[llvm] r215994 - Small refactor on VectorizerHint for deduplication
Yaron Keren
yaron.keren at gmail.com
Tue Aug 19 10:55:36 PDT 2014
Hi Renato,
Visual C++ 2013 does not like:
1>------ Build started: Project: LLVMVectorize, Configuration:
RelWithDebInfo Win32 ------
1> LoopVectorize.cpp
1>..\..\..\..\lib\Transforms\Vectorize\LoopVectorize.cpp(1016): error
C2536:
'`anonymous-namespace'::LoopVectorizeHints::`anonymous-namespace'::LoopVectorizeHints::Hints'
: cannot specify explicit initializer for arrays
1> ..\..\..\..\lib\Transforms\Vectorize\LoopVectorize.cpp(1016) :
see declaration of '`anonymous-namespace'::LoopVectorizeHints::Hints'
1> ..\..\..\..\lib\Transforms\Vectorize\LoopVectorize.cpp(1016) :
see declaration of '`anonymous-namespace'::LoopVectorizeHints::Hints'
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========
Yaron
2014-08-19 20:30 GMT+03:00 Renato Golin <renato.golin at linaro.org>:
> Author: rengolin
> Date: Tue Aug 19 12:30:43 2014
> New Revision: 215994
>
> URL: http://llvm.org/viewvc/llvm-project?rev=215994&view=rev
> Log:
> Small refactor on VectorizerHint for deduplication
>
> Previously, the hint mechanism relied on clean up passes to remove
> redundant
> metadata, which still showed up if running opt at low levels of
> optimization.
> That also has shown that multiple nodes of the same type, but with
> different
> values could still coexist, even if temporary, and cause confusion if the
> next pass got the wrong value.
>
> This patch makes sure that, if metadata already exists in a loop, the hint
> mechanism will never append a new node, but always replace the existing
> one.
> It also enhances the algorithm to cope with more metadata types in the
> future
> by just adding a new type, not a lot of code.
>
> Added:
> llvm/trunk/test/Transforms/LoopVectorize/duplicated-metadata.ll
> Modified:
> llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp
>
> Modified: llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp?rev=215994&r1=215993&r2=215994&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp (original)
> +++ llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp Tue Aug 19
> 12:30:43 2014
> @@ -970,7 +970,54 @@ private:
>
> /// Utility class for getting and setting loop vectorizer hints in the
> form
> /// of loop metadata.
> +/// This class keeps a number of loop annotations locally (as member
> variables)
> +/// and can, upon request, write them back as metadata on the loop. It
> will
> +/// initially scan the loop for existing metadata, and will update the
> local
> +/// values based on information in the loop.
> +/// We cannot write all values to metadata, as the mere presence of some
> info,
> +/// for example 'force', means a decision has been made. So, we need to be
> +/// careful NOT to add them if the user hasn't specifically asked so.
> class LoopVectorizeHints {
> + enum HintKind {
> + HK_WIDTH,
> + HK_UNROLL,
> + HK_FORCE
> + };
> +
> + /// Hint - associates name and validation with the hint value.
> + struct Hint {
> + const char * Name;
> + unsigned Value; // This may have to change for non-numeric values.
> + HintKind Kind;
> +
> + Hint(const char * Name, unsigned Value, HintKind Kind)
> + : Name(Name), Value(Value), Kind(Kind) { }
> +
> + bool validate(unsigned Val) {
> + switch (Kind) {
> + case HK_WIDTH:
> + return isPowerOf2_32(Val) && Val <= MaxVectorWidth;
> + case HK_UNROLL:
> + return isPowerOf2_32(Val) && Val <= MaxUnrollFactor;
> + case HK_FORCE:
> + return (Val <= 1);
> + }
> + return false;
> + }
> + };
> +
> + /// Vectorization width.
> + Hint Width;
> + /// Vectorization unroll factor.
> + Hint Unroll;
> + /// Vectorization forced
> + Hint Force;
> + /// Array to help iterating through all hints.
> + Hint *Hints[3] = { &Width, &Unroll, &Force };
> +
> + /// Return the loop metadata prefix.
> + static StringRef Prefix() { return "llvm.loop."; }
> +
> public:
> enum ForceKind {
> FK_Undefined = -1, ///< Not selected.
> @@ -979,70 +1026,40 @@ public:
> };
>
> LoopVectorizeHints(const Loop *L, bool DisableUnrolling)
> - : Width(VectorizationFactor),
> - Unroll(DisableUnrolling),
> - Force(FK_Undefined),
> - LoopID(L->getLoopID()) {
> - getHints(L);
> + : Width("vectorize.width", VectorizationFactor, HK_WIDTH),
> + Unroll("interleave.count", DisableUnrolling, HK_UNROLL),
> + Force("vectorize.enable", FK_Undefined, HK_FORCE),
> + TheLoop(L) {
> + // Populate values with existing loop metadata.
> + getHintsFromMetadata();
> +
> // force-vector-unroll overrides DisableUnrolling.
> if (VectorizationUnroll.getNumOccurrences() > 0)
> - Unroll = VectorizationUnroll;
> + Unroll.Value = VectorizationUnroll;
>
> - DEBUG(if (DisableUnrolling && Unroll == 1) dbgs()
> + DEBUG(if (DisableUnrolling && Unroll.Value == 1) dbgs()
> << "LV: Unrolling disabled by the pass manager\n");
> }
>
> - /// Return the loop metadata prefix.
> - static StringRef Prefix() { return "llvm.loop."; }
> -
> - MDNode *createHint(LLVMContext &Context, StringRef Name, unsigned V)
> const {
> - SmallVector<Value*, 2> Vals;
> - Vals.push_back(MDString::get(Context, Name));
> - Vals.push_back(ConstantInt::get(Type::getInt32Ty(Context), V));
> - return MDNode::get(Context, Vals);
> - }
> -
> /// Mark the loop L as already vectorized by setting the width to 1.
> - void setAlreadyVectorized(Loop *L) {
> - LLVMContext &Context = L->getHeader()->getContext();
> -
> - Width = 1;
> -
> - // Create a new loop id with one more operand for the
> already_vectorized
> - // hint. If the loop already has a loop id then copy the existing
> operands.
> - SmallVector<Value*, 4> Vals(1);
> - if (LoopID)
> - for (unsigned i = 1, ie = LoopID->getNumOperands(); i < ie; ++i)
> - Vals.push_back(LoopID->getOperand(i));
> -
> - Vals.push_back(
> - createHint(Context, Twine(Prefix(), "vectorize.width").str(),
> Width));
> - Vals.push_back(
> - createHint(Context, Twine(Prefix(), "interleave.count").str(),
> 1));
> -
> - MDNode *NewLoopID = MDNode::get(Context, Vals);
> - // Set operand 0 to refer to the loop id itself.
> - NewLoopID->replaceOperandWith(0, NewLoopID);
> -
> - L->setLoopID(NewLoopID);
> - if (LoopID)
> - LoopID->replaceAllUsesWith(NewLoopID);
> -
> - LoopID = NewLoopID;
> + void setAlreadyVectorized() {
> + Width.Value = Unroll.Value = 1;
> + writeHintsToMetadata({ Width, Unroll });
> }
>
> + /// Dumps all the hint information.
> std::string emitRemark() const {
> Report R;
> - if (Force == LoopVectorizeHints::FK_Disabled)
> + if (Force.Value == LoopVectorizeHints::FK_Disabled)
> R << "vectorization is explicitly disabled";
> else {
> R << "use -Rpass-analysis=loop-vectorize for more info";
> - if (Force == LoopVectorizeHints::FK_Enabled) {
> + if (Force.Value == LoopVectorizeHints::FK_Enabled) {
> R << " (Force=true";
> - if (Width != 0)
> - R << ", Vector Width=" << Width;
> - if (Unroll != 0)
> - R << ", Interleave Count=" << Unroll;
> + if (Width.Value != 0)
> + R << ", Vector Width=" << Width.Value;
> + if (Unroll.Value != 0)
> + R << ", Interleave Count=" << Unroll.Value;
> R << ")";
> }
> }
> @@ -1050,14 +1067,14 @@ public:
> return R.str();
> }
>
> - unsigned getWidth() const { return Width; }
> - unsigned getUnroll() const { return Unroll; }
> - enum ForceKind getForce() const { return Force; }
> - MDNode *getLoopID() const { return LoopID; }
> + unsigned getWidth() const { return Width.Value; }
> + unsigned getUnroll() const { return Unroll.Value; }
> + enum ForceKind getForce() const { return (ForceKind)Force.Value; }
>
> private:
> - /// Find hints specified in the loop metadata.
> - void getHints(const Loop *L) {
> + /// Find hints specified in the loop metadata and update local values.
> + void getHintsFromMetadata() {
> + MDNode *LoopID = TheLoop->getLoopID();
> if (!LoopID)
> return;
>
> @@ -1086,52 +1103,91 @@ private:
> continue;
>
> // Check if the hint starts with the loop metadata prefix.
> - StringRef Hint = S->getString();
> - if (!Hint.startswith(Prefix()))
> - continue;
> - // Remove the prefix.
> - Hint = Hint.substr(Prefix().size(), StringRef::npos);
> -
> + StringRef Name = S->getString();
> if (Args.size() == 1)
> - getHint(Hint, Args[0]);
> + setHint(Name, Args[0]);
> }
> }
>
> - // Check string hint with one operand.
> - void getHint(StringRef Hint, Value *Arg) {
> + /// Checks string hint with one operand and set value if valid.
> + void setHint(StringRef Name, Value *Arg) {
> + if (!Name.startswith(Prefix()))
> + return;
> + Name = Name.substr(Prefix().size(), StringRef::npos);
> +
> const ConstantInt *C = dyn_cast<ConstantInt>(Arg);
> if (!C) return;
> unsigned Val = C->getZExtValue();
>
> - if (Hint == "vectorize.width") {
> - if (isPowerOf2_32(Val) && Val <= MaxVectorWidth)
> - Width = Val;
> - else
> - DEBUG(dbgs() << "LV: ignoring invalid width hint metadata\n");
> - } else if (Hint == "vectorize.enable") {
> - if (C->getBitWidth() == 1)
> - Force = Val == 1 ? LoopVectorizeHints::FK_Enabled
> - : LoopVectorizeHints::FK_Disabled;
> - else
> - DEBUG(dbgs() << "LV: ignoring invalid enable hint metadata\n");
> - } else if (Hint == "interleave.count") {
> - if (isPowerOf2_32(Val) && Val <= MaxUnrollFactor)
> - Unroll = Val;
> - else
> - DEBUG(dbgs() << "LV: ignoring invalid unroll hint metadata\n");
> - } else {
> - DEBUG(dbgs() << "LV: ignoring unknown hint " << Hint << '\n');
> + for (auto H : Hints) {
> + if (Name == H->Name) {
> + if (H->validate(Val))
> + H->Value = Val;
> + else
> + DEBUG(dbgs() << "LV: ignoring invalid hint '" << Name << "'\n");
> + break;
> + }
> }
> }
>
> - /// Vectorization width.
> - unsigned Width;
> - /// Vectorization unroll factor.
> - unsigned Unroll;
> - /// Vectorization forced
> - enum ForceKind Force;
> + /// Create a new hint from name / value pair.
> + MDNode *createHintMetadata(StringRef Name, unsigned V) const {
> + LLVMContext &Context = TheLoop->getHeader()->getContext();
> + SmallVector<Value*, 2> Vals;
> + Vals.push_back(MDString::get(Context, Name));
> + Vals.push_back(ConstantInt::get(Type::getInt32Ty(Context), V));
> + return MDNode::get(Context, Vals);
> + }
> +
> + /// Matches metadata with hint name.
> + bool matchesHintMetadataName(MDNode *Node, std::vector<Hint>
> &HintTypes) {
> + MDString* Name = dyn_cast<MDString>(Node->getOperand(0));
> + if (!Name)
> + return false;
> +
> + for (auto H : HintTypes)
> + if (Name->getName().endswith(H.Name))
> + return true;
> + return false;
> + }
> +
> + /// Sets current hints into loop metadata, keeping other values intact.
> + void writeHintsToMetadata(std::vector<Hint> HintTypes) {
> + if (HintTypes.size() == 0)
> + return;
> +
> + // Reserve the first element to LoopID (see below).
> + SmallVector<Value*, 4> Vals(1);
> + // If the loop already has metadata, then ignore the existing
> operands.
> + MDNode *LoopID = TheLoop->getLoopID();
> + if (LoopID) {
> + for (unsigned i = 1, ie = LoopID->getNumOperands(); i < ie; ++i) {
> + MDNode *Node = cast<MDNode>(LoopID->getOperand(i));
> + // If node in update list, ignore old value.
> + if (!matchesHintMetadataName(Node, HintTypes))
> + Vals.push_back(Node);
> + }
> + }
> +
> + // Now, add the missing hints.
> + for (auto H : HintTypes)
> + Vals.push_back(
> + createHintMetadata(Twine(Prefix(), H.Name).str(), H.Value));
> +
> + // Replace current metadata node with new one.
> + LLVMContext &Context = TheLoop->getHeader()->getContext();
> + MDNode *NewLoopID = MDNode::get(Context, Vals);
> + // Set operand 0 to refer to the loop id itself.
> + NewLoopID->replaceOperandWith(0, NewLoopID);
> +
> + TheLoop->setLoopID(NewLoopID);
> + if (LoopID)
> + LoopID->replaceAllUsesWith(NewLoopID);
> + LoopID = NewLoopID;
> + }
>
> - MDNode *LoopID;
> + /// The loop these hints belong to.
> + const Loop *TheLoop;
> };
>
> static void emitMissedWarning(Function *F, Loop *L,
> @@ -1393,7 +1449,7 @@ struct LoopVectorize : public FunctionPa
> }
>
> // Mark the loop as already vectorized to avoid vectorizing again.
> - Hints.setAlreadyVectorized(L);
> + Hints.setAlreadyVectorized();
>
> DEBUG(verifyFunction(*L->getHeader()->getParent()));
> return true;
> @@ -2495,7 +2551,7 @@ void InnerLoopVectorizer::createEmptyLoo
> LoopScalarBody = OldBasicBlock;
>
> LoopVectorizeHints Hints(Lp, true);
> - Hints.setAlreadyVectorized(Lp);
> + Hints.setAlreadyVectorized();
> }
>
> /// This function returns the identity element (or neutral element) for
>
> Added: llvm/trunk/test/Transforms/LoopVectorize/duplicated-metadata.ll
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopVectorize/duplicated-metadata.ll?rev=215994&view=auto
>
> ==============================================================================
> --- llvm/trunk/test/Transforms/LoopVectorize/duplicated-metadata.ll (added)
> +++ llvm/trunk/test/Transforms/LoopVectorize/duplicated-metadata.ll Tue
> Aug 19 12:30:43 2014
> @@ -0,0 +1,30 @@
> +; RUN: opt < %s -loop-vectorize -S 2>&1 | FileCheck %s
> +target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
> +target triple = "x86_64-unknown-linux-gnu"
> +
> +; This test makes sure we don't duplicate the loop vectorizer's metadata
> +; while marking them as already vectorized (by setting width = 1), even
> +; at lower optimization levels, where no extra cleanup is done
> +
> +define void @_Z3fooPf(float* %a) {
> +entry:
> + br label %for.body
> +
> +for.body: ; preds = %for.body,
> %entry
> + %indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
> + %arrayidx = getelementptr inbounds float* %a, i64 %indvars.iv
> + %p = load float* %arrayidx, align 4
> + %mul = fmul float %p, 2.000000e+00
> + store float %mul, float* %arrayidx, align 4
> + %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
> + %exitcond = icmp eq i64 %indvars.iv.next, 1024
> + br i1 %exitcond, label %for.end, label %for.body, !llvm.loop !0
> +
> +for.end: ; preds = %for.body
> + ret void
> +}
> +
> +!0 = metadata !{metadata !0, metadata !1}
> +!1 = metadata !{metadata !"llvm.loop.vectorize.width", i32 4}
> +; CHECK-NOT: !{metadata !"llvm.loop.vectorize.width", i32 4}
> +; CHECK: !{metadata !"llvm.loop.interleave.count", i32 1}
>
>
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