> +
> + // If StepRecurrence of a SCEVExpr is a constant (c1 * c2, c2 = sizeof(ptr)),
> + // Return c1.
> + if (!MulSCEV && IV.getType()->isPointerTy())
> + if (const SCEVConstant *IncSCEV = dyn_cast<SCEVConstant>(SCEVExpr)) {
> + const PointerType *PTy = cast<PointerType>(IV.getType());
> + Type *ElTy = PTy->getElementType();
> + const SCEV *SizeOfExpr =
> + SE->getSizeOfExpr(SE->getEffectiveSCEVType(IV.getType()), ElTy);
> + if (IncSCEV->getValue()->getValue().isNegative()) {
> + const SCEV *NewSCEV =
> + SE->getUDivExpr(SE->getNegativeSCEV(SCEVExpr), SizeOfExpr);
> + return dyn_cast<SCEVConstant>(SE->getNegativeSCEV(NewSCEV));
> + } else {
> + return dyn_cast<SCEVConstant>(SE->getUDivExpr(SCEVExpr, SizeOfExpr));
> + }
> + }
> +
> + if (!MulSCEV)
> + return nullptr;
> +
> + // If StepRecurrence of a SCEVExpr is a c * sizeof(x), where c is constant,
> + // Return c.
> + const SCEVConstant *CIncSCEV = nullptr;
> + for (const SCEV *Operand : MulSCEV->operands()) {
> + if (const SCEVConstant *Constant = dyn_cast<SCEVConstant>(Operand)) {
> + CIncSCEV = Constant;
> + } else if (const SCEVUnknown *Unknown = dyn_cast<SCEVUnknown>(Operand)) {
> + Type *AllocTy;
> + if (!Unknown->isSizeOf(AllocTy))
> + break;
> + } else {
> + return nullptr;
> + }
> + }
> + return CIncSCEV;
> +}
> +
> // Collect the list of loop induction variables with respect to which it might
> // be possible to reroll the loop.
> void LoopReroll::collectPossibleIVs(Loop *L,
> @@ -469,7 +512,7 @@ void LoopReroll::collectPossibleIVs(Loop
> IE = Header->getFirstInsertionPt(); I != IE; ++I) {
> if (!isa<PHINode>(I))
> continue;
> - if (!I->getType()->isIntegerTy())
> + if (!I->getType()->isIntegerTy() && !I->getType()->isPointerTy())
> continue;
>
> if (const SCEVAddRecExpr *PHISCEV =
> @@ -478,9 +521,14 @@ void LoopReroll::collectPossibleIVs(Loop
> continue;
> if (!PHISCEV->isAffine())
> continue;
> - if (const SCEVConstant *IncSCEV =
> - dyn_cast<SCEVConstant>(PHISCEV->getStepRecurrence(*SE))) {
> - const APInt &AInt = IncSCEV->getAPInt().abs();
> + const SCEVConstant *IncSCEV = nullptr;
> + if (I->getType()->isPointerTy())
> + IncSCEV =
> + getIncrmentFactorSCEV(SE, PHISCEV->getStepRecurrence(*SE), *I);
> + else
> + IncSCEV = dyn_cast<SCEVConstant>(PHISCEV->getStepRecurrence(*SE));
> + if (IncSCEV) {
> + const APInt &AInt = IncSCEV->getValue()->getValue().abs();
> if (IncSCEV->getValue()->isZero() || AInt.uge(MaxInc))
> continue;
> IVToIncMap[&*I] = IncSCEV->getValue()->getSExtValue();
> @@ -651,10 +699,12 @@ static bool isSimpleArithmeticOp(User *I
>
> static bool isLoopIncrement(User *U, Instruction *IV) {
> BinaryOperator *BO = dyn_cast<BinaryOperator>(U);
> - if (!BO || BO->getOpcode() != Instruction::Add)
> +
> + if ((BO && BO->getOpcode() != Instruction::Add) ||
> + (!BO && !isa<GetElementPtrInst>(U)))
> return false;
>
> - for (auto *UU : BO->users()) {
> + for (auto *UU : U->users()) {
> PHINode *PN = dyn_cast<PHINode>(UU);
> if (PN && PN == IV)
> return true;
> @@ -1272,61 +1322,84 @@ void LoopReroll::DAGRootTracker::replace
>
> ++J;
> }
> - bool Negative = IVToIncMap[IV] < 0;
> - const DataLayout &DL = Header->getModule()->getDataLayout();
>
> // We need to create a new induction variable for each different BaseInst.
> - for (auto &DRS : RootSets) {
> + for (auto &DRS : RootSets)
> // Insert the new induction variable.
> - const SCEVAddRecExpr *RealIVSCEV =
> - cast<SCEVAddRecExpr>(SE->getSCEV(DRS.BaseInst));
> - const SCEV *Start = RealIVSCEV->getStart();
> - const SCEVAddRecExpr *H = cast<SCEVAddRecExpr>(SE->getAddRecExpr(
> - Start, SE->getConstant(RealIVSCEV->getType(), Negative ? -1 : 1), L,
> - SCEV::FlagAnyWrap));
> - { // Limit the lifetime of SCEVExpander.
> - SCEVExpander Expander(*SE, DL, "reroll");
> - Value *NewIV = Expander.expandCodeFor(H, IV->getType(), &Header->front());
> -
> - for (auto &KV : Uses) {
> - if (KV.second.find_first() == 0)
> - KV.first->replaceUsesOfWith(DRS.BaseInst, NewIV);
> - }
> -
> - if (BranchInst *BI = dyn_cast<BranchInst>(Header->getTerminator())) {
> - // FIXME: Why do we need this check?
> - if (Uses[BI].find_first() == IL_All) {
> - const SCEV *ICSCEV = RealIVSCEV->evaluateAtIteration(IterCount, *SE);
> -
> - // Iteration count SCEV minus 1
> - const SCEV *ICMinus1SCEV = SE->getMinusSCEV(
> - ICSCEV, SE->getConstant(ICSCEV->getType(), Negative ? -1 : 1));
> -
> - Value *ICMinus1; // Iteration count minus 1
> - if (isa<SCEVConstant>(ICMinus1SCEV)) {
> - ICMinus1 = Expander.expandCodeFor(ICMinus1SCEV, NewIV->getType(), BI);
> - } else {
> - BasicBlock *Preheader = L->getLoopPreheader();
> - if (!Preheader)
> - Preheader = InsertPreheaderForLoop(L, DT, LI, PreserveLCSSA);
> + replaceIV(DRS.BaseInst, IV, IterCount);
>
> - ICMinus1 = Expander.expandCodeFor(ICMinus1SCEV, NewIV->getType(),
> - Preheader->getTerminator());
> - }
> + SimplifyInstructionsInBlock(Header, TLI);
> + DeleteDeadPHIs(Header, TLI);
> +}
>
> - Value *Cond =
> - new ICmpInst(BI, CmpInst::ICMP_EQ, NewIV, ICMinus1, "exitcond");
> - BI->setCondition(Cond);
> +void LoopReroll::DAGRootTracker::replaceIV(Instruction *Inst,
> + Instruction *InstIV,
> + const SCEV *IterCount) {
> + BasicBlock *Header = L->getHeader();
> + int64_t Inc = IVToIncMap[InstIV];
> + bool Negative = Inc < 0;
> +
> + const SCEVAddRecExpr *RealIVSCEV = cast<SCEVAddRecExpr>(SE->getSCEV(Inst));
> + const SCEV *Start = RealIVSCEV->getStart();
>
> - if (BI->getSuccessor(1) != Header)
> - BI->swapSuccessors();
> + const SCEV *SizeOfExpr = nullptr;
> + const SCEV *IncrExpr =
> + SE->getConstant(RealIVSCEV->getType(), Negative ? -1 : 1);
> + if (auto *PTy = dyn_cast<PointerType>(Inst->getType())) {
> + Type *ElTy = PTy->getElementType();
> + SizeOfExpr =
> + SE->getSizeOfExpr(SE->getEffectiveSCEVType(Inst->getType()), ElTy);
> + IncrExpr = SE->getMulExpr(IncrExpr, SizeOfExpr);
> + }
> + const SCEV *NewIVSCEV =
> + SE->getAddRecExpr(Start, IncrExpr, L, SCEV::FlagAnyWrap);
> +
> + { // Limit the lifetime of SCEVExpander.
> + const DataLayout &DL = Header->getModule()->getDataLayout();
> + SCEVExpander Expander(*SE, DL, "reroll");
> + Value *NewIV =
> + Expander.expandCodeFor(NewIVSCEV, InstIV->getType(), &Header->front());
> +
> + for (auto &KV : Uses)
> + if (KV.second.find_first() == 0)
> + KV.first->replaceUsesOfWith(Inst, NewIV);
> +
> + if (BranchInst *BI = dyn_cast<BranchInst>(Header->getTerminator())) {
> + // FIXME: Why do we need this check?
> + if (Uses[BI].find_first() == IL_All) {
> + const SCEV *ICSCEV = RealIVSCEV->evaluateAtIteration(IterCount, *SE);
> +
> + // Iteration count SCEV minus or plus 1
> + const SCEV *MinusPlus1SCEV =
> + SE->getConstant(ICSCEV->getType(), Negative ? -1 : 1);
> + if (Inst->getType()->isPointerTy()) {
> + assert(SizeOfExpr && "SizeOfExpr is not initialized");
> + MinusPlus1SCEV = SE->getMulExpr(MinusPlus1SCEV, SizeOfExpr);
> }
> +
> + const SCEV *ICMinusPlus1SCEV = SE->getMinusSCEV(ICSCEV, MinusPlus1SCEV);
> + // Iteration count minus 1
> + Value *ICMinusPlus1 = nullptr;
> + if (isa<SCEVConstant>(ICMinusPlus1SCEV)) {
> + ICMinusPlus1 =
> + Expander.expandCodeFor(ICMinusPlus1SCEV, NewIV->getType(), BI);
> + } else {
> + BasicBlock *Preheader = L->getLoopPreheader();
> + if (!Preheader)
> + Preheader = InsertPreheaderForLoop(L, DT, LI, PreserveLCSSA);
> + ICMinusPlus1 = Expander.expandCodeFor(
> + ICMinusPlus1SCEV, NewIV->getType(), Preheader->getTerminator());
> + }
> +
> + Value *Cond =
> + new ICmpInst(BI, CmpInst::ICMP_EQ, NewIV, ICMinusPlus1, "exitcond");
> + BI->setCondition(Cond);
> +
> + if (BI->getSuccessor(1) != Header)
> + BI->swapSuccessors();
> }
> }
> }
> -
> - SimplifyInstructionsInBlock(Header, TLI);
> - DeleteDeadPHIs(Header, TLI);
> }
>
> // Validate the selected reductions. All iterations must have an isomorphic
>
> Added: llvm/trunk/test/Transforms/LoopReroll/ptrindvar.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopReroll/ptrindvar.ll?rev=258700&view=auto
> ==============================================================================
> --- llvm/trunk/test/Transforms/LoopReroll/ptrindvar.ll (added)
> +++ llvm/trunk/test/Transforms/LoopReroll/ptrindvar.ll Mon Jan 25 12:53:39 2016
> @@ -0,0 +1,81 @@
> +; RUN: opt -S -loop-reroll %s | FileCheck %s
> +target triple = "aarch64--linux-gnu"
> +
> +define i32 @test(i32* readonly %buf, i32* readnone %end) #0 {
> +entry:
> + %cmp.9 = icmp eq i32* %buf, %end
> + br i1 %cmp.9, label %while.end, label %while.body.preheader
> +
> +while.body.preheader:
> + br label %while.body
> +
> +while.body:
> +;CHECK-LABEL: while.body:
> +;CHECK-NEXT: %indvar = phi i64 [ %indvar.next, %while.body ], [ 0, %while.body.preheader ]
> +;CHECK-NEXT: %S.011 = phi i32 [ %add, %while.body ], [ undef, %while.body.preheader ]
> +;CHECK-NEXT: %scevgep = getelementptr i32, i32* %buf, i64 %indvar
> +;CHECK-NEXT: %4 = load i32, i32* %scevgep, align 4
> +;CHECK-NEXT: %add = add nsw i32 %4, %S.011
> +;CHECK-NEXT: %indvar.next = add i64 %indvar, 1
> +;CHECK-NEXT: %exitcond = icmp eq i32* %scevgep, %scevgep5
> +;CHECK-NEXT: br i1 %exitcond, label %while.end.loopexit, label %while.body
> +
> + %S.011 = phi i32 [ %add2, %while.body ], [ undef, %while.body.preheader ]
> + %buf.addr.010 = phi i32* [ %add.ptr, %while.body ], [ %buf, %while.body.preheader ]
> + %0 = load i32, i32* %buf.addr.010, align 4
> + %add = add nsw i32 %0, %S.011
> + %arrayidx1 = getelementptr inbounds i32, i32* %buf.addr.010, i64 1
> + %1 = load i32, i32* %arrayidx1, align 4
> + %add2 = add nsw i32 %add, %1
> + %add.ptr = getelementptr inbounds i32, i32* %buf.addr.010, i64 2
> + %cmp = icmp eq i32* %add.ptr, %end
> + br i1 %cmp, label %while.end.loopexit, label %while.body
> +
> +while.end.loopexit:
> + %add2.lcssa = phi i32 [ %add2, %while.body ]
> + br label %while.end
> +
> +while.end:
> + %S.0.lcssa = phi i32 [ undef, %entry ], [ %add2.lcssa, %while.end.loopexit ]
> + ret i32 %S.0.lcssa
> +}
> +
> +define i32 @test2(i32* readonly %buf, i32* readnone %end) #0 {
> +entry:
> + %cmp.9 = icmp eq i32* %buf, %end
> + br i1 %cmp.9, label %while.end, label %while.body.preheader
> +
> +while.body.preheader:
> + br label %while.body
> +
> +while.body:
> +;CHECK-LABEL: while.body:
> +;CHECK-NEXT: %indvar = phi i64 [ %indvar.next, %while.body ], [ 0, %while.body.preheader ]
> +;CHECK-NEXT: %S.011 = phi i32 [ %add, %while.body ], [ undef, %while.body.preheader ]
> +;CHECK-NEXT: %4 = mul i64 %indvar, -1
> +;CHECK-NEXT: %scevgep = getelementptr i32, i32* %buf, i64 %4
> +;CHECK-NEXT: %5 = load i32, i32* %scevgep, align 4
> +;CHECK-NEXT: %add = add nsw i32 %5, %S.011
> +;CHECK-NEXT: %indvar.next = add i64 %indvar, 1
> +;CHECK-NEXT: %exitcond = icmp eq i32* %scevgep, %scevgep5
> +;CHECK-NEXT: br i1 %exitcond, label %while.end.loopexit, label %while.body
> +
> + %S.011 = phi i32 [ %add2, %while.body ], [ undef, %while.body.preheader ]
> + %buf.addr.010 = phi i32* [ %add.ptr, %while.body ], [ %buf, %while.body.preheader ]
> + %0 = load i32, i32* %buf.addr.010, align 4
> + %add = add nsw i32 %0, %S.011
> + %arrayidx1 = getelementptr inbounds i32, i32* %buf.addr.010, i64 -1
> + %1 = load i32, i32* %arrayidx1, align 4
> + %add2 = add nsw i32 %add, %1
> + %add.ptr = getelementptr inbounds i32, i32* %buf.addr.010, i64 -2
> + %cmp = icmp eq i32* %add.ptr, %end
> + br i1 %cmp, label %while.end.loopexit, label %while.body
> +
> +while.end.loopexit:
> + %add2.lcssa = phi i32 [ %add2, %while.body ]
> + br label %while.end
> +
> +while.end:
> + %S.0.lcssa = phi i32 [ undef, %entry ], [ %add2.lcssa, %while.end.loopexit ]
> + ret i32 %S.0.lcssa
> +}
>
>
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Sanjoy Das
http://playingwithpointers.com
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