[llvm] [SLPVectorizer] Refactor HorizontalReduction::createOp (NFC) (PR #121549)

[Mel Chen via llvm-commits]

https://github.com/Mel-Chen created https://github.com/llvm/llvm-project/pull/121549

This patch refactors the `HorizontalReduction::createOp` function to simplify the logic for creating reduction operations. The changes include:
1. Moving the `RdxOpcode` initialization into specific cases where it is used, avoiding to call `getOpcode` when non-arithmetical reduction.
2. Consolidating logic for generating intrinsic-based min/max reductions by utilizing `llvm::getMinMaxReductionIntrinsicOp`.
3. Simplifying select-based integer min/max reductions by utilizing `llvm::getMinMaxReductionPredicate`.

This patch is mainly to achieve the first item. The main reason is to unify IAnyOf and FAnyOf reduction. #118393
The related patch is #118777.


>From 1e5ed86ded06ad07982c909feb3b10b52f4d0ca3 Mon Sep 17 00:00:00 2001
From: Mel Chen <mel.chen at sifive.com>
Date: Thu, 2 Jan 2025 23:31:28 -0800
Subject: [PATCH] [SLPVectorizer] Refactor createOp

---
 .../Transforms/Vectorize/SLPVectorizer.cpp    | 58 +++++++------------
 1 file changed, 21 insertions(+), 37 deletions(-)

diff --git a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
index f52ddfda5e64c7..5a6f952cc91db7 100644
--- a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -19357,59 +19357,43 @@ class HorizontalReduction {
   /// Creates reduction operation with the current opcode.
   static Value *createOp(IRBuilderBase &Builder, RecurKind Kind, Value *LHS,
                          Value *RHS, const Twine &Name, bool UseSelect) {
-    unsigned RdxOpcode = RecurrenceDescriptor::getOpcode(Kind);
+    if (UseSelect) {
+      if (RecurrenceDescriptor::isIntMinMaxRecurrenceKind(Kind)) {
+        CmpInst::Predicate Pred = llvm::getMinMaxReductionPredicate(Kind);
+        Value *Cmp = Builder.CreateCmp(Pred, LHS, RHS, Name);
+        return Builder.CreateSelect(Cmp, LHS, RHS, Name);
+      }
+      if ((Kind == RecurKind::Or || Kind == RecurKind::And) &&
+          LHS->getType() == CmpInst::makeCmpResultType(LHS->getType())) {
+        Value *TrueVal = Kind == RecurKind::Or ? Builder.getTrue() : RHS;
+        Value *FalseVal = Kind == RecurKind::Or ? RHS : Builder.getFalse();
+        return Builder.CreateSelect(LHS, TrueVal, FalseVal, Name);
+      }
+    }
+
     switch (Kind) {
     case RecurKind::Or:
-      if (UseSelect &&
-          LHS->getType() == CmpInst::makeCmpResultType(LHS->getType()))
-        return Builder.CreateSelect(LHS, Builder.getTrue(), RHS, Name);
-      return Builder.CreateBinOp((Instruction::BinaryOps)RdxOpcode, LHS, RHS,
-                                 Name);
     case RecurKind::And:
-      if (UseSelect &&
-          LHS->getType() == CmpInst::makeCmpResultType(LHS->getType()))
-        return Builder.CreateSelect(LHS, RHS, Builder.getFalse(), Name);
-      return Builder.CreateBinOp((Instruction::BinaryOps)RdxOpcode, LHS, RHS,
-                                 Name);
     case RecurKind::Add:
     case RecurKind::Mul:
     case RecurKind::Xor:
     case RecurKind::FAdd:
-    case RecurKind::FMul:
+    case RecurKind::FMul: {
+      unsigned RdxOpcode = RecurrenceDescriptor::getOpcode(Kind);
       return Builder.CreateBinOp((Instruction::BinaryOps)RdxOpcode, LHS, RHS,
                                  Name);
+    }
     case RecurKind::FMax:
-      return Builder.CreateBinaryIntrinsic(Intrinsic::maxnum, LHS, RHS);
     case RecurKind::FMin:
-      return Builder.CreateBinaryIntrinsic(Intrinsic::minnum, LHS, RHS);
     case RecurKind::FMaximum:
-      return Builder.CreateBinaryIntrinsic(Intrinsic::maximum, LHS, RHS);
     case RecurKind::FMinimum:
-      return Builder.CreateBinaryIntrinsic(Intrinsic::minimum, LHS, RHS);
     case RecurKind::SMax:
-      if (UseSelect) {
-        Value *Cmp = Builder.CreateICmpSGT(LHS, RHS, Name);
-        return Builder.CreateSelect(Cmp, LHS, RHS, Name);
-      }
-      return Builder.CreateBinaryIntrinsic(Intrinsic::smax, LHS, RHS);
     case RecurKind::SMin:
-      if (UseSelect) {
-        Value *Cmp = Builder.CreateICmpSLT(LHS, RHS, Name);
-        return Builder.CreateSelect(Cmp, LHS, RHS, Name);
-      }
-      return Builder.CreateBinaryIntrinsic(Intrinsic::smin, LHS, RHS);
     case RecurKind::UMax:
-      if (UseSelect) {
-        Value *Cmp = Builder.CreateICmpUGT(LHS, RHS, Name);
-        return Builder.CreateSelect(Cmp, LHS, RHS, Name);
-      }
-      return Builder.CreateBinaryIntrinsic(Intrinsic::umax, LHS, RHS);
-    case RecurKind::UMin:
-      if (UseSelect) {
-        Value *Cmp = Builder.CreateICmpULT(LHS, RHS, Name);
-        return Builder.CreateSelect(Cmp, LHS, RHS, Name);
-      }
-      return Builder.CreateBinaryIntrinsic(Intrinsic::umin, LHS, RHS);
+    case RecurKind::UMin: {
+      Intrinsic::ID Id = llvm::getMinMaxReductionIntrinsicOp(Kind);
+      return Builder.CreateBinaryIntrinsic(Id, LHS, RHS);
+    }
     default:
       llvm_unreachable("Unknown reduction operation.");
     }