[llvm] [LV] Get FMFs from VectorBuilder in createSimpleReduction. NFC (PR #132017)

[Luke Lau via llvm-commits]

https://github.com/lukel97 updated https://github.com/llvm/llvm-project/pull/132017

>From a7c5a13c39d318941860bee638177c3ad603d2bc Mon Sep 17 00:00:00 2001
From: Luke Lau <luke at igalia.com>
Date: Wed, 19 Mar 2025 20:40:45 +0800
Subject: [PATCH 1/2] [LV] Get FMFs from VectorBuilder in
 createSimpleReduction. NFC

The other createSimpleReduction takes the FMFs from the IRBuilder, so this aligns the VectorBuilder variant to do the same and reduce the possibility of there being a mismatch in flags.

Stacked on #132014
---
 llvm/include/llvm/IR/VectorBuilder.h           | 3 +++
 llvm/include/llvm/Transforms/Utils/LoopUtils.h | 3 +--
 llvm/lib/Transforms/Utils/LoopUtils.cpp        | 5 +++--
 llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp | 2 +-
 4 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/llvm/include/llvm/IR/VectorBuilder.h b/llvm/include/llvm/IR/VectorBuilder.h
index b0277c2b52595..35d8e57576817 100644
--- a/llvm/include/llvm/IR/VectorBuilder.h
+++ b/llvm/include/llvm/IR/VectorBuilder.h
@@ -87,6 +87,9 @@ class VectorBuilder {
     StaticVectorLength = ElementCount::getFixed(NewFixedVL);
     return *this;
   }
+
+  FastMathFlags &getFastMathFlags() const { return Builder.getFastMathFlags(); }
+
   // TODO: setStaticVL(ElementCount) for scalable types.
 
   // Emit a VP intrinsic call that mimics a regular instruction.
diff --git a/llvm/include/llvm/Transforms/Utils/LoopUtils.h b/llvm/include/llvm/Transforms/Utils/LoopUtils.h
index 6823967ebca16..193f505fb03fe 100644
--- a/llvm/include/llvm/Transforms/Utils/LoopUtils.h
+++ b/llvm/include/llvm/Transforms/Utils/LoopUtils.h
@@ -411,8 +411,7 @@ Value *createSimpleReduction(IRBuilderBase &B, Value *Src,
                              RecurKind RdxKind);
 /// Overloaded function to generate vector-predication intrinsics for
 /// reduction.
-Value *createSimpleReduction(VectorBuilder &VB, Value *Src, RecurKind RdxKind,
-                             FastMathFlags FMFs);
+Value *createSimpleReduction(VectorBuilder &VB, Value *Src, RecurKind RdxKind);
 
 /// Create a reduction of the given vector \p Src for a reduction of the
 /// kind RecurKind::IAnyOf or RecurKind::FAnyOf. The reduction operation is
diff --git a/llvm/lib/Transforms/Utils/LoopUtils.cpp b/llvm/lib/Transforms/Utils/LoopUtils.cpp
index 41f43a24e19e6..96d7b3342349e 100644
--- a/llvm/lib/Transforms/Utils/LoopUtils.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUtils.cpp
@@ -1333,14 +1333,15 @@ Value *llvm::createSimpleReduction(IRBuilderBase &Builder, Value *Src,
 }
 
 Value *llvm::createSimpleReduction(VectorBuilder &VBuilder, Value *Src,
-                                   RecurKind Kind, FastMathFlags FMFs) {
+                                   RecurKind Kind) {
   assert(!RecurrenceDescriptor::isAnyOfRecurrenceKind(Kind) &&
          !RecurrenceDescriptor::isFindLastIVRecurrenceKind(Kind) &&
          "AnyOf or FindLastIV reductions are not supported.");
   Intrinsic::ID Id = getReductionIntrinsicID(Kind);
   auto *SrcTy = cast<VectorType>(Src->getType());
   Type *SrcEltTy = SrcTy->getElementType();
-  Value *Iden = getRecurrenceIdentity(Kind, SrcEltTy, FMFs);
+  Value *Iden =
+      getRecurrenceIdentity(Kind, SrcEltTy, VBuilder.getFastMathFlags());
   Value *Ops[] = {Iden, Src};
   return VBuilder.createSimpleReduction(Id, SrcTy, Ops);
 }
diff --git a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
index 2d8ca3d4aba34..b40f7e6f99068 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
@@ -2358,7 +2358,7 @@ void VPReductionEVLRecipe::execute(VPTransformState &State) {
   if (isOrdered()) {
     NewRed = createOrderedReduction(VBuilder, Kind, VecOp, Prev);
   } else {
-    NewRed = createSimpleReduction(VBuilder, VecOp, Kind, getFastMathFlags());
+    NewRed = createSimpleReduction(VBuilder, VecOp, Kind);
     if (RecurrenceDescriptor::isMinMaxRecurrenceKind(Kind))
       NewRed = createMinMaxOp(Builder, Kind, NewRed, Prev);
     else

>From beb6e5b68e15a429fa0a0e8034d6e3fc6019bb3b Mon Sep 17 00:00:00 2001
From: Luke Lau <luke at igalia.com>
Date: Thu, 20 Mar 2025 01:46:22 +0800
Subject: [PATCH 2/2] Add const and copy over doc comment

---
 llvm/include/llvm/IR/VectorBuilder.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/llvm/include/llvm/IR/VectorBuilder.h b/llvm/include/llvm/IR/VectorBuilder.h
index 35d8e57576817..d526d52b433b9 100644
--- a/llvm/include/llvm/IR/VectorBuilder.h
+++ b/llvm/include/llvm/IR/VectorBuilder.h
@@ -88,7 +88,10 @@ class VectorBuilder {
     return *this;
   }
 
-  FastMathFlags &getFastMathFlags() const { return Builder.getFastMathFlags(); }
+  /// Get the flags to be applied to created floating point ops.
+  const FastMathFlags &getFastMathFlags() const {
+    return Builder.getFastMathFlags();
+  }
 
   // TODO: setStaticVL(ElementCount) for scalable types.