[llvm] 4790b21 - [VPlan] Add more generic VPCostContext::getCostDivisor (NFC). (#225413)

[via llvm-commits]

Author: Florian Hahn
Date: 2026-09-22T16:48:47+01:00
New Revision: 4790b21292d10b2cab1037ebef100e7f595e4209

URL: https://github.com/llvm/llvm-project/commit/4790b21292d10b2cab1037ebef100e7f595e4209
DIFF: https://github.com/llvm/llvm-project/commit/4790b21292d10b2cab1037ebef100e7f595e4209.diff

LOG: [VPlan] Add more generic VPCostContext::getCostDivisor (NFC). (#225413)

Replace getReplicateRegionCostDivisor with more general getCostDivisor,
which takes a frequency directly.

The frequency lookup is now done at the 3 call sites, which all have the
region at hand.

Will also be used in https://github.com/llvm/llvm-project/pull/196845.

PR: https://github.com/llvm/llvm-project/pull/225413

Added: 
    

Modified: 
    llvm/lib/Transforms/Vectorize/VPlan.cpp
    llvm/lib/Transforms/Vectorize/VPlanHelpers.h
    llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/Vectorize/VPlan.cpp b/llvm/lib/Transforms/Vectorize/VPlan.cpp
index fd6e77fffde7b..8071075701401 100644
--- a/llvm/lib/Transforms/Vectorize/VPlan.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlan.cpp
@@ -1950,13 +1950,9 @@ bool VPCostContext::isFreeScalarIntrinsic(Intrinsic::ID ID) {
                       ID);
 }
 
-uint64_t VPCostContext::getReplicateRegionCostDivisor(
-    const VPRegionBlock *Region) const {
-  if (CostKind == TTI::TCK_CodeSize)
-    return 1;
-  std::optional<VPExecutionFrequency> Freq =
-      Region->getEntryBranchOnMask()->getExecutionFrequency();
-  if (!Freq)
+uint64_t
+VPCostContext::getCostDivisor(std::optional<VPExecutionFrequency> Freq) const {
+  if (CostKind == TTI::TCK_CodeSize || !Freq)
     return 1;
   // A recorded frequency is neither zero nor always-executing, so the
   // probability is non-zero and the division below is safe.

diff  --git a/llvm/lib/Transforms/Vectorize/VPlanHelpers.h b/llvm/lib/Transforms/Vectorize/VPlanHelpers.h
index 3b7218ff1f908..b991dd12d3e34 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanHelpers.h
+++ b/llvm/lib/Transforms/Vectorize/VPlanHelpers.h
@@ -352,9 +352,9 @@ struct VPCostContext {
   /// transform replaced the original recipe.
   void invalidateWideningDecision(Instruction *I, ElementCount VF);
 
-  /// \returns how much the cost of the block predicated by replicate region
-  /// \p Region should be divided by.
-  uint64_t getReplicateRegionCostDivisor(const VPRegionBlock *Region) const;
+  /// \returns how much the cost of a block executing with recorded frequency
+  /// \p Freq should be divided by.
+  uint64_t getCostDivisor(std::optional<VPExecutionFrequency> Freq) const;
 
   /// Returns true if \p I is known to be scalarized at \p VF.
   bool willBeScalarized(Instruction *I, ElementCount VF) const;

diff  --git a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
index 602aff8090bf8..38c94512f0546 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
@@ -3236,7 +3236,8 @@ InstructionCost VPScalarIVStepsRecipe::computeCost(ElementCount VF,
   // probability.
   const VPRegionBlock *Region = getRegion();
   if (Region && Region->isReplicator())
-    Cost /= Ctx.getReplicateRegionCostDivisor(Region);
+    Cost /= Ctx.getCostDivisor(
+        Region->getEntryBranchOnMask()->getExecutionFrequency());
   return Cost;
 }
 
@@ -4067,7 +4068,8 @@ InstructionCost VPReplicateRecipe::computeCost(ElementCount VF,
     // Scale the cost by the probability of executing the predicated blocks.
     // This assumes the predicated block for each vector lane is equally
     // likely.
-    ScalarCost /= Ctx.getReplicateRegionCostDivisor(getRegion());
+    ScalarCost /= Ctx.getCostDivisor(
+        getRegion()->getEntryBranchOnMask()->getExecutionFrequency());
     return ScalarCost;
   }
   case Instruction::Load:
@@ -4126,7 +4128,8 @@ InstructionCost VPReplicateRecipe::computeCost(ElementCount VF,
     if (ParentRegion && ParentRegion->isReplicator()) {
       if (!PtrSCEV)
         break;
-      Cost /= Ctx.getReplicateRegionCostDivisor(ParentRegion);
+      Cost /= Ctx.getCostDivisor(
+          ParentRegion->getEntryBranchOnMask()->getExecutionFrequency());
       Cost += Ctx.TTI.getCFInstrCost(Instruction::CondBr, Ctx.CostKind);
 
       auto *VecI1Ty = VectorType::get(