[llvm] [VPlan] Implement VPReductionRecipe::computeCost(). NFC (PR #107790)

Elvis Wang via llvm-commits llvm-commits at lists.llvm.org
Tue Oct 8 20:05:11 PDT 2024


https://github.com/ElvisWang123 updated https://github.com/llvm/llvm-project/pull/107790

>From 49aead52e78fb2b9521908f70c4bef81372c4a0b Mon Sep 17 00:00:00 2001
From: Elvis Wang <elvis.wang at sifive.com>
Date: Wed, 4 Sep 2024 20:52:14 -0700
Subject: [PATCH 1/4] [VPlan] Implment VPReductionRecipe::computeCost(). NFC

Implementation of `computeCost()` function for `VPReductionRecipe`.
---
 llvm/lib/Transforms/Vectorize/VPlan.h         |  4 ++++
 .../lib/Transforms/Vectorize/VPlanRecipes.cpp | 24 +++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/llvm/lib/Transforms/Vectorize/VPlan.h b/llvm/lib/Transforms/Vectorize/VPlan.h
index 8c5246d613c13d..05d0da691354c0 100644
--- a/llvm/lib/Transforms/Vectorize/VPlan.h
+++ b/llvm/lib/Transforms/Vectorize/VPlan.h
@@ -2399,6 +2399,10 @@ class VPReductionRecipe : public VPSingleDefRecipe {
   /// Generate the reduction in the loop
   void execute(VPTransformState &State) override;
 
+  /// Return the cost of VPReductionRecipe.
+  InstructionCost computeCost(ElementCount VF,
+                              VPCostContext &Ctx) const override;
+
 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
   /// Print the recipe.
   void print(raw_ostream &O, const Twine &Indent,
diff --git a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
index 9b1294f2c42822..ca04d6c9c74b2e 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
@@ -2012,6 +2012,30 @@ void VPReductionEVLRecipe::execute(VPTransformState &State) {
   State.set(this, NewRed, /*IsScalar*/ true);
 }
 
+InstructionCost VPReductionRecipe::computeCost(ElementCount VF,
+                                               VPCostContext &Ctx) const {
+  RecurKind RdxKind = RdxDesc.getRecurrenceKind();
+  Type *ElementTy = RdxDesc.getRecurrenceType();
+  auto *VectorTy = dyn_cast<VectorType>(ToVectorTy(ElementTy, VF));
+  TTI::TargetCostKind CostKind = TTI::TCK_RecipThroughput;
+  unsigned Opcode = RdxDesc.getOpcode();
+
+  if (VectorTy == nullptr)
+    return InstructionCost::getInvalid();
+
+  // Cost = Reduction cost + BinOp cost
+  InstructionCost Cost =
+      Ctx.TTI.getArithmeticInstrCost(Opcode, ElementTy, CostKind);
+  if (RecurrenceDescriptor::isMinMaxRecurrenceKind(RdxKind)) {
+    Intrinsic::ID Id = getMinMaxReductionIntrinsicOp(RdxKind);
+    return Cost + Ctx.TTI.getMinMaxReductionCost(
+                      Id, VectorTy, RdxDesc.getFastMathFlags(), CostKind);
+  }
+
+  return Cost + Ctx.TTI.getArithmeticReductionCost(
+                    Opcode, VectorTy, RdxDesc.getFastMathFlags(), CostKind);
+}
+
 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
 void VPReductionRecipe::print(raw_ostream &O, const Twine &Indent,
                               VPSlotTracker &SlotTracker) const {

>From 86140e0ea1296d41cd16c95ba7ed43bce0ae2761 Mon Sep 17 00:00:00 2001
From: Elvis Wang <elvis.wang at sifive.com>
Date: Tue, 24 Sep 2024 23:31:24 -0700
Subject: [PATCH 2/4] Address comments.

---
 llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
index ca04d6c9c74b2e..6bd353b32bd120 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
@@ -2016,13 +2016,10 @@ InstructionCost VPReductionRecipe::computeCost(ElementCount VF,
                                                VPCostContext &Ctx) const {
   RecurKind RdxKind = RdxDesc.getRecurrenceKind();
   Type *ElementTy = RdxDesc.getRecurrenceType();
-  auto *VectorTy = dyn_cast<VectorType>(ToVectorTy(ElementTy, VF));
+  auto *VectorTy = cast<VectorType>(ToVectorTy(ElementTy, VF));
   TTI::TargetCostKind CostKind = TTI::TCK_RecipThroughput;
   unsigned Opcode = RdxDesc.getOpcode();
 
-  if (VectorTy == nullptr)
-    return InstructionCost::getInvalid();
-
   // Cost = Reduction cost + BinOp cost
   InstructionCost Cost =
       Ctx.TTI.getArithmeticInstrCost(Opcode, ElementTy, CostKind);

>From f15462230caeab6750536dd55208dc9135bfb38c Mon Sep 17 00:00:00 2001
From: Elvis Wang <elvis.wang at sifive.com>
Date: Fri, 4 Oct 2024 03:19:36 -0700
Subject: [PATCH 3/4] Address comments.

---
 llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
index 6bd353b32bd120..cc0231ce766128 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
@@ -2015,7 +2015,14 @@ void VPReductionEVLRecipe::execute(VPTransformState &State) {
 InstructionCost VPReductionRecipe::computeCost(ElementCount VF,
                                                VPCostContext &Ctx) const {
   RecurKind RdxKind = RdxDesc.getRecurrenceKind();
-  Type *ElementTy = RdxDesc.getRecurrenceType();
+  // TODO: Support any-of reduction and in-loop reduction
+  assert(!RecurrenceDescriptor::isAnyOfRecurrenceKind(RdxKind) &&
+         "Not support any-of reduction in VPlan-based cost model currently.");
+
+  Type *ElementTy = Ctx.Types.inferScalarType(this->getVPSingleValue());
+  assert(ElementTy->getTypeID() == RdxDesc.getRecurrenceType()->getTypeID() &&
+         "Infered type and recurrence type mismatch.");
+
   auto *VectorTy = cast<VectorType>(ToVectorTy(ElementTy, VF));
   TTI::TargetCostKind CostKind = TTI::TCK_RecipThroughput;
   unsigned Opcode = RdxDesc.getOpcode();

>From 20e90e70d0dd2bc502b0936f420a70b6c83de754 Mon Sep 17 00:00:00 2001
From: Elvis Wang <elvis.wang at sifive.com>
Date: Tue, 8 Oct 2024 20:03:47 -0700
Subject: [PATCH 4/4] Address comments and add `isInLoopReduction()`.

---
 .../Transforms/Vectorize/LoopVectorize.cpp    |  8 +++++++
 llvm/lib/Transforms/Vectorize/VPlan.h         |  4 ++++
 .../lib/Transforms/Vectorize/VPlanRecipes.cpp | 22 ++++++++++++-------
 3 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index 001c8987667df8..866568cb9b2a8a 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -7103,6 +7103,14 @@ bool VPCostContext::skipCostComputation(Instruction *UI, bool IsVector) const {
          SkipCostComputation.contains(UI);
 }
 
+bool VPCostContext::isInLoopReduction(const Instruction *UI, ElementCount VF,
+                                      Type *VectorTy) const {
+  return CM
+      .getReductionPatternCost(const_cast<Instruction *>(UI), VF, VectorTy,
+                               TTI::TCK_RecipThroughput)
+      .has_value();
+}
+
 InstructionCost
 LoopVectorizationPlanner::precomputeCosts(VPlan &Plan, ElementCount VF,
                                           VPCostContext &CostCtx) const {
diff --git a/llvm/lib/Transforms/Vectorize/VPlan.h b/llvm/lib/Transforms/Vectorize/VPlan.h
index 05d0da691354c0..41ae3a184091a4 100644
--- a/llvm/lib/Transforms/Vectorize/VPlan.h
+++ b/llvm/lib/Transforms/Vectorize/VPlan.h
@@ -718,6 +718,10 @@ struct VPCostContext {
   /// Return true if the cost for \p UI shouldn't be computed, e.g. because it
   /// has already been pre-computed.
   bool skipCostComputation(Instruction *UI, bool IsVector) const;
+
+  /// Return true if the \p UI is part of the in-loop reduction.
+  bool isInLoopReduction(const Instruction *UI, ElementCount VF,
+                         Type *VectorTy) const;
 };
 
 /// VPRecipeBase is a base class modeling a sequence of one or more output IR
diff --git a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
index cc0231ce766128..8217b8cda5118b 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
@@ -2015,18 +2015,24 @@ void VPReductionEVLRecipe::execute(VPTransformState &State) {
 InstructionCost VPReductionRecipe::computeCost(ElementCount VF,
                                                VPCostContext &Ctx) const {
   RecurKind RdxKind = RdxDesc.getRecurrenceKind();
-  // TODO: Support any-of reduction and in-loop reduction
-  assert(!RecurrenceDescriptor::isAnyOfRecurrenceKind(RdxKind) &&
-         "Not support any-of reduction in VPlan-based cost model currently.");
-
-  Type *ElementTy = Ctx.Types.inferScalarType(this->getVPSingleValue());
-  assert(ElementTy->getTypeID() == RdxDesc.getRecurrenceType()->getTypeID() &&
-         "Infered type and recurrence type mismatch.");
-
+  Type *ElementTy = Ctx.Types.inferScalarType(this);
   auto *VectorTy = cast<VectorType>(ToVectorTy(ElementTy, VF));
   TTI::TargetCostKind CostKind = TTI::TCK_RecipThroughput;
   unsigned Opcode = RdxDesc.getOpcode();
 
+  // TODO: Support any-of reduction and in-loop reductions.
+  assert(
+      (!RecurrenceDescriptor::isAnyOfRecurrenceKind(RdxKind) ||
+       ForceTargetInstructionCost.getNumOccurrences() > 0) &&
+      "Any-of reduction not implemented in VPlan-based cost model currently.");
+  assert(
+      (!Ctx.isInLoopReduction(getUnderlyingInstr(), VF, VectorTy) ||
+       ForceTargetInstructionCost.getNumOccurrences() > 0) &&
+      "In-loop reduction not implemented in VPlan-based cost model currently.");
+
+  assert(ElementTy->getTypeID() == RdxDesc.getRecurrenceType()->getTypeID() &&
+         "Infered type and recurrence type mismatch.");
+
   // Cost = Reduction cost + BinOp cost
   InstructionCost Cost =
       Ctx.TTI.getArithmeticInstrCost(Opcode, ElementTy, CostKind);



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