[llvm] [VPlan] Remove dead AnyOf reduction case in VPReductionRecipe. NFCI (PR #130048)

[Luke Lau via llvm-commits]

https://github.com/lukel97 updated https://github.com/llvm/llvm-project/pull/130048

>From 36e14063cc675bba90633d3fbf7690085692174f Mon Sep 17 00:00:00 2001
From: Luke Lau <luke at igalia.com>
Date: Thu, 6 Mar 2025 17:58:28 +0800
Subject: [PATCH 1/2] [VPlan] Remove dead AnyOf reduction case in
 VPReductionRecipe. NFCI

>From what I understand, we only create VPReductionRecipes for in-loop reductions, and we don't currently support in-loop AnyOf reductions.

We only create VPReductionRecipes in the !PhiR->isInLoop() section of adjustRecipesForReductions, and this comment from the initial patch seems to confirm this https://reviews.llvm.org/D108136#anchor-inline-1038338, so I think we can remove this check in the condition logic.

I checked compiling SPEC 2017 with -prefer-inloop-predicates and the added assertion doesn't trigger.
---
 llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
index d154d54c37862..6ee98b717a910 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
@@ -2222,6 +2222,8 @@ void VPReductionRecipe::execute(VPTransformState &State) {
   assert(!State.Lane && "Reduction being replicated.");
   Value *PrevInChain = State.get(getChainOp(), /*IsScalar*/ true);
   RecurKind Kind = RdxDesc.getRecurrenceKind();
+  assert(!RecurrenceDescriptor::isAnyOfRecurrenceKind(Kind) &&
+         "In-loop AnyOf reductions aren't currently supported");
   // Propagate the fast-math flags carried by the underlying instruction.
   IRBuilderBase::FastMathFlagGuard FMFGuard(State.Builder);
   State.Builder.setFastMathFlags(RdxDesc.getFastMathFlags());
@@ -2232,12 +2234,8 @@ void VPReductionRecipe::execute(VPTransformState &State) {
     VectorType *VecTy = dyn_cast<VectorType>(NewVecOp->getType());
     Type *ElementTy = VecTy ? VecTy->getElementType() : NewVecOp->getType();
 
-    Value *Start;
-    if (RecurrenceDescriptor::isAnyOfRecurrenceKind(Kind))
-      Start = RdxDesc.getRecurrenceStartValue();
-    else
-      Start = llvm::getRecurrenceIdentity(Kind, ElementTy,
-                                          RdxDesc.getFastMathFlags());
+    Value *Start = llvm::getRecurrenceIdentity(Kind, ElementTy,
+                                               RdxDesc.getFastMathFlags());
     if (State.VF.isVector())
       Start = State.Builder.CreateVectorSplat(VecTy->getElementCount(), Start);
 

>From 788b7d43aeb343c382b8f85e03226305db63b61c Mon Sep 17 00:00:00 2001
From: Luke Lau <luke at igalia.com>
Date: Thu, 6 Mar 2025 18:15:05 +0800
Subject: [PATCH 2/2] Remove llvm::

---
 llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
index 6ee98b717a910..5010bf029d140 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
@@ -2234,8 +2234,8 @@ void VPReductionRecipe::execute(VPTransformState &State) {
     VectorType *VecTy = dyn_cast<VectorType>(NewVecOp->getType());
     Type *ElementTy = VecTy ? VecTy->getElementType() : NewVecOp->getType();
 
-    Value *Start = llvm::getRecurrenceIdentity(Kind, ElementTy,
-                                               RdxDesc.getFastMathFlags());
+    Value *Start =
+        getRecurrenceIdentity(Kind, ElementTy, RdxDesc.getFastMathFlags());
     if (State.VF.isVector())
       Start = State.Builder.CreateVectorSplat(VecTy->getElementCount(), Start);